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Context: Horizontal hops can provide insight into how athletes can tolerate high-intensity single-leg stretch loads and are commonly used in athlete monitoring and injury management. Variables like flight, contact, and total time provide valuable diagnostic information to sports science professionals. However, gold-standard assessment tools (eg, 3-dimensional motion capture, force plates) require monetary and technological resources. Therefore, we used a tablet and free software to determine the between-rater, within-rater, and test–retest variability of the temporal events of multiple horizontal hop tests. Design: Reliability study. Methods: Nine healthy males (20.8 [1.3] y, 71.4 [9.8] kg, 171.7 [4.5] cm) across various university sports teams and clubs volunteered and performed several triple (3-Hop) and quintuple (5-Hop) horizontal hops over 3 testing sessions. Six raters detected temporal events from video to determine between-rater variability, while a single rater quantified within-session and test–retest variability. The temporal variables of flight time, ground contact time for each individual hop, and the total time of each hoping series were determined. The consistency of measures was interpreted using the coefficient of variation and interclass correlation coefficients (ICC). Results: Good to excellent between-rater consistency was observed for all hops (ICC =.85–1.00). Absolute (coefficient of variation ≤ 2.0%) and relative consistency (ICC =.98–1.00) was excellent. Test–retest variability showed acceptable levels of absolute consistency (coefficient of variation ≤ 8.7%) and good to excellent consistency in 10/16 variables (ICC =.81–.93), especially those later in the hopping cycle. Conclusions: A tablet and free digitizing software are reliable in detecting temporal events during multiple horizontal hops, which could have exciting implications for power diagnostics and return-to-play decisions. Therefore, rehabilitation and performance professionals can confidently utilize the highly accessible equipment from this study to track multiple hop performances. [ABSTRACT FROM AUTHOR]

Context: Analyzing flick movement kinematics biomechanically is important to prevent sport-related injuries in underwater hockey players since the aquatic-based flick movement is completely different from land-based flick movements. The study aimed to describe the flick movement kinematic biomechanically in underwater hockey players. Moreover, this study further aimed to investigate the effect of the Thrower's Ten exercises on flick movement kinematics in underwater hockey players. Design: Descriptive laboratory study. Methods: Seventeen underwater hockey players (age: 26.2 [4.3] y; sports age: 6.2 [4.5] y) were included. First, 2 underwater cameras using motion capture video analysis MATLAB were used to biomechanically analyze the angular changes on the shoulder, elbow, wrist, and body while players were performing the flick movements. Players were then recruited to the Thrower's Ten exercise program for 6 weeks. Flick movement kinematics and flick-throwing distance were recorded at baseline and 6 weeks. Results: The flick movement kinematic patterns demonstrated increased shoulder flexion (from 102.5° to 144.9°), wrist extension (from 9.5° to 10.8°), and upper-extremity rotation (from 5.7° to 56.8°) while decreased elbow extension (from 107.7° to 159.2°) from the stick met the puck until the competition of the movement. The Thrower's Ten exercises improved the elbow extension (P =.04), wrist extension (P =.01), body rotation (P <.001), and flick-throwing distance (P <.001) from baseline to 6 weeks. Conclusion: This study describes the underwater flick kinematic technique biomechanically and interprets preliminary findings for the first time. Thus, 6 weeks of Thrower's Ten exercise program provides more body muscle movements than the smaller ones during the flick movements and higher flick-throwing distance in underwater hockey players. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether caffeine gum influenced perceptual-cognitive and physical performance during the extra-time period of simulated soccer match-play. Semiprofessional male soccer players (n = 12, age: 22 ± 3 years, stature: 1.78 ± 0.06 m, mass: 75 ± 9 kg) performed 120-min soccer-specific exercise on two occasions. In a triple-blind, randomized, crossover design, players chewed caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum for 5 min following 90 min of soccer-specific exercise. Perceptual-cognitive skills (i.e., passing accuracy, reaction time, composure, and adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and posttrial. Neuromuscular performance (reactive-strength index, vertical jump height, absolute and relative peak power output, and negative vertical displacement) and sprint performance (15 and 30 m) were measured at pretrial, half-time, 90 min, and posttrial. Caffeine gum attenuated declines in reaction time (pre: 90.8 ± 0.8 AU to post: 90.7 ± 0.8 AU) by a further 4.2% than placebo (pre: 92.1 ± 0.8 AU to post: 88.2 ± 0.8 AU; p <.01). Caffeine gum reduced composure by 4.7% (pre: 69.1 ± 0.8 AU to post: 65.9 ± 0.8 AU) versus placebo (pre: 68.8 ± 0.8 AU to post: 68.3 ± 0.8 AU; p <.01). Caffeine gum did not influence any other variables (p >.05). Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and neuromuscular and sprint performance remain unchanged. Future work should assess caffeine gum mixes with substances like L-theanine that promote a relaxed state under stressful conditions. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the test–retest reliability and usefulness of the foot–ankle rebound-jump test (FARJT) for measuring foot–ankle reactive strength metrics in athletes. Methods: Thirty-six highly trained, healthy athletes (5 female; 21.5 [3.9] y; 1.80 [0.10] m; 72.7 [10.4] kg) performed 8 repeated bilateral vertical foot–ankle rebound jumps on 2 testing days. Testing days were 1 week apart, and these sessions were preceded by a familiarization session. Reactive strength metrics were calculated by dividing jump height (in meters) by contact time (in seconds) for the reactive strength index (RSI) and flight time (in seconds) by contact time (in seconds) for the reactive strength ratio (RSR). The mean of 4 jumps (excluding the first and last 2 jumps) on each testing session were considered for RSI and RSR reliability and usefulness analysis. Results: We found a high reliability of the FARJT for RSI (intraclass correlation coefficient [ICC] >.90 and coefficient of variation [CV] = 12%) and RSR (ICC ≥.90 and CV = 8%). Regarding their usefulness, both RSI and RSR were rated as "marginal" in detecting the smallest worthwhile change (typical error > smallest worthwhile change) and "good" in detecting a moderate change in performance. Conclusions: The results showed that a FARJT is a highly reliable test for measuring foot–ankle reactive strength in athletes and useful for quantifying changes, for example, following a training block. However, its usefulness as an accurate daily or weekly monitoring tool in practice is questionable. [ABSTRACT FROM AUTHOR]

Purpose: Performing back squats with elastic bands has been widely used in resistance training. Although research demonstrated greater training effects obtained from adding elastic bands to the back squat, little is known regarding the optimal elastic resistance and how it affects neuromuscular performance. This study aimed to compare the force, velocity, power, and muscle activity during back squats with different contributions of elastic resistance. Methods: Thirteen basketball players performed 3 repetitions of the back squat at 85% of 1-repetition maximum across 4 conditions: (1) total load from free weight and (2) 20%, (3) 30%, and (4) 40% of the total load from elastic band and the remaining load from free weight. The eccentric and concentric phases of the back squat were divided into upper, middle, and bottom phases. Results: In the eccentric phase, mean velocity progressively increased with increasing elastic resistance, and muscle activity of the vastus medialis and rectus femoris significantly increased with the largest elastic resistance in the upper phase (P ≤.036). In the concentric phase, mean power (P ≤.021) and rate of force development (P ≤.002) significantly increased with increasing elastic resistance. Furthermore, muscle activity of the vastus lateralis and vastus medialis significantly improved with the largest elastic resistance in the upper phases (P ≤.021). Conclusion: Velocity, power, rate of force development, and selective muscle activity increased as the elastic resistance increased in different phases during the back-squat exercise. [ABSTRACT FROM AUTHOR]

