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Purpose: To compare the effects of performing different unilateral strength training interventions on unilateral and bilateral jumping performance and their related asymmetries in young soccer players., Methods: Forty-five young (U-17) male soccer players were randomly assigned to 3 eccentric overload training programs. The first group executed the same volume with both legs starting with the weaker leg (SVW, n = 15); the second group carried out double volume with the weaker leg and also starting with the weaker leg (DVW, n = 15); and the third group performed the same volume with both legs starting with the stronger leg (SVS, n = 15). Jumping-performance assessment included a single-leg horizontal jump test, a triple single-leg horizontal jump test, a bilateral countermovement jump (CMJ) test, and a unilateral CMJ test. Asymmetries were also analyzed in the unilateral jumping tests., Results: CMJ was improved (effect size [ES]: 0.27-0.48) and CMJ asymmetry was possibly reduced (ES: 0.08-0.24) in all groups. Substantial improvements were found in triple hop (ES: 0.52-0.71) in SVW and DVW, and triple-hop asymmetry was substantially decreased (ES: 0.88) in DVW. Between-groups analysis showed a substantially better performance in triple hop and horizontal hop with right leg in SVW and DVW compared with SVS., Conclusions: Unilateral strength training programs were shown to substantially improve bilateral jumping performance, while unilateral jumping was substantially enhanced in the groups that started the training session with the weaker leg. Finally, between-limbs asymmetries in the triple hop were mainly reduced through performing double volume with the weaker leg.

No studies have assessed whether changes in physical performance and inter-limb asymmetries (ILA) can be achieved with the FIFA 11+ prevention programme in adolescent female soccer players. The aim of this study was to assess the effect of the FIFA 11+ programme compared with a standard warm-up on physical performance and ILA in adolescent female soccer players. Thirty-six adolescent female soccer players were randomly assigned to an experimental (EG; n = 19) or a control group (CG; n = 17). Unilateral/bilateral countermovement jump (CMJ), drop jump (DJ) and horizontal jump tests, two different change of direction tests, an ankle dorsiflexion test, the Y-Balance test (YBT) and inter-limb asymmetries were measured before and after 10 weeks of training. The results revealed no significant group-by-time interactions in the vast majority of variables (p>0.05). Paired t-test revealed significant improvements of the right [effect size (ES):0.56] and left (ES:0.49) CMJ, right (ES:0.74) and left (ES:0.54) DJ (ES:0.74), right (ES:1.27) and left (ES:1.26) posteromedial direction and right (ES:0.89) and left (ES:0.84) posterolateral direction in the YBT in the EG (p < 0.05). Right anterior direction in the YBT and V-cut test were significantly improved in both groups (p<0.05). For inter-limb asymmetry variables, no significant group-by-time interactions (ES:0 to 0.93) and an improvement between pre- and post-tests (ES:-0.76 to 0.49) were observed. Therefore, the FIFA 11+ programme led to improved unilateral jumping, dynamic balance and reduced lower extremity symmetries of several tests in adolescent female soccer players., (Copyright © Biology of Sport 2019.)

Purpose: To compare the effects of resisted change-of-direction (COD) movements, using several relative loads, on soccer players' physical performance., Methods: Fifty-four male soccer players were randomly assigned to 1 of the following 3 groups, which differed only in the magnitude of the external load used during the COD training: COD training without external load (COD-0; n = 16), COD training with a 12.5% body-mass external load (COD-12.5; n = 19), and COD training with a 50% body-mass external load (COD-50; n = 19). Participants performed the specific COD training twice per week for 6 wk. Before and after the training period, a battery of tests was completed: countermovement jump, 30-m running sprint (time in 10 m [T10], 20 m [T20], and 30 m [T30]), L-run test, and V-cut test., Results: Within-group comparisons showed substantial improvements in countermovement jump and T10 (likely) in COD-0, whereas countermovement jump, T10, and T20 were substantially enhanced (possibly to likely) in COD-50. COD-12.5 induced substantial improvements in all analyzed variables (likely to most likely). Between-groups comparisons showed better effects on all analyzed variables for COD-12.5 than for COD-0 (possibly to very likely), whereas COD-50 only showed possibly better effects than COD-0 on T10. In addition, COD-12.5 induced a better effect on L-run and V-cut tests than COD-50 (possibly to likely)., Conclusions: These results indicate that COD training, especially moderate load (12.5% body mass) resisted COD training, may have a positive effect on COD skills, running sprint performance, and jumping ability in young soccer players.

