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Individuals with intellectual disabilities often face unique challenges in physical capabilities, making traditional training methods less effective for their specific needs. This study aimed to investigate the effect of combining balance, plyometric, and strength (CBPS) training with sprint training on physical performance in male athletes with intellectual disabilities. Twenty-seven participants were randomly assigned to either a CBPS group or a control group that only maintained their regular sprint training. Participants underwent pre- and posttraining tests, including measures of balance, jumping, agility, and sprinting ability. The results showed that the CBPS group demonstrated significant improvements (p <.05) in one-leg stance, crossover-hop jump, squat jump, countermovement jump, and 10- and 30-m sprint at posttraining compared with pretraining. CBPS training combined with sprinting significantly improves physical performance in male athletes with intellectual disabilities, suggesting implications for tailored training programs to enhance their physical fitness and overall health. [ABSTRACT FROM AUTHOR]

Context: Among many unanticipated changes, access to rehabilitation was disrupted during the onset of the COVID-19 pandemic. It is unclear how the timing of late-stage rehabilitation following anterior cruciate ligament with surgical reconstruction (ACLR) during the initial months of the pandemic affected outcomes. The purpose of this study was to compare physical performance outcome measures in patients following ACLR prior to and following COVID-19-related restrictions. Design: Retrospective cohort study. Methods: Data from patients who underwent return-to-sport testing following ACLR were analyzed based on date. December 2018 through March of 2020 (n = 66) was defined as the baseline period, and June through October 2020 (n = 27) was defined as the surveillance period. Outcome measures included single leg hop, triple hop, single leg vertical jump, and the lower-extremity functional test (LEFT). Linear mixed models were used to compare outcome measures before and after the onset of pandemic-related restrictions, clustered by sex and sport. A 1-way analysis of variance was performed to analyze the association between the number of virtual rehabilitation visits and outcome measures for subjects in the surveillance period. Results: Subjects in the surveillance period performed significantly worse in the LEFT (+7.88 s; 95% confidence interval, 1.11 to 14.66; P =.02) and single leg vertical jump on the unaffected side (−4.32 cm; 95% confidence interval, −7.44 to −1.19, P <.01), and performed better with single leg vertical jump symmetry (+6.3%; 95% confidence interval, 1.0% to 11.5%; P =.02). There were no other statistically significant differences. There was no significant association between having virtual rehabilitation visits and any of the performance outcomes. Conclusions: There was a decline in physical performance outcome measures in patients following ACLR who did not attend regular in-person physical therapy sessions in the late-stage rehabilitation due to COVID-19-related restrictions. Other factors during this unique time period, such as access to training facilities or psychosocial stressors, may have also influenced outcomes. [ABSTRACT FROM AUTHOR]

Objective: To rate athletes' functional ability and return to sport (RTS) success at the end of their individual, formal, medically prescribed rehabilitation after anterior anterior cruciate ligament (ACL) reconstruction. Methods: In our prospective multicenter cohort study, 88 (42 females) adults aged 18-35 years after acute unilateral ACL rupture and subsequent hamstring grafting were included. All patients were prospectively monitored during their rehabilitation and RTS process until the end of their formal rehabilitation and RTS release. As outcome measures, functional hop and jump tests (front hop, balance hops, and drop jump screening test) and self-report outcomes (Knee Injury and Osteoarthritis Outcome Score, ACL-RTS after injury) were assessed. Literature-based cut-off values were selected to rate each performance as fulfilled or not. Results: At 7.5 months (SD 2.3 months) after surgery, the percentage of participants meeting the functional thresholds ranged from 4% (Knee Injury and Osteoarthritis Outcome Score SPORT) and over 44% (ACL-RTS after injury sum score) to 59% (Knee Injury and Osteoarthritis Outcome Score activities of all daily living) in the self-report and from 29% (Balance side hop) to 69% (normalized knee separation distance) in performance testing. Only 4% fulfilled all the cut-offs, while 45% returned to the same type and level of sport. Participants who successfully returned to their previous sport (type and level) were more likely to be "over-cut-off-performers." Conclusions: The low share of the athletes who fulfilled the functional RTS criteria highlights the importance of continuing the rehabilitation measures after the formal completion to assess the need for and success of, inter alia, secondary-preventive therapies. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to quantify jump performance in children with cerebral palsy (CP) and determine if the expected deficit is related to their lower body joint kinetics and kinematics. Methods: Twenty-four ambulatory (n = 17 level I and 7 level II in the Gross Motor Function Classification System) children with spastic CP (n = 13 unilateral and 11 bilateral) and 24 age-, sex-, and race matched typically developing controls were studied. Jump height and peak power and range of motion at the hip, knee, and ankle of the more affected limb in children with CP and the nondominant limb in controls were assessed during a countermovement jump using three-dimensional motion capture and a force platform. Results: Compared with controls, children with CP had lower jump height (33%, Cohen's d (d) = 1.217), peak power at the knee (39%, d = 1.013) and ankle (46%, d = 1.687), and range of motion at the hip (32%, d = 1.180), knee (39%, d = 2.067), and ankle (46%, d = 3.195; all P < 0.001). Jump height was positively related to hip, knee, and ankle power and range of motion in children with CP (rs range = 0.474-0.613, P < 0.05), and hip and ankle power and knee and ankle range of motion in controls (rs range = 0.458-0.630, P < 0.05). The group difference in jump height was no longer detected when ankle joint power, ankle range of motion, or knee range of motion was statistically controlled (P > 0.15). Conclusions: Jump performance is compromised in children with CP and is associated with low power generation and range of motion in the lower limb, especially at the ankle. [ABSTRACT FROM AUTHOR]

The purpose of reporting on selected cases is to increase the recognition and treatment of mechanical joint dysfunction (restrictions in movement at the joint level) in pediatric patients. The selected cases demonstrate a variety of clinical outcomes that are possible using manual therapy to improve mechanical joint dysfunction and chronic pain. The techniques used for these patents were performed by a physical therapist without formal manual therapy training to encourage more physical therapists to use manual therapy as an intervention to improve outcomes in pediatric patients. The hands-on treatment used to treat mechanical joint dysfunction improved participation and function in children of various ages with a variety of clinical issues. : Recognizing and treating mechanical joint restrictions that interfere with active movement in children may result in decreased pain and improved motor skills, balance, self-regulation, sleep hygiene, and social interactions. Clinicians should consider manual therapy as an intervention strategy for pediatric patients with mechanical joint restrictions. [ABSTRACT FROM AUTHOR]

The primary aim was to examine the relationship between sprint acceleration performance and the performance tests: isometric squat (ISqT), countermovement jump (CMJ), and reactive strength index (RSI). The secondary aim determined whether these tests could distinguish between sprint performance levels. Twenty-six male under-21 subjects completed the ISqT, with peak force (PF), relative PF, force at 100, 150, and 200 milliseconds (ms), and impulse (0-200 ms) measured. Jump height (JH) was calculated from the CMJ and RSI during the 10-5 repeated jump test. Subjects completed 3 x 30-m sprints with splits taken at 5, 10, 20, and 30 m. Pearson's product moment correlations were used to assess the relationships between measures, and independent samples t tests were used to determine whether differences existed in sprint ability of those in the top and bottom quartiles forforce at 100 ms, CMJ, and RSI. Significant negative moderate correlations were reported between force at 100 ms and 0-5 m and 5-10 m, significant moderate and large negative correlations between CMJ and all splits and significant large correlations between RSI and splits over 5 m. Force at 100 ms distinguished between performance levels from 0 to 5 m, CMJ from 10 to 20 m, and RSI from 20 to 30 m; faster subjects produced significantly higher force, JHs, and RSI scores. Three principal components explaining 86.1% of the variation in the data set were identified: sprint times and stretch shortening cycle capabilities (33.3%), time-specific force (29.9%), and absolute and relative strength (22.8%). [ABSTRACT FROM AUTHOR]

The unique physical profile of each player's role in sub-elite women's cricket is vital for optimizing performance as these players progress to the elite levels. This quantitative, cross-sectional study investigates the physical profiles of sub-elite women's cricket players as a group and compares these profiles across different player roles. Sub-elite female cricket players in the South African domestic women's cricket league were included in this study. A battery of physical assessments were conducted at the start of the 2022/23 season. The physical assessments included body composition, individual muscle strength testing using dynamometry, 2-km time trial (TT), countermovement jump (CMJ), single-leg jump (SLJ), isometric mid-thigh pull, push-up, and hop test on force plates. A total of 44 female players (20.86 ± 1.6 years) were included in the study. Differences were found in muscle mass (p = 0.004) and peak power (p = 0.040) for all-rounders and bowlers. Player roles presented with different dominant (p = 0.006) and non-dominant (p = 0.066) knee flexion strength. The bowlers' body composition and physical strength profile are compromised compared with batters and all-rounders. There were several physical strength and power differences between pace and spin bowlers in CMJ and SLJ tests for jump height (p = 0.009) and peak power (p = 0.006). Batters performed the best in the 2-km TT. Body composition and musculoskeletal profiles for each player role can be baseline markers in sub-elite women's cricket. Stakeholders can use this information to guide physical preparation for players advancing to elite levels. [ABSTRACT FROM AUTHOR]

