Youths Are Less Susceptible to Exercise-Induced Muscle Damage Than Adults: A Systematic Review With Meta-Analysis.

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.

Kinetic and Kinematic Assessment of the Band-Assisted Countermovement Jump.

ABSTRACT: Fernandes, JFT, Arede, J, Clarke, H, Garcia-Ramos, A, Perez-Castilla, A, Norris, JP, Wilkins, CA, and Dingley, AF. Kinetic and kinematic assessment of the band-assisted countermovement jump. J Strength Cond Res 37(8): 1588-1593, 2023-This study sought to elucidate kinetic and kinematic differences between unloaded and band-assisted countermovement jumps (CMJs). In a randomized order, 20 healthy subjects (mass 84.5 ± 18.6 kg) completed 3 repetitions of CMJs across 3 conditions: unloaded (at body mass), low, and moderate band (8.4 ± 1.9 and 13.3 ± 3.3 kg body mass reduction, respectively). For all repetitions, a force platform and linear position transducer were used to record and calculate kinetic and kinematic data. Body mass was significantly different between the unloaded, low, and moderate band conditions ( p < 0.05). Peak velocity, absolute peak, and mean force and movement duration displayed a trend that was mostly related to the condition (i.e., unloaded > low > moderate) ( p < 0.05). The opposing trend (i.e., moderate > low > unloaded) was generally observed for relative peak and mean force, reactive strength index modified, and flight time ( p < 0.05). No differences were observed for mean velocity, movement duration, and absolute and relative landing forces ( p > 0.05). The use of band assistance during CMJs can alter force, time, and velocity variables. Practitioners should be aware of the potential positive and negative effects of band assistance during CMJs.

Knowledge of results during vertical jump testing: an effective method to increase the performance but not the consistency of vertical jumps.

This study aimed to determine whether the provision of jump height feedback (knowledge of result; KR) can increase the performance and the consistency of output variables. In a randomised order, sixteen participants performed six squat or countermovement jumps (three from a 90º knee angle and three from a self-preferred knee angle) with or without KR over four sessions. The provision of KR significantly increased peak force (p = 0.046, 1.83%), mean force (p = 0.037, 1.45%), peak velocity (p < 0.001, 3.71%), mean velocity (p = 0.004, 3.44%), peak power (p < 0.001, 4.22%) and mean power (p = 0.001, 4.69%). A high within-session reliability was observed for all variables (coefficient of variation [CV] ≤ 5.62%, intraclass correlation coefficient [ICC] ≥ 0.95). No systematic differences in reliability were detected between the jumps performed without KR (CV = 3.00 ± 1.38%, ICC = 0.97 ± 0.03) and with KR (CV = 3.04 ± 1.49%, ICC = 0.97 ± 0.04). These results suggest that the provision of jump height feedback during vertical jump testing is effective to enhance vertical jump performance but it does not reduce the variability between jumps.

Feasibility of the 2-point method to determine the load-velocity relationship variables during the countermovement jump exercise.

PURPOSE: This study aimed to examine the reliability and validity of load-velocity (L-V) relationship variables obtained through the 2-point method using different load combinations and velocity variables. METHODS: Twenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads (20 kg, 40 kg, 60 kg, and 80 kg) and a heavy squat against a load linked to a mean velocity (MV) of 0.55 m/s (load0.55). The L-V relationship variables (load-axis intercept (L0), velocity-axis intercept (v0), and area under the L-V relationship line (Aline)) were obtained using 3 velocity variables (MV, mean propulsive velocity (MPV), and peak velocity) by the multiple-point method including (20-40-60-80-load0.55) and excluding (20-40-60-80) the heavy squat, as well as from their respective 2-point methods (20-load0.55 and 20-80). RESULTS: The L-V relationship variables were obtained with an acceptable reliability (coefficient of variation (CV) ≤ 7.30%; intra-class correlation coefficient ≥ 0.63). The reliability of L0 and v0 was comparable for both methods (CVratio (calculated as higher value/lower value): 1.11-1.12), but the multiple-point method provided Aline with a greater reliability (CVratio = 1.26). The use of a heavy squat provided the L-V relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load (CVratio: 1.06-1.19). The peak velocity provided the load-velocity relationship variables with the greatest reliability (CVratio: 1.15-1.86) followed by the MV (CVratio: 1.07-1.18), and finally the MPV. The 2-point methods only revealed an acceptable validity for the MV and MPV (effect size ≤ 0.19; Pearson's product-moment correlation coefficient ≥ 0.96; Lin's concordance correlation coefficient ≥ 0.94). CONCLUSION: The 2-point method obtained from a heavy squat load and MV or MPV is a quick, safe, and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the L-V relationship.

