Strength training using high and lower load such as contrast training (CST) seems to be beneficial as it addresses larger adaptive reserves in youth athletes. Therefore, the aim of this study was to investigate the effects of CST on dynamic balance (composite score during dynamic balance test (CS-YBT)), one repetition maximum lower-limb back squat (1RM), jumping performance (single-leg hop (SLH) or countermovement jump height (CMJ)), lower-limb asymmetry (predicted from the single-leg jump performance between two legs [ILA]) in elite youth male volleyball players. Thirty-one male youth volleyball players aged 14 years were randomly assigned to a CST group (n = 16) or a control group (n = 15). The tests were performed before and after 8 weeks of training. Significant group × time interactions was observed for CS-YBT [p < 0.001, η_p² = 0.70], 1RM [p < 0.001, η_p² = 0.95], SLH with right and left leg [p < 0.001, η_p² = 0.69 and 0.51], CMJ [p < 0.001, η_p² = 0.47]), whilst it was not notable in ILA [p < 0.294]. Post hoc tests showed that CST group demonstrated greater improvement in all of the dependent variables from medium to large effect size (for all p < 0.001). As a result, 8 weeks of CST twice a week can be an effective and efficient training along with volleyball training to improve skill-related fitness measures, except for lower-limb asymmetry in young volleyball players.

Tennis can be a mentally challenging sport, and emotional intelligence (EI) contributes significantly to an athlete’s psychological well-being. Thus, this study investigated the effects of 6 weeks of a combined Change of Direction (CoD) and reactive agility (RA) intervention program on emotional intelligence (EI) in pubertal tennis players. A total of 28 youth tennis players, aged 11 to 14 years, were randomly assigned to an experimental group (EXP-G, n = 15, 13 boys [age = 13.34 ± 0.98 years, maturity offset (MO) = −0.19 ± 0.96], and 2 girls [age = 12.77 ± 0.23 years, MO = 0.78 ± 0.04]) or a control group (CON-G, n = 13, 8 boys [age = 13.37 ± 0.75 years, MO = 0.00 ± 0.71], and 5 girls [age = 13.50 ± 0.92 years, MO = 1.41 ± 1.07]). The EXP-G performed combined CoD and RA training across the 6-week intervention period. The CON-G continued with the normal five 20 min regular tennis-specific training sessions per week, including technical and tactical drills and a small-sided games format. The overall training volume was similar between groups. Pre- and post-training, Profile of Emotional Competence (PEC, [EC TOTAL: global score of emotional competence level; EC INTRA: score of intra-personal emotional competence; EC INTER: score of inter-personal emotional competence]) and d2 attention tests were assessed. The present study employed an Analysis of Covariance (ANCOVA) with pre-test covariance to assess between-group differences (EXP-G vs. CON-G) at the post-test phase, utilizing baseline values as covariates. Noteworthy outcomes were observed, indicating statistically significant and substantial between-group disparities at post-test for various measures. Specifically, these differences were evident in the attention domain (effect size, d = 1.08 [Large], p = 0.001), the EC TOTAL test (effect size, d = 0.70 [Medium], p = 0.017), the EC INTA (effect size, d = 1.35 [Large], p = 0.001), and the EC INTER (effect size, d = 0.83 [Large], p = 0.009) tests. Due to the importance of agility training for overall competitive performance in tennis, our results suggest that young players should perform such training programs as part of conditioning training if the goal is to improve emotional intelligence and mental well-being.

