ECSS Paris 2023: CP-AP29
INTRODUCTION: Metronome-synchronized training utilizes rhythm perception and is suggested to enhance motor performance [1]. In soccer, precise synchronization of sensory and motor functions is crucial for optimal timing and coordination between the upper and lower limbs. Rhythm Jump Training (RJT) is a training method that incorporates auditory rhythms cues to enhance movement synchronization, potentially improving agility and jumping performance. However, its effectiveness in adolescent athletes remains unclear. This study aimed to clarify the effects of RJT on agility and jumping ability in junior high school soccer players through a randomized controlled trial. METHODS: A randomized controlled trial was conducted with 25 male junior high school soccer players (age: 13.1 ± 0.2 years) who trained five days per week in their school club. Participants were randomly assigned to either the RJT group, which performed 30-minute rhythm jump training once per week for eight weeks, or the control group, which continued regular warm-up exercises without rhythmic training. To evaluate the effects of RJT on athletic performance, pre- and post-intervention assessments were conducted using the Pro-agility Test (PAT) to measure agility and the Reactive Strength Index (RSI) to assess jumping performance. A mixed-model two-way ANOVA was performed to analyze the effects of RJT, with group (RJT vs. Control) as the between-individual factor and time (pre vs. post) as the within-individual repeated factor. Additionally, age in months was included as a covariate to account for growth-related changes. RESULTS: A total of 19 participants completed the study. No significant interaction effects were observed for the PAT (p = 0.97) or RSI (p = 0.99). CONCLUSION: A previous study conducted with elementary school students demonstrated significant improvements in PAT, but no effect on RSI [2]. However, in this study, no significant improvements were observed in junior high school soccer players. This suggests that the intensity and frequency of RJT may have been insufficient for this age group. Additionally, RSI performance is highly dependent on maximum muscle strength [3], which may not be effectively enhanced through RJT. Future research should explore increased training intensity and frequency, as well as age-specific adaptations, to optimize the benefits of RJT in adolescent athletes. Reference: [1] Ronnqvist L, McDonald R, Sommer M. Influences of synchronized metronome training on soccer players timing ability, performance accuracy, and lower-limb kinematics. Front Psychol. 2018;9:2469. [2] Kato Y, Watanabe H, Kawabata M, et al. The effects of rhythm jump training on the rhythmic reproduction ability in jumping and agility in elementary school soccer players. Children (Basel). 2025;12(2):133. [3] Beattie K, Carson BP, Lyons M, Kenny IC. The relationship between maximal strength and reactive strength. Int J Sports Physiol Perform. 2017;12(4):548-553.
Read CV Naoko TsunekawaECSS Paris 2023: CP-AP29
INTRODUCTION: Youth football performance depends on psychophysiological skills, but the relative age effect (RAE) often favors those born earlier in the year (1). While physical fitness contributes significantly to technical performance, some studies (2) find no direct link. On the other hand, motor control has been highlighted as a good predicting factor of football-specific skills, with no regard for chronological age. However, age-based groupings are common, neglecting actual motor skills. Therefore, this study evaluates motor skill differences between adjacent age groups in a youth soccer academy, examining the development of physical and technical parameters. METHODS: 170 male soccer players (aged 8-12) were divided into five groups based on chronological age. At the beginning of the regular season, participants underwent physical and technical tests, including: Counter Movement Jump with arm swing (CMJA) and without arms (CMJ); 15-meter linear sprint with (LSB) and without the ball (LS); 15-meter agility test with (ATB) and without the ball (ATB); and a sit and reach test for flexibility (SeR). A non-parametric Kruskal-Wallis test was used to identify group differences at T0, with Mann-Whitney tests for post-hoc comparisons between adjacent age categories. RESULTS: Kruskal-Wallis tests revealed significant differences across all age groups (p ≤ 0.01). Post-hoc analysis comparing adjacent groups yielded interesting results. For the jump tests (CMJ vs. CMJA), significant differences were only observed between the 10- and 11-year-old groups (p = 0.032). However, when arm use was incorporated (CMJA), differences also emerged between the 8- and 9-year-old groups (p = 0.045). The linear sprint (LS, LSB) and agility test (AT, ATB) results showed similar trends. For tests without the ball (LS and AT), differences were found between the 8- and 9-year-old groups (p ≤ 0.010) and the 11- and 12-year-old groups (p < 0.01). With the ball, differences were only present between the 10- and 11-year-old (p < 0.01) and 11- and 12-year-old groups (p ≤ 0.01). Finally, the 9- and 10-year-old groups showed no significant differences across any of the tests. CONCLUSION: For the CMJ tests, the increase between 10- and 11-year-olds likely reflects increased lower limb power, while the difference between 8- and 9-year-olds reveals a significant coordination improvement (CMJA). Differences in LS and AT between 8-9 and 11-12 year olds could be attributed to sensitive periods of speed development. However, with the ball, differences emerge only between 10-11 and 11-12 year olds, likely due to better ball control related to game experience. Finally, the lack of significant differences between 9- and 10-year-olds across all tests suggests similar characteristics, potentially justifying their practical grouping by age.