Biological maturation, contextual factors, and future career in basketball: A possible interrelationship?

This study aimed to analyse the relationship between the maturational state and contextual factors with future basketball career success in Under-16 (U16) Portuguese youth preparing for the U16 European Basketball Championships. Eighty-five Under-15 (U15) and U16 male basketball players (height: 189.7 ± 6.53 cm; body mass: 81.1 ± 9.96 kg; the age of peak height velocity: 13.3 ± 0.7 y) were selected by the Portuguese national coaching staff to participate in a national team training camp in 2016, 2017, and 2018 years. A binary logistic regression was employed to identify the influence of maturation, born quartile, demographic, geographic and economic characteristics, and sport career (i.e., drop out during first season and chance of playing professionally). Early maturing players were typically classified as inside players. Training experience and predicted adult height, and type of first club were able to predict players who dropped out during their first season at senior level (both p < 0.01). No variables were able to predict who played in a professional league during their first season at senior level. Practitioners should use these data to consider how national level basketball players are identified and developed, but also keep in mind of their specific contextual factors.

Differential Repeated Sprinting Training in Youth Basketball Players: An Analysis of Effects According to Maturity Status.

The differential learning approach, which includes fluctuations that occur without movement repetitions and without corrections has received growing interest in the skill acquisition field. This study aimed to determine the effects of a 9-week training intervention involving differential repeated sprint training on a series of physical tests in youth basketball players. A total of 29 participants with different maturity statuses (pre-peak height velocity (PHV), n = 7; mid-PHV, n = 6; post-PHV, n = 16) completed 2 sessions per week of differential repeated sprint training for a period of 9 weeks. Sessions consisted of 2 × 10 repetitions sprints of 20-m whereby participants were instructed to perform various additional fluctuations for each repetition. Before and after the training intervention, participants completed jumping tests (countermovement jump (CMJ), single-leg CMJs, the modified 505 agility test, and straight sprinting tests (0-10 splits time), and maturity status was evaluated as well. Within-group analysis showed improvement in CMJ asymmetries and changes in direction asymmetries and 10-m sprint performance for the pre-, mid-, and post-PHV groups, respectively (p < 0.05), with large to very large effects. Analysis of covariance demonstrated that changes in sprint time in post-PHV players were greater than in the pre- and mid-PHV groups (p < 0.05), with moderate effect. Adding random fluctuations during repeated sprint training appear to be a suitable and feasible training strategy for maintaining and enhancing physical performance in youth basketball players, irrespective of maturity status. Furthermore, the present findings encourage practitioners to implement the present approach in youth athletes to improve their physical performance, but they should be aware that training response can vary according to maturity status.

Training Load, Maturity Timing and Future National Team Selection in National Youth Basketball Players.

Despite its importance to the management of training stress, monotony and recovery from exercise, training load has not been quantified during periods of intensity training in youths. This study aimed to (1) examine and quantify the training load (TL) in youth national team basketball players during a 2-week training camp according to maturity timing and (2) determine which parameters were related to under-18 (U18) national team selection. Twenty-nine U-16 national team basketball players underwent an anthropometric assessment to determine maturity timing. Players were categorised by maturity timing (early vs. average), whilst TL parameters during a 2-week training camp (i.e., 21 sessions) prior to FIBA U16 European Championship were used for group comparison and to predict future U-18 national team selection. The early-maturing players, who were taller and heavier (p < 0.05), experienced greater training strain in week 1 (p < 0.05) only. Irrespective of maturity timing, training loads in week 2 were predictive of onward selection for the U-18 national team. Conclusion: Based on present findings, practitioners are encouraged to develop their athletes' ability to tolerate high weekly loads, but also to be mindful that athletes' perceived exertion during national team training may be influenced by maturity timing.

