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This study aimed to 1) identify what starting block outcome kinetics have the greatest relationship to 15 m start time; 2) investigate key mechanistic determinants of the block phase and how these forces are sequenced. One hundred and fifty-two high-level competitive swimmers were included in the study. Linear mixed modelling identified four on-block outcome kinetic variables (work, average power, horizontal take-off velocity (HTOV), and average acceleration) as having a very large relationship (R 2  = 0.79-0.83) to 15 m start time, with average power having the most substantial impact. On-block force sequencing started with the rear leg, followed by upper limb grab forces and the front leg. Further exploration of underlying determinants was performed for average power and HTOV of the centre of mass. Multiple linear regression identified grab resultant peak force, rear resultant average force, front horizontal peak force, and resultant peak force as significant predictors of average power (R 2  = 0.88). HTOV was predicted using the same variables, apart from the inclusion of rear horizontal peak force instead of rear resultant average force (R 2  = 0.73). These findings may influence how strength and conditioning and skill acquisition interventions are designed to improve swim start performance.

Purpose: To describe the beliefs, barriers and promotion practices of Indian nurses' regarding healthy eating (HE) behaviours amongst cancer survivors, and to gain insights into whether their educational qualifications might affect the promotion of HE., Methods: Data was gathered using a validated questionnaire, 388 of the approached 400 nurses who worked at a tertiary care hospital in India gave informed consent to participate in the study. The Mann-Whitney U test and the Chi square analysis (for continuous and categorical variables respectively) were performed to carry out sub-group comparisons based on the qualification of the nurses i.e., Bachelor of Science in Nursing (BSc) and General Nursing and Midwifery (GNM)., Results: The nurses believed that dieticians/nutritionists were primarily responsible for educating the cancer survivors regarding HE. HE was promoted by nurses' relatively equally across multiple treatment stages ("during" treatment 24.4%, "post" treatment 23.1%; and "pre" treatment 22.3%). Nurses' believed HE practices had numerous benefits, with improved health-related quality of life (HRQoL) (75.7%), and mental health (73.9%) being the most frequent responses. The most frequently cited barriers by the nurses in promoting HE were lack of time (22.2%), and lack of adequate support structure (19.9%). Sub-group comparisons generally revealed no significant difference between the BSc and GNM nurses in their perceptions regarding HE promotion to cancer survivors. Exceptions were how the GNM group had significantly greater beliefs regarding whether HE can "reduce risk of cancer occurrence" ( p  = 0.004) and "whether or not I promote HE is entirely up to me" ( p  = 0.002)., Conclusion: The nurses in India believe in the promotion of HE practices among cancer survivors across various stages of cancer treatments. However, they do face a range of barriers in their attempt to promote HE. Overcoming these barriers might facilitate effective promotion of HE among cancer survivors and help improve survivorship outcomes., Implications for Cancer Survivors: Indian nurses employed in the two tertiary care hospitals wish to promote HE among cancer survivors, but require further knowledge and support services for more effective promotion of HE., Competing Interests: Justin William Leslie Keogh is an Academic Editor for PeerJ., (©2024 Pai et al.)

Background: Disrupted circadian rhythm commonly reported in cancer survivors is closely associated with cancer related fatigue, sleep disturbances and compromised quality of life. As more cancer survivors request non-pharmacological treatment strategies for the management of their chronic sleep-related symptoms, there is a need for meta-analyses of various interventions such as exercise on sleep and circadian rhythm disturbances., Methods: A search for RCT's was conducted in April 2020 and updated in July 2023 using relevant keywords for cancer, sleep, circadian rhythm and exercise interventions on PubMed, Scopus, Web of Science, PEDro and CINAHL., Results: Thirty-six studies were included for qualitative analysis and 26, for meta-analysis. Thirty-five studies analyzed sleep outcomes, while five analyzed circadian rhythm. RCT's studying the effect of aerobic exercise, resistance exercise, combined aerobic and resistance exercise, physical activity, yoga, or tai chi were included. Meta-analysis results showed significant exercise-related improvements on sleep quality assessed by Pittsburgh Sleep Quality index (PSQI) (SMD = -0.50 [-0.87, -0.13], p  = 0.008), wake after sleep onset (WASO) (SMD = -0.29 [-0.53, -0.05], p  = 0.02) and circadian rhythm, assessed by salivary cortisol levels (MD = -0.09 (95% CI [-0.13 to -0.06]) mg/dL, p  < 0.001). Results of the meta-analysis indicated that exercise had no significant effect on sleep efficiency, sleep onset latency, total sleep time and circadian rhythm assessed by accelerometry values., Conclusion: While some sleep and circadian rhythm outcomes (PSQI, WASO and salivary cortisol) exhibited significant improvements, it is still somewhat unclear what exercise prescriptions would optimize different sleep and circadian rhythm outcomes across a variety of groups of cancer survivors., Implication: As exercise does not exacerbate cancer-related circadian rhythm and sleep disturbances, and may actually produce some significant benefits, this meta-analysis provides further evidence for cancer survivors to perform regular exercise., Competing Interests: Justin Keogh is an Academic Editor for PeerJ., (©2024 Gururaj et al.)

Abstract: Winwood, PW, Keogh, JW, Travis, SK, Grieve, I, and Pritchard, HJ. The training and tapering practices of Highland Games heavy event athletes. J Strength Cond Res 38(3): e116-e124, 2024-This study provides the first empirical evidence of how Highland Games heavy event athletes train and taper for Highland Games competitions. Athletes (n = 169) (mean ± SD: age 40.8 ± 10.7 years, height 181.2 ± 9.5 cm, weight 107.2 ± 23.0 kg, 18.8 ± 10.3 years of general resistance training, and 8.1 ± 6.9 years of competitive Highland Games experience) completed a self-reported 4-page online survey on training and tapering practices. Analysis by sex (male and female) and competitive standard (local or regional, national, and international) was conducted. Seventy-eight percent (n = 132) of athletes reported that they used a taper. Athletes stated that their taper length was 5.2 ± 3.5 days, with the step (36%) and linear tapers (33%) being the most performed. Athletes reported that their highest training volume and intensity were 5.5 and 3.8 weeks out (respectively) from competition, and all training ceased 2.4 ± 1.4 days before competition. Training volume decreased during the taper by 34%. Athletes typically stated that, tapering was performed to achieve recovery, peak performance, and injury prevention; training intensity, frequency, and duration stayed the same or decreased; game-specific training increased with reductions in traditional exercises; the caber toss, weight for height, and heavy weight throw were performed further out from competition than other events; muscular power and strength were the most common types of training performed; static stretching, foam rolling, and massage were strategies used in the taper; and poor tapering occurred because of life/work circumstances, lack of sleep/rest, or training too heavy/hard. These results may aid Highland Games athletes to optimize training and tapering variables leading to improved performances., (Copyright © 2023 National Strength and Conditioning Association.)

Background: Short-term restorative care (STRC) aims to reduce the demand for long-term aged care services through 8 weeks of intensive, multidisciplinary services designed to enhance the independence of community-dwelling older Australians at risk of functional decline. Evidence surrounding the effectiveness and feasibility of STRC is limited., Objective: This study aimed to examine the effectiveness of an existing exercise-based STRC model and help inform successful service delivery to maximise participant outcomes nationally., Methods: An observational cohort study was conducted to evaluate the potential benefits accrued by community-dwelling older adults accessing Southern Cross Care's current exercise-based STRC model in Adelaide, South Australia. Program effectiveness was determined via improvements in outcome measures specific to functional decline risk factors from baseline (Week 0) to discharge (Week 8)., Results: Results demonstrated significant improvements (p < 0.001) in participants' (n = 62) lower extremity function (44.9%), depressive symptoms (52.4%), anxiety (45.8%), frailty stage (57.9%), independence in activities of daily living (17.3%) and health-related quality of life (24.0%). No significant change was found for grip strength or BMI post-intervention. The most frequent services were exercise-based (54.3% of total services), with participants receiving an average of two to three exercise services per week., Conclusions: An exercise-based STRC model is an effective mechanism to reverse functional decline and associated risk factors among community-dwelling older Australians. Adoption of multidisciplinary intervention as a standardised STRC service model could help improve client outcomes nationally and offset expected increases in community and long-term aged care demand., (© 2024 The Authors. Australasian Journal on Ageing published by John Wiley & Sons Australia, Ltd on behalf of AJA Inc’.)