Purpose: To determine the discriminators as variables to select the under-16 national-team players and to examine the influence of biological age on physical/technical parameters among young basketball players., Methods: Thirty-four under-15 male basketball players performed several anthropometrical (height, wingspan, body mass, and fingers length) and physical (jumping, sprinting, throwing, flexibility, change-of-direction speed, and aerobic fitness) tests during the under-15 male national-team training camp. Maturity offset, lower-limb asymmetry index, and power outputs for jumping and sprinting were also computed. In addition, game performance was taken into consideration using game-related statistics (assists, turnovers, steals, rebounds, blocks, and points) of 5 games of during the previous regional tournament (April 2016). Cluster analysis was used to analyze the between-maturation status (prepubertal, pubertal, and postpubertal) differences in physical parameters., Results: The postpubertals showed a significantly better performance in power outputs (jumping and sprinting), throwing abilities, and blocks, whereas prepubertal performed significantly better in aerobic fitness and assists. Receiver-operating-characteristic curve confirmed maturational status (area under the curve [AUC] = 0.804; P < .05) and training experience (AUC = 0.789; P < .05) as the most important attributes in predicting under-16 national-team selection. Players with more than 5.5 years of training experience and less than 1.4 y to the age at peak height velocity were most likely to be selected., Conclusion: Maturational status seems to be a key variable that increases the probability of selection for the Portuguese under-16 national team.

Background: The aim of this study was to evaluate the effects of an in-season strength and conditioning program on physical abilities in under-16 sub-elite basketball players., Methods: Sixteen young male basketball players were assessed using countermovement jump (CMJ), squat jump (SJ), 10-meters sprint and Pro Agility Test, before and after an 8-week in-season strength and conditioning program. Both the control group (BASK; N.=7) and the experimental group (SC; N.=9) were involved in regular basketball practice; additionally, the SC group performed 4 sessions per week of training intervention considering postmatch days and prior days to next match. The training protocol consisted of three components: a stabilization block, a neuromuscular/strength block (i.e. circuit of mobility, plyometric, coordination, reaction, and stability exercises) and a power block (i.e. resisted movement training performed with VertiMax V6 platform)., Results: Substantial improvements in CMJ (likely; d=0.30-0.47) were found in both groups. Moreover, the SC group displayed substantial increase in SJ (likely; d=0.07-1.26) and also in 10 m-sprint (d=-0.13-1.34). The between-group analysis also revealed greater improvements for the SC group in 10-m sprint (d=1.37) and SJ (d=0.50)., Conclusions: In -season regular basketball practice plus strength and conditioning training program can lead to a greater improvement on jumping and sprinting abilities in male young basketball players comparing to the regular basketball training.

The aim of this study was to compare the activity profile (external loads) during soccer-7 competition versus 6 vs 6 small-sided games ( SSGs) in U12 players. Peak velocity (V max ), total distance completed (DT), total distance relative to match duration, the percentage of DT in acceleration (%DAC) and in deceleration (%DEA), and the percentage of DT at different speeds were recorded. Six types of SSGs were randomly implemented: without pitch orientation-delimitation and with a limit of three ball-contacts per player (3TOU), with no limit of ball-contacts (MAN), with a greater number of players as internal-offensive wildcard players (2WI) or external-offensive wildcard players (4WE); and with pitch orientation-delimitation and crossing the rival goal-line while dribbling the ball without goalkeepers (INV) or using official goalkeepers (GKP). The physical demands of SSGs were compared with the average of two soccer-7 match plays. During soccer-7 match plays a lower %DAC and %DEA (p < 0.05) were observed compared to 2WI, 4WE, INV and GKP, and to INV and GKP, respectively. The V max and %HI were greater (p < 0.05) in soccer-7 match plays compared to all SSGs. In conclusion, the demands imposed on U12 players during different formats of SSGs differ from the soccer-7 match play demands, presenting a low stimulation of the actions performed at high-speed and an adequate simulation of acceleration-deceleration actions.