Purpose: The relationship between external load and creatine-kinase (CK) response at the team/position or individual level using Global Positioning Systems (GPS) has been studied. This study aimed to compare GPS-derived and Football Movement Profile (FMP) –derived CK-prediction models for national-team soccer players. The second aim was to compare the performance of general and individualized CK prediction models. Methods: Four hundred forty-four national-team soccer players (under 15 [U15] to senior) were monitored during training sessions and matches using GPS. CK was measured every morning from whole blood. The players had 19.3 (18.1) individual GPS-CK pairs, resulting in a total of 8570 data points. Machine learning models were built using (1) GPS-derived or (2) FMP-based parameters or (3) the combination of the 2 to predict the following days' CK value. The performance of general and individual-specific prediction models was compared. The performance of the models was described by R2 and the root-mean-square error (RMSE, in units per liter for CK values). Results: The FMP model (R2 =.60, RMSE = 144.6 U/L) performed similarly to the GPS-based model (R2 =.62, RMSE = 141.2 U/L) and the combination of the 2 (R2 =.62, RMSE = 140.3 U/L). The prediction power of the general model was better on average (R2 =.57 vs R2 =.37) and for 73% of the players than the individualized model. Conclusions: The results suggest that FMP-based CK-prediction models perform similarly to those based on GPS-derived metrics. General machine learning models' prediction power was higher than those of the individual-specific models. These findings can be used to monitor postmatch recovery strategies and to optimize weekly training periodization. [ABSTRACT FROM AUTHOR]

Context: High secondary injury rates after orthopedic surgeries have motivated concern toward the construct validity of return-to-sport test batteries, as it is evident that common strength and functional assessments fail to elicit pertinent behaviors like visual search and reactive decision making. This study aimed to establish the test–retest reliability of 2 reactive agility tasks and evaluate the impact of visual perturbation on physical performance. Methods: Fourteen physically active individuals completed 2 agility tasks with reaction time (ie, 4 corner agility), working memory, and pathfinding (ie, color recall) components. Participants completed both tasks 4 times in 2 sessions scheduled 7 days apart. Outcomes included performance metrics of reaction time, time to target, number of targets, and total time assessed with reactive training timing gates. To assess test–retest reliability, we used intraclass correlation coefficients (ICCs), standard error of measurement (SEM), and minimal detectable change (MDC). Stroboscopic goggles induced visual perturbation during the fourth trial of each task. To assess the effect of visual perturbation, we used paired t tests and calculated performance costs. Results: The 4-corner agility task demonstrated excellent reliability with respect to reaction time (ICC3,1 =.907, SEM = 0.13, MDC = 0.35 s); time to light (ICC3,1 =.935, SEM = 0.07, MDC = 0.18 s); and number of lights (ICC3,1 =.800, SEM = 0.24, MDC = 0.66 lights). The color recall task demonstrated good-to-excellent test–retest reliability for time to lights (ICC3,1 =.818–.953, SEM = 0.07–0.27, MDC = 0.19–0.74 s); test time (ICC3,1 =.969, SEM = 5.43, MDC = 15.04 s); and errors (ICC3,1 =.882, SEM = 0.19, MDC = 0.53 errors). Visual perturbation resulted in increased time to target (P =.022–.011), number of targets (P =.039), and total test time (P =.013) representing moderate magnitude degradation of performance (d = 0.55–0.87, performance costs = 5%–12%). Conclusions: Both tasks demonstrated acceptable test–retest reliability. Performance degraded on both tasks with the presence of visual perturbation. These results suggest standardized reactive agility tasks are reliable and could be developed as components of dynamic RTS testing. [ABSTRACT FROM AUTHOR]

Context: Poor knee biomechanics contribute to knee joint injuries. Neuromuscular control over knee position is partially derived from the hip. It is unknown whether isolated activation training of the gluteal muscles improves lower-extremity frontal plane mechanics. This study examined if a home-based hip muscle activation program improves performance on the Forward Step-Down Test as well as increases surface electromyography (sEMG) activation of the gluteal muscles. Design: The study utilized a single-group repeated-measures design. Methods: Thirty-five participants (24 females, mean age = 23.17 [SD 1.36] years) completed an 8-week hip muscle activation program. The Forward Step-Down Test score and sEMG of gluteus maximus and medius were assessed preintervention and postintervention. Results: Forward Step-Down Test scores improved significantly from preintervention (Mdn = 3.5) to postintervention (Mdn = 3.0, T = 109, P =.010, r =.31.), but this result did not meet clinical significance. sEMG analysis revealed a significant increase in mean gluteus maximus activation (P =.028, d = 1.19). No significant dose–response relationship existed between compliance and the Forward Step-Down Test scores or sEMG results. Conclusions: A home-based hip activation program increases gluteus maximus activation without clinically significant changes in frontal plane movement quality. Future studies may find clinical relevance by adding motor learning to the activation training program to improve functional muscle use. [ABSTRACT FROM AUTHOR]

This study aimed to clarify the differences in muscular coordination during butterfly swimming between high- and low-performance swimmers using muscle synergy analysis. Eight female competitive swimmers and 8 female recreational swimmers participated in this study. The participants swam a 25-m butterfly stroke with maximum effort. Surface electromyography was measured from 12 muscles and muscle synergy analysis was performed from the data using nonnegative matrix factorization algorithms. From the results of the muscle synergy analysis, 4 synergies were extracted from both groups. Synergies 1 and 2 were characterized by coactivation of the upper and lower limb muscles in the recreational swimmers, whereas only synergy 1 was characterized by this in the competitive swimmers. Synergy 3 was involved in arm recovery in both groups. Synergy 4 was only involved in the downward kick in the competitive swimmers. From these results, it can be concluded that muscle synergies with combined coordination of upper and lower limb muscles were extracted more in the recreational swimmers and that the competitive swimmers controlled the downward kick with an independent synergy and that the adjustment of the timing of the downward kick may be an important factor for the efficient performance of butterfly swimming. [ABSTRACT FROM AUTHOR]

We aimed to investigate the effects of dual- and single-task training in older adults with age-related hearing loss. Intervention groups included single-, dual-task training, and control groups. The dual- and single-task trainings were held 2 days a week for 40 min for a total of 10 sessions for 5 weeks. We evaluated physical, cognitive, and auditory functions, quality-of-life, balance, concerns about falling, independence in activities of daily living, and dual-task performance. A total of 42 patients fully participated in this study. Statistically significant differences were observed in chair stand, chair sit-and-reach, global cognitive function, and delayed recall between the intervention groups and control group (p <.05). There was no statistically significant difference in quality-of-life, balance, falling concerns, independence in activities of daily living, and dual-task performance between all groups (p >.05). In conclusion, single- and dual-task training had a positive effect on physical and cognitive functioning in older adults with age-related hearing loss. [ABSTRACT FROM AUTHOR]

Purpose: This study assessed the reliability and load–velocity profiles of 3 different landmine-punch-throw variations (seated without trunk rotation, seated with trunk rotation, and standing whole body) with different loads (20, 22.5, and 25.0 kg), all with the dominant hand and nondominant hand. Methods: In a quasi-randomized order, 14 boxers (24.1 [4.3] y, 72.6 [10.1] kg) performed 3 repetitions of each variation with their dominant hand and their nondominant hand, with maximal effort and 3 minutes of interset rest. Peak velocity was measured via the GymAware Power Tool (Kinetic Performance Technologies). The interclass correlation coefficients and their 95% CIs were used to determine the intrasession reliability of each variation × load × hand combination. Additionally, a 2 (hand) × 3 (variation) repeated-measures analysis of variance assessed the load–velocity profile slope, and a 3 (variation) × 2 (hand) × 3 (load) repeated-measures analysis of variance assessed the peak velocity of each variation. Results: Most variations were highly reliable (intraclass correlation coefficient >.91), with the nondominant hand being as reliable or more reliable than the dominant hand. Very strong linear relationships were observed for the group average for each variation (R2 ≥.96). However, there was no variation × hand interaction for the slope, and there was no main effect for variation or hand. Additionally, there was no interaction for the peak velocity, but there were main effects for variation, hand, and load (P <.01). Conclusion: Each variation was reliable and can be used to create upper-body ballistic unilateral load–velocity profiles. However, as with other research on load–velocity profile, individual data allowed for more accurate profiling than group average data. [ABSTRACT FROM AUTHOR]