Objectives: To explore the relationships between physical fitness and i) technical skills and ii) time-loss from Australian football injury in female players across the talent and participation pathways., Methods: This study uses a subset of data from two cross-sectional and one prospective cohort studies. A total of 223 female Australian football players across five competition levels (elite/non-elite senior, high-level junior, and non-elite junior (14-17 years)/(10-13 years)) were included in this study. Comprehensive physical fitness assessments and modified Australian football kicking and handballing tests were conducted in the 2018/19 pre-seasons. During the respective competitive in-season, time-loss injuries were recorded by team personnel. Stepwise multiple linear regressions were performed to determine the relationship between physical fitness and kicking and handballing scores. Cox proportional regressions were conducted to identify physical fitness factors associated with injury., Results: Increased running vertical jump height, greater hip abduction strength, and faster timed 6 m hop speed demonstrated a relationship with kicking accuracy when adjusted for years of Australian football playing experience (adjusted R2 = 0.522, p < 0.001). Faster agility time and increased lean mass were associated with better handballing accuracy (adjusted R2 = 0.221, p < 0.001). Multivariate Cox regression revealed an increased risk for sustaining a time-loss injury in less agile players (adjusted HR 2.41, 95% CI 1.23, 4.73, p = 0.010). However, this relationship no longer remained when adjusted for age and years of Australian football experience (adjusted HR 1.68, 95% CI 0.81, 3.50, p = 0.166)., Conclusions: Physical fitness may be a significant factor contributing to development of Australian football technical skills in female players. However, its role is unclear in protecting against injury risk in this athlete population. Further research is needed to explore the multifactorial and complex phenomenon of talent development and injury risk reduction in female Australian football players., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Farley et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: The repeat power ability (RPA) assessment is used to test the ability to repeatedly produce maximal ballistic efforts with an external load. The underpinning physical qualities influencing RPA are undetermined. This study aimed to gain further insight into the physical qualities that determine RPA by analysing the association between physical qualities and an assessment of RPA., Materials and Methods: Ten well-trained male field hockey players performed an RPA assessment consisting of 20 repetitions of loaded countermovement jumps (LCMJ20), with a percent decrement score of peak power output calculated. Over a two-week period, each participant performed the YoYo Intermittent Recovery Test 2 (IRT2), a repeated speed ability assessment incorporating a 180° change of direction (RSA 180 ), a 40-meter linear speed test (40 mST), an isometric mid-thigh pull (IMTP), a countermovement jump (CMJ), and a 3-repetition maximum half squat (HS) assessment. Pearson's correlation analysis was used to determine the strength of relationships between each assessment variable and the LCMJ20. The assessment variables with the strongest relationships within each assessment were used in a stepwise multiple linear regression analysis to determine the best predictor model of LCMJ20., Results: RSA 180 percent decrement score (RSA 180 % had a very strong, significant relationship with LCMJ20 ( r  = 0.736: p  < 0.05). HS relative strength (HSrel) was found to have a significant and very strong, negative relationship with LCMJ20 ( r  =  - 0.728: p  < 0.05). Stepwise multiple linear regression analysis showed RSA180 to explain 48.4% of LCMJ20 variance (Adjusted R 2 = 0.484) as the only covariate included in the model., Conclusion: The findings indicate that RSA 180 as a repeated high intensity effort (RHIE) task is strongly related to LCMJ20 and is also the best predictor of LCMJ20. This may suggest that RPA can provide practitioners with information on RHIE performance. The variance between assessment methods indicates that RPA may be a distinct physical quality, future research should assess other physical capacities to better understand the factors contributing to RPA., Competing Interests: Justin Keogh is an Academic Editor for PeerJ., (©2024 Natera et al.)

Abstract: Ross, JA, Keogh, JWL, Lorenzen, C, and Lake, J. Effects of 56-kilogram kettlebell swing endpoint on total body mechanics. J Strength Cond Res 37(12): 2333-2338, 2023-In the past 2 decades, kettlebell training popularity has increased and the range of kettlebells has expanded to 2-92 kg. However, commercially available kettlebells above 56 kg have 12 kg increments, so alternatives to load are required to provide a suitable way of increasing training stimulus until the athlete is strong enough for a load increase. This study aimed to determine the differences in the force plate-derived biomechanical characteristics of heavy kettlebell swings to 3 different heights, as altering the height of the kettlebell swing may be one way to alter the mechanical demands with the same kettlebell mass. Fifteen resistance-trained men performed the kettlebell swing to acromion process height (AH), acromion process height + 20% (AH+20), and acromion process height-20% (AH-20). Swing height significantly affected vertical braking and propulsion phase net impulse and displacement, vertical braking velocity, and braking and propulsion work but not braking and propulsion duration. Altering kettlebell swing trajectory endpoint is a method to regress/progress the demands of kettlebell training. Coaches may be able to alter the acute demands and likely chronic adaptations of kettlebell training by prescribing different swing heights and kettlebell masses to their athletes., (Copyright © 2023 National Strength and Conditioning Association.)

Background: Repeat power ability (RPA) assessments are a valuable evaluation of an athlete's ability to repeatedly perform high intensity movements. Establishing the most reliable and valid loaded jump RPA assessment and method to quantify RPA has yet to be determined. This study aimed to compare the reliability and validity of an RPA assessment performed with loaded squat jumps (SJ) or countermovement jumps (CMJ) using force-time derived mean and peak power output., Materials and Methods: RPA was quantified using calculations of average power output, a fatigue index and a percent decrement score for all repetitions and with the first and last repetitions removed. Validity was established by comparing to a 30 second Bosco repeated jump test (30BJT). Eleven well-trained male field hockey players performed one set of 20 repetitions of both SJs (20SJ) and CMJs (20CMJ) on separate occasions using a 30% one repetition maximum half squat load. These assessments were repeated 7 days apart to establish inter-test reliability. On a separate occasion, each participant performed the 30BJT., Results: The reliability of average peak power for 20SJ and 20CMJ was acceptable (CV < 5%; ICC > 0.9), while average mean power reliability for 20CMJ (CV < 5%; ICC > 0.9) was better than 20SJ (CV > 5%; ICC > 0.8). Percent decrement of 20CMJ peak power, with the first and final jump removed from the percent decrement calculation (PD%CMJ peak18 ), was the most reliable measurement of power output decline (CV < 5 %; ICC > 0.8). Average mean and peak power for both RPA protocols had moderate to strong correlations with 30BJT average mean and peak power (r = 0.5-0.8; p < 0.05-0.01). No RPA measurements of power decline were significantly related to BJT measurements of power decline., Conclusions: These findings indicate that PD%CMJ peak18 is the most reliable measure of RPA power decline. The lack of relationship between power decline in the loaded RPA and the 30BJT assessment suggest that each assessment may be measuring a different physical quality. These results provide sport science practitioners with additional methods to assess RPA and provide useful information on the reliability and validity of these outcome measures. Additional research needs to be performed to examine the reliability and validity of the novel RPA assessments in other athletic populations and to determine the sensitivity of these measurements to training and injury., Competing Interests: Justin Keogh is an Academic Editor for PeerJ., (©2023 Natera et al.)

Abstract: Winwood, PW, Keogh, JW, Travis, SK, and Pritchard, HJ. The tapering practices of competitive weightlifters. J Strength Cond Res 37(4): 829-839, 2023-This study explored the tapering strategies of weightlifting athletes. Weightlifting athletes ( n = 146) (mean ± SD ; age: 29.2 ± 8.7 years, height: 172.5 ± 10.1 cm, body mass: 84.0 ± 17.2 kg, 4.7 ± 3.4 years of weightlifting training experience, and 3.9 ± 3.3 years of competitive weightlifting experience) completed a self-reported 4-page, 39-item internet survey on tapering practices. Subgroup analysis by sex (male and female) and competitive standard (local or regional, national and international level) was conducted. Ninety-nine percent ( n = 144) of weightlifting athletes reported they used a taper. Athletes stated that their typical taper length was 8.0 ± 4.4 days, with the linear (36%) and step tapers (33%) being the most performed. Training volume decreased during the taper by 43.1 ± 14.6%, and athletes ceased all training 1.5 ± 0.6 days out from competition. Muscular strength, light technique work, and aerobic conditioning were the most common types of training performed in the taper. Athletes typically stated that tapering was performed to achieve rest and recovery, physical preparation for peak performance and mental preparation; training intensity and training duration decreased whereas training frequency remained the same or decreased; traditional exercises were performed further out from competition than weightlifting exercises; assistance exercises and some strength work were reduced; nutritional changes, foam rolling, static stretching, and massage were strategies used in the taper; and poor tapering occurred because of training too heavy, too hard, or too light and life-work circumstances. These results may aid athletes and coaches in strength sports to optimize tapering variables leading to improved performances., (Copyright © 2022 National Strength and Conditioning Association.)

Background: The first women's Australian football (AF) professional competition was established in 2017, resulting in advancement in performance analysis capabilities within the sport. Given the specific constraints of women's AF, it is currently unclear what match-play performance analysis methods and techniques are implemented. Therefore, the aim of this scoping review was to describe and critically appraise physical, technical, and tactical performance analysis methods that have been employed in women's and girls' AF match-play., Methodology: A systematic search was conducted on the 27th of June 2022 through five databases. Eligibility criteria were derived from the PCC framework with the population (P) of women and girls AF players, of any level of play; concepts (C) of interest which were measures, data, and methods related to the sport's physical, technical, and tactical performance; and the context (C) of methods that analysed any match-play performance. A narrative synthesis was conducted using extracted study characteristic data such as sample size, population, time period, collection standards, evaluation metrics for results, and application of thematic categorisations of previous sports performance reviews. Critical appraisal of eligible studies' methodologies was conducted to investigate research quality and identify methodological issues., Results: From 183 studies screened, twelve eligible studies were included, which examined match-play through physical (9/12, 75%), technical (4/12, 33%), and tactical analysis (2/12, 17%). Running demands and game actions analysis were the most researched in senior women's AF. Research into junior girls' AF match-play performance has not been investigated. No research has been conducted on non-running physical demands, contact demands, acceleration, and tactical aspects of women's AF. All studies utilised either inferential statistics or basic predictive models. Critical appraisal deemed most studies as low risk of bias (11/12, 92%), with the remaining study having satisfactory risk., Conclusions: Future research utilising increased longitudinal and greater contextual data is needed to combat the prominent issue of data representativeness to better characterise performance within women's and girls' AF. Additionally, research involving junior and sub-elite AF players across the talent pathways is important to conduct, as it provides greater context and insight regarding development to support the evolving elite women's AF competition. Women's AF has been constrained by its resource environment. As such, suggestions are provided for better utilisation of existing data, as well as for the creation of new data for appropriate future research. Greater data generation enables the use of detailed machine learning predictions, neural networks, and network analysis to better represent the intertwined nature of match-play performance from technical, physical, and tactical data., Competing Interests: Justin Keogh is an Academic Editor for PeerJ., (©2023 van der Vegt et al.)