The aim of this study was to compare the effects of different warm-up conditioning intensities on the physical fitness (i.e., post-activation potentiation -PAP), of professional male field soccer players. Athletes ( n = 10; age: 21.6 ± 3.2 years) completed a control warm-up and warm-ups aimed to induce PAP, in random and counterbalanced order. After control and experimental warm-up sessions participants completed a triple hop test with the dominant (H3Jd) and a non-dominant (H3Jnd) leg, a squat jump (SJ), a countermovement jump (CMJ), a change of direction ability (COD) test, a repeated sprint with a COD (RSCOD) test and a linear 30-m sprint test (S-30). The control warm-up (WU) protocol was designed according to athlete's regular warm-up practice. The experimental warm-ups included the same exercises as the WU, with addition of one set of half-back squats for 10 repetitions at 60%, 5 repetitions at 80%, and 1 repetition at 100% of 1RM (60%-1RM, 80%-1RM and 100%-1RM, respectively.) Threshold values for Cohen's effect sizes (ES) were calculated and used for group's comparison. Likely to most likely improvements were shown in H3Jd ( ES = 0.52), H3Jnd ( ES = 0.51), COD ( ES = 0.38), fasted sprint (RSCODb) ( ES = 0.58) and the total time of all sprints (RSCODt) ( ES = 0.99) only after the 80%-1RM protocol in comparison to the WU. Conversely, 100%-1RM and 60%-1RM protocols, compared to WU, induced possibly to most likely poorer performance in all jumps, COD and RSCODb ( ES = -0.07 to -1.03 and ES = -0.48 to -0.91, respectively). Possibly to most likely improvements were shown in all jumps, COD, RSCODb and RSCODt after the 80%-1RM warm-up protocol in comparison to the 100%-1RM and 60%-1RM warm-up protocols ( ES = 0.35 to 2.15 and ES = 0.61 to 1.46, respectively). A moderate warm-up intensity (i.e., 80%-1RM back squat) may induce greater PAP, including improvements in jumping, repeated and non-repeated change of direction speed in male soccer players.

Plyometric training composed by unilateral exercises with horizontal jumping direction seems to be an effective way to improve physical performance in athletes. The present study aimed to compare the influence of a combined jumping direction and force application (horizontal-unilateral vs. vertical-bilateral) plyometric training on linear sprinting, jumping, change of direction (COD) and dynamic balance in young elite basketball players. Twenty young (U-13 to U-14) male basketball players (age: 13.2 ± 0.7 years, body mass: 59.5 ± 12.7 kg, height: 172.9 ± 7.9 cm) were randomly assigned either to a unilateral-horizontal (UH, n = 10) or bilateral-vertical (BV, n = 10) plyometric group, twice a week for 6-wk. Both groups performed between 60 and 100 jumps/session. UH executed all jumps unilaterally with horizontal direction, while jumps in the BV were bilaterally with vertical direction. Performance was assessed by a linear sprinting test, vertical and horizontal jumping tests, COD tests (V-cut and 5+5 m with a 180°COD test), an ankle dorsiflexion test and dynamic balance tests (anterior and postero-lateral directions). Within-group differences showed substantial improvements (Effect size (ES):0.31-1.01) in unilateral vertical and horizontal jumping, V-cut test and postero-lateral direction with right leg after both training interventions. Furthermore, UH group also substantially improved (ES:0.33-0.78) all sprinting times and postero-lateral direction with left leg, while BV enhanced anterior direction with left leg (ES:0.25). Between-group analyses showed substantially greater improvements (ES:0.33) in 10-m and V-cut test in UH than in BV. The likely beneficial effect (small ES) achieved in sprinting abilities suggests the combination of unilateral-horizontal jumps to improve such abilities.