Purpose: In this study, we compared the influence of movement specificity during velocity–load jump testing to predict on-ice acceleration performance in elite speed skaters. Methods: Elite long-track speed skaters (N = 27) performed velocity–load testing with 3 external loads during unilateral horizontal jumping, lateral jumping, and bilateral vertical countermovement jumping. For the unilateral tests, external load conditions were set to 10 N, 7.5% and 15% of external load relative to body weight. For the countermovement jumping, load conditions were body weight and 30% and 60% of external load relative to body weight. On-ice performance measures were obtained during maximal 50-m accelerations from a standing start, including maximal skating speed, maximal acceleration capacity, and maximum horizontal power. The 100-m split time from a 500-m race was also obtained. Regularized regression models were used to identify the most important predictors of on-ice acceleration performance. In addition to regularized regression coefficients, Pearson correlation coefficients (r) were calculated for all variables retained by the model to assess interrelationships between single predictors and on-ice performance measures. Results: The countermovement jump with 30% of body mass demonstrated the strongest association with maximal skating speed, maximum horizontal power, and 100-m time (regularized regression coefficient =.16−.49, r =.84−.97, P <.001). Horizontal jump with 15% of body mass was the strongest predictor of maximal acceleration capacity performance (regularized regression coefficient =.08, r =.83, P <.001). Conclusions: The findings of this study suggest that mechanical specificity rather than movement specificity was more relevant for predicting on-ice acceleration performance. [ABSTRACT FROM AUTHOR]

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: Sport-related dystonia is a rare form of activity-specific dystonia that can severely impair an athlete's ability to perform. Due to a lack of data on the condition, it is difficult to diagnose and often overlooked, and no gold standard treatment has yet been defined. Case Presentation: We present a rare and challenging case of sport-related dystonia that affected a 24-year-old male professional soccer player. The patient presented with severe rigidity and dystonia of the right lower-extremity, particularly the ankle and foot. The symptoms set on >1 year prior to the presentation to our outpatient clinic. He began to complain of stiffness and difficulty moving his lower limbs, especially his right leg, initially when playing soccer, but then also when walking normally. On presentation, he was unable to run and walked with difficulty, supporting his body weight only on the outside of his right foot. He also reported a motor trick and reverse motor trick involving the oral musculature in order to move his lower limb more freely. Management and Outcomes: An integrated rehabilitation approach based on postural rehabilitation, neuromuscular rehabilitation, and dental intervention was used to successfully treat this condition. The approach included: (1) postural rehabilitation with the Mézières-Bertelè method to reduce muscular stiffness, (2) neuromuscular re-education with Tai Chi exercises and electromyography-guided biofeedback, and (3) dental intervention and swallowing rehabilitation to limit impaired oral habits (due to the relationship between his impaired lower limb movements and motor tricks of the oral musculature). After 7 months of integrated rehabilitation, the patient returned to professional soccer. Conclusions: This case report highlights the potential efficacy of an integrative rehabilitation approach for sports dystonia, particularly in cases where traditional treatments may not be effective. Such an approach could be considered a valuable option in the management of this rare, but debilitating, condition in athletes. Further research is needed to assess the effectiveness of this approach in larger populations. [ABSTRACT FROM AUTHOR]

Context: The persistence and the recurrence of posterior medial knee pain (PKP) after anterior cruciate ligament reconstruction (ACLR) using hamstring tendon graft are often overlooked during rehabilitation. Design: Cross-sectional observational study. Methods: The study aimed (1) to evaluate the prevalence of these types of PKP before 4 months post-ACLR, (2) to measure their consequences on the knee flexors strength, and (3) to evaluate the role of the type of ACLR. From a cohort of patients operated on with hamstring tendon procedures, the persistent and the recurrent PKP were sought at 4 months post-ACLR. The evolution of isokinetic muscle strength recovery in PKP subjects was compared with those of nonpainful subjects. The functional deficit was measured at 6/7 months post-ACLR by a hop test. Results: Three hundred seventeen subjects (25.8 [6.0] y) were included. At 4 months post-ACLR, 2 populations were identified based on the recurrent onset of PKP (PKP+, n = 40) or the absence of knee pain (PKP−, n = 277). The prevalence of PKP was 8.3%. At the fourth month post-ACLR, the PKP+ group had a higher flexor strength deficit compared with the PKP− group (limb symmetry index at 60°/s: 67.2% [12.4%] vs 84.3% [12.6%]; P <.05). At 6/7 months, the loss of strength persisted (limb symmetry index at 60°/s: 82.3% [13.4%] vs 87.7% [12.8%]; P <.05). The hop test deficit was comparable, and no difference was shown according to the type of graft. Conclusions: Persistent and recurrent PKP during the rehabilitation period were not uncommon and were associated with a worsening of flexors strength loss on the ACLR side. [ABSTRACT FROM AUTHOR]

Background: Relative energy deficiency in sport (REDs) is a condition that is associated with negative health and performance outcomes in athletes. Insufficient energy intake relative to exercise energy expenditure, resulting in low energy availability, is the underlying cause, which triggers numerous adverse physiological consequences including several associated with musculoskeletal (MSK) health and neuromuscular performance. Purpose: This commentary aims to (1) discuss the health and performance implications of REDs on the skeletal and neuromuscular systems and (2) examine the role that MSK training (ie, strength and plyometric training) during treatment and return to performance following REDs might have on health and performance in athletes, with practical guidelines provided. Conclusions: REDs is associated with decreases in markers of bone health, lean body mass, maximal and explosive strength, and muscle work capacity. Restoration of optimal energy availability, mainly through an increase in energy intake, is the primary goal during the initial treatment of REDs with a return to performance managed by a multidisciplinary team of specialists. MSK training is an effective nonpharmacological component of treatment for REDs, which offers multiple long-term health and performance benefits, assuming the energy needs of athletes are met as part of their recovery. Supervised, prescribed, and gradually progressive MSK training should include a combination of resistance training and high-impact plyometric-based exercise to promote MSK adaptations, with an initial focus on achieving movement competency. Progressing MSK training exercises to higher intensities will have the greatest effects on bone health and strength performance in the long term. [ABSTRACT FROM AUTHOR]

Purpose: Successful participation in taekwondo (TKD) requires athletes to possess quick decision-making abilities and demonstrate technical proficiency during competition. Dehydration, occurring during both training and competition, is widely recognized to have various negative effects. Methods: This study investigated the impact of different levels of dehydration on cognitive function, as measured by the Vienna Test System, and the specific performance of kicking techniques among TKD athletes. Using a randomized crossover design, 12 participants were involved in the study. Before and after 1 hour of training at 80% of maximal heart rate, participants were weighed and provided urine samples. All participants were randomly assigned to 3 different hydration conditions: the euhydrated (EUH) group had unrestricted access to fluid consumption, while the hypohydrated (HYP) and severely HYP (S-HYP) groups experienced reductions of 2.0% and 4.0% of their initial body weight, respectively. Results: The EUH group exhibited better reaction speed in reaction-time test-form S1 than the HYP and S-HYP groups. Notably, the EUH group demonstrated a significantly higher success rate in the front-side kick (EUH 98%, HYP 90%, S-HYP 88%; P <.05). However, the success rates of back roundhouse kick and free head kick were similar among the 3 statuses. Furthermore, postexercise heart rates were found to be significantly higher in the HYP and S-HYP groups compared with the EUH group. Conclusions: This study provides insight into the negative effects of dehydration on cognitive function and TKD-specific performance. It is recommended that TKD athletes maintain optimal hydration levels during training and competition to ensure optimal performance. [ABSTRACT FROM AUTHOR]