To assess the effects of a specific injury prevention neuromuscular training programme (IPP) on balance and lower-limb asymmetry in female competitive dancers (age 12-20 years; height 1.57 ± 0.06 m; weight 24.27 ± 2.79 kg) were randomly allocated to an active general control (GIPP, n = 7) and specific (SIPP n = 7) group. Both programmes were conducted for 6 weeks, with a frequency of three sessions per week. Dynamic balance and lower-limb asymmetry were assessed before and after the intervention. A greater improvement in right-leg total balance (86.6[84.0-90.5] vs 93.8[86.7-99.4];p = 0.035), left-leg total balance(87.8[81.0-89.1] vs 93.6[90.6-100.0];p = 0.013), left-leg anterior balance (71.9[69.1-72.2] vs 74.6[72.0-77.3];p = 0.041), left-leg posteromedial balance (80.5[72.9-83.3] vs 85.9[83.0-94.0];p = 0.048), and left-leg posterolateral balance (79.5[70.4-84.5] vs 85.0[80.0-88.5];p = 0.048) was observed in the SIPP group compared to the GIPP group. No other significant intra-group changes nor inter-group differences were noted. Therefore, compared to a GIPP, a SIPP induced greater improvements in lower-limb dynamic balance in female dancers, potentially leading to greater reduction in lower-limb injury risk.

Objective: To quantify the variation in body composition, physical function and cognitive health changes resulting from the Muscling Up Against Disability (MUAD) resistance and balance training program and the potential for baseline characteristics to predict the magnitude of training-related response., Methods: The study represented a secondary analysis of a stepped-wedge randomised controlled trial involving 245 community-dwelling adults receiving Australian Government-funded aged care services who performed 26 weeks of supervised progressive resistance and balance training (PRBT). The primary outcome was the proportion of response that described the number of individuals expected to make any positive change due to the intervention and not external factors., Results: For all outcomes, the observed average change in the PRBT group was more favourable than the control. Analyses identified that most participants completing the PRBT program would be expected to respond positively to the intervention (86%-99%) with respect to their physical performance (SPPB summary, grip strength, chair stand and isometric knee strength). A smaller proportion completing the PRBT program group would be expected to respond positively in aspects of body composition (45%-60%) or cognitive function (44%-84%). The strongest predictors of positive change were baseline physical function, whereby those with the poorest baseline function experienced the greatest benefits., Conclusions: This study strongly supports the promotion of PRBT as a standard component of any care plan for community-dwelling older adults, especially those with low levels of physical function., (© 2022 AJA Inc.)

Background: Research into the kettlebell swing has increased in the last decade. There has been a paucity of literature assessing an individual's ability to perform the kettlebell swing exercise. The purpose of this study was to determine the test-retest reliability of the one and five repetition maximum (1RM and 5RM) kettlebell swing., Materials & Methods: Twenty four recreational resistance-trained participants performed an isometric mid-thigh pull (IMTP) and two familiarization sessions followed by three test sessions for each RM load approximately one week apart, using a custom-built plate-loaded kettlebell. On each test occasion, subjects completed a series of warm-up sets followed by 3-4 progressively heavier kettlebell swings to a standardized height until 1RM or 5RM was reached. Test-retest reliability was calculated using the intra-class correlation (ICC) and typical error was represented as the coefficient of variation (CV%) with 90% confidence limits (90% CL). The smallest worthwhile change (SWC%) representing the smallest change of practical importance, was calculated as 0.2 × between-subject standard deviation. The relationship of kettlebell swing performance and maximum strength was determined by Pearson correlation with ±90% CL between the absolute peak force recorded during IMTP and 1RM or 5RM., Results: Results demonstrated a high test-retest reliability for both the 1RM (ICC = 0.97, 90% CL [0.95-0.99]; CV = 2.7%, 90% CL [2.2-3.7%]) and 5RM (ICC = 0.98, 90% CL [0.96-0.99]; CV = 2.4%, 90% CL [1.9-3.3%]), respectively. The CV% was lower than the SWC for both the 1RM (SWC = 2.8%, 90% CL [1.9-3.5]) and 5RM (SWC = 2.9%, 90% CL [1.9-3.6]) kettlebell swing. The correlation between IMTP absolute peak force and the 1RM (r = 0.69, 90% CL 0.43-0.83) was large and very large for the 5RM (r = 0.75, 90% CL [0.55-0.87])., Conclusions: These results demonstrate the stability of 1RM and 5RM kettlebell swing performance after two familiarization sessions. Practitioners can be confident that changes in kettlebell swing 1RM and 5RM performance of >3.6 kg represent a practically important difference, which is the upper limit of the 90% CL., Competing Interests: Justin Keogh is an Academic Editor for PeerJ. The authors declare no other competing interests associated with the publication of this article., (© 2022 Ross et al.)

Objectives: This study examined older adults' experiences of participating in the Ballistic Exercise of the Lower Limb (BELL) trial, involving 12-weeks of group-based hardstyle kettlebell training., Methods: In the BELL trial, 28 insufficiently active older adults (15 women, 13 men, 59-79 years) completed six weeks of face-to-face group training, and six weeks of home-based training. In-depth semi-structured interviews were audio recorded, transcribed, and inductively coded, with themes constructed from patterns of shared meaning., Results: Four higher-order themes were developed that reflect older adults' experiences participating in a group-exercise program of hardstyle kettlebell training. These included: (1) "It's one of the best things we've done"-enjoying the physical and psychosocial benefits, (2) "It's improved it tremendously!"-change in a long-term health condition, (3) "It put me on a better course"-overcoming challenges, and (4) "I wasn't just a number"-feeling part of a group/community., Discussion: Findings highlight the perceived physical and psychological benefits of older adults participating in hardstyle group kettlebell training, and the value attributed to being part of an age-matched community of like-minded people engaged in group exercise. Implications for program design and delivery, and future research, are discussed., (© 2022. The Author(s).)

Background: The decline in motor function associated with chronic ankle instability (CAI) can be assessed using Functional Performance tests. Ankle muscular strength, endurance and range of motion (ROM) has been assessed in previous studies but functional activities such as sprinting and change of direction are less well studied in athletes with CAI. Hence the aim of this study was to determine how sprint, change of direction, ankle isometric strength, endurance and ROM measures may be associated with discriminate athletes with and without CAI., Methods: One hundred and six participants (CAI: n = 53 or no CAI: n = 53) provided informed consent to participate in this study. Participants performed three functional performance tests, (30-m sprint test, Modified Illinois change of direction test (MICODT)) and change of direction test. Range of motion for dorsiflexion was measured using weight bearing lunge test and inversion, eversion and plantarflexion using Saunders® digital inclinometer. Strength was assessed using Baseline® hand-held dynamometer for plantarflexors, dorsiflexors, invertors and evertors. Muscular endurance was assessed by single heel raise test and Modified single heel raise test. Between-group comparisons utilised Student's t-test and Mann-Whitney U-tests, with a number of unique variable and multivariable binomial logistic regression performed to determine which performance measures may discriminate participants with CAI., Results: The CAI participants performed significantly worse in the three functional performance tests as well as multiple measures of ankle ROM, isometric strength and muscular endurance ( p < 0.008). While several measures of ROM (plantarflexion and dorsiflexion), strength (inversion and eversion) and both muscular endurance tests were significantly associated with CAI in the univariable analysis, the strongest association was the functional performance tests, especially MICDOT time (odds ratio (95% CI): 0.06 [0.02-0.17], sensitivity 94.3%, specificity 88.7%). Multivariable regression analyses indicated that performance across the functional performance tests were more strongly associated with CAI than any ankle ROM, muscular strength or endurance test. Further, the inclusion of the best ankle range of motion, strength or muscular endurance tests did not significantly improve upon the association of the MICDOT with CAI., Conclusions: Chronic ankle instability in athletic populations appears to be highly associated with declines in functional performance and to a somewhat lesser extent, ankle range of motion, strength and muscle endurance measures. This may suggest that optimal rehabilitation for athletes with CAI may require a greater focus on improving sprinting speed and change of direction ability in the mid to latter stages of rehabilitation, with regular assessments of these functional performance tests necessary to guide the progression and overload of this training., Competing Interests: Justin Keogh is an Academic Editor for PeerJ., (© 2022 S. Jamsandekar et al.)

Purpose: To describe the physical activity (PA) promotion practices, beliefs, and barriers of Indian nurses working with cancer survivors, and to gain preliminary insights into how their educational qualification might affect PA promotion practices., Methods: A validated questionnaire was used to obtain the data ( N  = 388). Sub-group comparisons were performed based on nursing qualification i.e. , Bachelor of Science in Nursing (BSc) and General Nursing and Midwifery (GNM) using Mann-Whitney U test and chi square analysis for continuous and categorical variables, respectively., Results: The nurses believed that oncologists (47%) followed by physiotherapists (28.9%) were primarily responsible for providing information regarding PA to cancer survivors. The most common period in which the nurses' promoted PA was post treatment (31.7%), although very few nurses (13.3%) promoted PA across more than one of the three treatment periods. Nurses felt that PA had many benefits for cancer survivors; improved mental health (87.7%) and HRQoL (81.1%). Lack of knowledge (42.2%) and lack of time (41.6%) were the most frequently cited barriers. The comparisons based on educational qualification did not typically reveal many significant differences., Conclusion: Indian nurses both BSc and GNM qualified, wish to promote PA to cancer survivors despite numerous barriers, across various stages of treatment and believe PA is beneficial to the survivors in the process of recovery. Overcoming these barriers might aid in better promotion of PA to cancer survivors., Implication for Cancer Survivors: Nurses working in a tertiary care hospital in India are willing to promote PA amongst cancer survivors but require more training and support in this area of practice., Competing Interests: Justin W.L. Keogh is an Academic Editor for PeerJ., (©2022 Pai et al.)