The present study aimed to examine the reliability, usefulness, responsiveness, age-related differences and construct validity of a novel decision-making RSA test (RSA-RANDOM test) in young soccer players. Twenty-five young male soccer players performed the RSA-RANDOM test on 2 occasions separated by 5-7 days to assess test-retest reliability and determine a priori usefulness. Furthermore, the same players executed the RSA-RANDOM test 4 times throughout the season to analyse responsiveness. Forty-five players (U-13 to U-17) were evaluated in such test to examine age-related differences. Finally, 9 players were used to determine the construct validity of the test. Reliability scores showed a high intraclass correlation coefficient (ICC=0.88 to 0.90) and low coefficient of variation (CV=1.0-1.2%). The responsiveness of the RSA-RANDOM test was good, as the typical short- (1.2-1.9%), mid- (1.4-2.4%) and long-term (2.3-3.2%) changes in RSA-RANDOM performance were higher than the CV. Age-related differences analysis showed better RSA-RANDOM performance as age increased in young soccer players. Low (r=-0.50) to moderate (r=-0.75) relationships were found between the RSA-RANDOM test variables (RSA best and mean times) with high-intensity and total distance covered, respectively. A novel decision-making RSA test (RSA-RANDOM) has shown to be reliable and valid in young soccer players., Competing Interests: The authors declare that they have no conflict of interest., (© Georg Thieme Verlag KG Stuttgart · New York.)

The aim of this study was to compare changes in young soccer player's fitness after traditional bilateral vs. unilateral combined plyometric and strength training. Male athletes were randomly divided in two groups; both received the same training, including strength training for knee extensors and flexors, in addition to horizontal plyometric training drills. The only difference between groups was the mode of drills technique: unilateral (UG; n = 9; age, 17.3 ± 1.1 years) vs. bilateral (TG; n = 9; age, 17.6 ± 0.5 years). One repetition maximum bilateral strength of knee muscle extensors (1RM&#95;KE) and flexors (1RM&#95;KF), change of direction ability (COD), horizontal and vertical jump ability with one (unilateral) and two (bilateral) legs, and limb symmetry index were measured before and after an 8-week in-season intervention period. Some regular soccer drills were replaced by combination of plyometric and strength training drills. Magnitude-based inference statistics were used for between-group and within-group comparisons. Beneficial effects ( p < 0.05) in 1RM&#95;KE, COD, and several test of jumping performance were found in both groups in comparison to pre-test values. The limb symmetry index was not affected in either group. The beneficial changes in 1RM&#95;KE (8.1%; p = 0.074) and 1RM&#95;KF (6.7%; p = 0.004), COD (3.1%; p = 0.149), and bilateral jump performance (from 2.7% [ p = 0.535] to 10.5% [ p = 0.002]) were possible to most likely beneficial in the TG than in the UG. However, unilateral jump performance measures achieved likely to most likely beneficial changes in the UG compared to the TG (from 4.5% [ p = 0.090] to 8.6% [ p = 0.018]). The improvements in jumping ability were specific to the type of jump performed, with greater improvements in unilateral jump performance in the UG and bilateral jump performance in the TG. Therefore, bilateral strength and plyometric training should be complemented with unilateral drills, in order to maximize adaptations.

Background: There is a lack of information about the influence of age on functional movement tests (FMT) and performance tests as well as in their relationships in young basketball players., Purpose: The purpose of the present study was to determine the variations in FMT and jump and/or sprint performance scores between age groups (U-14 vs. U-16) in Highly-trained young basketball players. The second purpose was to investigate the relationship between FMT for lower body and jump and/or sprint performance in highly-trained young (U-14 and U-16) male basketball players., Study Design: Descriptive study., Methods: Thirty elite young (U-14 to U-16) male basketball players performed several FMT (weight-bearing dorsiflexion test [WB-DF] and a modified Star Excursion Balance test [SEBT]) and performance including unilateral and bilateral countermovement jumps, unilateral horizontal jumping, linear sprinting and performance tests., Results: All anthropometric and performance tests showed a statistically significant advantage (p<0.05) in the U-16 group, excluding the unilateral jump with left leg (p=0.127). Five out of the eight FMT performed showed a statistically significant advantage (p<0.05) in the U-16 group. The U-14 group did not differ statistically from the U-16 group in WB-DF with left leg and the SEBT anterior right leg and posteromedial left leg reaches. Effect size calculations did show small to moderate effects in favor of U-16. Only two significant correlations (p<0.05) between functional movement and performance measures were identified in the U-16 group for either limb (10-m sprint and SEBT-PL L , SEBT-Composite L ), while a total of 13 significant correlations (p<0.05) in the U-14 group were found., Conclusions: The results of this study demonstrated differences in FMT and jump and/or sprint performance test between age groups (U-16 vs U-14). The findings of this study support the idea that the age of the player should be considered when interpreting FMT scores, which could have implications when implementing the FMT for injury risk prediction., Level of Evidence: 2b.