Maximum strength has a strong influence on speed-strength performances such as sprints and jumps. Important for sports practice is whether these findings are also reflected in game performance. Therefore, the aim of this study was to explore the influence of maximum strength and power performance on linear on-ice skating performance in testing and during game play. A cross-sectional study was conducted, and 24 highly trained male youth ice hockey players participated. Jump performances (countermovement jump [CMJ], drop jumps), maximum strength (1 repetition maximum [1RM] squat and isometric trap bar pull [ITBP]), and on-ice linear sprints (15 m [LS15], 30 m [LS30], flying 15 m [FLY15]) were measured. Match performances (among others: peak skating speed) were collected of 4 regular league games using a local positioning system. Correlation coefficient and explained variance were calculated (p # 0.05). Correlations between maximum strength and jump with on-ice linear sprint performance showed 1-35% explained variance. Correlations between "off ice" test (CMJ, relative 1RM) and game data (peak skating speed) showed 22-30% explained variance, respectively, while ITBP and DJ missed significant level. Between linear sprint and game performance showed 15-59% explained variance. In this study, a clear influence of 1RM in squatting and CMJ performance on on-ice linear sprint as well as in-game peak skating speed was observed. These findings show that strength and jumping performance can be valuable tests within a comprehensive test battery and indicate the relevance of strength and jumping tasks within the regular exercise program to improve in-game skating performance. [ABSTRACT FROM AUTHOR]

The aim of our study was to compare the effects of two different plyometric training programs (targeting knee extensors or plantar flexors) on jump height and strength of leg muscles. Twenty‐nine male basketball players were assigned to the knee‐flexed (KF), knee‐extended (KE), or control groups. In addition to regular training, the KF group performed plyometric jumps (10 sets of 10 jumps, 3 sessions/week, 4 weeks) from 50 cm boxes with the knee flexed (90°–120°), whereas the KE group performed the jumps from 30 cm boxes with the knee much more extended (130°–170°). Jumping ability was evaluated with squat jumps (SJs), countermovement jumps (CMJs), and drop jumps from 20 cm (DJ20) and 40 cm (DJ40). Knee and ankle muscles were assessed during maximal isokinetic and isometric tests, and EMG activity was recorded from vastus lateralis and medial gastrocnemius. The KF group increased SJ (+10%, d = 0.86) and CMJ (+11%, d = 0.70) but decreased DJ40 height (−7%, d = −0.40). Conversely, the KE group increased DJ20 (+10%, d = 0.74) and DJ40 (+12%, d = 0.77) but decreased SJ height (−4%, d = −0.23). The reactivity index during DJs increased (+10% for DJ20, d = 0.47; +20% for DJ40, d = 0.91) for the KE group but decreased (−10%, d = −0.48) for the KF group during DJ40. Plantar flexor strength increased for the KE group (d = 0.72–1.00) but not for the KF group. Negative transfer across jumps is consistent with the principle of training specificity. Basketball players interested to perform fast rebounds in their training should avoid plyometric jumps with large knee flexions and long contact times. Highlights: Plyometric training specificity: different jump techniques (knee flexed vs. knee extended) elicited specific adaptations in jumping performance. Training with the knees flexed improved squat jump and countermovement jump height, whereas training with the knees extended augmented drop jump height.Negative transfer: the different jump techniques can have a negative influence on jump height and reactivity index. Drop jump height declined after knee‐flexed training, whereas squat jump height decreased after knee‐extended training.Plyometric training exercises should be aligned with sport‐specific movements to optimize performance. Basketball players who perform fast, powerful movements should avoid plyometric jumps with large knee flexions and long contact times. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to investigate the relationship between metatarsophalangeal joint (MTPj) flexion torque and sprint acceleration, cutting and jumping performance, and kinetics. A secondary aim was to explore this relationship when MTP flexion strength was associated with other foot and lower limb neuromuscular outputs. After an initial MTPj flexion torque assessment using a custom-built dynamometer, 52 high-level athletes performed the following tasks on a force platform system: maximal sprint acceleration, 90-degree cutting, vertical and horizontal jumps, and foot-ankle hops. Their foot posture, foot passive stiffness and foot-ankle reactive strength were assessed using the Foot Posture Index, the Arch Height Index Measurement System and the Foot-Ankle Rebound Jump Test. Ankle plantarflexion and knee extension isometric torque were assessed using an isokinetic dynamometer. During maximal speed sprinting, multiple linear regressions suggested a major contribution of MTPj flexion torque, foot passive stiffness and foot-ankle reactive strength to explain 28% and 35% of the total variance in the effective vertical impulse and contact time. Ankle plantarflexor and quadriceps isometric torques were aggregately contributors of acceleration performance and separate contributors of cutting and jumping performance. In conclusion, MTPj flexion torque was more strongly associated with sprinting performance kinetics especially at high-speed. [ABSTRACT FROM AUTHOR]

There is limited research on female football players, especially related to their physical and cognitive performance under different climactic conditions. We analyzed the impact of a hot environmental temperature on physical performance and anticipation in elite female football players during a fatigue‐inducing intermittent protocol. Elite female players (n = 21) performed the countermovement jump (CMJ) and responded to filmed sequences of offensive play under two distinct environmental temperatures (i.e., mild environment temperature‐ 20°C and 30% rh versus hot environment temperature‐ 38°C and 80% rh), interspersed by 1‐week interval. Linear mixed models were used. CMJ performance declined following the intermittent protocol on both temperature conditions (p < 0.05). Moreover, there were significant main effects for protocol on CMJ speed (m/s) (p = 0.001; ηp2 = 0.12), CMJ power (p = 0.002; ηp2 = 0.11), and CMJ Heightmax (p = 0.002; ηp2 = 0.12). After performing the intermittent protocol, exposure to a hot temperature caused a greater decline in anticipation accuracy (mild temperature = 64.41% vs. hot temperature = 53.44%; p < 0.001). Our study shows impaired performance in elite female football players following an intermittent protocol under hot compared with mild environmental conditions. We report decreased performance in both CMJ and anticipation performance under hotter conditions. The results reveal that exposure to hot temperatures had a negative effect on the accuracy of their anticipatory behaviors. We consider the implication of the work for research and training interventions. [ABSTRACT FROM AUTHOR]

Up to 75% of marathon runners ingest non-steroidal anti-inflammatory drugs (NSAIDs) during competition. Despite the doubt whether or not they contribute to performance, the effect of NSAID in endurance sports is unclear. We evaluated the effect of ibuprofen (IBU) use on oxidative stress, muscle damage, physical performance, and vertical jump of runners participating in a 42-km-trail running. The sample consisted of 12 men randomly divided into 2 groups: a placebo group (placebo) and an ibuprofen group (IBG). A 400-mg IBU capsule was administered to the IBG 15 min prior to the start of the trial and during the course after 5 h. In the intergroup analysis, placebo 70.1% increase (p < 0.0001; Cohen's d = 4.77) of the thiobarbituric acid reactive substances (TBARS); the IBG exhibited a 31.46% increase of the sulphhydryl groups (SH) (p = 0.024, Cohen's d = 0.27), 55% of squat jump (SJ) (p < 0.01; Cohen's d = 1.41) with no significant effect on creatine kinase (CK), pace, speed, and finish time. In summary, IBU had positive evidence on oxidative stress and muscle fatigue, but had no effect on physical performance and muscle damage. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the influence of strength level between stronger and weaker handball players on handball specific fitness elements and to explore the correlations between strength and sport-specific fitness elements. Twenty-one professional male handball-players (age: 25.9 ± 6.9 years; mass: 87.9 ± 13.9 kg; height: 1.81 ± 0.08 m), participated in the study. Players were divided into the stronger (SG) and weaker group (WG) according to their relative to body mass 1 repetition maximum strength (1RM). Measurements included body composition, countermovement jump (CMJ), isometric leg extension peak torque (IPT) and rate of torque development (RTD), 5-step long-jump, 0-20 m linear sprint, T-half test, throwing velocity, and 1RM in bench press and squat. No significant difference was found for body composition between SG and WG (p > 0.05). However, SG had significantly higher CMJ height (21.5%, p = 0.002), IPT (22.4%, p = 0.008), RTD relative to body mass (p < 0.05), 5-step long jump (10.9%, p = 0.005), lower 0-20 linear sprint (-6.3%, p = 0.012), lower T-half test time trial (-7.3%, p = 0.001), and higher throwing velocity compared with WG (p < 0.05). When all players included in one group, large to very large correlations were found between 1RM strength and IPT with fat-free mass (r = 0.518-0.774) and throwing velocity (r = 0.472-0.819). Very large correlations were found between RTD with fat-free mass (r = 0.760) and throwing velocity (r = 0.780-0.835). Stronger players have greater performance in all handball-fitness attributes compared with their weaker counterparts. The significant correlations between handball-specific fitness elements with strength and RTD suggest that strength training is essential for handball players as it may link to higher on court performance. [ABSTRACT FROM AUTHOR]