The Ballistic Exercise of the Lower Limb (BELL) trial examined the efficacy and safety of a pragmatic hardstyle kettlebell training program in older adults. Insufficiently active men and women aged 59-79 years, were recruited to a 6-month repeated measures study, involving 3-months usual activity and 3-months progressive hardstyle kettlebell training. Health-related physical fitness outcomes included: grip strength [GS], 6-min walk distance [6MWD], resting heart rate [HR], stair-climb [SC], leg extensor strength [LES], hip extensor strength [HES], Sit-To-Stand [STS], vertical jump [CMVJ], five-times floor transfer [5xFT], 1RM deadlift, body composition (DXA), attendance, and adverse events. Sixteen males (68.8 ± 4.6 yrs, 176.2 ± 7.8 cm, 90.7 ± 11.0 kg, 29.2 ± 2.6 kg/m 2 ) and sixteen females (68.6 ± 4.7 yrs, 163.9 ± 5.4 cm, 70.4 ± 12.7 kg, 26.3 ± 4.9 kg/m 2 ) were recruited. Compliance with the supervised exercise program was very high (91.5%). Kettlebell training increased GS (R: MD = 7.1 kg 95% CI [4.9, 9.3], L: MD = 6.3 kg 95% CI [4.1, 8.4]), 6MWD (41.7 m, 95% CI [17.9, 65.5]), 1RM (16.2 kg, 95% CI [2.4, 30.0]), 30 s STS (3.3 reps, 95% CI [0.9, 5.7]), LES (R: MD = 61.6 N, 95% CI [4.4, 118.8]), HES (L: MD = 21.0 N,95% CI [4.2,37.8]), appendicular skeletal lean mass (MD = 0.65 kg, 95% CI [0.08, 1.22]), self-reported health change (17.1%, 95% CI [4.4, 29.8]) and decreased SC time (2.7 s, 95% CI [0.2, 5.2]), 5xFT time (6.0 s, 95% CI [2.2, 9.8]) and resting HR (7.4 bpm, 95% CI [0.7, 14.1]). There were four non-serious adverse events. Mean individual training load for group training sessions during the trial was 100,977 ± 9,050 kg. High-intensity hardstyle kettlebell training was well tolerated and improved grip strength and measures of health-related physical fitness in insufficiently active older adults.Trial registration: Prospectively registered: 20/08/2019, Australian New Zealand Clinical Trials Registry (ACTRN12619001177145)., (© 2022. The Author(s).)

Abstract: Gallardo-Meza, C, Simon, K, Bustamante-Ara, N, Ramirez-Campillo, R, García-Pinillos, F, Keogh, JWL, and Izquierdo, M. Effects of 4 weeks of active exergames training on muscular fitness in elderly women. J Strength Cond Res 36(2): 427-432, 2022-To analyze the effects of 4 weeks of an active exergames training program on muscular fitness in older women, 2 groups of community dwelling physically active subjects were formed by block-design randomization. One was deemed the control group (CG, n = 37; age 68.1 ± 3.3 years), and a second group completed 4 weeks of an active exergames training program (ExG, n = 35; age, 69.2 ± 3.7 years). Training included active exergames (Wii Fit Plus) performed on the Wii Balanceboard, 2 sessions per week. The exergames required mainly balance-related movements, such as leaning forward, leftward, and rightward, also requiring isometric squat positions and explosive leg extension. A supervisor-to-subject ratio method of 2:1 was used. An intensity-based individual progressive overload was applied. There were no significant (all p > 0.05, d = 0.01-0.07) baseline differences between-groups for all dependent variables. For the ExG, significant improvements were observed in static balance right leg test (Δ75.5%, d = 0.89), static balance left leg (Δ33.7%, d = 0.57), timed up-and-go test (Δ14.8%, d = 0.85) and sit-to-stand velocity test (Δ83.8%, d = 1.62). For the control group, trivial to small decrements in performance were observed across all tests (Δ -2.1 to -8.4%, d = -0.08 to 0.32). Group × time interactions were observed for the static balance right and left leg, timed up-and-go test, and the mean velocity achieved in the 5-repetition sit-to-stand test (all p < 0.001; d = 0.33-0.60). In conclusion, exergames training improves muscular fitness in older women. These results should be considered when designing appropriate and better exercise training programs for older women., (Copyright © 2020 National Strength and Conditioning Association.)

Objectives: To examine physical fitness profiles of female Australian football players and investigate differences according to competition level., Methods: A testing battery of 28 physical fitness assessments was undertaken with 240 players across five competition levels: elite senior (≥18 years), non-elite senior (≥18 years), high-level junior (<18 years), non-elite junior (14-17 years), and non-elite junior (10-13 years). Physical fitness profiles were examined and competition level differences were investigated using multivariate analyses of variance., Results: Significant differences ( p <0.001) were observed between competition levels in body composition (η 2 p =0.225), flexibility (η 2 p =0.071), muscular strength and endurance (η 2 p =0.238), balance (η 2 p =0.093), reaction time (η 2 p =0.103), and whole-body locomotor performance (η 2 p =0.200). Elite seniors and high-level juniors were stronger ( p <0.001-0.043), faster ( p =0.001-0.022), more responsive ( p <0.001-0.048), and had better cardiorespiratory fitness ( p <0.001) compared to the non-elite groups. Additionally, body composition and muscular strength and endurance differences were common between the senior and non-elite junior groups., Conclusions: This is the first study to comprehensively profile physical characteristics of female Australian footballers across a broader development pathway. These preliminary findings may assist sport practitioners to better understand athlete development, provide insight on talent identification and development programs, and injury management in this population.

Objectives: To profile the kicking and handballing accuracy of female Australian football (AF) players and investigate potential differences across five competition levels., Methods: Female AF players were classified into five competition levels: elite senior (≥18 years) ( n =35), non-elite senior (≥18 years) ( n =58), high-level junior (<18 years) ( n =32), non-elite junior (14-17 years) ( n =38), and non-elite junior (10-13 years) ( n =42). Modified AF kicking and handballing tests examined accuracy outcomes. Competition level differences in accuracy were modelled using multivariate analysis of variance., Results: A large, significant difference between the competition levels was noted ( F =11.508, p <0.001, Wilk's Λ=0.462, η 2 p =0.227), with significant differences ( p <0.001) observed in the modified AF kicking (ω 2 =0.514) and handballing (η 2 p =0.150-0.250) tests. Elite seniors and high-level juniors performed the modified AF kicking test more accurately than all non-elite competition levels ( p ≤0.001). Elite seniors were also more accurate in the modified AF handballing test (dominant hand) compared to all non-elite competition levels ( p ≤0.001)., Conclusions: This study is the first to report technical skill characteristics in female AF across a broader participation pathway. These exploratory findings could be used as reference data for player development and inform training designs, namely by incorporating non-dominant handballing competitive play situations to develop this skill in female AF players.

Objectives: To describe injury profiles of Australian football players and explore trends across five, women's and girls' competition levels., Design: Prospective cohort study., Methods: Injuries were prospectively recorded by team personnel across one or two seasons of Australian football (2017-18 and/or 2018-19) including five, women's and girls' competition levels (elite senior, non-elite senior, high-level junior, non-elite junior (14-17 years), and non-elite junior (10-13 years)). Injury incidence rates were calculated per 1000 h and injury prevalence calculated for pre-season, early-season, mid-season, and late-season. Descriptive statistics present injury profiles according to activity, body region, pathology, mechanism, and severity., Results: From the 392 included players, 760 injuries were recorded. Overall injury incidence was 20.9 injuries per 1000 h. Injury prevalence was highest during pre-season (64.1%). Most injuries were to the lower extremity (n = 440; 58.0%). Ligament/joint sprain injuries were common (n = 147, 19.3%). Several injuries resulted from contact mechanisms (n = 314, 61.4%), with many due to contact with another player (n = 131, 52.8%). Injuries resulting in time lost from participation were common (n = 444, 58.9%). Competition level injury trends were observed, with elite senior (125.1 injuries per 1000 h) and high-level junior (116.9 injuries per 1000 h) players having greater match injury incidence compared to their non-elite counterparts (15.5-41.4 injuries per 1000 h)., Conclusions: This study provides preliminary insight into injury profiles of Australian football players in women's and girls' competitions. These findings can drive future injury risk reduction research specific to this population across the developmental pathway., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The goals of this narrative review are to provide a brief overview of the muscle and tendon adaptations to eccentric resistance exercise and address the applications of this form of training to aid rehabilitative interventions and enhance sports performance. This work is centered on the author contributions to the Special Issue entitled "Eccentric Exercise: Adaptations and Applications for Health and Performance". The major themes from the contributing authors include the need to place greater attention on eccentric exercise mode selection based on training goals and individual fitness level, optimal approaches to implementing eccentric resistance exercise for therapeutic purposes, factors that affect the use of eccentric exercise across the lifespan, and general recommendations to integrate eccentric exercise in athletic training regimens. The authors propose that movement velocity and the absorption or recovery of kinetic energy are critical components of eccentric exercise programming. Regarding the therapeutic use of eccentric resistance training, patient-level factors regarding condition severity, fitness level, and stage of rehabilitation should govern the plan of care. In athletic populations, use of eccentric exercise may improve movement competency and promote improved safety and performance of sport-specific tasks. Eccentric resistance training is a viable option for youth, young adults, and older adults when the exercise prescription appropriately addresses program goals, exercise tolerability, and compliance. Despite the benefits of eccentric exercise, several key questions remain unanswered regarding its application underscoring the need for further investigation.