Purpose: To analyze the effects of 2 different eccentric-overload training (EOT) programs, using a rotational conical pulley, on functional performance in team-sport players. A traditional movement paradigm (ie, squat) including several sets of 1 bilateral and vertical movement was compared with a novel paradigm including a different exercise in each set of unilateral and multi-directional movements., Methods: Forty-eight amateur or semiprofessional team-sport players were randomly assigned to an EOT program including either the same bilateral vertical (CBV, n = 24) movement (squat) or different unilateral multidirectional (VUMD, n = 24) movements. Training programs consisted of 6 sets of 1 exercise (CBV) or 1 set of 6 exercises (VUMD) × 6-10 repetitions with 3 min of passive recovery between sets and exercises, biweekly for 8 wk. Functional-performance assessment included several change-of-direction (COD) tests, a 25-m linear-sprint test, unilateral multidirectional jumping tests (ie, lateral, horizontal, and vertical), and a bilateral vertical-jump test., Results: Within-group analysis showed substantial improvements in all tests in both groups, with VUMD showing more robust adaptations in pooled COD tests and lateral/horizontal jumping, whereas the opposite occurred in CBV respecting linear sprinting and vertical jumping. Between-groups analyses showed substantially better results in lateral jumps (ES = 0.21), left-leg horizontal jump (ES = 0.35), and 10-m COD with right leg (ES = 0.42) in VUMD than in CBV. In contrast, left-leg countermovement jump (ES = 0.26) was possibly better in CBV than in VUMD., Conclusions: Eight weeks of EOT induced substantial improvements in functional-performance tests, although the force-vector application may play a key role to develop different and specific functional adaptations.

Purpose: To compare the effects of unilateral and bilateral resistance training on single-leg power output, between-limbs imbalance (BLI), bilateral deficit (BLD), change of direction (COD), and linear sprinting and jumping performance in young elite basketball players., Methods: Twenty-two young (U-16-U-19) male basketball players were randomly assigned either to an exclusive unilateral (UNI) (n = 11) or a bilateral (BIL) (n = 11) resistance-training group during a 6-wk period. Both groups training consisted of 3 unilateral or bilateral 90° back-squat sets. A postdetermined number of repetitions was set until power output dropped to <10% of maximum power (MP) output. In addition, both groups performed 2 sets of 5 unilateral or bilateral drop jumps and 2 sets of 5 unilateral or bilateral countermovement jumps (CMJ). Pre- and posttraining, performance was assessed by an incremental bilateral and unilateral squat-load test, a multiple-COD test (V-cut test), a 15-m-sprint test (7.5 + 7.5 m) with one 180° COD performed with both right (180° RCOD) and left (180° LCOD) legs, a 25-m-sprint test (5- and 15-m split time), and a CMJ test., Results: Within-group analyses showed substantial improvements in 180° RCOD, bilateral and unilateral MP, 25-m-sprint test, and CMJ in both groups. Between-groups analyses showed substantially better results in 180° LCOD, MP with right and left legs, BLI, and BLD in UNI than in BIL., Conclusions: Both training programs substantially improved most of the physical-fitness tests, but only UNI reduced between-limbs asymmetry and achieved greater enhancements in actions that mostly required applying force unilaterally in basketball players.

