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  • Author: Oliver Gonzalo-Skok x
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David Rodríguez-Osorio, Oliver Gonzalo-Skok and Fernando Pareja-Blanco

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.

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Jorge Arede, António Paulo Ferreira, Oliver Gonzalo-Skok and Nuno Leite

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.

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Julio Tous-Fajardo, Oliver Gonzalo-Skok, José Luis Arjol-Serrano and Per Tesch

Purpose:

To examine the effects of a novel isoinertial eccentric-overload and vibration training (EVT) paradigm on change-ofdirection (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.

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Luis Suarez-Arrones, Julio Tous-Fajardo, Javier Núñez, Oliver Gonzalo-Skok, Javier Gálvez and Alberto Mendez-Villanueva

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 (RSAmean; +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 (RSAbest; +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 RSAmean were largely correlated with the RSAbest. However, there were only unclear, small to moderate correlations between individual changes in squat power output and either RSAmean or RSAbest.

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.

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Oliver Gonzalo-Skok, Alejandro Moreno-Azze, José Luis Arjol-Serrano, Julio Tous-Fajardo and Chris Bishop

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.

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Oliver Gonzalo-Skok, Julio Tous-Fajardo, Luis Suarez-Arrones, José Luis Arjol-Serrano, José Antonio Casajús and Alberto Mendez-Villanueva

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.

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Oliver Gonzalo-Skok, Julio Tous-Fajardo, José Luis Arjol-Serrano, Luis Suarez-Arrones, José Antonio Casajús and Alberto Mendez-Villanueva

Purpose:

To examine the effects of a low-volume repeated-power-ability (RPA) training program on repeated-sprint and changeof-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 low-volume (4–14 min/wk) RPA training improved several physical-fitness tests in basketball players.

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Moisés de Hoyo, Marco Pozzo, Borja Sañudo, Luis Carrasco, Oliver Gonzalo-Skok, Sergio Domínguez-Cobo and Eduardo Morán-Camacho

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.

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Oliver Gonzalo-Skok, Julio Tous-Fajardo, Carlos Valero-Campo, César Berzosa, Ana Vanessa Bataller, José Luis Arjol-Serrano, Gerard Moras and Alberto Mendez-Villanueva

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.