Stiffness, the resistance to deformation due to force, has been used to model the way in which the lower body responds to landing during cyclic motions such as running and jumping. Vertical, leg, and joint stiffness provide a useful model for investigating the store and release of potential elastic energy via the musculotendinous unit in the stretch-shortening cycle and may provide insight into sport performance. This review is aimed at assessing the effect of vertical, leg, and joint stiffness on running performance as such an investigation may provide greater insight into performance during this common form of locomotion. PubMed and SPORTDiscus databases were searched resulting in 92 publications on vertical, leg, and joint stiffness and running performance. Vertical stiffness increases with running velocity and stride frequency. Higher vertical stiffness differentiated elite runners from lower-performing athletes and was also associated with a lower oxygen cost. In contrast, leg stiffness remains relatively constant with increasing velocity and is not strongly related to the aerobic demand and fatigue. Hip and knee joint stiffness are reported to increase with velocity, and a lower ankle and higher knee joint stiffness are linked to a lower oxygen cost of running; however, no relationship with performance has yet been investigated. Theoretically, there is a desired "leg-spring" stiffness value at which potential elastic energy return is maximised and this is specific to the individual. It appears that higher "leg-spring" stiffness is desirable for running performance; however, more research is needed to investigate the relationship of all three lower limb joint springs as the hip joint is often neglected. There is still no clear answer how training could affect mechanical stiffness during running. Studies including muscle activation and separate analyses of local tissues (tendons) are needed to investigate mechanical stiffness as a global variable associated with sports performance., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2021 Artur Struzik et al.)

Background: As participants who engage in CrossFit training and competition perform a large volume of high intensity overhead activities, injuries to the shoulder are one of the most common in this sport. Previous research in other sports has indicated that the isokinetic force power profile of the shoulder joint (IPSJ) rotator muscles may assist in the prediction of shoulder injury., Aim: Therefore, the objective of this study was to determine the IPSJ in males engaged in CrossFit training at different competitive levels., Methods: In a cross-sectional study design, participants (age, 24.1 ± 2.7 years) classified as 'beginner' ( n = 6), 'intermediate' ( n = 7) or 'advanced' ( n = 9) provided informed consent to participate in this study. The IPSJ assessment involved rotational and diagonal movements, including internal and external shoulder rotator muscles, at both 180°.s -1 and 300°.s -1 . The variables analysed were peak torque/body mass (%), mean power (W) and the external/internal peak torque/body mass ratio (%). A Kruskal-Wallis test was used to compare the IPSJ of the three groups, with Dunn's test used for post-hoc analysis. The alpha level was set at p < 0.05., Results: The IPSJ showed greater torque and power values in those who competed at the advanced level as compared to those at a lower competitive level ( i.e . intermediate, beginner). This was observed mainly for the internal rotation and internal diagonal movements at both 180°.s -1 and 300°.s -1 . However, such differences between competitive levels were, in general, absent for the external rotation and external diagonal movements. Moreover, the participants from the advanced competitive level exhibited an imbalance of peak torque between the muscles responsible for the external-internal rotational and external-internal diagonal movements of the shoulder ( i.e . peak torque external/internal ratio <66%), particularly in the dominant shoulder., Conclusion: These findings suggest greater development of the shoulder internal rotators and a higher probability of shoulder injury in CrossFit athletes at the advanced competitive level. Based on these results, participants engaged in CrossFit training and competition may wish to increase the volume of training for the shoulder external rotator muscles to complement the large increases in shoulder internal rotator strength that occur as a part of their regular training regimes., Competing Interests: Rodrigo Ramirez-Campillo and Justin W.L. Keogh are Academic Editors for PeerJ., (© 2021 Torres-Banduc et al.)

Background: The atlas stone lift is a popular strongman exercise where athletes are required to pick up a large, spherical, concrete stone and pass it over a bar or place it on to a ledge. The aim of this study was to use ecologically realistic training loads and set formats to (1) establish the preliminary biomechanical characteristics of athletes performing the atlas stone lift; (2) identify any biomechanical differences between male and female athletes performing the atlas stone lift; and (3) determine temporal and kinematic differences between repetitions of a set of atlas stones of incremental mass., Methods: Kinematic measures of hip, knee and ankle joint angle, and temporal measures of phase and repetition duration were collected whilst 20 experienced strongman athletes (female: n = 8, male: n = 12) performed three sets of four stone lifts of incremental mass (up to 85% one repetition maximum) over a fixed-height bar., Results: The atlas stone lift was categorised in to five phases: the recovery, initial grip, first pull, lap and second pull phase. The atlas stone lift could be biomechanically characterised by maximal hip and moderate knee flexion and ankle dorsiflexion at the beginning of the first pull; moderate hip and knee flexion and moderate ankle plantarflexion at the beginning of the lap phase; moderate hip and maximal knee flexion and ankle dorsiflexion at the beginning of the second pull phase; and maximal hip, knee extension and ankle plantarflexion at lift completion. When compared with male athletes, female athletes most notably exhibited: greater hip flexion at the beginning of the first pull, lap and second pull phase and at lift completion; and a shorter second pull phase duration. Independent of sex, first pull and lap phase hip and ankle range of motion (ROM) were generally smaller in repetition one than the final three repetitions, while phase and total repetition duration increased throughout the set. Two-way interactions between sex and repetition were identified. Male athletes displayed smaller hip ROM during the second pull phase of the first three repetitions when compared with the final repetition and smaller hip extension at lift completion during the first two repetitions when compared with the final two repetitions. Female athletes did not display these between-repetition differences., Conclusions: Some of the between-sex biomechanical differences observed were suggested to be the result of between-sex anthropometric differences. Between-repetition differences observed may be attributed to the increase in stone mass and acute fatigue. The biomechanical characteristics of the atlas stone lift shared similarities with the previously researched Romanian deadlift and front squat. Strongman athletes, coaches and strength and conditioning coaches are recommended to take advantage of these similarities to achieve greater training adaptations and thus performance in the atlas stone lift and its similar movements., Competing Interests: Justin Keogh is an Academic Editor for PeerJ. The authors declare no other competing interests associated with the publication of this article., (© 2021 Hindle et al.)

Abstract: Ramirez-Campillo, R, Moran, J, Drury, B, Williams, M, Keogh, JW, Chaabene, H, and Granacher, U. Effects of equal volume but different plyometric jump training intensities on components of physical fitness in physically active young males. J Strength Cond Res 35(7): 1916-1923, 2021-An 8-week single-blind randomized controlled trial was conducted to compare the effects of separate programs of equal volume, but different intensity, plyometric jump training (PJT), on physical fitness in healthy adults. Thirty-eight physically active males (mean age: 21.8 ± 2.5 years) participated. Subjects were randomly assigned to one of 3 PJT groups or a control (CON, n = 9) according to their jump performance. Plyometric jump training was conducted at maximal (PJT-100, n = 10), high (PJT-80, n = 9), or moderate (PJT-65, n = 10) intensity within each group. Baseline and follow-up tests were performed for the assessment of countermovement jump (CMJ) height, CMJ height with arm swing (CMJA), and drop jump height from a 20-cm drop box (DJ20), linear speed (30 m), and change-of-direction speed (CODS) (the Illinois CODS test). Results revealed significant group × time interactions for CMJ, CMJA, DJ20, 30-m sprint, and CODS (all p < 0.001; d = 0.39-0.76). Post hoc analyses showed significant improvements in all 5 fitness measures for PJT-100 (all p < 0.01, Δ3.7-13.5%, d = 0.26-1.4). For PJT-80, 3 of 5 fitness tests demonstrated significant change (CMJ: p < 0.001, Δ5.9%, d = 0.33; CMJA: p < 0.001, Δ7.0%, d = 0.43; CODS: p < 0.001, Δ3.9%, d = 0.9), and for PJT-65, only 1 test was significant (CMJ: p < 0.05, Δ2.8%, d = 0.15). No significant changes were observed in CON. Except for similar gains in DJ20 and 30-m sprint in PJT-100 and PJT-80, gains in physical fitness were, in general, greater (p < 0.05) after PJT-100 vs. PJT-80 vs. PJT-65 vs. CON. Therefore, maximal PJT intensity may induce larger physical fitness gains, although high and moderate intensities may also be useful, but to a lesser extent., (Copyright © 2019 National Strength and Conditioning Association.)

The yoke walk is a popular strongman exercise where athletes carry a heavily loaded frame balanced across the back of their shoulders over a set distance as quickly as possible. The aim of this study was to use ecologically realistic training loads and carry distances to (1) establish the preliminary biomechanical characteristics of the yoke walk; (2) identify any biomechanical differences between male and female athletes performing the yoke walk; and (3) determine spatiotemporal and kinematic differences between stages (intervals) of the yoke walk. Kinematic and spatiotemporal measures of hip and knee joint angle, and mean velocity, stride length, stride rate and stance duration of each 5 m interval were taken whilst 19 strongman athletes performed three sets of a 20 m yoke walk at 85% of their pre-determined 20 m yoke walk one repetition maximum. The yoke walk was characterised by flexion of the hip and slight to neutral flexion of the knee at heel strike, slight to neutral extension of the hip and flexion of the knee at toe-off and moderate hip and knee range of motion (ROM), with high stride rate and stance duration, and short stride length. Between-interval comparisons revealed increased stride length, stride rate and lower limb ROM, and decreased stance duration at greater velocity. Although no main between-sex differences were observed, two-way interactions revealed female athletes exhibited greater knee extension at toe-off and reduced hip ROM during the initial (0-5 m) when compared with the final three intervals (5-20 m), and covered a greater distance before reaching maximal normalised stride length than males. The findings from this study may better inform strongman coaches, athletes and strength and conditioning coaches with the biomechanical knowledge to: provide athletes with recommendation on how to perform the yoke walk based on the technique used by experienced strongman athletes; better prescribe exercises to target training adaptations required for improved yoke walk performance; and better coach the yoke walk as a training tool for non-strongman athletes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Dr. Justin Keogh who was one of the editors of this special issue., (Copyright © 2021 Hindle, Lorimer, Winwood, Brimm and Keogh.)