The study was divided into 2 parts to investigate the acute postactivation performance enhancement (PAPE) responses to lower repetitions at the same load of 87% 1 repetition maximum (1RM) in the upper and lower body. In part 1, 14 athletes performed plyometric push-up (PPU) after the conditioning activity (CA) of bench press (BP). In part 2, 13 athletes performed a countermovement jump (CMJ) after the CA of parallel squat (PS). Subjects completed 3, 4, or 5 repetitions (trials CA-3, CA-4, or CA-5) of BP or PS in randomized and counterbalanced order. The velocity of each movement of the trial was recorded. The PPU or CMJ was tested every 2 minutes after the trial up to 12 minutes to assess the Post-Max and optimal individual PAPE time. The mean velocity of the last movement of BP in CA-5 was significantly lower than that in CA-3 (0.23 6 0.06 vs. 0.28 6 0.06 m·second-1, p, 0.05), and the velocity of PS in CA-4 or CA-5 was significantly lower than that in CA-3 (0.53 6 0.07 and 0.50 6 0.05 vs. 0.57 6 0.07 m·second-1, p, 0.05). The peak force of PPU and jump height of CMJ at Post-Max in the 3 trials were significantly greater than those at Pre (p, 0.05). There were no significant differences among trials in the optimal individual PAPE times in either part of the study. A single set of 87% 1RM resistance exercises with 3 or 4 repetitions in both the upper body and the lower body induces similar PAPE to repetition maximum. [ABSTRACT FROM AUTHOR]

This study compared the effects of a weekly lower body resistance‐training program divided into low frequency (LOW, one long session) versus high frequency (HIGH, four shorter sessions) in resistance‐trained individuals. Twenty‐two adults with more than 6 months resistance training experience were randomized to either the LOW or HIGH intervention group. Both groups completed an 8‐week training program consisting of four multi‐joint exercises targeting the hip and knee extensors. The program progressed from 12‐repetition maximum (RM) to 6‐RM, with 4–5 sets per exercise performed throughout the intervention. The four exercises were conducted either in one session or four sessions (one exercise per session) per week. 1‐RM in the squat, muscle thickness of the vastus lateralis, muscle mass of the lower body (measured using bioelectrical impedance), and jump height were assessed pre‐ and post‐intervention. The HIGH group demonstrated a statistically significant increase in 1‐RM compared to the LOW group (7 kg, p = 0.01), while no statistically significant differences were found between the groups for the other outcomes (p = 0.26–0.63). Both interventions resulted in statistically significant increases in 1‐RM squat (8 and 15 kg), muscle thickness (2.3 and 2.8 mm), and jump height (1.5 and 1.9 cm) from pre‐to post‐test. There were no statistical changes in lower‐body muscle mass for either group (p = 0.16–0.86). In conclusion, a weekly training protocol of four multi‐joint lower‐limb exercises distributed over four sessions resulted in greater increases in maximal strength compared to one session in resistance‐trained adults. Both frequencies were similarly effective in improving muscle hypertrophy and jump height. Highlights: Both high and low resistance training frequencies are viable options for increasing maximal strength, hypertrophy, and jump height.High resistance training frequency seems to favor lower limb muscle strength in trained adults.High and low resistance training frequencies lead to similar improvement in muscle hypertrophy and jump height in trained adults. [ABSTRACT FROM AUTHOR]

Background: Young athletes who specialize early in a single sport may subsequently be at increased risk of injury. While heightened injury risk has been theorized to be related to volume or length of exposure to a single sport, the development of unhealthy, homogenous movement patterns, and rigid neuromuscular control strategies may also be indicted. Unfortunately, traditional laboratory assessments have limited capability to expose such deficits due to the simplistic and constrained nature of laboratory measurement techniques and analyses. Methods: To overcome limitations of prior studies, the authors proposed a soccer-specific virtual reality header assessment to characterize the generalized movement regularity of 44 young female athletes relative to their degree of sport specialization (high vs low). Participants also completed a traditional drop vertical jump assessment. Results: During the virtual reality header assessment, significant differences in center of gravity sample entropy (a measure of movement regularity) were present between specialized (center of gravity sample entropy: mean = 0.08, SD = 0.02) and nonspecialized center of gravity sample entropy: mean = 0.10, SD = 0.03) groups. Specifically, specialized athletes exhibited more regular movement patterns during the soccer header than the nonspecialized athletes. However, no significant between-group differences were observed when comparing participants' center of gravity time series data from the drop vertical jump assessment. Conclusions: This pattern of altered movement strategy indicates that realistic, sport-specific virtual reality assessments may be uniquely beneficial in exposing overly rigid movement patterns of individuals who engage in repeated sport specialized practice. [ABSTRACT FROM AUTHOR]

BACKGROUND: Endurance training can have a negative impact on strength training and may lead to reduced strength gains, known as the interference effect. However, high-intensity interval training (HIIT) as an endurance training mode may reduce this interference effect. OBJECTIVE: This systematic review and meta-analysis aim to investigate the effects of concurrent HIIT and resistance training (RT) on lower body explosive strength and maximum strength. METHODS: Five electronic databases were searched. Subgroup analyses were performed to assess the effects of HIIT modality, training status, and training duration on strength development following concurrent HIIT and RT. RESULTS: Meta-analysis showed that compared to RT alone, concurrent HIIT and RT will not affect the development of countermovement jump (CMJ) (WMD = - 0.17, 95%CI = - 1.45 to - 1.11) and half squat (WMD = - 0.05, 95%CI = - 2.42 to 2.32). Further, subgroup analysis revealed that HIIT-running workout was conducive to the development of both CMJ and half squat. Longer training duration was found to be more effective in developing CMJ, while shorter training duration was more suitable for developing half squat. Additionally, athletes showed greater improvement than non-athletes. CONCLUSIONS: Combining HIIT and RT can enhance CMJ and half squat. The results of intervention are moderated by training variables and training status. [ABSTRACT FROM AUTHOR]

Context: Quadriceps strength is considered a key contributor to performance in various athletic tasks. Yet, past research has reported conflicting results based on population, with little data available in highly trained female athletes. Design: Cross-sectional. Method: To examine how athletic performance relates to quadriceps strength and neural function, we measured the quadriceps maximum voluntary isometric contraction force (MVIC) and rate of force development over 0 to 50 ms (rate of force development [RFD]0−50ms), and various performance measures in 34 highly trained female athletes. Results: Stepwise multiple regression analysis revealed that the quadriceps variables explained 16 of 21 performance variables (R2 =.08–.36, P ≤.10). Squat performance related to RFD0−50ms alone (R2 =.17–.20, P <.05; βRFD = 0.41 to 0.45, P <.05) but only MVIC explained the variance in sprinting and vertical jump performance (R2 =.08–.34, P ≤.10; βMVIC = −0.51 to 0.58, P ≤.10). The broad jump model included both parameters and their interaction (R2 =.20, P =.08; βRFD = 0.06, P =.76; βMVIC = −0.39, P =.03; βRFD×MVIC = −0.24, P =.10). Conclusion: The contribution of the quadriceps MVIC or RFD0–50ms varies in size and nature depending on the task or leg dominance. While quadriceps are significant contributors to performance, because our models leave most of the variance in performance unexplained, rehabilitation and performance professionals should refrain from interpreting peak athletic performance as a reflection of knee-extensors function in highly trained female athletes. [ABSTRACT FROM AUTHOR]

Unanticipated trunk perturbation is commonly observed when anterior cruciate ligament (ACL) injuries occur during direction-changing manoeuvres. This study aimed to quantify the effect of mid-flight medial-lateral external trunk perturbation directions/locations on ACL loading variables during sidestep cuttings. Thirty-two recreational athletes performed sidestep cuttings under combinations of three perturbation directions (no-perturbation, ipsilateral-perturbation, and contralateral-perturbation relative to the cutting leg) and two perturbation locations (upper-trunk versus lower-trunk). The pushing perturbation was created by customised devices releasing a slam ball to contact participants near maximum jump height prior to cutting. Perturbation generally resulted in greater peak vertical ground reaction force and slower cutting velocity. Upper-trunk contralateral perturbation showed the greatest lateral trunk bending away from the travel direction, greatest peak knee flexion and abduction angles, and greatest peak internal knee adduction moments compared to other conditions. Such increased ACL loading variables were likely due to the increased lateral trunk bending and whole-body horizontal velocity away from the cutting direction caused by the contralateral perturbation act at the upper trunk. The findings may help understand the mechanisms of indirect contact ACL injuries and develop effective cutting techniques for ACL injury prevention. [ABSTRACT FROM AUTHOR]