Prediction of One Repetition Maximum Using Reference Minimum Velocity Threshold Values in Young and Middle-Aged Resistance-Trained Males.

BACKGROUND: This study determined the accuracy of different velocity-based methods when predicting one-repetition maximum (1RM) in young and middle-aged resistance-trained males. METHODS: Two days after maximal strength testing, 20 young (age 21.0 ± 1.6 years) and 20 middle-aged (age 42.6 ± 6.7 years) resistance-trained males completed three repetitions of bench press, back squat, and bent-over-row at loads corresponding to 20-80% 1RM. Using reference minimum velocity threshold (MVT) values, the 1RM was estimated from the load-velocity relationships through multiple (20, 30, 40, 50, 60, 70, and 80% 1RM), two-point (20 and 80% 1RM), high-load (60 and 80% 1RM) and low-load (20 and 40% 1RM) methods for each group. RESULTS: Despite most prediction methods demonstrating acceptable correlations (r = 0.55 to 0.96), the absolute errors for young and middle-aged groups were generally moderate to high for bench press (absolute errors = 8.2 to 14.2% and 8.6 to 20.4%, respectively) and bent-over-row (absolute error = 14.9 to 19.9% and 8.6 to 18.2%, respectively). For squats, the absolute errors were lower in the young group (5.7 to 13.4%) than the middle-aged group (13.2 to 17.0%) but still unacceptable. CONCLUSION: These findings suggest that reference MVTs cannot accurately predict the 1RM in these populations. Therefore, practitioners need to directly assess 1RM.

Eccentric Resistance Training in Youth: A Survey of Perceptions and Current Practices by Strength and Conditioning Coaches.

BACKGROUND: Eccentric resistance training (ERT) in youth is advocated for aiding performance and injury risk. However, research investigating the applied practices of ERT in youth is in its infancy. In this study, we surveyed the perceptions and practices of practitioners utilizing ERT in youth to provide an understanding of its current application in practice. METHODS: Sixty-four strength and conditioning coaches completed an online survey reporting their current use of ERT in youth using both open and closed questions. RESULTS: Coaches deemed the inclusion of ERT important in youth with its inclusion based upon factors such as maturation status, training age and strength levels. Coaches also displayed an awareness of the physiological responses to eccentric exercise in youth compared to adults. ERT was primarily used for injury prevention, with the majority of coaches using body-weight and tempo exercises. Furthermore, utilizing eccentric hamstrings exercises was reported as highly important. The frequency of ERT tended to increase in older age groups and coaches mainly prescribed self-selected rest intervals. Finally, the need for further research into the training guidelines of ERT in youth was highlighted, in which coaches require more information on how maturation influences training adaptations and the fatigue-recovery responses. CONCLUSION: Coaches emphasized the importance of including ERT for both performance and injury prevention factors in youth although further research is required to generate practical guidelines for coaches in order to support its inclusion within practice.

Validity of Different Velocity-Based Methods and Repetitions-to-Failure Equations for Predicting the 1 Repetition Maximum During 2 Upper-Body Pulling Exercises.