The coronavirus disease outbreak in China has become the world's leading health headline and is causing major panic and public concerns. Public health guidelines in many countries are suggesting that people stay at home to avoid human-to-human transmission of the virus, which may lead to reduced physical activity and greater feelings of isolation. Such effects may be particularly problematic in older adults due to their reduced physical capacities and their potential for increased mental health issues, such as anxiety and depression. A potential way to minimize many of these side effects of stay-at-home guidelines may be progressive home-based resistance training. A simple way to provide progressive overload in home-based resistance training may involve elastic resistance, which has been demonstrated to provide similar benefits to traditional resistance training equipment typically found in gymnasiums. Recommendations on how older adults can safely and effectively perform elastic resistance training at home are provided.

Inertial-based motion capture (IMC) has been suggested to overcome many of the limitations of traditional motion capture systems. The validity of IMC is, however, suggested to be dependent on the methodologies used to process the raw data collected by the inertial device. The aim of this technical summary is to provide researchers and developers with a starting point from which to further develop the current IMC data processing methodologies used to estimate human spatiotemporal and kinematic measures. The main workflow pertaining to the estimation of spatiotemporal and kinematic measures was presented, and a general overview of previous methodologies used for each stage of data processing was provided. For the estimation of spatiotemporal measures, which includes stride length, stride rate, and stance/swing duration, measurement thresholding and zero-velocity update approaches were discussed as the most common methodologies used to estimate such measures. The methodologies used for the estimation of joint kinematics were found to be broad, with the combination of Kalman filtering or complimentary filtering and various sensor to segment alignment techniques including anatomical alignment, static calibration, and functional calibration methods identified as being most common. The effect of soft tissue artefacts, device placement, biomechanical modelling methods, and ferromagnetic interference within the environment, on the accuracy and validity of IMC, was also discussed. Where a range of methods have previously been used to estimate human spatiotemporal and kinematic measures, further development is required to reduce estimation errors, improve the validity of spatiotemporal and kinematic estimations, and standardize data processing practices. It is anticipated that this technical summary will reduce the time researchers and developers require to establish the fundamental methodological components of IMC prior to commencing further development of IMC methodologies, thus increasing the rate of development and utilisation of IMC., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2021 Benjamin R. Hindle et al.)

Background: The block phase in the swimming start requires a quick reaction to the starting signal and a large take-off velocity that is primarily horizontal in direction. Due to the principle of specificity of training, there is a potential benefit of performing a greater proportion of horizontal force production exercises in a swimmers' dry-land resistance training sessions. Therefore, the purpose of this pilot study was to provide an insight into the effects of a horizontal- (HF) vs vertical-force (VF) training intervention on swim start performance., Methods: Eleven competitive swimmers (six males (age 20.9 ± 1.8 years, body mass 77.3 ± 9.7 kg, height 1.78 ± 0.05 m) and five females (age 21.4 ± 2.0 years, body mass 67.5 ± 7.4 kg, height 1.69 ± 0.05 m)) completed 2 weekly sessions of either a horizontal- or vertical-force focused resistance training programme for 8 weeks. Squat jump force-time characteristics and swim start kinetic and kinematic parameters were collected pre- and post-intervention., Results: Across the study duration, the swimmers completed an average of nine swimming sessions per week with an average weekly swim volume of 45.5 ± 17.7 km (HF group) and 53 ± 20.0 km (VF group), but little practice of the swim start per week ( n = 9). Within-group analyses indicated a significant increase in predicted one repetition maximum (1RM) hip thrust strength in the HF group, as well as significant increases in grab resultant peak force but reductions in resultant peak force of the block phase for the VF group. No significant between-group differences in predicted 1RM hip thrust and back squat strength, squat jump force-time and swim start performance measures were observed after 8 weeks of training. Significant correlations in the change scores of five block kinetic variables to time to 5 m were observed, whereby increased block kinetic outputs were associated with a reduced time to 5 m. This may be indicative of individual responses to the different training programmes., Discussion: The results of this current study have been unable to determine whether a horizontal- or vertical-force training programme enhances swim start performance after an 8-week training intervention. Some reasons for the lack of within and between group effects may reflect the large volume of concurrent training and the relative lack of any deliberate practice of the swim start. Larger samples and longer training duration may be required to determine whether significant differences occur between these training approaches. Such research should also look to investigate how a reduction in the concurrent training loads and/or an increase in the deliberate practice of the swim start may influence the potential changes in swim start performance., Competing Interests: Justin W.L. Keogh is an Academic Editor for PeerJ., (© 2021 Thng et al.)

Background: The acute changes of running biomechanics in habitually shod children when running barefoot have been demonstrated. However, the long-term effects of barefoot running on sprinting biomechanics in children is not well understood., Research Question: How does four years of participation in a daily school barefoot running program influence sprint biomechanics and stretch-shortening cycle jump ability in children?, Methods: One hundred and one children from barefoot education school (age, 11.2 ± 0.7 years-old) and 93 children from a control school (age, 11.1 ± 0.7 years-old) performed 50 m maximal shod and barefoot sprints and counter movement jump and five repeated-rebound jumping. To analyse sprint kinematics, a high-speed camera (240 fps) was used. In addition, foot strike patterns were evaluated by using three high-speed cameras (300 fps). Jump heights for both jump types and the contact times for the rebound jump were measured using a contact mat system. Two-way mixed ANOVA was used to examine the effect of school factor (barefoot education school vs control school) and footwear factor (barefoot vs shod) on the sprinting biomechanics., Results: Sprinting biomechanics in barefoot education school children was characterised by significantly shorter contact times (p = 0.003) and longer flight times (p = 0.005) compared to control school children regardless of footwear condition. In shod sprinting, a greater proportion of barefoot education school children sprinted with a fore-foot or mid-foot strike compared to control school children (p < 0.001). Barefoot education school children also had a significantly higher rebound jump height (p = 0.002) and shorter contact time than control school children (p = 0.001)., Significance: The results suggest that school-based barefoot running programs may improve aspects of sprint biomechanics and develop the fast stretch-shortening cycle ability in children. In order to confirm this viewpoint, adequately powered randomised controlled trials should be conducted., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Little is known about contrast training and post-activation performance enhancement (PAPE) in a same day concurrent training model. The aim of the current study was to examine the use of two short duration (1-min and 4-min) recovery periods on drop jump performance in same day concurrently trained athletes., Methods: Ten professional Australian Rules footballers (age, 20.6 ± 1.9 yr; height, 184.8 ± 6.9 cm; body mass, 85.8 ± 8.4 kg) completed two resistance training sessions with different PAPE recovery durations; 1-min and 4-min, 1 h following a field-based endurance session. Baseline (pre) drop jumps were compared to post-test maximal drop jumps, performed after each set of three squats (where each participant was encouraged to lift as heavy as they could), to determine changes between 1-min and 4-min recovery periods. Data were analysed by fitting a mixed model (significance was set at P ≤ 0.05). Corrected Hedges' g standardised effect sizes ±95% confidence limits were calculated using group means ± SDs., Results: There were no significant differences between baseline and experimental sets 1, 2 and 3 for reactive strength index (RSI), flight time, and total and relative impulse for either recovery duration. However, for contact time, 1-min baseline was significantly different from set 2 (mean difference; 95% CI [0.029; 0.000-0.057 s], P = 0.047, ES; 95% CI [-0.27; -1.20 to 0.66]). For RSI and flight time, 1-min was significantly higher than 4-min (RSI: 0.367; 0.091 to 0.642, P = 0.010, ES; 95% CI [0.52; -0.37 to 1.42]; flight time: 0.033; 0.003 to 0.063 s, P = 0.027, ES; 95% CI [0.86; -0.06 to 1.78])., Discussion: Short recovery periods of 1-min may be a time-efficient form of prescribing strength-power exercise in contrast loading schemes. Longer recovery periods do not appear to benefit immediate, subsequent performance., Competing Interests: Justin Keogh is an Academic Editor for PeerJ. Dean Ritchie is employed by the Gold Coast Suns FC., (© 2020 Ritchie et al.)