Altering baseball pitching mechanics affects both performance and the risk of injury. The purpose of this study is to investigate the relationships of shoulder external over internal rotation ratio (SEIR) and other shoulder rotational properties during physical exam and biomechanics of pitching for 177 collegiate baseball pitchers. The shoulder range of motion was quantitatively measured using a custom-made wireless device. Pitching motion data were collected at 240 Hz, and a custom program was created to calculate the throwing arm motion and loading during baseball pitching. Linear regression and analysis of variance tests were performed to investigate the relationships between the shoulder physical exam outcomes and throwing arm biomechanics. SEIR had significant correlations with shoulder horizontal adduction angle at foot contact, maximum shoulder external rotation angle, maximum shoulder linear velocity, and elbow angle at ball release. SEIR groups had significant differences in shoulder proximal force, adduction torque, internal rotation torque, and horizontal adduction torque, and in elbow medial force and varus torque. Glenohumeral internal rotation deficit and total rotational motion deficit had no relationships with throwing arm motions or joint loadings. Shoulder health should be monitored to improve understanding of pitching mechanics in collegiate baseball pitchers. [ABSTRACT FROM AUTHOR]

No studies have reported ground reaction force (GRF) profiles of the repeated depth jump (DJ) protocols commonly used to study exercise-induced muscle damage. Furthermore, while compression garments (CG) may accelerate recovery from exercise-induced muscle damage, any effects on the repeated bout effect are unknown. Therefore, we investigated the GRF profiles of 2 repeated bouts of damage-inducing DJs and the effects of wearing CG for recovery. Nonresistance-trained males randomly received CG (n = 9) or placebo (n = 8) for 72 hours recovery, following 20 × 20 m sprints and 10 × 10 DJs from 0.6 m. Exercise was repeated after 14 days. Using a 3-way (set × bout × group) design, changes in GRF were assessed with analysis of variance and statistical parametric mapping. Jump height, reactive strength, peak, and mean propulsive forces declined between sets (P <.001). Vertical stiffness, contact time, force at zero velocity, and propulsive duration increased (P <.05). According to statistical parametric mapping, braking (17%–25% of the movement) and propulsive forces (58%–81%) declined (P <.05). During the repeated bout, peak propulsive force and duration increased (P <.05), while mean propulsive force (P <.05) and GRF from 59% to 73% declined (P <.001). A repeated bout of DJs differed in propulsive GRF, without changes to the eccentric phase, or effects from CG. [ABSTRACT FROM AUTHOR]

Introduction: Is there an association between self-reported dual-task performance and fear of falling in older adults? Background/Objectives: Fear of falling tends to increase with age and can negatively impact dual-task abilities, leading to potential declines in overall quality of life. Therefore, it becomes crucial to evaluate dual-task performance in older adults, particularly prior to the onset of fear of falling. This study aims to investigate the potential association between self-reported dual-task performance and fear of falling in older adults. Methods: A total of 51 individuals (19 females and 32 males) were recruited. The participants met the inclusion criteria were administered the Dual-Task Questionnaire (DTQ), Falls Efficiency Scale International, and Physical Activity Scale for the Elderly. Multiple linear regression was performed to predict DTQ scores based on age, body mass index, and Physical Activity Scale for the Elderly. Results: A moderate positive correlation was found between Falls Efficiency Scale International scores and self-reported DTQ scores (r:.448, p:.001). Age, body mass index, and Physical Activity Scale for the Elderly were not found to be significant predictors of DTQ scores. Conclusions: Our study reveals a moderate positive association between fear of falling and self-reported dual-task performance in older adults. A direct relationship between physical activity performance, fear of falling, and self-reported dual-task performance was observed among older adults. Significance/Implications: Integrating self-reported measures like the DTQ in clinical evaluations can provide valuable insights into dual-task abilities of older adults. [ABSTRACT FROM AUTHOR]

Manipulating the amount of muscle mass engaged during exercise can noninvasively inform the contribution of central cardiovascular and peripheral vascular-oxidative functions to endurance performance. To better understand the factors contributing to exercise limitation in older and younger individuals, exercise performance was assessed during single-leg and double-leg cycling. 16 older (67 ± 5 years) and 14 younger (35 ± 5 years) individuals performed a maximal exercise using single-leg and double-leg cycling. The ratio of single-leg to double-leg cycling power (RatioPower SL/DL) was compared between age groups. The association between fitness (peak oxygen consumption, peak power output, and physical activity levels) and RatioPower SL/DL was explored. The RatioPower SL/DL was greater in older compared with younger individuals (1.14 ± 0.11 vs. 1.06 ± 0.08, p =.041). The RatioPower SL/DL was correlated with peak oxygen consumption (r =.886, p <.001), peak power output relative to body mass (r =.854, p <.001), and levels of physical activity (r =.728, p =.003) in the younger but not older subgroup. Reducing the amount of muscle mass engaged during exercise improved exercise capacity to a greater extent in older versus younger population and may reflect a greater reduction in central cardiovascular function compared with peripheral vascular-oxidative function with aging. [ABSTRACT FROM AUTHOR]

Purpose: To explore the association of the load–velocity (L-V) relationship variables and ability to maintain maximal mechanical performance during the prone bench-pull exercise with sprint swimming performance and in-water forces. Methods: Eleven competitive adult male swimmers (50-m front crawl World Aquatics points: 488 [66], performance level 4) performed 1 experimental session. The L-V relationship variables (L0 [ie, maximal theoretical load at 0 velocity]; v0 [ie, maximal theoretical velocity at 0 load], and Aline [ie, area under the L-V relationship]) and maximal mechanical maintenance capacity were assessed at the beginning of the session. Afterward, sprint swimming performance and in-water force production were tested through a 50-m front-crawl all-out trial and 15-s fully-tethered swimming, respectively. Results: Only v0 presented high positive associations with 50-m time and swimming kinematics (r >.532; P <.046). The L0, v0, and Aline showed very high positive associations with the in-water forces during tethered swimming (r >.523; P <.049). However, the ability to maintain maximal mechanical performance, assessed by the mean velocity decline during the prone bench pull, was only significantly correlated with stroke rate (r = −.647; P =.016) and stroke index (r =.614; P =.022). Conclusions: These findings indicate that maximal neuromuscular capacities, especially v0, have a stronger correlation with swimming performance and in-water force production than the ability to maintain maximal mechanical performance in level 4 swimmers. [ABSTRACT FROM AUTHOR]

Purpose: To determine between-limbs differences in isometric rate of force development (RFD) measured during open- (OKC) and closed-kinetic-chain (CKC) strength testing and establish which method had the strongest relationship to single-leg vertical-jump performance and knee mechanics after anterior cruciate ligament (ACL) reconstruction. Methods: Subjects (n = 19) 1 to 5 years from ACL reconstruction performed isometric knee extensions (OKC), unilateral isometric midthigh pulls (CKC), and single-leg vertical jumps on the ACL-involved and -noninvolved limbs. Between-limbs differences were assessed using paired t tests, and the relationship between RFD, jump performance, and knee mechanics was assessed using correlation coefficients (r; P ≤.05). Results: There were significant between-limbs differences in OKC RFD (P =.008, d = −0.69) but not CKC RFD. OKC RFD in the ACL-involved limb had a strong association with jump height (r =.64, P =.003), knee-joint power (r =.72, P <.001), and peak knee-flexion angle (r =.72, P =.001). CKC RFD in the ACL-involved limb had a strong association with jump height (r =.65, P =.004) and knee-joint power (r =.67, P =.002) but not peak knee-flexion angle (r =.40, P =.09). Conclusions: While both OKC and CKC RFD were strongly related to jump performance and knee-joint power, OKC RFD was able to detect between-limbs RFD asymmetries and was strongly related to knee-joint kinematics. These findings indicate that isometric knee extension may be optimal for assessing RFD after ACL reconstruction. [ABSTRACT FROM AUTHOR]