ABSTRACT: Pérez-Castilla, A, Suzovic, D, Domanovic, A, Fernandes, JFT, and García-Ramos, A. Validity of different velocity-based methods and repetitions-to-failure equations for predicting the 1 repetition maximum during 2 upper-body pulling exercises. J Strength Cond Res 35(7): 1800-1808, 2021-This study aimed to compare the accuracy of different velocity-based methods and repetitions-to-failure equations for predicting the 1 repetition maximum (i.e., maximum load that can be lifted once; 1RM) during 2 upper-body pulling exercises. Twenty-three healthy subjects (twelve men and eleven women) were tested in 2 sessions during the lat pull-down and seated cable row exercises. Each session consisted of an incremental loading test until reaching the 1RM followed by a set of repetitions-to-failure against the 80% 1RM load. The 1RM was estimated from the individual load-velocity relationships modeled through 4 (∼40, 55, 70, and 85% 1RM; multiple-point method) or 2 loads (∼40 and 85% 1RM; 2-point method). Mean velocity was recorded with a linear position transducer and a Smartphone application. Therefore, 4 velocity-based methods were used as a result of combining the 2 devices and the 2 methods. Two repetitions-to-failure equations (Mayhew and Wathen) were also used to predict the 1RM from the load and number of repetitions completed. The absolute differences with respect to the actual 1RM were higher for the repetitions-to-failure equations than velocity-based methods during the seated cable row exercise (p = 0.004), but not for the lat pull-down exercise (p = 0.200). The repetitions-to-failure equations significantly underestimated the actual 1RM (p < 0.05; range: -6.65 to -2.14 kg), whereas no systematic differences were observed for the velocity-based methods (range: -1.75 to 1.65 kg). All predicted 1RMs were highly correlated with the actual 1RM (r ≥ 0.96). The velocity-based methods provide a more accurate estimate of the 1RM than the Mayhew and Wathen repetitions-to-failure equations during the lat pull-down and seated cable row exercises.

Comparison of the FitroDyne and GymAware Rotary Encoders for Quantifying Peak and Mean Velocity During Traditional Multijointed Exercises.

ABSTRACT: Fernandes, JFT, Lamb, KL, Clark, CCT, Moran, J, Drury, B, Garcia-Ramos, A, and Twist, C. Comparison of the FitroDyne and GymAware rotary encoders for quantifying peak and mean velocity during traditional multijointed exercises. J Strength Cond Res 35(6): 1760-1765, 2021-The FitroDyne and GymAware rotary encoders are being increasingly used in resistance training to monitor movement velocity, but how closely their velocity outcomes agree is unknown. Consequently, this study aimed to determine the level of agreement between the FitroDyne and GymAware for the assessment of movement velocity in 3 resistance training exercises. Fifteen men performed 3 repetitions of bench press, back squat, and bent-over-row exercises at 10% 1 repetition maximum increments (from 20 to 80%). For each repetition, the FitroDyne and GymAware recorded peak and mean barbell velocity (cm·s-1). Although strongly correlated (r = 0.79-1.00), peak velocity values for the GymAware were significantly lower than the FitroDyne for all exercises and loads. Importantly, the random errors between the devices, quantified through Bland and Altman's 95% limits of agreement, were unacceptable, ranging from ±3.8 to 25.9 cm·s-1. Differences in mean velocity were smaller (and nonsignificant for most comparisons) and highly correlated (r = 0.86-1.00) between devices. Notwithstanding smaller random errors than for the peak values, mean values still reflected poor agreement (random errors between ±2.1 and 12.0 cm·s-1). These findings suggest that the FitroDyne and GymAware cannot record peak or mean velocity with acceptable agreement and should neither be used interchangeably nor their data compared.

Aging and Recovery After Resistance-Exercise-Induced Muscle Damage: Current Evidence and Implications for Future Research.

Aging is anecdotally associated with a prolonged recovery from resistance training, though current literature remains equivocal. This brief review considers the effects of resistance training on indirect markers of muscle damage and recovery (i.e., muscle soreness, blood markers, and muscle strength) in older males. With no date restrictions, four databases were searched for articles relating to aging, muscle damage, and recovery. Data from 11 studies were extracted for review. Of these, four reported worse symptoms in older compared with younger populations, while two have observed the opposite, and the remaining studies (n = 6) proposed no differences between age groups. It appears that resistance training can be practiced in older populations without concern for impaired recovery. To improve current knowledge, researchers are urged to utilize more ecologically valid muscle-damaging bouts and investigate the mechanisms which underpin the recovery of muscle soreness and strength after exercise in older populations.

