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Purpose: This meta-analysis aimed to (1) provide a comparison of peak changes in indirect markers of exercise-induced muscle damage (EIMD) in youths versus adults and (2) determine if the involved limb moderated this effect. Method: Studies were eligible for inclusion if they (1) provided a human youth versus adult comparison; (2) provided data on muscle strength, soreness, or creatine kinase markers beyond ≥24 hours; and (3) did not provide a recovery treatment. Effect sizes (ES) were presented alongside 95% confidence intervals. Results: EIMD exhibited larger effects on adults than in youths for muscle strength (ES = −2.01; P <.001), muscle soreness (ES = −1.52; P <.001), and creatine kinase (ES = −1.98; P <.001). The random effects meta-regression indicated that the effects of upper- and lower-limb exercise in youths and adults were significant for muscle soreness (coefficient estimate = 1.11; P <.001) but not for muscle strength or creatine kinase (P >.05). As such, the between-group effects for muscle soreness (ES = −2.10 vs −1.03; P <.05) were greater in the upper than lower limbs. Conclusion: The magnitude of EIMD in youths is substantially less than in their adult counterparts, and this effect is greater in upper than lower limbs for muscle soreness. These findings help guide practitioners who may be concerned about the potential impact of EIMD when training youth athletes. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of a 10-month neuromuscular training (NMT) intervention on muscle architecture, isometric force production, and stretch-shortening cycle (SSC) function. Thirty-seven girls aged 6-12 years were placed into gymnastics + NMT (gNMT; n = 15), gymnastics only (GYM; n = 10), or maturity-matched control (CON; n = 12) groups. The gNMT group followed a 10-month NMT program in addition to gymnastics training, whereas the GYM group only participated in gymnastics training. Isometric midthigh pull (IMTP) and drop jump (DJ) kinetics were measured, in addition to muscle thickness, fascicle length, and pennation angle of the gastrocnemius medialis at baseline and at 4, 7, and 10 months. A3 x 4 (group x time) repeated-measures ANCOVA (covariate, % predicted adult height) was used to evaluate within-group changes. Significance level was set at p < 0.05. Significant interaction effects were observed in muscle thickness, absolute (PFabs) and relative peak force (PFrel) in the IMTP and various DJ variables. The gNMT group demonstrated improvements in muscle thickness, IMTP PFabs and PFrel, and DJ kinetics, most commonly evidenced from 7 months onward. The GYM group's muscle thickness also significantly improved, accompanied by improvements in some DJ kinetics. The CON group did not experience any desirable changes. Overall, NMT elicited positive changes in muscle thickness, PFabs and PFrel, and SSC function to a greater extent than gymnastics training alone or growth and maturation. As most adaptations took 7 months, longer-term NMT programs should be implemented with youth female gymnasts. [ABSTRACT FROM AUTHOR]

Relationships between force-generating capabilities and weightlifting performance (e.g., snatch, clean and jerk [C&J], and combined total) have previously been explored in adult weightlifters; however, associations in young athletes are unknown. The purpose of this study was twofold: (a) to examine the relationships between countermovement jump (CMJ) and isometric midthigh pull (IMTP) kinetics and weightlifting performance in young weightlifters and (b) to determine the proportion of weightlifting performance that could be accounted for by CMJ and IMTP kinetics using principal component analysis (PCA). Thirty-seven young weightlifters (12-18 years of age) completed 3 trials of CMJ and 2 trials of the IMTP assessments on dual force plates. Recent competition maximum loads, obtained within 2 weeks of the data collection, for the C&J and snatch were also recorded. Pearson's zero-order correlation coefficients demonstrated moderate to very high correlations (r = 0.359-0.801; all p ≤ Benjamini-Hochberg critical values [B-Hα]) between CMJ kinetic variables, including jump height, average braking force, average braking velocity, absolute and relative braking net impulse, absolute and relative force at minimum displacement, absolute and relative propulsive force, absolute and relative propulsive net impulse and average propulsive velocity, and weightlifting performance. High to very high correlations were evident between IMTP peak force and relative peak force and all weightlifting performance metrics (snatch, C&J, combined total, combined total [kg]/body mass [kg-0.67], and Sinclair's total; r = 0.538-0.796; p ≤ B-Hα). Components from the PCA were used to conduct stepwise, multiple, linear regression analyses. Moderate (45.8-52.9%) and large percentages (79.1-81.3%) of variance in absolute measures of weightlifting performance were explained by IMTP peak force variables and CMJ propulsive variables, respectively. These novel findings indicate that IMTP peak force variables and CMJ propulsive variables could provide valuable insight for talent identification and long-term athletic development in junior weightlifting pathways. [ABSTRACT FROM AUTHOR]