Background: Understanding the relationships between physical fitness characteristics and sports injury may assist with the development of injury minimisation programs. The purpose of this systematic review was to investigate the association between physical fitness attributes and sports injury in female, team ball sport players., Methods: Four scientific databases (MEDLINE, EMBASE, SPORTDiscus, Scopus) and reference lists of relevant research were searched for eligible studies up to September 2, 2019. Full-text articles examining the relationship between physical fitness and sports injury in female, team ball sport players were included. A modified Downs and Black checklist was used to assess methodological quality. Data synthesis determined summary conclusions based on the number of significant relationships divided by the total relationships investigated and reported as a percentage. Level of certainty was identified for summary conclusions based on level of evidence. Sub-analyses regarding competition level, age, and single injury types were also conducted., Results: A total of 44 studies were included. Data synthesis revealed no associations (low to moderate certainty) between body composition (1/9; 11%), flexibility (18-20%), and balance (2/8; 25%) and 'any injury' classification. No associations (mostly of moderate certainty) were found between flexibility (0-27%), muscular strength (0-27%), and body composition (14-33%) and various body region injury classifications, whereas mixed summary conclusions were shown for balance (0-48%). Many associations between physical fitness and sports injury were deemed 'unknown' or with an insufficient level of certainty. Sub-analyses revealed no association between strength and noncontact ACL injuries (0/5; 0%) or ankle sprains (0/12; 0%), and between flexibility and ankle sprains (1/5; 20%); however, insufficient certainty of these results exists. Clear associations were concluded between balance and lower body injuries in female, non-elite (10/16; 63%) and junior (9/12; 75%) team ball sport players, with moderate and insufficient certainty of these results, respectively., Conclusion: Limited evidence is available to demonstrate relationships between physical fitness and sports injury in female, team ball sport players. High-quality evidence investigating the multifactorial nature of sports injury, including the interactions physical fitness qualities have with other injury determinants, is needed to better understand the role of physical fitness in minimising sports injuries in female, team ball sport players., Trial Registration: CRD42017077374 (PROSPERO on September 14, 2017).

This study proposes a minimal modeling magnetic, angular rate and gravity (MARG) methodology for assessing spatiotemporal and kinematic measures of functional fitness exercises. Thirteen healthy persons performed repetitions of the squat, box squat, sandbag pickup, shuffle-walk, and bear crawl. Sagittal plane hip, knee, and ankle range of motion (ROM) and stride length, stride time, and stance time measures were compared for the MARG method and an optical motion capture (OMC) system. The root mean square error (RMSE), mean absolute percentage error (MAPE), and Bland-Altman plots and limits of agreement were used to assess agreement between methods. Hip and knee ROM showed good to excellent agreement with the OMC system during the squat, box squat, and sandbag pickup (RMSE: 4.4-9.8°), while ankle ROM agreement ranged from good to unacceptable (RMSE: 2.7-7.2°). Unacceptable hip and knee ROM agreement was observed for the shuffle-walk and bear crawl (RMSE: 3.3-8.6°). The stride length, stride time, and stance time showed good to excellent agreement between methods (MAPE: (3.2 ± 2.8)%-(8.2 ± 7.9)%). Although the proposed MARG-based method is a valid means of assessing spatiotemporal and kinematic measures during various exercises, further development is required to assess the joint kinematics of small ROM, high velocity movements.

Background: High volume power training (HVPT) involves high volumes of high-velocity resistance training, with the aim to improve repeated high-intensity efforts (RHIEs). Repeat power ability (RPA) is the ability to repeatedly produce maximal or near maximal efforts. Assessments of RPA using external loading may determine the ability to perform repeat RHIEs typical of many sports and, therefore, provide useful information on the effectiveness of training., Objectives: (1) Identify the different HVPT protocols; (2) examine the acute responses and chronic adaptations to different HVPT protocols; (3) identify different lower body RPA assessment protocols and highlight similarities, differences and potential limitations between each protocol, and; (4) describe the reliability and validity of RPA assessments., Methods: An electronic search was performed using SPORTDiscus, PubMed, CINAHL and Embase for studies utilising HVPT protocols and assessments of RPA. Eligible studies included peer-reviewed journal articles published in English., Results: Twenty studies met the inclusion criteria of the final review. Of the eight longitudinal studies, three were rated as fair and five were rated as poor methodological quality, respectively. In contrast, all 12 cross-sectional studies were considered to have a low risk of bias. Preliminary evidence suggests that HVPT can enhance RHIE, RPA, anaerobic capacity, anaerobic power and aerobic performance. HVPT generally consists of 2-3 sessions per week, utilising loads of 30-40% 1 repetition maximum (RM), for 3-5 sets of 10-20 repetitions, with inter-set rest periods of 2-3 min. RPA assessments can be valid and reliable and may provide useful information on an athlete's ability to perform RHIE and the success of HVPT programmes., Conclusions: HVPT can be used to improve a number of physical qualities including RPA and RHIE; while a variety of RPA assessments provide valid and reliable information regarding the athlete's ability to perform RHIEs. Considering the heterogeneity in the HVPT protocols currently used and the relatively low volume and quality of longitudinal publications in this area, further studies are needed to identify the effects of a variety of HVPT methods on RPA, RHIE and other performance outcomes and to identify the most valid and reliable RPA outcomes to use in such studies.

Del Monte, MJ, Opar, DA, Timmins, RG, Ross, JA, Keogh, JWL, and Lorenzen, C. Hamstring myoelectrical activity during three different kettlebell swing exercises. J Strength Cond Res 34(7): 1953-1958, 2020-Kettlebell exercises have become an increasingly popular form of resistance training and component of lower-body rehabilitative training programs, despite a lack of scientific literature illustrating internal mechanisms and effectiveness of these approaches. Participants (n = 14) performed 3 different styles of kettlebell swings (hip hinge, squat, and double knee extension) and were assessed for medial hamstrings (MHs) and biceps femoris (BF) myoelectrical activity through surface electromyography (sEMG). Bipolar pregelled Ag/AgCl sEMG electrodes (10 mm diameter, 20 mm interelectrode distance) were placed on the participant's dominant limb after correct skin preparation. There was a main effect for swing type (p = 0.004), where the hip hinge swing elicited a greater overall MH and BF sEMG in comparison with the squat swing (mean difference = 3.92; 95% confidence interval [CI] = 1.53-6.32; p = 0.002) and the double knee extension swing (mean difference = 5.32; 95% CI = 0.80-9.83; p = 0.020). Across all swing types, normalized percentage of MH sEMG was significantly higher compared with the BF (mean difference = 9.93; 95% CI = 1.67-18.19; p = 0.022). The hip hinge kettlebell swing produced the greatest amount of hamstring sEMG for the 3 styles of kettlebell swings assessed. These findings have implications for the application of kettlebell swing exercises in strength and conditioning, injury prevention, and rehabilitation programs.

Background: Depending on the stroke and distances of the events, swim starts have been estimated to account for 0.8% to 26.1% of the overall race time, with the latter representing the percentage in a 50 m sprint front crawl event (Cossor & Mason, 2001). However, it is still somewhat unclear what are the key physiological characteristics underpinning swim start performance. The primary aim of this study was to develop a multiple regression model to determine key lower body force-time predictors using the squat jump for swim start performance as assessed by time to 5 m and 15 m in national and international level swimmers. A secondary aim was to determine if any differences exist between males and females in jump performance predictors for swim start performance., Methods: A total of 38 males (age 21 ±  3.1 years, height 1.83 ±  0.08 m, body mass 76.7 ±  10.2 kg) and 34 females (age 20.1 ±  3.2 years, height 1.73 ±  0.06 m, body mass 64.8 ±  8.4 kg) who had competed at either an elite ( n  = 31) or national level ( n  = 41) participated in this study. All tests were performed on the same day, with participants performing three bodyweight squat jumps on a force platform, followed by three swim starts using their main swimming stroke. Swim start performance was quantified via time to 5 m and 15 m using an instrumented starting block., Results: Stepwise multiple linear regression with quadratic fitting identified concentric impulse and concentric impulse 2 as statistically significant predictors for time to 5 m ( R 2 = 0.659) in males. With time to 15 m, concentric impulse, age and concentric impulse 2 were statistically significant predictors for males ( R 2 = 0.807). A minimum concentric impulse of 200-230 N.s appears required for faster times to 5 m and 15 m, with any additional impulse production not being associated with a reduction in swim start times for most male swimmers. Concentric impulse, Reactive strength index modified and concentric mean power were identified as statistically significant predictors for female swimmers to time to 5 m ( R 2 = 0.689). Variables that were statistically significant predictors of time to 15 m in females were concentric impulse, body mass, concentric rate of power development and Reactive strength index modified ( R 2 = 0.841)., Discussion: The results of this study highlight the importance of lower body power and strength for swim start performance, although being able to produce greater than 200 or 230 N.s concentric impulse in squat jump did not necessarily increase swim start performance over 5 m and 15 m, respectively. Swimmers who can already generate greater levels of concentric impulse may benefit more from improving their rate of force development and/or technical aspects of the swim start performance. The sex-related differences in key force-time predictors suggest that male and female swimmers may require individualised strength and conditioning programs and regular monitoring of performance., Competing Interests: Justin Keogh is an Academic Editor for PeerJ., (©2020 Thng et al.)

Background: Understanding the relationships between physical fitness attributes and sport-specific technical skills may assist with the establishment of beneficial training interventions. The aim of this systematic review was to determine if physical fitness qualities were associated with performance of sport-specific technical skills in female, team-based ball players., Methods: Five databases (MEDLINE, EMBASE, SPORTDiscus, ProQuest, and Scopus) were searched for relevant studies up to April 15, 2019. Full-text articles investigating relationships between physical fitness and sport-specific technical skills in female, team-based ball players were included. Methodological quality of included studies was appraised using a modified Downs and Black checklist. Data synthesis was conducted to determine the summary of evidence based on the number of significantly associated relationships divided by the total relationships assessed. An individual relationship was defined as a reported result examining the association between a single physical fitness variable and a single sport-specific technical skill., Results: Data synthesis of grouped female ball players from 41 included studies revealed three clear associations: (i) body composition and defensive technical skills (19/29; 66%), (ii) agility and movement with a ball (4/6; 67%), and (iii) coordination and movement with a ball (3/5; 60%). An uncertain association exists between cardiorespiratory fitness and defensive technical skills (2/5; 40%). No association or an unknown conclusion (< 5 relationships reported) exists between all remaining physical fitness attributes and sport-specific technical skills. Sub-analyses revealed clear associations between body composition and throwing/shooting (using hands) in junior ball players (15/15; 100%) and with movement with a ball in elite (6/9; 67%) and senior (6/6; 100%) ball players. Three uncertain associations were found between offensive technical skills and agility in elite ball players (3/8; 38%), and with speed in elite (6/14; 43%) and junior (7/18; 39%) female ball players., Conclusion: There is limited evidence available to demonstrate relationships between physical fitness qualities and sport-specific technical skills in female, team-based ball players. This lack of association is possibly due to reductionist methods in available literature and a lack of research in female ball players globally., Registration: CRD42017065339 (PROSPERO on 12 May 2017).