Influence of Coaching Condition on the Magnitude and Reliability of Drop Jump Height in Men and Women.

This study examined the effect of different coaching conditions on the magnitude and reliability of drop jump height in men and women. Nineteen collegiate sport sciences students (10 men) performed two sets of 10 drop jumps under four different coaching conditions: neutral, augmented feedback, external focus of attention, and a combination of augmented feedback and external focus of attention. The augmented feedback condition revealed a significantly higher jump height than the neutral condition (p = .002), while no significant differences were observed for the remaining conditions (p ≥ .38). The external focus of attention condition was more reliable than the neutral and augmented feedback conditions (coefficient of variationratio ≥ 1.15), while no differences were observed between the remaining conditions. These results suggest that both the magnitude and reliability of the drop jump height performance are influenced by the coaching condition.

Self-Selected Versus Standardised Warm-Ups; Physiological Response on 500 m Sprint Kayak Performance.

This study investigated the effectiveness of a self-selected (SS) warm-up on 500 m sprint kayak performance (K500) compared to continuous (CON) and intermittent high intensity (INT)-type warm-ups. Twelve nationally ranked sprint kayakers (age 17.7 ± 2.3 years, mass 69.2 ± 10.8 kg) performed CON (15 min at the power at 2 m·mol-1), INT (10 min at 2 m·mol-1, followed by 5 × 10 s sprints at 200% power at VO2max with 50 s recovery at 55% power at VO2max), and SS (athlete's normal competition warm-up) warm-ups in a randomised order. After a five-minute passive recovery, K500 performance was determined on a kayak ergometer. Heart rate and blood lactate (BLa) were recorded before and immediately after each warm-up and K500 performance. Ratings of perceived exertion (RPE) were recorded at the end of the warm-up and K500. BLa, heart rate, and RPE were generally higher after the INT than CON and SS warm-ups (p < 0.05). No differences in these parameters were found between the conditions for the time trial (p > 0.05). RPE and changes in BLa and heart rate after the K500 were comparable. There were no differences in K500 performance after the CON, SS, or INT warm-ups. Applied practitioners can, therefore, attain similar performance independent of warm-up type.

Group versus Individualised Minimum Velocity Thresholds in the Prediction of Maximal Strength in Trained Female Athletes.

This study examined the accuracy of different velocity-based methods in the prediction of bench press and squat one-repetition maximum (1RM) in female athletes. Seventeen trained females (age 17.8 ± 1.3 years) performed an incremental loading test to 1RM on bench press and squat with the mean velocity being recorded. The 1RM was estimated from the load-velocity relationship using the multiple- (8 loads) and two-point (2 loads) methods and group and individual minimum velocity thresholds (MVT). No significant effect of method, MVT or interaction was observed for the two exercises (p > 0.05). For bench press and squat, all prediction methods demonstrated very large to nearly perfect correlations with respect to the actual 1RM (r range = 0.76 to 0.97). The absolute error (range = 2.1 to 3.8 kg) for bench press demonstrated low errors that were independent of the method and MVT used. For squat, the favorable group MVT errors for the multiple- and two-point methods (absolute error = 7.8 and 9.7 kg, respectively) were greater than the individual MVT errors (absolute error = 4.9 and 6.3 kg, respectively). The 1RM can be accurately predicted from the load-velocity relationship in trained females, with the two-point method offering a quick and less fatiguing alternative to the multiple-point method.

Low Body Fat Does Not Influence Recovery after Muscle-Damaging Lower-Limb Plyometrics in Young Male Team Sport Athletes.