Purpose: The study aimed to conduct a comparative analysis of physical performance indicators and assess the levels of performance monotony and strain experienced by basketball referees. Methods: The study involved the participation of 12 basketball referees (mean age: 40.0 [4.9] y) affiliated with the International Basketball Federation. The investigation was carried out throughout 2 density tournaments, wherein the maximum heart rate, average heart rate, performance monotony, and performance strain were documented for 3 variables. Results: The findings indicated significant variations in the mean heart rate, maximum heart rate, total distance monotony, total distance strain, the total number of sprints monotony, the total number of sprints strain, calories monotony, and calories strain (P <.05). Decreasing the density of elite-level basketball competitions has been observed to reduce the monotony and strain experienced by referees. However, this action does not increase motion distance or speed zones. Conclusions: The environmental stressors experienced by senior-level athletes (World Cup) differ from those encountered by younger athletes (World Cup Under 19). Further investigation is required to ascertain the potential effects of competition monotony and strain on decision-making processes and the overall quality of refereeing. [ABSTRACT FROM AUTHOR]

Purpose: Monitoring performance athletes' training responses can be efficiently completed at competitive events. This study aimed to explore the changes in swimming, countermovement-jump (CMJ), and pull-up (PU) performance following training across a competitive phase, as well as immediately before and after each race. Methods: Fourteen well-trained male sprint/middle-distance swimmers (height 179 [7] cm, mass 70 [8] kg, age 18 [2] y), from 3 regional training groups, completed CMJ and PU tests before and after the national competitions in October and May, when race performance was also assessed. Results: Swimming race performance was significantly improved from before the national competitions in October to after the national competitions in May (1.8% [3.2%], P =.044, d = 0.60, moderate effect). Although there were no significant changes in PU velocity, CMJ performance significantly improved from before the national competitions in October to after the national competitions in May (mean difference 2.29 cm, P =.004, d = 3.52) and showed before-to-after race decreases (mean difference −1.64 cm, P =.04, d = 2.28). Conclusion: Swimming performance and CMJ performance improved as the season progressed, although these improvements were not directly correlated. PU performance did not appear to be sensitive to training or race-induced fatigue, in contrast to CMJ, in this group of male swimmers. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the preliminary effects of movement pattern training (MoveTrain) versus strengthening/flexibility (standard) treatment on hip and pelvic biomechanics in patients with chronic hip-related groin pain. This is a secondary analysis of data collected during a pilot randomized clinical trial. Thirty patients with hip pain, between the ages of 15 and 40 years, were randomized to MoveTrain or standard. Both groups completed 10 treatment sessions over 12 weeks along with a daily home exercise program. Three-dimensional motion analysis was used to collect kinematic and kinetic data of the pelvis and hip during a single-leg squat task at pretreatment and immediately posttreatment. Compared with the standard group, the MoveTrain group demonstrated smaller hip adduction angles (P =.006) and smaller hip external adduction moments (P =.008) at posttreatment. The desired changes to hip joint biomechanics, as found in this study, may require specificity in training that could allow health care professionals to better customize the rehabilitation of patients with hip pain. These findings can also be applied to the design and implementation of future clinical trials to strengthen our understanding of the long-term implications of different rehabilitation techniques for patients with hip pain. [ABSTRACT FROM AUTHOR]

This study investigated the impact of multimorbidity patterns on physical activity and capacity outcomes over the course of a year-long exercise intervention, and on physical activity 1 year later. Participants were 314 physically inactive community-dwelling men and women aged 70–85 years, with no contraindications for exercise at baseline. Physical activity was self-reported. Physical capacity measurements included five-time chair-stand time, 6-minute walking distance, and maximal isometric knee-extension strength. The intervention included supervised and home-based strength, balance, and walking exercises. Multimorbidity patterns comprised physician-diagnosed chronic disease conditions as a predictor cluster and body mass index as a measure of obesity. Multimorbidity patterns explained 0%–12% of baseline variance and 0%–3% of the change in outcomes. The magnitude and direction of the impact of unique conditions varied by outcome, time point, and sex. Multimorbid older adults with no contraindications for exercise may benefit from multimodal physical training. [ABSTRACT FROM AUTHOR]

This study aimed to compare community-dwelling older adults' physical activity (PA) during the COVID-19 restrictions in 2020 to their PA levels 2 years before and investigate associations between earlier physical performance and PA levels over the follow-up. Participants' (n = 809, initial age 75–85 years) self-reported PA was assessed at baseline in 2017–2018 and May/June 2020 as total weekly minutes of walking and vigorous PA. Physical performance was assessed at baseline using the maximal handgrip strength and Short Physical Performance Battery tests. During the first wave of the COVID-19 pandemic, a median change in total weekly minutes of walking and vigorous PA among all participants was + 20.0 (interquartile range: −60.0 to 120.0, p <.001) min per week compared with 2 years earlier. Higher baseline Short Physical Performance Battery total scores were associated with higher total weekly minutes of walking and vigorous PA over the follow-up in men and women, and better handgrip strength in women. [ABSTRACT FROM AUTHOR]

Purpose: An inspiratory muscle warm-up (IMW) improves inspiratory muscle function, but the effects of high-intensity exercise are inconsistent. We aimed to determine the effects of high-intensity IMW on high-intensity exercise performance and muscle oxygenation. Methods: Ten healthy men (maximal oxygen uptake [ V ˙ O 2 max ] 52.2 [5.0] mL·kg–1·min–1) performed constant-load exercise to exhaustion on a cycle ergometer at V ˙ O 2 max under 2 IMW conditions: a placebo condition (PLA) and a high-intensity IMW condition (HIGH). The inspiratory loads were set at 15% and 80% of maximal inspiratory pressure, respectively. Maximal inspiratory pressure was measured before and after IMW. Oxyhemoglobin was measured in the vastus lateralis by near-infrared spectroscopy during exercise. Rating of perceived exertion (RPE) for a leg was measured after 1 and 2 minutes of exercise. Results: Exercise tolerance was significantly higher under HIGH than PLA (228 [49] s vs 218 [49] s, P =.003). Maximal inspiratory pressure was significantly increased by IMW under HIGH (from 125 [20] to 136 [25] cm H2O, P =.031). Oxyhemoglobin was significantly higher under HIGH than PLA at 80% of the total duration of exercise (P =.048). RPE for the leg was significantly lower under HIGH than PLA after 2 minutes of exercise (P =.019). Conclusions: Given that oxyhemoglobin is an index of local oxygen supply, the results of this study suggest that high-intensity IMW increases the oxygen supply to active limbs. It may also reflect a reduction in RPE in the leg. In addition, high-intensity IMW may improve exercise performance. [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]