Read CV Davide CurziECSS Paris 2023: CP-AP29
INTRODUCTION: High cardiorespiratory fitness (CRF) is a key determinant of elite performance in soccer. In Saudi Arabia, the hosts of the FIFA 2034 World Cup, adult and youth soccer players demonstrated consistently lower CRF than international counterparts1,2 which could be attributed to genetic factors. The aim of this study was to compare CRF between elite youth Saudi and maturity-matched UK soccer players, and assess the cumulative genetic influences on CRF phenotype in elite youth Saudi soccer players. METHODS: Anthropometric and CRF (measured V̇O2max during Yo-Yo IRL1 using COSMED-K5) phenotypes were compared between post-peak height velocity (PHV) youth male soccer players from Saudi Arabia (n=20) and the UK (n=23). Subsequently, 98 Saudi players were genotyped for 6 SNPs (ACE, BDKRB2, NOS3, PRDM1, GRIN3A, KCNH8), using TaqMan PCR. Associations between genotypes and V̇O2max from Yo-Yo IRL1 were assessed individually and as part of a total genotype score (TGS). A TGS of 100 represents a ‘perfect’ polygenic profile, and 0 the ‘worst’ possible profile for CRF. Independent t-tests were used to determine significant differences in anthropometric and CRF phenotypes of the post-PHV players from Saudi and UK. In the Saudi players, a one-way ANOVA was conducted to determine significant differences in anthropometric and CRF phenotypes between maturity offset groups and genotypes individually and as part of a TGS. RESULTS: In comparison to post-PHV UK-based players, post-PHV Saudi players were smaller, lighter, younger and had a significantly lower V̇O2max (0.09±0.01 m; 11.0±2.1 kg; 2±0.3 years, 10.8±3.3 mL·kg·min-1; P<0.001 respectively) but there was no difference between groups for age at PHV (P=1.00). In the sub-group of Saudi players, age (P=0.004), height (P<0.001), body mass (P<0.001) and maturity offset (P<0.001) differed between maturity groups. V̇O2max was not significantly different (P=0.183) between maturity sub-groups for the Saudi players but there was a main effect of PRDM1 rs10499043 genotype on age (P=0.016), age at PHV (P=0.007) and V̇O2max (P=0.003). TGS was significantly different between maturity groups (P=0.029), with the TGS for the pre-PHV group lower than circa-PHV (13±5, P=0.031). CONCLUSION: Saudi elite youth male soccer players are smaller in size and possess inferior CRF compared to UK counterparts matched for maturity status. While this is likely explained by a lower training age of Saudi players, genetic factors are also important to consider. It is possible that PRDM1 TT homozygotes, achieved higher CRF via enhanced mitochondrial efficiency, oxygen transport and/or increased proportion of type I fibres. Interestingly, it appears that existing talent ID processes in Saudi reflect CRF polygenic profiles, as older and more mature players had higher TGS scores than younger players. 1AlHazzaa H et al. Journal of Sports Medicine and Physical Fitness 2001; 41(1): 54. 2ALSowayan M. Gazzetta Medica Italiana 2023;182(12):956-65.
Read CV Georgina StebbingsECSS Paris 2023: CP-AP29