This study investigates the inter-week test-retest reliability of 9.14 meter (10 yard) sprint times in youth athletes. Although essential for assessing athletic ability and training efficacy, the critical and comprehensive examination of both relative and absolute reliability indices for short-distance sprints has been insufficient in youth contexts. One hundred ninety-eight youth athletes (128 males and 70 females) underwent 2 sprint attempts across 2 separate trials 24 hours apart and within 7 days of each other. The sprints were measured using dual-beam timing gates to capture split times for 0-4.57 meter (0-5 yards), 4.57-9.14 meter (5-10 yards), and 0-9.14 meter (0-10 yards). The minimal mean difference between the best sprint times across trials was 0.02 ± 0.13 seconds for males and 0.003 ± 0.14 seconds for females. No significant mean differences were found between trials for either gender (males: p = 0.0875; females: p = 0.8752), suggesting no systematic bias in sprint times. The SEM was 0.092 seconds for males and 0.099 seconds for females, with a corresponding SEMCV% of 4.6 and 4.8%. The overall coefficient of variation was 9.8% for males and 8.9% for females. Intraclass correlation coefficient values suggested that the sprint times across trials were reliable (males: 0.80; females: 0.76). The minimal detectable change was 0.25 seconds for males, 0.27 seconds for females. Cohen's d indicated trivial effects (<0.2) for males (0.154) and females (0.021). Minimal mean differences, a low SEM, and consistent ICC values demonstrate that the 0-9.14 meter sprint is a reliable assessment in youth athletes. [ABSTRACT FROM AUTHOR]

This aim of this study was to investigate the effects of a 12-week resistance training program in talented junior golfers. Eighteen talented youth golfers were pair matched by maturity status and handicap, and subsequently allocated to an experimental (EXP) or control group. During the 12-week intervention, both groups continued with their normal golf practice while the EXP group also completed a progressive twice-weekly resistance training program. At baseline, subjects performed multiple trials of an isometric midthigh pull (IMTP), counter-movement jump (CMJ), standing long jump, golf movement screen (GMS), and isometric plank hold. Club head speed (CHS) and carry distance for a 6-iron and driver were also measured using a commercial launch monitor. When controlled for maturity offset, there were significant (p < 0.05) interaction effects in favor of the EXP group for absolute (g = 1.29) and relative (g = 2.06) peak force forthe IMTP, CMJ absolute (g = 0.73) and relative (g = 0.66) peak power, jump height (g = 1.05), modified reactive strength index (g = 1.30), lateral (g = 0.48-0.88) and horizontal jump distance (g = 1.20), and GMS total score (g = 1.07). Significant interaction effects were also reported in 6-iron and driver CHS and carry distance in favor of the EXP group (p < 0.05; g = 0.41-1.64). These findings indicate that twice-weekly resistance training in combination with regular golf practice can stimulate increases in measures of strength, power, and movement competency in youth golfers, which should contribute to enhanced golf swing performance. [ABSTRACT FROM AUTHOR]

Golfers who want to improve their technical proficiency will undoubtedly hire a swing coach who may also influence and give advice on how the golfer can improve outside of technical enhancement (i.e. strength and conditioning, warm-ups, cool-downs etc.). With research examining the effects of strength and conditioning on youth golfers beginning to materialise, it is important to ascertain golf coaches' perceptions of strength and conditioning, warm-ups and cool-downs and how they are utilised with youth golfers. Fifty Professional Golfers' Association Professionals and Assistant Professionals completed an online questionnaire on their perceptions of, and approaches to, strength and conditioning, warm-up and cool-down activities for youth golfers. Data indicated that 84% and 80% of coaches perceived strength and conditioning could enhance golf swing performance and reduce the risk of injury, respectively. Although all coaches agreed golfers aged 18 years and under can take part in strength and conditioning activities, there was no consensus on when a golfer should start strength and conditioning activities, with most coaches unaware of the existing guidelines surrounding youth resistance training. Warm-ups are perceived by coaches to be beneficial for youth golfers with > 75% of coaches stating their players completed a warm-up, however, the modes of exercise coaches deemed suitable for a warm-up were varied. Cool-downs were deemed beneficial for aiding recovery post-round, yet over half of coaches selected their players did not habitually complete one. Findings from the questionnaire highlight that although perceptions towards strength and conditioning, warm-ups and cool-downs are positive, educational solutions to disseminate the underlying contemporary guidelines and practical applications to coaches and players are required. [ABSTRACT FROM AUTHOR]