The aims of the present study were to assess the validity and reliability of a novel simple test [Five Seconds Power Test (W5″ Test)] for estimating the mean power output during the bench press exercise at different loads, and its sensitivity to detect training-induced changes. Thirty trained young men completed as many repetitions as possible in a time of ≈5 s at 25%, 45%, 65% and 85% of one-repetition maximum (1RM) in two test sessions separated by four days. The number of repetitions, linear displacement of the bar and time needed to complete the test were recorded by two independent testers, and a linear encoder was used as the criterion measure. For each load, the mean power output was calculated in the W5″ Test as mechanical work per time unit and compared with that obtained from the linear encoder. Subsequently, 20 additional subjects (10 training group vs. 10 control group) were assessed before and after completing a seven-week training programme designed to improve maximal power. Results showed that both assessment methods correlated highly in estimating mean power output at different loads (r range: 0.86-0.94; p < .01) and detecting training-induced changes (R(2): 0.78). Good to excellent intra-tester (intraclass correlation coefficient (ICC) range: 0.81-0.97) and excellent inter-tester (ICC range: 0.96-0.99; coefficient of variation range: 2.4-4.1%) reliability was found for all loads. The W5″ Test was shown to be a valid, reliable and sensitive method for measuring mean power output during the bench press exercise in subjects who have previous resistance training experience.

The aim of the current study was to analyse the effect of 10-week eccentric overload training on kinetic parameters during change of direction (COD) in U-19 football players. The outcome measured included relative peak braking (rPB) and propulsive force (rPF), contact time (CT), time spent during braking (BT) and propulsive phase (PT), relative total (rTOT&#95;IMP), braking (rB&#95;IMP) and propulsive (rP&#95;IMP) impulses. Between-group results showed a substantial better improvement (likely) in CT (ES: 0.72) and BT (ES: 0.74) during side-step cutting, and in rPB (ES: 0.84) and rB&#95;IMP (ES: 0.72) during crossover cutting, in the experimental group (EXP) in comparison to control group (CON). Within-group analysis showed a substantially better performance (likely to almost certain) in CT (ES: 1.19), BT (ES: 1.24), PT (ES: 0.70), rPB (ES: 0.75), rPF (ES: 0.68), rTOT&#95;IMP (ES: 0.48) and rB&#95;IMP (ES: 0.50) in EXP during side-step cutting. Regarding crossover cutting, within-group analysis showed a substantial better performance (likely to almost certain) in CT (ES: 0.75), rPB (ES: 0.75), rPF (ES: 1.34), rTOT&#95;IMP (ES: 0.61), rB&#95;IMP (ES: 0.76) and rP&#95;IMP (ES: 0.46) in EXP. In conclusion, the eccentric overload-based programme led to an improvement in kinetic parameters during COD football tasks.

Purpose: To examine the effects of a low-volume repeated-power-ability (RPA) training program on repeated-sprint and change-of- direction (COD) ability and functional jumping performance., Methods: Twenty-two male elite young basketball players (age 16.2 ± 1.2 y, height 190.0 ± 10.0 cm, body mass 82.9 ± 10.1 kg) were randomly assigned either to an RPA-training group (n = 11) or a control group (n = 11). RPA training consisted of leg-press exercise, twice a week for 6 wk, of 1 or 2 blocks of 5 sets × 5 repetitions with 20 s of passive recovery between sets and 3 min between blocks with the load that maximized power output. Before and after training, performance was assessed by a repeated-sprint-ability (RSA) test, a repeated-COD-ability test, a hop for distance, and a drop jump followed by tests of a double unilateral hop with the right and left legs., Results: Within-group and between-groups differences showed substantial improvements in slowest (RSAs) and mean time (RSAm) on RSA; best, slowest and mean time on repeated-COD ability; and unilateral right and left hop in the RPA group in comparison with control. While best time on RSA showed no improvement in any group, there was a large relationship (r = .68, 90% CI .43;.84) between the relative decrement in RSAm and RSAs, suggesting better sprint maintenance with RPA training. The relative improvements in best and mean repeated-COD ability were very largely correlated (r = .89, 90% CI .77;.94)., Conclusions: Six weeks of lowvolume (4-14 min/wk) RPA training improved several physical-fitness tests in basketball players.