Background: This study aimed to determine the reliability of the velocity achieved during the last repetition of sets to failure ( V last ) and the association of V last with the velocity of the 1-repetition maximum ( V 1RM ) during the paused and touch-and-go bench press (BP) exercises performed in a Smith machine., Methods: A total of 96 healthy men participated in this study that consisted of two testing sessions. A single BP variant (paused BP or touch-and-go BP) was evaluated on each session in a randomized order. Each session consisted of an incremental loading test until reaching the 1RM, followed by two sets of repetitions to failure against a load ranging from 75% to 90% of 1RM., Results: The reliability of V last was unacceptable for both BP variants (CV > 18.3%, ICC < 0.60). The correlations between V 1RM and V last were small for the paused BP ( r = 0.18) and moderate for the touch-and-go BP ( r = 0.37)., Conclusions: Although these results suggest that V last could be a better indicator of the minimal velocity threshold than V 1RM , the low reliability of V last and the similar values of V last for both BP variants suggest that a standard V 1RM should be used to estimate the 1RM from the individualized load-velocity relationship., Competing Interests: Amador García-Ramos and Justin W.L. Keogh are Academic Editors for PeerJ., (© 2020 García-Ramos et al.)

INTRODUCTION The Green Prescription is a primary care programme designed to increase physical activity in individuals with low activity levels. Older adults tend to engage in insufficient physical activity to obtain health-related gain. AIM To examine participants' ratings of the Healthy Steps intervention and to assess how participants rated the use of a pedometer-based Green Prescription in aiding their physical activity. METHODS In total, 330 community-dwelling older adults who have low levels of activity were randomised to receive either a standard time-based Green Prescription or a modified pedometer-based Green Prescription. Post-intervention, 259 participants completed the participant evaluation questionnaire via postal survey. Data were analysed using descriptive statistics and Chi-squared analyses. RESULTS The standard components of the Green Prescription (general practitioner consultations and telephone counselling) received similar and higher ratings across both allocation groups than the use of print materials. A pedometer-based Green Prescription was rated as being helpful in aiding physical activity. DISCUSSION This study supports the importance of general practitioners' initial role in prescribing physical activity for older adults and of ongoing telephone support for longer-term adherence. Incorporating a pedometer can be effective in helping low-active older adults initiate and maintain regular physical activity.

Introduction: Muscle wasting conditions such as sarcopenia may be highly prevalent in advanced head and neck cancer (HNC) patients (16-71%), with these prevalence rates substantially greater in those who have received chemo-radiotherapy (CRT). According to the updated European Working Group on Sarcopenia in Older People consensus statement, sarcopenia is defined as the age-related loss of muscle strength, muscle mass and physical performance. The high prevalence of sarcopenia in HNC patients is concerning as it has been associated with substantially increased risk of CRT toxicity, respiratory complications and early mortality. With the high prevalence of HNC and sarcopenia in India and the strong link between sarcopenia and poor HNC patient outcomes, it is important to screen for the presence of sarcopenia in Indian patients receiving CRT for HNC., Methods: This longitudinal pilot study aimed to routinely monitor 19 men receiving CRT for their HNC for a variety of sarcopenic-related outcomes over three time points during their 7 weeks of CRT. Participants were required to be male, with a minimum age of 30 years, with a Stage III, IVa or IVb diagnosis of HNC and be currently undergoing a 7 weeks course of CRT in an oncology department. Outcomes included probable sarcopenic diagnosis were estimated by the SARC-F, handgrip strength, skeletal muscle mass was estimated by bioelectrical impedance and physical performance was assessed by the Timed Up and Go. Repeated measures ANOVA and Bonferroni post-hoc tests were used to identify significant differences at the three time points with a p < 0.05., Results: The 19 participants in this trial at a mean age of 56.5 ± 10.2 years (range = 39-75 years), with most ( n = 13, 68.4%) employed in laboring occupations. At baseline, 31.5% ( n = 6) of the participants already had probable sarcopenia based on their total SARC-F score, with this increasing to 89.4% ( n = 17) at the end of 7 weeks CRT. In addition, significant decreases in strength, skeletal muscle mass and Timed Up and Go performance were observed, with these declines significantly greater at 7 weeks than 3 weeks after commencing CRT., Conclusions: Patients with HNC undergoing 7 weeks of CRT showed clinically significant increases in the incidence of probable sarcopenia based on their total SARC-F score as well as clinically significant declines in handgrip strength, skeletal muscle mass and Timed Up and Go performance. Due to the relationship between sarcopenia and a host of adverse events related to CRT in HNC patients, these results suggest that oncologists and their allied health teams should routinely monitor these patients during CRT and provide the relevant exercise therapy and nutritional support to those patients in need., Competing Interests: Justin Keogh is an Academic Editor for PeerJ., (© 2020 Chauhan et al.)

As the sport of strongman is becoming increasingly popular, and such exercises are being commonly used by strength and conditioning coaches for a wide range of athletic groups, a greater understanding of the biomechanics of strongman exercises is warranted. To improve the quality of research, this systematic review summarised the research methodology used in biomechanical studies of strongman exercises and identified potential improvements to current approaches. A search of 5 databases found 10 articles adherent to the pre-defined inclusion criteria. The studies assessed 8 strongman exercises and included male participants of relatively similar body mass but varying training backgrounds. Due to the complexity of strongman exercises and the challenges in collecting advanced biomechanical data in the field, most studies used simplified measurement/analysis methods (e.g., 2D motion capture). Future strongman biomechanical studies should: assess under/un-researched strongman exercises; include a greater number of experienced and female strongman athletes; utilise more advanced (e.g., 3D motion capture and/or inertial sensor) technology so to provide a broader range and greater quality of data. Such approaches will provide strength and conditioning coaches, strongman coaches and athletes with a greater understanding of strongman exercises, thereby further improving exercise prescription, athlete performance and minimising risk of injury.

Background: The sport of strongman is becoming increasingly popular, catering for females, lightweight, and Masters competitors, with strongman exercises also being used by strength and conditioning coaches for a range of athletic groups. Thus, a systematic review was conducted to examine researchers' current understanding of the biomechanics of strongman exercises, with a view to improve strongman athlete performance, provide biomechanical evidence supporting the transferability of strongman exercises to strength and conditioning/rehabilitation programs, and identify gaps in the current knowledge of the biomechanics of strongman exercises., Methods: A two-level search term strategy was used to search five databases for studies relevant to strongman exercises and biomechanics., Results: Eleven articles adherent to the inclusion criteria were returned from the search. The studies provided preliminary biomechanical analysis of various strongman exercises including the key biomechanical performance determinants of the farmer's walk, heavy sled pull, and tire flip. Higher performing athletes in the farmer's walk and heavy sled pull were characterized by a greater stride length and stride rate and reduced ground contact time, while higher performing athletes in the tire flip were characterized by a reduced second pull phase time when compared with lower performing athletes. Qualitative comparison of carrying/walking, pulling and static lifting strongman, traditional weight training exercises (TWTE), and common everyday activities (CEA), like loaded carriage and resisted sprinting, were discussed to further researchers' understanding of the determinants of various strongman exercises and their applications to strength and conditioning practice. A lack of basic quantitative biomechanical data of the yoke walk, unilateral load carriage, vehicle pull, atlas stone lift and tire flip, and biomechanical performance determinants of the log lift were identified., Conclusions: This review has demonstrated the likely applicability and benefit of current and future strongman exercise biomechanics research to strongman athletes and coaches, strength and conditioning coaches considering using strongman exercises in a training program, and tactical operators (e.g., military, army) and other manual labor occupations. Future research may provide a greater understanding of the biomechanical determinants of performance, potential training adaptations, and risks expected when performing and/or incorporating strongman exercises into strength and conditioning or injury rehabilitation programs.

Background: The swim start requires an explosive muscular response of the lower body musculature to effectively initiate movement off the starting blocks. There are currently key gaps in the literature evaluating the relationship between dry-land resistance training and swim start performance and the effects of this training on swim start performance, as assessed by the time to 5, 10 or 15 m., Objectives: The aims of this systematic review were to critically appraise the current literature on (1) the acute relationship between dry-land resistance training and swim start performance and (2) the acute and chronic effects of dry-land resistance training on swim start performance., Methods: An electronic search using AusportMed, Embase, Medline (Ovid), SPORTDiscus and Web of Science was performed. The methodological quality of the studies was evaluated using the Newcastle-Ottawa quality assessment scale (NOS) (cross-sectional studies) and the Physiotherapy Evidence Database (PEDro) scale (intervention studies)., Results: Sixteen studies met the eligibility criteria, although the majority did not utilise the starting blocks or technique currently used in elite swimming. Swim start performance was near perfectly related (r > 0.90) to vertical bodyweight jumps and jump height. Post-activation potentiation and plyometrics were found to produce significant improvements in acute and chronic swim start performance, respectively., Conclusion: While there appears to be strong evidence supporting the use of plyometric exercises such as vertical jumps for monitoring and improving swim start performance, future studies need to replicate these findings using current starting blocks and techniques and compare the chronic effects of a variety of resistance training programmes.