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Background: Undulatory underwater swimming (UUS) has become an integral component of the start and turn phases in competitive swimming allowing higher velocities than can be achieved swimming at the surface. An understanding of the most important determinants for UUS performance and how these can be optimised to different swimmers is poorly understood. Objective: The aim of this systematic review was to systematically assess the current peer-reviewed literature on the relationship between UUS performance determinants and underwater velocity in competitive swimmers. Methods: An electronic search using AusSportMed, Embase, PubMed, SPORTDiscus and Biomechanics and Medicine in Swimming was performed. The methodological quality of the studies was evaluated using a biomechanics-specific checklist developed by Hindle and colleagues (Sports Med Open. 5(1):49, 2019. 10.1186/s40798-019-0222-z). Results: Twenty-five studies met the eligibility criteria. While UUS velocity was nearly perfectly related (r > 0.90) to foot resultant acceleration and kick frequency, several other biomechanical factors were also significant correlates. UUS velocity and frequency were typically higher in high-performance swimmers and during prone versus dorsal positions. UUS velocity, kick frequency and kick amplitude were also significantly correlated with high angular velocities of the hip, knee and ankle joints and knee range of motion. Conclusion: While there appears to be evidence supporting some performance variables to be related to UUS, future research should examine how to optimise the kinematic and kinetic characteristics with respect to the imposed task constraints and organism constraints between swimmers. Additional research should also investigate the effect of biomechanically informed interventions to improve UUS performance. Registration: Open Science Framework. [ABSTRACT FROM AUTHOR]

Background: While chronic exercise training has been demonstrated to be an effective non-pharmacological treatment for chronic low back pain (CLBP), there has been a relative lack of evidence or clinical guidelines for whether a posterior chain resistance training programme provides any benefits over general exercise (GE). Objectives: To determine if chronic posterior chain resistance training (PCRT), defined as exercise programmes of ≥6 weeks duration focused on the thoracic, lumbar and hip extensor musculature, is more effective than GE in improving pain, level of disability, muscular strength and the number of adverse events in recreationally active and sedentary individuals with CLBP. Methods: Four electronic databases were systematically searched from 25 September 2019 until 30 August 2020. Using the Joanna Briggs Institute (JBI) Critical Appraisal Tools checklist for randomized controlled trials (RCTs), articles were critically appraised and compared against the inclusion/exclusion criteria. Standardized mean difference (SMD), risk difference (RD) and confidence interval (CI) were calculated using Review Manager 5.3. Results: Eight articles were included, with a total of 408 participants (203 PCRT, 205 GE). Both PCRT and GE were effective in improving a number of CLBP-related outcomes, but these effects were often significantly greater in PCRT than GE, especially with greater training durations (i.e. 12–16 weeks compared to 6–8 weeks). Specifically, when compared to GE, PCRT demonstrated a greater reduction in pain (SMD = − 0.61 (95% CI − 1.21 to 0.00), p = 0.05; I2 = 74%) and level of disability (SMD = − 0.53 (95% CI − 0.97 to − 0.09), p = 0.02; I2 = 52%), as well as a greater increase in muscle strength (SMD = 0.67 (95% CI 0.21 to 1.13), p = 0.004; I2 = 0%). No differences in the number of adverse events were reported between PCRT and GE (RD = − 0.02 (95% CI − 0.10 to 0.05), p = 0.57; I2 = 72%). Conclusion: Results of the meta-analysis indicated that 12–16 weeks of PCRT had a statistically significantly greater effect than GE on pain, level of disability and muscular strength, with no significant difference in the number of adverse events for recreationally active and sedentary patients with CLBP. Clinicians should strongly consider utilizing PCRT interventions for 12–16 weeks with patients with CLBP to maximize their improvements in pain, disability and muscle strength. Future research should focus on comparing the efficacy and adverse events associated with specific PCRT exercise training and movement patterns (i.e. deadlift, hip lift) in treating this population. Trial registration: PROSPERO CRD42020155700. [ABSTRACT FROM AUTHOR]