The aim of this study was to analyze the effects of 3 different low/moderate load strength training methods (full-back squat [SQ], resisted sprint with sled towing [RS], and plyometric and specific drills training [PLYO]) on sprinting, jumping, and change of direction (COD) abilities in soccer players. Thirty-two young elite male Spanish soccer players participated in the study. Subjects performed 2 specific strength training sessions per week, in addition to their normal training sessions for 8 weeks. The full-back squat protocol consisted of 2-3 sets × 4-8 repetitions at 40-60% 1 repetition maximum (∼ 1.28-0.98 m · s(-1)). The resisted sprint training was compounded by 6-10 sets × 20-m loaded sprints (12.6% of body mass). The plyometric and specific drills training was based on 1-3 sets × 2-3 repetitions of 8 plyometric and speed/agility exercises. Testing sessions included a countermovement jump (CMJ), a 20-m sprint (10-m split time), a 50-m (30-m split time) sprint, and COD test (i.e., Zig-Zag test). Substantial improvements (likely to almost certainly) in CMJ (effect size [ES]: 0.50-0.57) and 30-50 m (ES: 0.45-0.84) were found in every group in comparison to pretest results. Moreover, players in PLYO and SQ groups also showed substantial enhancements (likely to very likely) in 0-50 m (ES: 0.46-0.60). In addition, 10-20 m was also improved (very likely) in the SQ group (ES: 0.61). Between-group analyses showed that improvements in 10-20 m (ES: 0.57) and 30-50 m (ES: 0.40) were likely greater in the SQ group than in the RS group. Also, 10-20 m (ES: 0.49) was substantially better in the SQ group than in the PLYO group. In conclusion, the present strength training methods used in this study seem to be effective to improve jumping and sprinting abilities, but COD might need other stimulus to achieve positive effects.

Purpose: To examine the effects of a novel isoinertial eccentric-overload and vibration training (EVT) paradigm on change-of-direction (COD) speed and multiple performance tests applicable to soccer., Methods: Twenty-four young male players were assigned to an EVT (n = 12) or conventional combined (CONV, n = 12) group, once weekly for 11 wk. EVT consisted of 2 sets of 6-10 repetitions in 5 specific and 3 complementary exercises. CONV used comparable volume (2 sets of 6-10 reps in 3 sequences of 3 exercises) of conventional combined weight, plyometric, and linear speed exercises. Pre- and postintervention tests included 25-m sprint with 4 × 45° COD every 5th m (V-cut test), 10- and 30-m sprints, repeat-sprint ability, countermovement jump, and hopping (RJ5)., Results: Group comparison showed very likely to likely better performance for EVT in the COD (effect size [ES] = 1.42), 30-m (ES = 0.98), 10-m (ES = 1.17), and average power (ES = 0.69) and jump height (ES = 0.69) during RJ5. There was a large (r = -.55) relationship between the increase in average hopping power and the reduced V-cut time., Conclusions: As EVT, not CONV, improved not only COD ability but also linear speed and reactive jumping, this "proof-of-principle" study suggests that this novel exercise paradigm performed once weekly could serve as a viable adjunct to improve performance tasks specific to soccer.

Purpose/background: Sprinting and jumping are two common and important components of high-level sport performance. The weight-bearing dorsiflexion test (WB-DF) and Star Excursion Balance Test (SEBT) are tools developed to identify athletes at risk for lower extremity injury and may be related to running and jumping performance among athletes. The purposes of the present study were: 1) to identify any relationships between functional movement tests (WB-DF and SEBT) and performance tests (jumping, sprinting and changing direction); 2) to examine any relationships between asymmetries in functional movements and performance tests., Study Design: Descriptive cohort study., Methods: Fifteen elite male basketball players (age: 15.4 ± 0.9 years) were assessed during a three-week period to determine the reliability of functional screening tools and performance tests and to examine the relationships between these tests. Relative (intraclass correlation coefficient) and absolute (coefficient of variation) reliability were used to assess the reproducibility of the tests., Results: Significant correlations were detected between certain functional movement tests and performance tests. Both left and right excursion composite scores related to slower performance times in sprint testing, demonstrating that greater dynamic reach relates to decreased quickness and acceleration among these elite basketball athletes. The various relationships between dynamic functional movement testing, speed, and jump performance provide guidance for the strength and conditioning professional when conducting and evaluating data in an effort to improve performance and reduce risk of injury., Conclusions: The results of the present study suggest that these functional and performance tests do not measure the same components of human movement, and could be paired as outcome measures for the clinical and sport assessment of lower extremity function., Level of Evidence: 2b.