Changes in physiological markers and physical performance in relation to paratroopers' initial body composition were investigated during a 20-day winter military field training (MFT) and the subsequent 10-day recovery period. Body composition, serum hormone concentrations and enzymatic biomarkers, and physical performance of 58 soldiers were measured before, during, and after MFT. Comparisons were done according to soldiers' body fat percentage before MFT between low-fat (<12% body fat) and high-fat (>12% body fat) groups. Correlations between body fat percentage preceding MFT and changes in muscle mass, physical performance, and serum hormone concentrations and enzymatic biomarkers were investigated. It was hypothesized that soldiers with a higher fat percentage would have smaller decrements in muscle mass, physical performance, and serum testosterone concentration. The change in muscle and fat mass was different between groups (p < 0.001) as the low-fat group lost 0.8 kg of muscle mass and 2.0 kg of fat mass, while there was no change in muscle mass and a loss of 3.7 kg of fat mass in the high-fat group during MFT. Fat percentage before MFT correlated with the changes in muscle mass (R2 = 0.26, p < 0.001), serum testosterone concentration (R2 = 0.22, p < 0.001), and evacuation test time (R2 = 0.10, p < 0.05) during MFT. The change in muscle mass was correlated with the changes in evacuation test time (R2 = 0.11, p < 0.05) and countermovement jump test results (R2 = 0.13, p < 0.01) during MFT. Soldiers with a higher initial fat percentage lost less muscle mass, and had smaller decrements in some aspects of physical performance, as well as in serum testosterone concentration during MFT. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine acute stimulus and fatigue responses to combined accentuated eccentric loading and rest redistribution (AEL + RR). Resistance-trained men (n = 12,25.6 ± 4.4 years, 1.77 ± 0.06 m, and 81.7 ± 11.4 kg) completed a back squat (BS) 1 repetition maximum (1RM) and weight releaser familiarization session. Three BS exercise conditions (sets x repetitions x eccentric-concentric loading) consisted of (a) 3 x (5 x 2) x 110/60% (AEL + RR 5), (b) 3 x (2 x 5) x 110/60% (AEL + RR 2), and (c) 3 x 10 x 60/60% 1RM (traditional sets [TS]). Weight releasers (50% 1RM) were attached to every first repetition of each cluster set (every first, third, fifth, seventh, and ninth repetition in AEL + RR 5 and every first and sixth repetition in AEL + RR 2). The AEL + RR 5 resulted in greater total volume load (sets x repetitions x eccentric + concentric loading) (6,630 ± 1,210 kg) when compared with AEL + RR 2 (5,944 ± 1,085 kg) and TS (5,487 ± 1,002 kg). In addition, AEL + RR 5 led to significantly (p < 0.05) greater rating of perceived exertion (RPE) after set 2 and set 3 and lower blood lactate (BL) after set 3 and 5,15, and 25 minutes postexercise than AEL + RR 2 and TS. There was a main effect of condition for BL between AEL + RR 5 (5.11 ± 2.90 mmol⋅L-1), AEL+ RR 2 (6.23 ± 3.22 mmol⋅L-1), and TS (6.15 ± 3.17 mmol⋅L-1). In summary, AEL + RR 5 results in unique stimulus and fatigue responses. Although it may increase perceived exertion, coaches could use AEL + RR 5 to achieve greater back squat total volume load while reducing BL accumulation. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effects of power loss (PL) autoregulated volume (PL10 and PL20) with standardized fixed-load (FL) prescription on strength, sports performance, and lean body mass (LBM). Thirty-five female basketball players from a sports college were randomly assigned to 3 experimental groups (PL10, n = 12; PL20, n = 12; and FL, n = 11, respectively) that performed a resistance training (RT) program with wave-like periodization for 10 weeks using the back squat exercise. Assessments performed before (Pre) and after (Post) intervention included assessed 1 repetition maximum (1RM), body composition, 20-m sprint (T20M), change of direction (COD), and jump performance, including countermovement jump with arm swing, maximum vertical jump, and reactive strength index. Three groups showed significant improvements in strength (effect size [ES]: PL10 = 2.98, PL20 = 3.14, and FL = 1.90; p < 0.001) and jump performance (ES: PL10 = 0.74, PL20 = 1.50, and FL = 0.50; p <0.05-0.001). However, PL10 and PL20 demonstrated different advantages in sports performance compared with FL (group x time interaction, p <0.05). Specifically, PL10 significantly improved COD performance (ES = -0.79 ~ -0.53, p <0.01), whereas PL20 showed greater improvements in sprint (ES = -0.57, p <0.05) and jump performance (ES = 0.67-1.64, p <0.01-0.001). Moreover, PL10 resulted in similar gains to PL20 and beneficial improvements compared with FL in LBM, despite performing the least repetitions. Overall, the study indicates that power loss-based autoregulation induces greater gains in LBM and sports performance, as well as eliciting a higher efficiency dose response than standardized FL prescriptions, particularly for PL10. Therefore, incorporating PL monitoring in training programs is recommended, and further studies on power-based RT would be worthwhile. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine test‐retest reliability and concurrent validity of vertical force‐velocity‐power (FVP) profiles using Smith machine and free‐weight countermovement jumps (CMJs). A repeated‐measure cross‐over design with randomized load order and counterbalanced trials was employed. Sixteen resistance‐trained males (age: 26.4 ± 3.9 years, height: 179.6 ± 8.1 cm, body mass: 84.5 ± 10.8 kg) performed maximal loaded CMJs with 4–50 kg on six occasions, with three trials utilizing a Smith machine and three utilizing free‐weights. Jump height was estimated with a linear‐position transducer, and the Samozino computation method estimated theoretical maximal jump parameters. Reliability and concurrent validity were determined for jump height for each jump load and estimated theoretical maximal jump parameters using estimates of bias (mean difference, 95% limits of agreement) and agreement (intraclass correlation coefficients, ICCs). The jump height and maximum theoretical power demonstrated good‐to‐excellent reliability between sessions for both methods (ICC: 0.872–0.947) and concurrent validity between methods (ICC: 0.885–0.969). However, reliability for theoretical maximal force, velocity, and force‐velocity gradient was not as high using either method (ICC = 0.320–0.615) and concurrent validity was poor (ICC: 0.122–0.340). In summary, using both jump methods, a linear‐position transducer provides reliable jump height and theoretical maximal power values. However, our data do not support the reliability or validity of FV relationships using linear position transducers. Highlights: Countermovement jump (CMJ) height can be reliably assessed with a linear‐position transducer when adding mass (4–50 kg) with either a Smith machine or free‐weights.Theoretical maximum force, velocity, and force‐velocity gradients derived from the Smith machine and free‐weights are neither reliable, nor consistent between methods.Smith machine and free‐weight CMJ methods cannot be used interchangeably to develop force‐velocity‐power profiles with a linear position transducer. [ABSTRACT FROM AUTHOR]

Vertical jump is an important skill that influences volleyball performance. In this study, we analyzed the relationship between vertical jump performance and birth quartile of Brazilian male youth volleyball players. We calculated chi-square goodness-of-fit tests to compare the athletes' birthdate distributions in quarters of their birth years (Q1, Q2, Q3, and Q4) according to player age categories (U17, U18, U19, and U21). We calculated one-way ANOVAs to compare spike jump and block jump heights of players born in different quarters of the same year. Overall, we found a relative age effect (i.e., more players with birth dates early in the birth year) in U17 (p <.001), U18 (p <.001), U19 (p <.001), and U21 (p =.04). Regarding vertical jump performance, U18 athletes born in Q2 reached higher spike jump heights (p =.006) and block jump heights (p =.002) than athletes born in Q4, and U19 athletes born in Q1 reached higher block jump heights than athletes born in Q3 (p =.049). There were no significant differences in vertical jump performance across birth quartiles among U17 and U21 athletes. Thus, a relative age effect was present in all age categories but not always reflected in vertical jump performance. Volleyball coaches and policymakers are still advised to employ strategies to ensure fairer opportunities for players born later in the year of their eligibility dates, as we found RAE to be sometimes, but not always, related to higher spike or block jump heights even among these older adolescents and young adult athletes. [ABSTRACT FROM AUTHOR]

This study aims to investigate the inrun position in ski-jumping, in search for factors increasing the inrun speed without compromising the take-off. The inrun position of eight World Cup (WC) and fifteen Continental Cup (COC) ski jumpers were investigated in a wind tunnel at NTNU. A preferred position, replicating a jumper's position in competition, was measured for each athlete. Improvements, based on common sense aerodynamics, with the aim to improve the aerodynamic drag were executed. The aerodynamically best of these was compared with the preferred position. A numerical model simulating the inrun speed in ski-jumping hills was used to evaluate the impact the results will have in different hill sizes, for comparisons of drag measurements and inrun speed in competitions. In the preferred position, COC had 15.5% higher drag area than the WC athletes. In their best tested position, a group difference of 10.8% was found. These differences correspond with speed differences between 0.4 and 1.3 kmh−1, or 1–3 gates (as found by the numerical model). Group difference in drag was explained by a larger trunk angle for COC. Both groups improved from their preferred to their best position, due to reductions in thigh and leg angle. [ABSTRACT FROM AUTHOR]