AIM: This study assessed the influence of fat mass to fat-free mass ratio (FM:FFM) on recovery from plyometric exercise. METHOD: After assessment of body composition, 20 male team sport players (age 20.7 ± 1.1 years; body mass 77.1 ± 11.5 kg) were divided into low- (n = 10; 0.11 ± 0.03) and normal- (n = 10; 0.27 ± 0.09) fat groups based on FM:FFM ratio. Thereafter, participants completed measurements of knee extensor torque at 60 and 240°âˆ™s-1, countermovement jump flight time, plasma creatine kinase (CK) activity and perceived muscle soreness (VAS) before and at 0, 24 and 48 h after 10 × 10 maximal plyometric vertical jumps. RESULTS: Evidence of muscle damage was confirmed by alterations in VAS, peak torque at 60 and 240°âˆ™s-1 and flight time at 0, 24 and 48 h after plyometric exercise (P < 0.05). CK was increased at 0 and 24 h (P < 0.05) but returned to baseline values by 48 h. No time by group effects were observed for any of the dependent variables (P > 0.05). CONCLUSION: The current findings indicate that while muscle damage was present after plyometric exercise, the magnitude was similar across the two body composition groups. Applied practitioners can allow for a similar recovery time after plyometric exercise in those with low and normal body fat.

Exercise-Induced Muscle Damage and Recovery in Young and Middle-Aged Males with Different Resistance Training Experience.

This study compared the time course of recovery after a squatting exercise in trained young (YG; n = 9; age 22.3 ± 1.7 years) and trained (MT; n = 9; 39.9 ± 6.2 years) and untrained (MU; n = 9; age 44.4 ± 6.3 years) middle-aged males. Before and at 24 and 72 h after 10 × 10 squats at 60% one-repetition maximum (1RM), participants provided measurements of perceived muscle soreness (VAS), creatine kinase (CK), maximal voluntary contraction (MVC), voluntary activation (VA), and resting doublet force of the knee extensors and squatting peak power at 20% and 80% 1RM. When compared to the YG males, the MT experienced likely and very likely moderate decrements in MVC, resting doublet force, and peak power at 20% and 80% 1RM accompanied by unclear differences in VAS, CK, and VA after the squatting exercise. MU males, compared to MT, experienced greater alterations in peak power at 20% and 80% 1RM and VAS. Alterations in CK, MVC, VA, and resting doublet force were unclear at all time-points between the middle-aged groups. Middle-aged males experienced greater symptoms of muscle damage and an impaired recovery profile than young resistance trained males. Moreover, regardless of resistance training experience, middle-aged males are subject to similar symptoms after muscle-damaging lower-body exercise.

Effects of Small-Sided Games vs. Conventional Endurance Training on Endurance Performance in Male Youth Soccer Players: A Meta-Analytical Comparison.

BACKGROUND: Small-sided games have been suggested as a viable alternative to conventional endurance training to enhance endurance performance in youth soccer players. This has important implications for long-term athlete development because it suggests that players can increase aerobic endurance through activities that closely resemble their sport of choice. OBJECTIVES: The objectives of this meta-analysis were to compare male youth soccer players' adaptability to small-sided games vs. conventional endurance training and to establish exercise prescription guidelines for this population. DATA SOURCES: The data sources utilised were Google Scholar, PubMed and Microsoft Academic. STUDY ELIGIBILITY CRITERIA: Studies were eligible for inclusion if interventions were carried out in male soccer players (aged < 18 years) and compared the effects of small-sided games and conventional endurance training on aerobic endurance performance. We defined small-sided games as "modified [soccer] games played on reduced pitch areas, often using adapted rules and involving a smaller number of players than traditional games". We defined conventional endurance training as continuous running or extensive interval training consisting of work durations > 3 min. STUDY APPRAISAL AND SYNTHESIS METHODS: The inverse-variance random-effects model for meta-analyses was used because it allocates a proportionate weight to trials based on the size of their individual standard errors and facilitates analysis whilst accounting for heterogeneity across studies. Effect sizes were represented by the standardised mean difference and presented alongside 95% confidence intervals. RESULTS: Seven studies were included in this meta-analysis. Both modes of training were effective in increasing endurance performance. Within-mode effect sizes were both of moderate magnitude [small-sided games: 0.82 (95% confidence interval 0.05, 1.60), Z = 2.07 (p = 0.04); conventional endurance training: 0.89 (95% confidence interval 0.06, 1.72), Z = 2.10 (p = 0.04)]. There were only trivial differences [0.04 (95% confidence interval - 0.36, 0.43), Z = 0.18 (p = 0.86)] between the effects on aerobic endurance performance of small-sided games and conventional endurance training. Subgroup analyses showed mostly trivial differences between the training methods across key programming variables such as set duration (≥ or < 4 min) and recovery period between sets (≥ or < 3 min). Programmes that were longer than 8 weeks favoured small-sided games [effect size = 0.45 (95% confidence interval - 0.12, 1.02), Z = 1.54 (p = 0.12)], with the opposite being true for conventional endurance training [effect size = - 0.33 (95% confidence interval - 0.79, 0.14), Z = 1.39 (p = 0.16)]. Programmes with more than 4 sets per session favoured small-sided games [effect size = 0.53 (95% confidence interval - 0.52, 1.58), Z = 0.98 (p = 0.33)] with only a trivial difference between those with 4, or fewer, sets [effect size = - 0.13 (95% confidence interval - 0.52, 0.26), Z = 0.65 (p = 0.52)]. CONCLUSIONS: Small-sided games are as effective as conventional endurance training for increasing aerobic endurance performance in male youth soccer players. This is important for practitioners as it means that small-sided games can allow both endurance and skills training to be carried out simultaneously, thus providing a more efficient training stimulus. Small-sided games offer the same benefits as conventional endurance training with two sessions per week, with ≥ 4 sets of 4 min of activity, interspersed with recovery periods of 3 min, recommended in this population.