Purpose: To analyze the effect of an eccentric-overload training program (ie, half-squat and leg-curl exercises using flywheel ergometers) with individualized load on muscle-injury incidence and severity and performance in junior elite soccer players., Methods: Thirty-six young players (U-17 to U-19) were recruited and assigned to an experimental (EXP) or control group (CON). The training program consisted of 1 or 2 sessions/wk (3-6 sets with 6 repetitions) during 10 wk. The outcome measured included muscle injury (incidence per 1000 h of exposure and injury severity) and performance tests (countermovement jump [CMJ], 10-m and 20-m sprint test)., Results: Between-groups results showed a likely (ES: 0.94) lower number of days of absence per injury and a possible decrement of incidence per 1000 h of match play in EXP than in CON. Regarding muscle performance, a substantial better improvement (likely to very likely) was found in 20-m sprint time (ES: 0.37), 10-m flying-sprint time (ES: 0.77), and CMJ (ES: 0.79) for EXP than for CON. Within-group analysis showed an unclear effect in each variable in CON. Conversely, substantial improvements were obtained in CMJ (ES: 0.58), 20-m sprint time (ES: 0.32), 10-m flying-sprint time (ES: 0.95), and injury severity (ES: 0.59) in EXP. Furthermore, a possible decrement in total injury incidence was also reported in EXP., Conclusions: The eccentric-based program led to a reduction in muscle-injury incidence and severity and showed improvements in common soccer tasks such as jumping ability and linear-sprinting speed.

Purpose: To examine the effect of repeated-sprint training (RST) vs combined RST and resistance training with superimposed vibrations on repeated-sprint ability (RSA) and lower-body power output in male rugby players., Methods: Players were divided into 2 training groups. One group performed RST (n = 10) 2 d/wk and the other performed RST 1 d/wk and squat resistance training with superimposed vibrations on the second day (RS+ST; n = 10). The squat training was carried out with a volume similar (ie, number of sets and repetitions) to that of the RST. The training period lasted 6 wk, and it was carried out as a supplement to the regular rugby training sessions., Results: Substantial improvements in RSA mean time (RSA(mean); +2.3%/ES: 0.77 vs +4.1%/ES: 0.91), RSA percent decrement (%Dec; -25.6%/ES: 1.70 vs -23.2%/ES: 0.99), and squat absolute power output (+5.0%/ES:0.36 vs +17.2%/ES: 0.93) were obtained in RST and RS+ST, respectively. Substantial improvements in RSA best time (RSA(best); +2.6%/ES: 0.61) and squat power output normalized to body mass (+18.6%/ES: 0.76) only occurred in RS+ST. Both pretest and posttest RSA(mean) were largely correlated with the RSA(best). However, there were only unclear, small to moderate correlations between individual changes in squat power output and either RSA(mean) or RSA(best)., Conclusion: Combined RST and resistance training induced improvements of greater magnitude in both repeated-sprint performance and muscle power output than the RST alone. The lack of substantial correlations between individual changes in repeated-sprint and muscle-power performance suggests that the same subjects were not systematically low or high responders to both RST and strength training.

The aim of the present study was to analyze the main determinants of an upper-body repeated power ability (RPA) test and to examine its reliability and usefulness. Forty-five highly trained, male, young basketball players performed the RPA test (5 sets of 5 repetitions with 30 seconds of passive recovery within sets) on 2 sessions separated by 5-7 days. Power output was registered using a linear encoder attached to the barbell. Results showed no significant differences (p > 0.05) between each set in both sessions and trivial (<0.2) effect sizes in all the analyzed variables. For every set, intraclass correlation coefficient was very high (0.96-0.98) and coefficient of variation was low (3.3%-4.3%). Because the typical error of measurement values were lower or similar than the smallest worthwhile change (SWC0.2 = 0.2 × between-subject SD), the usefulness of most variables was rated as "good" or "OK" considering that small changes would be detected by this test. The percentage of power decrement could only be used to detect large effects (>1.2 × between-subject SD). An almost perfect correlation (r = 0.99; 90% confidence interval, 0.98-0.99) was found between the average power in set 1 (APbest) and the average power over 5 sets (APmean). In conclusion, the main determinant of RPA test is APbest, and because of the high reliability scores obtained, this protocol may be used to assess upper-body RPA in relatively experienced young athletes.