The purpose was to evaluate reliability of measurements during drop jump (DJ) and magnitude of differences in vertical jump height (VJH) when calculated using two variables: time-in-the-air and center-of-mass velocity. Thirty-seven handball players performed three single-leg and double-leg DJs on a portable force plate during two sessions. Sixteen outcome measures and four sets of reliability metrics, including intraclass correlation coefficients (ICCs), were estimated. All outcome measures, except vertical time-to-stabilization, yielded high (0.70–0.89) to very high (0.90–0.96) interday and intraday ICCs for the single-leg and double-leg DJ tests. These results indicated that the single-leg and double-leg DJ tests can be considered reliable for short-term and long-term monitoring of collegiate handball players of both sexes. In addition, the single-leg DJ VJH calculated using these two variables differed in magnitude (mean difference in test measurements: 0.64 cm, p <.001, effect size: 0.165). Therefore, we recommend using the same method to calculate single-leg VJH for long-term monitoring. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to evaluate patellar tendon loading profiles (loading index, based on loading peak, loading impulse, and loading rate) of rehabilitation exercises to develop clinical guidelines to incrementally increase the rate and magnitude of patellar tendon loading during rehabilitation. Methods: Twenty healthy adults (10 females/10 males, 25.9 ± 5.7 yr) performed 35 rehabilitation exercises, including different variations of squats, lunge, jumps, hops, landings, running, and sports specific tasks. Kinematic and kinetic data were collected, and a patellar tendon loading index was determined for each exercise using a weighted sum of loading peak, loading rate, and cumulative loading impulse. Then the exercises were ranked, according to the loading index, into tier 1 (loading index ≤0.33), tier 2 (0.33 < loading index <0.66), and tier 3 (loading index ≥0.66). Results: The single-leg decline squat showed the highest loading index (0.747). Other tier 3 exercises included single-leg forward hop (0.666), single-leg countermovement jump (0.711), and running cut (0.725). The Spanish squat was categorized as a tier 2 exercise (0.563), as was running (0.612), double-leg countermovement jump (0.610), single-leg drop vertical jump (0.599), single-leg full squat (0.580), double-leg drop vertical jump (0.563), lunge (0.471), double-leg full squat (0.428), single-leg 60° squat (0.411), and Bulgarian squat (0.406). Tier 1 exercises included 20 cm step up (0.187), 20 cm step down (0.288), 30 cm step up (0.321), and double-leg 60° squat (0.224). Conclusions: Three patellar tendon loading tiers were established based on a combination of loading peak, loading impulse, and loading rate. Clinicians may use these loading tiers as a guide to progressively increase patellar tendon loading during the rehabilitation of patients with patellar tendon disorders and after anterior cruciate ligament reconstruction using the bone–patellar tendon–bone graft. [ABSTRACT FROM AUTHOR]

BACKGROUND: The restoration and management of the uninvolved side have been emphasized to prevent a second anterior cruciate ligament (ACL) injury and to ensure that athletes return to sports after ACL reconstruction. OBJECTIVE: To determine the factors influencing the single leg hop test (SLHT) and single leg vertical jump test (SLVJT) at 1 year postoperatively after ACL reconstruction in both the involved and uninvolved sides. METHODS: Ninety-four patients who underwent ACL reconstruction were assessed at 1 year postoperatively. Multiple regression models included eight independent variables with two dependent variables (SLHT and SLVJT.), each on the involved and uninvolved side. RESULTS: On the involved side, the Y balance test (YBT), extensor peak torque per body weight (PT/BW), Biodex balance system anteroposterior index (BBS-API), and sex accounted for 53.9% of the variance in SLHT (P = 0.002), and extensor PT/BW and YBT accounted for 26.3% of the variance in SLVJT (P = 0.027). On the uninvolved side, YBT, sex, age, BBS-API, and flexor PT/BW accounted for 47.0% of the variance in SLHT (P = 0.046), and flexor PT/BW, YBT, and age accounted for 44.9% of the variance in SLVJT (P = 0.002). CONCLUSION: Knee extensor strength on the involved side and flexor strength on the uninvolved side influence the two functional performance tests. The YBT was an important factor in the two functional performance tests in both sides. Anteroposterior stability was the only factor that influenced the SLHT bilaterally. [ABSTRACT FROM AUTHOR]

The primary objective of this systematic review with meta-analysis is to methodically discern and compare the impact of diverse warm-up strategies, including both static and dynamic stretching, as well as post-activation potentiation techniques, on the immediate performance of gymnasts. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this paper evaluated studies that examined the gymnasts' performance after different warm-up strategies namely stretching (static [SS] or dynamic), vibration platforms (VP) or post-activation, in comparison to control conditions (e.g., mixed warm-up routines; no warm-up). The principal outcomes were centered on technical performance metrics (e.g., split, gymnastic jumps) and physical performance metrics (e.g., squat jump, countermovement jump, drop jump, balance, range of motion). Methodological assessments of the included studies were conducted using the Downs and Black Checklist. From the initial search across PubMed, Scopus, and the Web of Science databases, a total of 591 titles were retrieved, and 19 articles were ultimately incorporated in the analysis. The results revealed a non-significant differences (p > 0.05) between the SS condition and control conditions in squat jump performance, countermovement jump and gymnastic technical performance (e.g., split; split jump). Despite the difference in warm-up strategies and outcomes analyzed, the results suggest that there is no significant impairment of lower-limb power after SS. Additionally, technical elements dependent on flexibility appear to be enhanced by SS. Conversely, dynamic stretching and VP seem to be more effective for augmenting power-related and dynamic performance in gymnasts. [ABSTRACT FROM AUTHOR]

McAuley, ABT, Hughes, DC, Tsaprouni, LG, Varley, I, Suraci, B, Bradley, B, Baker, J, Herbert, AJ, and Kelly, AL. Genetic associations with acceleration, change of direction, jump height, and speed in English academy football players. J Strength Cond Res 38(2): 350-359, 2024--High-intensity movements and explosive actions are commonly assessed during athlete development in football (soccer). Although many environmental factors underpin these power-orientated traits, research suggests that there is also a sizeable genetic component. Therefore, this study examined the association of 22 single-nucleotide polymorphisms (SNPs) with acceleration, change of direction, jump height, and speed in academy football players. One hundred and forty-nine, male, under-12 to under-23 football players from 4 English academies were examined. Subjects performed 5-, 10-, 20-, and 30-m sprints, countermovement jumps (CMJs), and the 5-0-5 agility test. Simple linear regression was used to analyze individual SNP associations, whereas both unweighted and weighted total genotype scores (TGS; TWGS) were computed to measure the combined influence of all SNPs. To control for multiple testing, a Benjamini-Hochberg false discovery rate of 0.05 was applied to all genotype model comparisons. In isolation, the GALNT13 (rs10196189)Gallele and IL6 (rs1800795) G/G genotype were associated with faster (;4%) 5-, 10-, and 20-m sprints and higher (;16%) CMJs, respectively (p, 0.001). Furthermore, the TGS and TWGS significantly correlated with all performance assessments, explaining between 6 and 33% of the variance (p, 0.001). This study demonstrates that some genetic variants are associated with power-orientated phenotypes in youth football players and may add value toward a future polygenic profile of physical performance. [ABSTRACT FROM AUTHOR]

Cornejo-Daza, PJ, Villalba-Fernández, A, González-Badillo, JJ, and Pareja-Blanco, F. Time course of recovery from different velocity loss thresholds and set configurations during full-squat training. J Strength Cond Res 38(2): 221-227, 2024--The aims of the research were to examine the effects of (a) velocity loss (VL) thresholds and (b) set configuration, traditional or cluster, on timecourse recovery. A randomized cross-over research design was conducted, in which 15 resistance-trained men performed 4 protocols consisting of 3 sets of 70% 1RM in full squat (SQ), differing in the VL incurred during the set assessed with a linear velocity transducer: (a) 20% (70-20), (b) 30% (70-30), (c) 40% (70-40), and in the set configuration (d) 20% of VL using a cluster methodology (70-CLU). Movement velocity against the load that elicited a 1 m·s21 velocity at baseline measurements (V1-load) in SQ, countermovement jump (CMJ) height, and sprint time in 20 m (T20) were assessed at baseline (Pre) and postintervention (Post, 6 hour-Post, 24 hour-Post, and 48 hour-Post). The 70-20 protocol resulted in fewer total repetitions than the other protocols (p 5 0.001), whereas 70-CLU, 70-30, and 70-40 completed similar total repetitions. The 70-30 protocol significantly worsened T20 at 6 hours-Post, CMJ at 48 hours-Post, and V1-load at 6 hours-Post (p < 0.05). The 70-40 protocol significantly impaired T20 at 6 hours-Post, and CMJ and V1-load at 24 hours-Post (p, 0.05). No significant performance reductions were observed for 70-20 and 70-CLU at 6 hours-Post, 24 hours-Post, and 48 hours-Post. Protocols with higher VL resulted in more pronounced fatigue and a slower rate of recovery. Cluster sets (70-CLU) resulted in higher volume than protocols with a similar level of fatigue (70-20) and a quicker recovery than protocols with a similar volume (70-30 and 70-40). [ABSTRACT FROM AUTHOR]