Androgen deprivation therapy (ADT) forms the cornerstone in the treatment of advanced prostate cancer. However, by suppressing testosterone ADT results in a decrease of skeletal muscle mass. In this narrative review, we explore the magnitude and mechanisms of ADT-induced muscle mass loss and the consequences for muscle strength and physical performance. Subsequently, we elucidate the effectiveness of supervised resistance exercise training as a means to mitigate these adverse effects. Literature shows that resistance exercise training can effectively counteract ADT-induced loss of appendicular lean body mass and decline in muscle strength, while the effect on physical performances is inconclusive. As resistance exercise training is feasible and can be safely implemented during ADT (with special attention for patients with bone metastases), it should be incorporated in standard clinical care for prostate cancer patients (starting) with ADT. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of unilateral flywheel training (FT), using a rotational conical pulley, including multidirectional movements with either preplanned or random unanticipated/unexpected executions on functional performance in football players. Methods: A total of 32 young male football players were randomly assigned to an FT program including preplanned unilateral multidirectional movements (PTG, n = 11), an FT executing the same unilateral movements through random (ie, right or left leg) unanticipated (ie, verbal or visual cue) or unexpected (ie, moment where the cue was provided) situations (UTG, n = 11), or a control group (n = 10) that followed their football training routine. FT consisted of 1 set × 5–12 repetitions of 4 exercises performed once a week for 10 weeks. Intermittent endurance performance, repeated unilateral and bilateral jumping ability, change-of-direction (COD) ability, linear sprint velocity, preplanned repeated-sprint ability (RSA), and uncertainty RSA (RSA-RANDOM) were assessed preintervention and postintervention. Results: Significant improvements were found in RSA-RANDOM performance (P <.05, effect size [ES] range: UTG [1.83–2.16], PTG [0.69–0.73]) and COD (P <.05, ES: UTG = 1.34, PTG = 0.98]) in both training groups. Furthermore, significant improvements were also found in intermittent endurance performance (P =.016, ES = 0.37) and sprinting (P =.006, ES = 0.45) in UTG. No changes in any variable were found in the control group. No significant between-groups differences (P >.05) were reported between UTG and PTG, while differences were observed to the control group in unilateral jumping ability, COD, and RSA-RANDOM for UTG, and in RSA-RANDOM for PTG. Conclusions: A 10-week unilateral FT improved RSA-RANDOM and COD ability in youth football players, so both preplanned and unexpected situations should be included on strength training. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effects of 4 programming models (linear [LP], undulating [UP], reverse [RP], and constant [CP]) on physical performance. Methods: Forty-eight moderately strength-trained men were randomly assigned to LP, UP, RP, and CP groups according to their 1-repetition maximum (1RM) in the full-squat exercise (SQ) and followed an 8-week training intervention using the SQ and monitoring movement velocity for every repetition. All groups trained with similar mean relative intensity (65% 1RM), number of repetitions (240), sets (3), and interset recovery (4 min) throughout the training program. Pretraining and posttraining measurements included, in the SQ, 1RM load, the average velocity attained for all absolute loads common to pretests and posttests (AV), and the average velocity for loads that were moved faster (AV > 1) and slower (AV < 1) than 1 m·s−1 at pretraining tests. Moreover, countermovement jump height and 20-m running sprint time were measured. Results: A significant time effect was found for all variables analyzed (P <.05), except for 20-m running sprint time. Significant group × time interactions were observed for 1RM, AV > 1, and AV (P <.05). After training, all groups attained significant strength gains on 1RM, AV, AV > 1, and AV < 1 (P <.001–.01). LP and RP groups improved their countermovement jump height (P <.01), but no significant changes were observed for UP and CP. No significant improvements were achieved in 20-m running sprint time for any groups. Conclusions: These different programming models are all suitable for improving physical performance. LP and RP induce similar or greater gains in physical performance than UP and CP. [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]

Prior studies have explored the relationship between knee valgus and musculoskeletal variables to formulate injury prevention programs, primarily for females. Nonetheless, there is insufficient evidence pertaining to professional male soccer players. Here, the aim was to test the correlation of lateral trunk inclination, hip adduction, hip internal rotation, ankle dorsiflexion range of motion, and hip isometric strength with knee valgus during the single-leg vertical jump test. Twenty-four professional male soccer players performed a single-leg vertical hop test, hip strength assessments, and an ankle dorsiflexion range of motion test. A motion analysis system was employed for kinematic analysis. Maximal isometric hip strength and ankle dorsiflexion range of motion were tested using a handheld dynamometer and a digital inclinometer, respectively. The correlation of peak knee valgus with peak lateral trunk inclination was.43 during the landing phase (P =.04) and with peak hip internal rotation was −.68 (P <.001). For knee valgus angular displacement, only peak lateral trunk inclination presented a moderate positive correlation (r =.40, P =.05). This study showed that trunk and hip kinematics are associated with knee valgus, which could consequently lead to increased knee overload in male professional soccer players following a unilateral vertical landing test. [ABSTRACT FROM AUTHOR]

The purpose of this investigation was (1) to test the effect of movement restriction of the free leg during unilateral vertical jump on performance and power output comparing 2 different jump techniques: flexed (Classic technique) and straight (FC Luzern technique) free leg, and (2) to test the correlation between performance and power output obtained using these 2 techniques. Twenty elite soccer players performed squat (SJ) and countermovement (CMJ) jumps on each leg. The jump height and peak power output were compared between the 2 techniques for both legs. The jump height and peak power were significantly higher for the classic test for SJ and CMJ (P <.001) with no side effects or interactions. The angular range of motion of the free leg was higher for the Classic test than for the FC Lucerne test (P <.001), with no difference in the angular range of motion of the trunk. A moderate correlation was found between the 2 techniques on peak power (SJ: r =.626; CMJ: r =.649) and jump height (SJ: r =.742; CMJ: r =.891). Consequently, FC Lucerne technique, limiting the contribution of the free leg, is more appropriate to assess lower limb strength capacities during unilateral jump test. [ABSTRACT FROM AUTHOR]

The study compared superficial trunk muscle activity and postural control among an active extension subgroup of people with nonspecific chronic low back pain (AE-NSCLBP) with painfree controls during functional tasks. Thirty-two people (17 people with low back pain [LBP] and 15 painfree controls) participated in this study. Muscle activity of 5 trunk muscles and postural control were investigated during both standing tasks (eyes open/closed; single/double-leg balance) and dynamic functional tasks (spinal forward flexion and return, and a sit to stand transfer). Results showed that during single-leg standing, people with AE-NSCLBP exhibit higher muscle activity than painfree controls for 3 trunk muscles, especially with their eyes closed. There were no significant differences in muscle activity between eye conditions during double-leg standing and sit to stand transfer, forward flexion, and return from flexion. The AE-NSCLBP subgroup also demonstrated significantly impaired postural control (lower time to boundary) in 4 of 8 conditions, especially during single-leg standing and with their eyes closed. These findings show people with LBP typically demonstrated greater trunk muscle activity and poorer postural control while maintaining standing posture. This pattern was most evident when the postural challenge was higher, such as single-leg standing or with eyes closed. While this study design cannot infer causality, these findings have implications for LBP rehabilitation, particularly regarding approaches which seek to alter muscle activation among people with LBP. [ABSTRACT FROM AUTHOR]