While there is ample evidence on the effects of single-mode aerobic and speed training on physical fitness in soccer players, less is known on the combined effects of these exercise regimens on physical and psychological factors. This study aimed to compare the effects of aerobic and speed training with soccer-specific training versus soccer-specific training only on aerobic performance during the YOYO intermittent fitness test level 1 (final velocity, total distance [TD], maximal oxygen consumption [VO2max]), repeated sprint ability (best, total sprint time [RSABT, RSATT], sprint decrement [RSA dec]) performance and somatic anxiety (SA), cognitive anxiety (CA), and self-confidence (SC) adaptations in soccer players. Thirty-eight highly trained male athletes aged 18.9 ± 0.5 years were randomly assigned to an aerobic and speed training group (COMB-G; n = 20) or an active control group (CON-G; n = 18). Aerobic training comprised intermittent exercises at 110–120% of the final velocity achieved at the end of the YOYO IL1 test. Speed training involved maximal sprints over 15–20-m with 5–6 sets per session. Aerobic or speed training lasted 20 min per session and replaced parts of the soccer-specific training. CON-G performed the soccer-specific training including technical, tactical drills and small-sided games. Training volume was similar between groups. Pre, post intervention, all participants performed a repeated-sprint ability (RSA) test, the YO-YO IL1 test and the players completed a Competitive Scale Anxiety Inventory (CSAI-2). A two (group: COMB-G, CON-G) by two (time: pre, post) mixed ANOVA (group-by-time) was computed. Significant group-by-time interactions were found for RSATT (F = 117.3; p < 0.001; Pη2 = 1.78), RSABT (F = 82.4; p < 0.001; Pη2 = 1.53), final velocity (F = 85.8; p < 0.001; Pη2 = 1.53), TD (F = 87.1; p < 0.001; Pη2 = 1.56), and VO2max (F = 18.0; p < 0.001; Pη2 = 0.72). In addition, significant group-by-time interactions were observed for SC (F = 90.2; p < 0.001; d = 1.60), SA (F = 60.5; p < 0.001; Pη2 = 1.70), and CA (F = 20.7; p < 0.001; Pη2 = 0.75). Post-hoc analyses indicated significant improvements for all dependent variables from pre- to post-training in favor of COMB-G. Aerobic and speed training in combination with soccer-specific training is a safe and effective training method as it exerts positive effects not only for physical fitness but also for self-confidence and the coping of anxiety in male soccer players.

Hammami, R, Noomen, N, Negra, Y, Selmi, W, and Granacher, U. Effects of upper-body stable plyometric versus unstable strength training on upper-body strength, proxies of power, and dynamic stability in trained prepubertal baseball players. J Strength Cond Res XX(X): 000–000, 2026—In sports such as baseball, which involve high-intensity actions like throwing, hitting, and fielding, targeted upper-body strength training (ST) is essential for developing strength, power, and dynamic stability required for optimal performance in training and competition. Moreover, the physical fitness foundations necessary for later sport-specific performance should be established during childhood and adolescence. This study compared the effects of upper-body plyometric training on stable (SPT) vs. upper-body ST on unstable surfaces (UST) on strength, power proxies, and dynamic balance in prepubertal baseball players. Twenty-eight male players aged 11 ± 1 year (tier 2, trained/developmental) completed a 6-week program (2 × 30 min·wk ⁻¹ ) integrated into regular baseball practice. Push-up exercises were performed with body-mass loading in both groups. The SPT group conducted the exercises explosively on stable surfaces, incorporating brief flight phases and minimal ground contact to engage the stretch-shortening cycle, whereas the UST group executed the same exercises on unstable devices at a controlled pace, without a flight phase, emphasizing trunk stability. Pre- and post-training, assessments included upper-quarter dynamic balance (CS-UYBT), maximal back extensor strength, one repetition maximum bench press, and seated front, back, and side medicine ball throws. Both groups showed significant changes over time ( p < 0.01) in dynamic balance ( d = 2.54), back extensor strength ( d = 2.54), bench press strength ( d = 1.73), and medicine ball throw performance ( d = 1.23–2.82). No significant group-by-time interactions were observed for all outcome measures ( d = 0.00–0.44, p > 0.05). Six weeks of SPT and UST are easy-to-implement upper-body training modalities for physical fitness development of young athletes. However, given the short intervention (i.e., 6 weeks) and subjects' prior training experience, the results reflect short-term training responses rather than evidence of equal efficacy or superiority between training methods.