The effects of low‐load resistance exercise combined with external limb compression (ELC) to augment post‐activation performance enhancement during countermovement jumps have yet to be examined. We assessed the separate and combined effects of ELC and sets of low‐load (back squats) resistance exercise (both compared with controls) during conditioning routines, and determine their subsequent neuromechanical consequences during countermovement jumps. On separate days, twenty strength‐trained men completed a familiarization session followed by four experimental trials in a randomized design that included one of the following conditioning routines: passive rest (Control [CON], no occlusion/standing), exercise (sets of low‐intensity resistance exercise [RE] with 30% 1RM, no occlusion/exercise), ELC ([ELC] at 80% of the individual arterial occlusion pressure, occlusion/standing), and combined ELC and exercise ([ELC + RE], occlusion/exercise). Countermovement jump performance (jump height, relative peak power output, vertical impulse, and rate of force development) was assessed at baseline, immediately after, and at the third, sixth, ninth and twelfth minute following each conditioning routine. Compared to baseline, jump height, relative peak power output and vertical impulse values were lower at 0 min for [RE] (−3.5%–8.2%; p ≤ 0.014) and higher at +3 min for [ELC] (+2.0%–3.8%; p ≤ 0.013). Regarding [ELC + RE], values for these three variables were lower at 0 min (−4.8%–8.0%; p < 0.001) but higher at +12 min (+2.9%–5.5%; p < 0.001) versus baseline. In strength‐trained men, using ELC either alone (while standing) or combined with low‐load resistance exercise sets (during back squats) can be a useful way to improve CMJ mechanics. However, the duration and magnitude of post‐activation potentiation performance benefits varied depending on the type of ELC protocol used. Highlights: Athletes can incorporate external limb compression while standing into their conditioning routine, yet they should be aware that the enhancement may take up to 3 min to manifest.Another effective solution is to combine external limb compression and low‐load resistance exercise sets but enhancement would not appear until after 12 minutes.Low‐load resistance exercise alone does not yield any positive effects and led to an immediate decrease in countermovement jump performance, thus it is not recommended.Athletes should monitor their own countermovement jump performance data to assess the individual nature of post‐activation performance enhancement responses. [ABSTRACT FROM AUTHOR]

Context: Identifying gender-specific differentiation in each sport type is significant. In this way, sport- and gender-specific gains can be predicted. Therefore, this study aimed to examine the effects of skiing on physical performance, pain, quality of life, and gender-based differentiation. Design: Crossover trial. Methods: Sixty-eight volunteers, between 18 and 25 years of age, with no history of severe trauma in the spine and extremities, participated in our study. The skiers group consisted of licensed athletes (17 males and 17 females) who did active skiing for at least the past 2 years, the control group consisted of nonathletic and age-matched participants with no skiing experience (17 males and 17 females). Step test, vertical jump test, Flamingo balance test. hand-grip strength, and back-leg-chest strength measurements were performed to evaluate physical performance. Visual Analog Scale, McGill Pain Questionnaire, and Oswestry Low Back Pain Disability Questionnaire were used to evaluate pain experience. Quality of life was evaluated with Short Form-36 (SF-36). Results: Compared to the sedentary controls. VAS-activity and Oswestry Disability Index scores were lower: and aerobic performance. balance. hand-grip strength, back-leg-chest strength, and quality of life (SF-36-general health, SF-36-vitality, SF-36-mental health, and SF-total score) were higher iii skiers. Skiing was found to be effective in eliminating gender-based differentiation of the variables of hand-grip strength. pain, and quality of life: however, back-leg-chest strength and anaerobic performance variables were found to be ineffective in eliminating gender differentiation. Conclusions: Skiing allows that the individual increases physical performance and quality of life. It can also minimize gender-based differentiation of certain variables, such as muscular force, pain, and quality of life. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to compare functional movement screen (FMS) scores and drop vertical jump (DVJ) kinematics between those with and without anterior cruciate ligament reconstruction (ACLR), and to evaluate the association between FMS composite score and DVJ kinematics. Design: Cross-sectional. Participants: Sixty individuals with and without a history of ACLR. Main Outcome Measures: Composite FMS score and the dorsiflexion, knee-flexion, hip-flexion, knee abduction, hip adduction, and trunk-flexion angles during a DVJ. Results: The FMS scores did not differ between groups (P > .05). There were smaller peak and initial contact hip-flexion angles in the ACLR and contralateral limbs compared with controls, and smaller peak dorsiflexion angles in the ACLR compared with contralateral limbs (P < .05). Lower FMS score was associated with a smaller peak dorsiflexion angle, smaller peak knee-flexion angle, and larger peak knee abduction angle in the ACLR limb (ΔR² = .14-.23); a smaller peak dorsiflexion angle and smaller peak knee-flexion angle in the contralateral limb (ΔR² = .17-.19); and a smaller peak dorsiflexion angle, smaller peak knee-flexion angle, and larger peak knee abduction angle in the control limb (ΔR² = .16-.22). Conclusion: The FMS scores did not differ between groups, but were associated with DVJ kinematics and should be a complementary rather than substitute assessment. [ABSTRACT FROM AUTHOR]

Context: Lower-extremity musculoskeletal injury is commonly associated with poor movement patterns at the trunk, hip, and knee. Efforts have been focused on identifying poor lower-extremity movement using clinically friendly movement assessments, such as rubrics and 2D measures. Assessments used clinically or for research should have acceptable measurement properties, such as reliability and validity. However, the literature on reliability and validity of movement assessments to analyze jump landings has not been summarized. Objective: To systematically review measurement properties of rubrics and 2D measurements that aim to classify movement quality during jump landings. Evidence Acquisition: The search strategy was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The search was performed in PubMed, SPORTDiscus, and Web of Science databases. The COnsensus-based Standards for the selection of health Measurement INstruments multiphase procedure was used to extract relevant data, evaluate methodological quality of each study, score the results of each movement assessment, and synthesize the evidence. Evidence Synthesis: Twenty-two studies were included after applying eligibility criteria. Reliability and construct validity of the landing error scoring system were acceptable. Criterion validity of 2D knee flexion angle and medial knee displacement is acceptable. Reliability of 2D knee ankle separation ratio and knee frontal plane projection angle are acceptable. Conclusion: The landing error scoring system is a valid way to determine poor movement quality and injury risk. Measures of 2D knee flexion angle and medial knee displacement are valid alternatives for 3D knee flexion angle and knee abduction moment, respectively. Knee ankle separation ratio and knee frontal plane projection angle are reliable but lack validity justifying their clinical use. [ABSTRACT FROM AUTHOR]

The main purpose of the study was to establish, whether future cardiorespiratory fitness might be predicted by the level of muscular fitness at baseline. In this 3-year follow-up study, we recruited 240 secondary school girls at the age of 15 y, who were followed until the age of 17 y. Muscular fitness included the following tests: (i) standing broad jump (cm), (ii) sit-ups in 60 s (#) and (iii) squats in 60 s (#). Cardiorespiratory fitness was split into aerobic endurance (the 800-m run test) and speed endurance (the 400-m run test). Better performances in the 800-m run and the 400-m run tests at follow-up were correlated with higher levels of standing broad jump, sit-ups and squats in 60 s measured at baseline. In regression models adjusted for fat mass and maturity offset, standing broad jump, sit-ups and squats in 60 s were positively associated with the 800-m run test, while only standing broad jump remained significantly and positively associated with the 400-m run test. These data suggest that interventions enhancing muscular fitness should be recommended, as the effects are likely to be associated with future cardiorespiratory fitness in adolescent girls. [ABSTRACT FROM AUTHOR]

This systematic review investigates influences of mobility training in sporting populations on performance outcomes. The search strategy involved Embase, MEDLINE Complete, Sports Discus and manual search from inception to March 2022. Mobility training studies with a minimum three-week, or 10-session duration in healthy sporting populations of any age were included. Twenty-two studies comprising predominantly young adult or junior athletes were analysed from 319 retrieved articles. Performance outcomes were strength, speed, change of direction, jumping, balance, and sport-specific skills. Fifteen studies randomized participants with only four indicating systematic allocation concealment and blinding of outcomes assessors in only one study. In 20 of 22 studies mobility training was of some benefit or helped to maintain sports performance to a larger degree than control conditions. Control conditions, which were generally no activity conditions, were primarily non-significant. The majority of evidence suggests that a range of mobility training methods may improve key sports performance variables or are unlikely to impair performance over time. Therefore, coaches can consider the potential benefits of including comprehensive mobility programmes with minimal risk of impairing performance. Higher-quality studies in homogenous populations are necessary to confirm performance changes. [ABSTRACT FROM AUTHOR]