Background: Reductions in muscle size and strength occur with aging. These changes can be mitigated by participation in resistance training. At present, it is unknown if sex contributes to differences in adaptation to resistance training in older adults. Objective: The aim of this systematic review was to determine if sex differences are apparent in adaptations to resistance training in older adults. Design: Systematic review with meta-analysis. Data Sources: Web of Science; Science Direct; SPORTDiscus; CINAHL; and MEDLINE were searched from inception to June 2020. Eligibility Criteria: Studies where males and females older than 50 years of age performed identical resistance training interventions and had outcome measures of muscle strength or size. Results: We initially screened 5337 studies. 30 studies (with 41 comparison groups) were included in our review (1410 participants; 651 males, 759 females). Mean study quality was 14.7/29 on a modified Downs and Black checklist, considered moderate quality. Females gained more relative lower-body strength than males (g = − 0.21 [95% CI − 0.33, − 0.10], p = 0.0003) but there were no differences in relative change for upper-body strength (g = − 0.29 [95% CI − 0.62, 0.04], p = 0.08) or relative muscle size (g = 0.10 [95% CI − 0.04, 0.23], p = 0.16). Males gained more absolute upper-body strength (g = 0.48 [95% CI 0.09, 0.88], p = 0.016), absolute lower-body strength (g = 0.33 [95% CI 0.19, 0.47], p < 0.0001), and absolute muscle size (g = 0.45 [95% CI 0.23, 0.66], p < 0.0001). Conclusion: Our results indicate that sex differences in adaptations to resistance training are apparent in older adults. However, it is evident that the interpretation of sex-dependent adaptations to resistance training is heavily influenced by the presentation of the results in either an absolute or relative context. Study Registration: Open Science Framework (osf.io/afn3y/). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

The original article [1] contained an error whereby the symbol '☼' originally included in and below Tables 2–5 did not display properly. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: The ageing process and several health conditions may increase tremor and reduce force steadiness and dexterity, which can severely impact on function and quality of life. Resistance training can evoke a range of neuromuscular adaptions that may significantly reduce tremor and/or increase force steadiness and/or dexterity in older adults, irrespective of their health condition. Objectives: The objective of this study was to systematically review the literature to determine if a minimum of 4 weeks' resistance training can reduce postural tremor and improve force steadiness and/or dexterity in older adults, defined as aged 65 years and over. Methods: An electronic search using Ovid, CINAHL, SPORTDiscus and EMBASE was performed. Risk of bias was assessed using the Cochrane Risk of Bias Tool. Results: Fourteen studies met the eligibility criteria, including six randomised controlled trials and two quasi-randomised controlled trials. All eight studies that recruited healthy older adults reported significant reductions in postural tremor and/or improvements in force steadiness and dexterity. Five out of seven studies that examined older adults with a particular health condition reported some improvements in force steadiness and/or dexterity. Specifically, significant benefits were observed for older adults with chronic obstructive pulmonary disease and essential tremor; however, small or no changes were observed for individuals with osteoarthritis or stroke. Conclusions: Resistance training is a non-pharmacological treatment that can reduce tremor and improve force steadiness and dexterity in a variety of older adult populations. Future research should employ randomised controlled trials with larger sample sizes, better describe training programme methods, and align exercise prescription to current recommendations for older adults. [ABSTRACT FROM AUTHOR]

Our aim was to synthesise the existing empirical literature and theoretical perspectives on the physical activity (PA) promotion practices and determinants of cancer clinicians and health professionals. We conducted a narrative review of theory and evidence to develop practice recommendations for improving the promotion of PA to cancer patients. Surveyed health professionals were aware of many benefits of PA for their cancer patients, although only ~40 % promoted PA to selected cancer patients. Walking was the most commonly promoted form of PA, with this promoted to assist patients control their weight and cardiovascular health risk. Barriers to promotion of PA included lack of time and knowledge of PA and behaviour change skills. Health professionals appear interested in promoting PA to their cancer patients, yet encounter several barriers. Further research is warranted to assist health professionals improve their PA promotion. An adapted reflective-impulsive model of social behaviour shows promise for assisting health professionals overcome barriers and provides an evidence-based theoretical framework for improving communication with patients. Universities, hospitals and/or health-care accreditation organisations also have important roles to play in assisting health professionals improve their promotion of PA to patients. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

No sources of funding were used in the preparation of this article. [ABSTRACT FROM AUTHOR]