Purpose: To investigate performance progression from early-junior to peak performance age and compare variety in race distances and swimming strokes between swimmers of various performance levels. Methods: Using a longitudinal data analysis and between-groups comparisons 306,165 annual best times of male swimmers (N = 3897) were used to establish a ranking based on annual best times at peak performance age. Individual performance trajectories were retrospectively analyzed to compare distance and stroke variety. Performances of world-class finalists and international- and national-class swimmers (swimming points: 886 [30], 793 [28], and 698 [28], respectively) were compared across 5 age groups—13–14, 15–16, 17–18, 19–20, and 21+ years—using a 2-way analysis of variance with repeated measures. Results: World-class finalists are not significantly faster than international-class swimmers up to the 17- to 18-year age group (F2|774 = 65, P <.001, η p 2 =.14) but specialize in short- or long-distance races at a younger age. World-class breaststroke finalists show faster breaststroke times compared to their performance in other swimming strokes from an early age (P <.05), while world-class freestyle and individual medley finalists show less significant differences to their performance in other swimming strokes. Conclusions: While federation officials should aim for late talent selection, that is, not before the 17- to 18-year age group, coaches should aim to identify swimmers' preferred race distances early on. However, the required stroke variety seems to be specific for each swimming stroke. Breaststroke swimmers could aim for early and strong specialization, while freestyle and individual medley swimmers could maintain large and very large stroke variety, respectively. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to report the reliability (intrasession) values of initial maximum push-rim propulsion (IMPRP) and sprint performance in elite wheelchair basketball (WB) players and to assess the involvement of strength in sprint capacity. Methods: Fifteen Spanish international WB male players participated in this study. The maximum single wheelchair push from a stationary position (IMPRP) and the sprint performance (ie, 3, 5, and 12 m) of WB players were measured in this study. Results: IMPRP mechanical outputs V, Vmax, P, Rel. P, F, and Rel. F variables presented high reliability values (intraclass correlation coefficient [ICC] ≥.92; coefficient of variation [CV] ≤ 8.04 ± 7.37; standard error of measurement [SEM] ≤ 29.92), but the maximum strength variables Pmax, Rel. Pmax, Fmax, and Rel. Fmax (ICC ≥.63; CV ≤ 13.19 ± 16.63; SEM ≤ 203.76) showed lower ICC values and by contrast higher CV and SEM values. The most substantial correlations were identified between maximum IMPRP values (ie, V, Vmax, P, Rel. P, F, and Rel. F) and sprint performance in 3 m (r ± confidence limits ≥ −0.74 ± 0.22, very large; R2 ≥.55), 5 m (r ± confidence limits ≥ −0.72 ± 0.24, very large; R2 ≥.51), and 12 m (r ± confidence limits ≥ −0.67 ± 0.27, large; R2 ≥.44). Conclusions: The IMPRP test and sprint tests (3, 5, and 12 m) are practical and reliable for measuring strength and speed in WB players. In addition, there were large to very large associations among strength variables (ie, P, Rel. P, F, and Rel. F) and all sprint variables. This could indicate a need to implement specific strength exercises in WB players to improve sprint capacity. [ABSTRACT FROM AUTHOR]

Precise protein supplementation strategies for muscle improvement are still lacking. The timing or type of protein supplementation has been debated as a window of opportunity to improve muscle mass, strength, and physical performance. We conducted a network meta-analysis of randomized controlled trials with protein supplements and resistance training. PubMed, Web of Science, Cochrane Library, and SPORTDiscus databases were searched until May 1, 2023. We included 116 eligible trials with 4,711 participants that reported on 11 timing and 14 types of protein supplementation. Compared with placebo, protein supplementation after exercise (mean difference [MD]: 0.54 kg [95% confidence intervals 0.10, 0.99] for fat-free mass, MD: 0.34 kg [95% confidence intervals 0.10, 0.58] for skeletal muscle mass) and at night (MD: 2.85 kg [0.49, 5.22] for handgrip strength, MD: 12.12 kg [3.26, 20.99] for leg press strength) was most effective in improving muscle mass and strength, respectively (moderate certainty). Milk proteins (milk, whey protein, yogurt, casein, and bovine colostrum), red meat, and mixed protein were effective for gains in both muscle mass and strength (moderate certainty). No timing or type of protein showed a significant enhancement in physical performance (timed up-to-go test, 6-min walk test, and gait speed). Pre/postexercise and Night are key recommended times of protein intake to increase muscle mass and strength, respectively. Milk proteins are the preferred types of protein supplements for improving muscle mass and strength. Future randomized controlled trials that directly compare the effects of protein timing or types are needed. This trial was registered at International Prospective Register of Systematic Reviews as CRD42022358766. [ABSTRACT FROM AUTHOR]

Resistance exercise training (RET) can be applied effectively to increase muscle mass and function in older adults (65–75 years). However, it has been speculated that older adults above 85 years are less responsive to the benefits of RET. This study compares the impact of RET on muscle mass and function in healthy older adults 65–75 years versus older adults above 85 years. We subjected 17 healthy older adults 65–75 years (OLDER 65–75, n = 13/4 [female/male]; 68 ± 2 years; 26.9 ± 2.3 kg/m2) and 12 healthy older adults above 85 years (OLDER 85+, n = 7/5 [female/male]; 87 ± 3 years; 26.0 ± 3.6 kg/m2) to 12 weeks of whole-body RET (three times per week). Prior to, and after 6 and 12 weeks of training, quadriceps and lumbar spine vertebra 3 muscle cross-sectional area (computed tomography scan), whole-body lean mass (dual-energy X-ray absorptiometry scan), strength (one-repetition maximum test), and physical performance (timed up and go and short physical performance battery) were assessed. Twelve weeks of RET resulted in a 10% ± 4% and 11% ± 5% increase in quadriceps cross-sectional area (from 46.5 ± 10.7 to 51.1 ± 12.1 cm2, and from 38.9 ± 6.1 to 43.1 ± 8.0 cm2, respectively; p <.001; η2 =.67); a 2% ± 3% and 2% ± 3% increase in whole-body lean mass (p =.001; η2 =.22); and a 38% ± 20% and 46% ± 14% increase in one-repetition maximum leg extension strength (p <.001; η2 =.77) in the OLDER 65–75 and OLDER 85+ groups, respectively. No differences in the responses to RET were observed between groups (Time × Group, all p >.60; all η2 ≤.012). Physical performance on the short physical performance battery and timed up and go improved (both p <.01; η2 ≥.22), with no differences between groups (Time × Group, p >.015; η2 ≤.07). Prolonged RET increases muscle mass, strength, and physical performance in the aging population, with no differences between 65–75 years and 85+ years older adults. [ABSTRACT FROM AUTHOR]

Despite a strong body of evidence supporting benefits of exercise to reduce severity of motor symptoms of Parkinson's Disease (PD) over time, research on the immediate impact of exercise as an adjunctive therapy for nonpharmacologic management of motor symptoms and mobility performance in people with PD is limited. The purpose of this study was to examine immediate effects of a single bout of high-cadence cycling on motor symptoms of PD and performance-based outcomes. Twenty individuals with idiopathic PD participated in a pretest/posttest study investigating immediate impacts of a single high-cadence cycling session on performance-based outcomes across multiple domains of motor function, mobility, and balance. Outcomes were analyzed based on time since last dose of levodopa/carbidopa medication. Immediate improvements were observed in motor symptoms of PD with significant improvements in performance across multiple balance systems, dynamic gait, and upper-extremity coordination following a cycling intervention. [ABSTRACT FROM AUTHOR]

Exercise is the single most effective strategy to reduce the risk of falls. Online classes have grown in popularity, but the benefits of online classes remain unknown. Zoomers on the Go is a peer-led 12-week exercise program offered twice weekly to adults 50+ years old. The main outcome was lower body strength measured by the 30-s chair stand test. Other outcomes included dropout, attendance, balance, cardiorespiratory fitness, and perceived health. A total of 74 participants (age 66.3 ± 7.1 years) in the online group and 84 participants in the in-person group (age 67.3 ± 7.2 years) completed the program, with attendance for the online group. Both groups significantly improved their 30-s chair stand, cardiorespiratory fitness, and balance (p <.001) with no difference in functional benefits between groups. The in-person group improved their perceived health and significantly reduced levels of stress and depression, while no such changes were observed in the online group. [ABSTRACT FROM AUTHOR]