Purpose: The current biomechanical research on the application of Kinesio taping (KT) to patients with chronic ankle instability (CAI) has focused on testing the expected movements. However, unexpected movements are more common in actual sports. Therefore, the present study aimed to investigate the effects of KT on the biomechanical characteristics of the knee and ankle joints during unexpected jumping movements. Methods: Twenty‐one patients with unilateral CAI were recruited to capture the biomechanical parameters during unexpected jumping movements under different interventions: no taping (NT), placebo taping (PT), and KT. A one‐way repeated measures analysis of variance was used to compare the differences in knee and ankle biomechanical characteristics among patients with CAI between the three intervention conditions. Results: At initial contact, the KT group demonstrated a significant decrease in ankle plantarflexion and knee flexion angles compared to the NT group (p < 0.05). At the early landing phase, the KT group had a significant increase in peak ankle dorsiflexion angle, peak ankle eversion angle, peak ankle dorsiflexion moment, and peak ankle eversion moment compared to the NT and PT groups (p < 0.05). Furthermore, the KT group had a significantly reduced peak knee flexion angle, peak knee eversion angle, and peak vertical ground reaction force (p < 0.05) compared to the NT and PT groups. Conclusion: KT significantly improves the sprain‐prone touchdown posture of patients with CAI. And reducing the risk of ankle sprains during the early landing phase by promoting ankle dorsiflexion and eversion angles and moments. [ABSTRACT FROM AUTHOR]

Despite the importance of the developing cerebellum on cognition, the associations between physical fitness and cerebellar volume in adolescents remain unclear. We explored the associations of physical fitness with gray matter (GM) volume of VI, VIIb and Crus I & II, which are cerebellar lobules related to cognition, in 40 (22 females; 17.9 ± 0.8 year‐old) adolescents, and whether the associations were sex‐specific. Peak oxygen uptake (V̇O2peak) and power were assessed by maximal ramp test on a cycle ergometer, muscular strength with standing long jump (SLJ), speed‐agility with the shuttle‐run test (SRT), coordination with the Box and Block Test (BBT) and neuromuscular performance index (NPI) as the sum of SLJ, BBT and SRT z‐scores. Body composition was measured using a dual‐energy X‐ray absorptiometry. Cerebellar volumes were assessed by magnetic resonance imaging. V̇O2peak relative to lean mass was inversely associated with the GM volume of the cerebellum (standardized regression coefficient (β) = −0.038, 95% confidence interval (CI) ‐0.075 to 0.001, p = 0.044). Cumulative NPI was positively associated with the GM volume of Crus I (β = 0.362, 95% CI 0.045 to 0.679, p = 0.027). In females, better performance in SRT was associated with a larger GM volume of Crus I (β = −0.373, 95% CI ‐0.760 to −0.028, p = 0.036). In males, cumulative NPI was inversely associated with the GM volume of Crus II (β = −0.793, 95% CI ‐1.579 to −0.008 p = 0.048). Other associations were nonsignificant. In conclusion, cardiorespiratory fitness, neuromuscular performance and speed‐agility were associated with cerebellar GM volume, and the strength and direction of associations were sex‐specific. [ABSTRACT FROM AUTHOR]

This study aimed to examine whether a conditioning activity (CA) performed by the legs (barbell back squat) may cause postactivation performance enhancement (PAPE) on muscle groups other than leg extensors in isokinetic (eccentric [ECC] and concentric [CON]) and dynamic movement. Twelve male basketball players (age: 21.3 6 3.2, body mass: 89.6 6 14.1 kg, height: 187.464.6 cm, and 1 repetition maximum (1RM) barbell back squat: 113621 kg) with previous resistance-training experience of at least 2 years, performed 3 sets of 3-4 repetitions of back-squats with submaximal load (60, 90, and 90% 1RM) as CA. Before and after the CA, they performed pretest and post-test in the form of countermovement jumps (CMJs) (localized) or explosive push-ups (EPUs) (nonlocalized) along with isokinetic flexion and extension at the knee (localized) or at the elbow (nonlocalized). The localized and nonlocalized protocols were divided into 2 days in a randomized order. The back squat as CA significantly increased peak torque (PT) (p, 0.05) in all CON and ECC muscle actions and average power per repetition (APPR) (p, 0.05) (all muscle actions except ECC flexion) of the localized isokinetic tests with large (.0.8) and medium (0.4-0.79) effect sizes and significantly decreased (p, 0.01) the PT and APPR (p, 0.01) of the nonlocalized isokinetic test in the ECC flexion. The CMJ and EPU tests showed no significant differences (p. 0.05) between premeasures and postmeasures of take-off height. The effect of PAPE seems to be specific to the muscles most involved in the CA, and the CA inhibits PT of subsequent muscle ECC contractions in muscles not involved in the CA. [ABSTRACT FROM AUTHOR]

The aim of this brief study was to investigate the effects of repeated jump testing on performance over 2 consecutive days while considering the possibility of diurnal changes. Fourteenmale subjects and 14 recreationally active female subjects completed countermovement jump (CMJ) and squat jump (SJ) testing on 5 occasions (baseline [0,800], 5 minutes [0,820], 8 hours [1,600], 24 hours [0,800], and 32 hours [1,600]) over 32 hours. An additional rested baseline test was conducted on a separate day in the afternoon (1,600) to compare jump performance between morning and afternoon baseline values. Excluding small decreases in CMJ height at 24 hours (p50.292, Cliff's delta520.225) in male subjects and similar decreases in CMJ height at 5 minutes (p 5 0.034, Cliff's delta 5 20.245) in addition to SJ height:contraction time at 32 hours (p 5 0.126, Cliff's delta5 0.153) in female subjects, findings generally showed no changes in jump performance over multiple assessments. Squat jumpmetrics may have showed small improvements betweenmorning and afternoon baseline values inmale subjects (SJ height:contraction time [p50.030, Cliff's delta50.225]) and female subjects (SJ height [p50.013, Cliff's delta50.173] and SJ height:contraction time [p50.091, Cliff's delta50.163)]. As jump performance was largely unaffected by repeated jump testing, the present findings support the use ofmonitoring practices and research designs that require multiple jump assessments within acute periods (;32 hours). [ABSTRACT FROM AUTHOR]

The aim of this study was to examine responses at 3 and 27 hours after low-load jump squat (LL) and maximal isometric half-squat (ISO) priming stimuli. Fifteen resistance-trained males performed LL (4 3 3 at 20% 1 repetition maximum [1RM]), ISO (4 3 3 seconds), and control (CON) activities (standardized warm-up) in a randomized and counterbalanced order. Countermovement jump (CMJ) and isometric midthigh pull tests were conducted to assess performance changes after priming and CON activities. No clear changes in CMJ measures were found after priming activities compared with CON. However, small effect size improvements were found after priming stimuli completed on the same day. A 2.9% decrease in concentric phase duration (CI 5 0.3-5.9, p 5 0.333, Cliff's delta520.156) and a 9.1% increase in RSImod (CI 50.2-12.3, p50.151, Cliff's delta520.218) occurred at 3 hours after LL compared with CON. Braking phase duration (CI 5 0.8-10.6, p 5 0.333, Cliff's delta520.213) was 2.9% shorter at 3 hours after ISO compared with CON. No clear changes in isometric peak force occurred after priming activities compared with CON. Additionally, questionnaires were completed to assess perceptual state and perceived effectiveness of the priming stimulus to influence performance. An increase in the "effect of activity" was perceived at 3 hours after LL and ISO (p 5 0.013-0.044, Cliff's delta 5 0.578-0.6) and at 27 hours after ISO (p 5 0.99, Cliff's delta 5 0.173) compared with CON. An increase in "muscular heaviness" was also reported at 3 hours after ISO compared with CON (p 5 0.199, Cliff's delta 5 0.320). The collective findings suggest limited benefits over the day after LL and ISO priming stimuli. However, as there was substantial variation in individual responses, the relative nature of priming responses should be considered when prescribing similar strategies in practical environments. [ABSTRACT FROM AUTHOR]

Considering the growing prevalence of commercial force plates providing automated force-time analyses, understanding levels of agreement across force plate systems is warranted. Countermovement jump (CMJ) metrics across Vald ForceDecks (FD), Hawkin Dynamics (HD), and Sparta Science (SS) force plate systems were compared. Twenty-two subjects completed CMJ testing (â128 comparisons) on each force plate system separately with rest between jumps. Baseline testing occurred 3 times and demonstrated poor test-retest reliability for modified reactive strength index (mRSI) and rate of force development (RFD). ForceDecks and HD comparisons yielded acceptable agreement for concentric/propulsive relative force and net impulse, jump height, eccentric/braking RFD, and mRSI, but systematic and proportionate bias existed for RFD. Sparta Science jump height and reactive strength index (RSI) demonstrated systematic overestimations compared with HD and FD, but jump height had acceptable agreement according to concordance correlation coefficients (CCC = 0.92-0.95). Agreement between SS load (eccentric RFD) and HD braking RFD was acceptable (CCC = 0.91), whereas agreement between SS load and FD deceleration RFD was considered acceptable (CCC = 0.81-0.87) but demonstrated systematic and proportionate bias. ForceDecks (CCC = 0.89) and HD (CCC = 0.85) average relative concentric/propulsive force yielded acceptable agreement with SS explode (average relative concentric force), but SS explode demonstrated systematically lower values than FD and HD. Sparta Science drive (concentric impulse) yielded acceptable agreement with HD relative propulsive impulse (CCC = 0.85), but not FD concentric impulse. Human performance practitioners need to be aware of inconsistencies among testing procedures and analyses across force plate systems, such as differences in metric definitions and units of measurement, before making comparisons across systems. [ABSTRACT FROM AUTHOR]