Influence of Playing Standard on Upper- and Lower-Body Strength, Power, and Velocity Characteristics of Elite Rugby League Players.

BACKGROUND: To compare load-velocity and load-power relationships among first grade (n = 26, age 22.9 ± 4.3 years), academy (n = 23, age 17.1 ± 1.0 years), and scholarship (n = 16, age 15.4 ± 0.5 years) Super League rugby league players. METHODS: Participants completed assessments of maximal upper- and lower-body strength (1RM) and peak velocity and power at 20, 40, 60, and 80 kg during bench press and squat exercises, in a randomised order. RESULTS: Bench press and squat 1RM were highest for first grade players compared with other standards (effect size (ES) = -0.43 to -3.18). Peak velocities during bench and squat were greater in the higher playing standards (ES = -0.39 to -3.72 range), except for the squat at 20 and 40 kg. Peak power was higher in the better playing standards for all loads and exercises. For all three groups, velocity was correlated to optimal bench press power (r = 0.514 to 0.766), but only 1RM was related to optimal power (r = 0.635) in the scholarship players. Only squat 1RM in the academy was related to optimal squat power (r = 0.505). CONCLUSIONS: Peak velocity and power are key physical qualities to be developed that enable progression from junior elite rugby league to first grade level. Resistance training should emphasise both maximal strength and velocity components, in order to optimise upper- and lower-body power in professional rugby league players.

Eccentric Resistance Training in Youth: Perspectives for Long-Term Athletic Development.

The purpose of this narrative review is to discuss the role of eccentric resistance training in youth and how this training modality can be utilized within long-term physical development. Current literature on responses to eccentric exercise in youth has demonstrated that potential concerns, such as fatigue and muscle damage, compared to adults are not supported. Considering the importance of resistance training for youth athletes and the benefits of eccentric training in enhancing strength, power, speed, and resistance to injury, its inclusion throughout youth may be warranted. In this review we provide a brief overview of the physiological responses to exercise in youth with specific reference to the different responses to eccentric resistance training between children, adolescents, and adults. Thereafter, we discuss the importance of ensuring that force absorption qualities are trained throughout youth and how these may be influenced by growth and maturation. In particular, we propose practical methods on how eccentric resistance training methods can be implemented in youth via the inclusion of efficient landing mechanics, eccentric hamstrings strengthening and flywheel inertia training. This article proposes that the use of eccentric resistance training in youth should be considered a necessity to help develop both physical qualities that underpin sporting performance, as well as reducing injury risk. However, as with any other training modality implemented within youth, careful consideration should be given in accordance with an individual's maturity status, training history and technical competency as well as being underpinned by current long-term physical development guidelines.