Adequate body composition is essential for health, function, and independence in older adults. However, standard body composition assessments require complex and costly modalities, limiting their use for early detection of body composition changes and periodic follow-up. This study explored the ability of three practical measures—handgrip strength, five times sit-to-stand test, and upper limb loading during seated push-up test (ULL-SPUT)—to determine body composition in 109 older adults with and without sarcopenia. Participants (average age 76 years) were cross-sectionally measured for outcomes of the study. The ULL-SPUT and handgrip strength, but not the five times sit-to-stand test, significantly correlated with body composition (rs, r =.297–.827, p <.01). The ULL-SPUT, in combination with demographic data, could determine body composition up to 82%. Therefore, the ULL-SPUT may be a practical preliminary measure to identify older adults for whom standard body composition assessments and follow-up would prove timely and beneficial. [ABSTRACT FROM AUTHOR]

Gait asymmetry is a predictor of fall risk and may contribute to increased falls during pregnancy. Previous work indicates that pregnant women experience asymmetric joint laxity and pelvic tilt during standing and asymmetric joint moments and angles during walking. How these changes translate to other measures of gait asymmetry remains unclear. Thus, the purpose of this case study was to determine the relationships between pregnancy progression, subsequent pregnancies, and gait asymmetry. Walking data were collected from an individual during 2 consecutive pregnancies during the second and third trimesters and 6 months postpartum of her first pregnancy and the first, second, and third trimesters and 6 months postpartum of her second pregnancy. Existing asymmetries in step length, anterior–posterior (AP) impulses, AP peak ground reaction forces, lateral impulses, and joint work systematically increased as her pregnancy progressed. These changes in asymmetry may be attributed to pelvic asymmetry, leading to asymmetric hip flexor and extensor length, or due to asymmetric plantar flexor strength, as suggested by her ankle work asymmetry. Relative to her first pregnancy, she had greater asymmetry in step length, step width, braking AP impulse, propulsive AP impulse, and peak braking AP ground reaction force during her second pregnancy, which may have resulted from increased joint laxity. [ABSTRACT FROM AUTHOR]

Muscle fiber conduction velocity (MFCV) can be affected by muscle fiber geometry at different joint angles and during joint movements. This study aimed to investigate MFCV during electrically evoked contraction at different joint angles, during joint movements, and during voluntary contractions. Sixteen healthy young men participated. A stimulation electrode was attached on the innervation zone of the vastus lateralis, and a linear electrode array was attached on the vastus lateralis. Under a static condition, electrically evoked electromyography signals were recorded at knee joint angles set every 15° between 0° and 105°. Under a passive movement condition, signals were recorded during knee extension and flexion passively. Under a voluntary contraction condition, signals were recorded while performing 30% or 60% of maximum voluntary contraction. MFCV was calculated using cross-correlation coefficients. Under the static condition, there were no differences in MFCV among various joint angles. Under the passive movement condition, MFCV was significantly greater during high velocity or shortening. Under the voluntary contraction condition, MFCV was significantly greater during high-intensity voluntary contraction and with a shortened muscle length. Joint angles do not influence MFCV markedly during relaxation, but it is possible to overestimate MFCV during movement or voluntary contraction. [ABSTRACT FROM AUTHOR]

The purpose of this study was to test the feasibility and acceptability of a staff-delivered physical exercise program embedded into the daily lives of older adults living in nursing homes. A randomized controlled pilot feasibility study was carried out, which included quantitative, qualitative, and economic assessments at baseline, 12 weeks, and 12 months. Two nursing homes (one intervention and one control) took part. The exercise program was carried out on 3 days per week for 12 weeks and consisted of a program of Morning Movement (walking and sit-to-stand exercises) and Activity Bursts. The results confirm that the intervention and study processes are largely acceptable and feasible to implement in the nursing home setting. Potential short-term improvements in physical mobility and quality of life were noticed as positive mean changes and supported by qualitative assessment. Future randomized controlled trials should consider using the 6-meter walk test and refining nursing home and participant eligibility criteria. [ABSTRACT FROM AUTHOR]

Time spent in physical activity, sedentary behavior, and sleep collectively impact health of older adults. There is a need for valid self-reported methods for the assessment of movement behaviors across the entire 24-hr day. The aim of this study was to explore the validity of the German version of Daily Activity Behaviours Questionnaire (DABQ), the "Schlaf- und Aktivitätsfragebogen (SAF)," among older adults. Participants were asked to wear activity monitor (activPAL) for a period of 8 days and to complete the German version of DABQ. Seventy-seven participants (45 females; 68 ± 5 years of age) completed the protocol. Spearman's correlation coefficients between DABQ and activPAL estimates for time spent in sleep, sedentary behavior, light physical activity, and moderate to vigorous physical activity were.69,.35,.24, and.52, respectively. The German version of the DABQ showed satisfactory validity to be used in epidemiological research and population surveillance among older adults. [ABSTRACT FROM AUTHOR]

Purpose: Ice hockey is a team invasion sport characterized by repeated high-intensity skating efforts, technical and tactical skill, physical contact, and collisions requiring considerable levels of muscular strength. The purpose of this study was to evaluate the relationships between lower-body vertical force–time metrics and skating qualities in subelite female ice hockey players. Methods: A cross-sectional cohort design was employed utilizing 14 athletes (body mass = 66.7 [1.8] kg; height = 171.6 [6.2] cm; age = 21.1 [1.7] y). The relationships between metrics of lower-body strength collected from a drop jump, squat jump, countermovement jump, loaded countermovement jump, and an isometric squat and 4 skating qualities collected from a linear sprint, repeated sprint test, and a multistage aerobic test were evaluated. Results: The regression models revealed a positive relationship between relative peak force in the isometric squat and skating multistage aerobic test performance (r2 =.388; P =.017) and a positive relationship between repeated-sprint ability and eccentric mean force during the loaded countermovement jump (r2 =.595; P =.001). No significant relationships were observed between strength metrics and skating acceleration or maximal velocity. Conclusions: These data suggest that skating ability is most affected by relative isometric strength in female ice hockey players. It is recommended that practitioners focus training on tasks that improve relative force output. It is also recommended that isometric relative peak force be used as a monitoring metric for this cohort. [ABSTRACT FROM AUTHOR]

Purpose: The study examined the longitudinal interplay of anthropometric, metabolic, and neuromuscular development related to performance in adolescent national-level swimmers over 12 months. Methods: Seven male and 12 female swimmers (14.8 [1.3] y, FINA [International Swimming Federation] points 716 [51]) were tested before (T0) and after the preparation period (T1), at the season's peak (T2), and before the next season (T3). Anthropometric (eg, fat percentage) and neuromuscular parameters (squat and bench-press load-velocity profile) were assessed on dry land. Metabolic (cost of swimming [C], maximal oxygen uptake [ V ˙ O 2 peak ], and peak blood lactate [bLapeak]) and performance (sprinting speed [vsprint] and lactate thresholds [LT1 and 2]) factors were determined using a 500-m submaximal, 200-m all-out, 20-second sprint, and incremental test (+0.03 m·s−1, 3 min), respectively, in front-crawl swimming. Results: vsprint (+0.6%) and LT1 and 2 (+1.9–2.4%) increased trivially and slightly, respectively, from T0 to T2 following small to moderate strength increases (≥+10.2%) from T0 to T1 and V ˙ O 2 peak (+6.0%) from T1 to T2. Bench-press maximal strength and peak power correlated with vsprint from T0 to T2 (r ≥.54, P <.05) and LT2 at T1 (r ≥.47, P <.05). Changes in fat percentage and V ˙ O 2 peak (T2–T1 and T3–T2, r ≤ −.67, P <.01) and C and LT2 (T2–T0, r = −.52, P =.047) were also correlated. Conclusions: Increases in strength and V ˙ O 2 peak from preparation to the competition period resulted in improved sprint and endurance performance. Across the season, upper-body strength was associated with vsprint and LT2, although their changes were unrelated. [ABSTRACT FROM AUTHOR]