We compared neuromechanical adjustments between traditional and eccentric load reduction weighted jump squats (WJSs). On separate visits, sixteen strength‐trained men performed three sets of six consecutive WJS with 0% (traditional WJS) or 50% eccentric loading reduction with a mechanical braking unit, while concentric load was set at 30% of 1 RM in all trials. A force platform and a motion capture system were used to assess neuromechanical parameters during eccentric and concentric phases of WJS. Peak power output (+4.5 ± 4.1%; p < 0.001), maximal concentric velocity (+3.2 ± 3.6%; p = 0.004), jump height (+19.6 ± 17.4%; p < 0.001), and reactive strength index (+28.2 ± 20.0%; p < 0.001) were higher when eccentric load was reduced by 50% versus 0%. Compared with traditional jump squat, eccentric phase duration (−6.7 ± 9.9%; p = 0.014), contact time (−6.3 ± 7.2%; p = 0.004), and time to reach peak power output (−7.8 ± 7.6%; p < 0.001) were shorter, while peak vertical force (−15.2 ± 17.5%; p = 0.005) and eccentric mechanical work (−23.9 ± 6.6%; p < 0.001) were lower with eccentric load reduction. Eccentric depth (p = 0.613), eccentric velocity (p = 0.070), amortization time (p = 0.060), maximal concentric force (p = 0.727), and concentric mechanical work (p = 0.396) did not differ significantly between conditions. Compared with traditional isoinertial loading, eccentric load reduction promoted more favorable neuromechanical adjustments during landing and propulsion phases in turn maximizing WJS performance. Highlights: Eccentric load reduction weighted jump squat is a form of plyometric exercise during which a rapid, eccentrically braked downward movement is immediately followed by a maximal effort jump.In strength‐trained men, we found this approach advantageous compared with no braking for potentiating weighted jump squat performance due to more favorable eccentric‐ and concentric‐phase metrics.It is possible that smaller training volumes could be completed in each exercise session without compromising on concentric outputs. Under such circumstances, employing eccentric load reduction weighted jump squat might be a more suitable approach when attempting to execute greater workloads while minimizing fatigue. [ABSTRACT FROM AUTHOR]

Background: The number of inpatient mental health facilities for children and adolescents in the United States is growing rapidly. While undergoing inpatient treatment, children and adolescents can benefit from innovative play opportunities designed to foster social interaction and learning. Methods: The Playful Learning Landscapes (PLL) initiative is a group of projects designed to transform everyday spaces into opportunities for playful learning. As a part of this initiative, two designs—Lifesize Ruler and Jumping Feet—were installed in an inpatient mental health facility for children and adolescents in the Mid‐Atlantic region of the United States. Results: Results of pre‐installation and post‐installation naturalistic observations suggested that social interactions, the use of STEM‐related language and 21st century skills, including confidence, increased after interacting with the installations. Conclusions: While previous research on PLL projects has demonstrated the efficacy of transforming public spaces into places for playful learning, this research provides support that, even in private, targeted settings, using a trauma‐informed approach, children and adolescents, can reap the benefits of playful learning. [ABSTRACT FROM AUTHOR]

The PUSH band 2.0 is a wearable technology used to measure mean and peak velocity and power in strength-based movements. The agreement between the PUSH band 2.0 and the criterion measure (force plates) during progressively loaded squat jumps was assessed. Fifteen participants performed 3 squat jumps at increasing loads. Linear regression and Bland–Altman plots assessed data simultaneously recorded from both devices. Mean velocity and power showed deviation from the identity line and an overestimation of 7.40% and 25%, respectively. Peak velocity and power showed an overestimation of 14% and underestimation of 6%, respectively. The results support the use of Push Band 2.0 to measure velocity during ballistic squat movements. However, errors in power measurement are greater than acceptable to support in-field use. While peak velocity maintains a consistent overestimation bias across various velocities, mean velocity error increases at higher velocities and can only be considered valid at slow velocities. [ABSTRACT FROM AUTHOR]

This research aims to provide a better understanding of the swimming push-off specificity comparing force production and electromyographic (EMG) activity on squat-jumps (SJ) and countermovement-jumps (CMJ) performed underwater (similar to swimming turns push-off) and dryland conditions on two different level of expertise participants (swimmers and non-swimmers). Thirteen male swimmers and nine non-trained male sport sciences students participated in this study. Each subject carried out 10 CMJ and 10 SJ jumps in dryland (vertical) and underwater (horizontal). During these trials, force production was recorded by force platforms and muscular activity of Vastus Lateralis, Biceps Femoris, Gastrocnemius Medialis and Tibialis Anterior was analysed through EMG. A three-way ANOVA showed that swimmers increased the differences in values obtained from SJ to CMJ between dry and underwater conditions during the first impulse phase—Impulse 1 (p < 0.01), the second phase of impulse—Impulse 2 (p < 0.001) and duration from peak force to take off (p < 0.001) in contrast to non-swimmers. Patterns relating to force production and EMG were non-consistent between muscles. Jumping performance was not significantly correlated between dry land and underwater conditions; nevertheless, results emphasise that environmental constraints are decisive to define the neuro-motor response to apparently similar tasks performed in different contexts. [ABSTRACT FROM AUTHOR]

We investigated the associations and differences between dynamic strength index (DSI) calculated from different types of vertical jump (countermovement jump; CMJ and squat jump; SJ) and different isometric knee joint angles (30, 60 and 90°), and associations with force-velocity (FV) profile and its constituent variables (maximal theoretical force (V0), power (Pmax) and velocity (V0) and the slope of the FV relationship (Sfv), on a sample of young athletes and active participants (n = 28). There were moderate associations between Pmax and all DSI values (r = 0.42–0.69; p <.05), V0 and all DSI values from CMJ and DSI30 from SJ (r = 0.43–0.56; p <.05), while Sfv was associated only with DSI30 and DSI90 in CMJ (r = 0.40–0.43; p <.05). This suggests that DSI and FV methods provide similar information and can be used in a similar manner to direct an individual's training. [ABSTRACT FROM AUTHOR]

The aim of the present study is to determine the associations between lower body muscle strength qualities and change of direction (CoD) performance. Three databases were used to perform a systematic literature search up to September 30, 2022. Based on the studies that met the inclusion criteria, we calculated Pearson's r correlation coefficient to examine the relationships between muscle strength qualities and CoD performance. The quality of the studies included was evaluated by the modified version of the Downs and Black Quality Index Tool. Heterogeneity was determined via the Q statistic and I2 , and Egger's test was used to assess small study bias. The results revealed that lower body maximal strength (pooled: r =− 0.54, dynamic: r =− 0.60, static: r =− 0.41), joint strength (pooled: r =− 0.59, EXT-ecc: r =− 0.63, FLEX-ecc: r =− 0.59), reactive strength (r =− 0.42) and power (pooled: r =− 0.45, jump height: r =− 0.41, jump distance: r =− 0.60, peak power: r =− 0.41) were negatively and moderately related to CoD performance. To conclude, the results highlight that a number of muscle strength qualities are associated with CoD performance and are pertinent to specific phases of a directional change. It should be noted that the conclusions of this study do not establish causality, and further research is needed to better understand their training effects and underlying mechanisms. [ABSTRACT FROM AUTHOR]

We compared the effects of two 4-week strength-power-speed training protocols on physical performance of young soccer players. Twenty-three highly trained under-20 soccer players were randomly allocated to two mixed-training groups: 1) "traditional" (TRAD: n=11), comprising vertically oriented strength-power exercises and linear sprints; or 2) "multidirectional" (MULTI: n=12), combining vertically and horizontally oriented strength-power exercises, linear sprints, and change-of-direction (COD) drills. Squat jump (SJ) and countermovement jump, 2) linear sprint, COD speed, and 3) jump-squat (JS) and hip-thrust (HT) power tests were performed pre- and post-training. Differences were determined using a two-way ANOVA with repeated measures and "target scores" were used to detect real changes in performance. No group-time interactions were found for any of the variables (p >0.05). Significant increases (p <0.05) in 20-m sprint velocity, JS- and HT-power were found in both groups, and in SJ in TRAD. Individual analyses revealed a greater number of meaningful changes in zig-zag velocity in MULTI while most players in TRAD displayed meaningful increases in SJ height. In conclusion, both training protocols resulted in similar adaptations but, at the individual level, it appears that MULTI protocol is superior to improve COD ability while TRAD should be preferred to maximize vertical jumping capabilities during short soccer pre-seasons. [ABSTRACT FROM AUTHOR]