Longitudinal Assessment of Muscle Peak Power Generated in Vertical Jump During Middle Childhood

Abstract

Physical activity in children consist mostly of high intensity short burst requiring muscle power. However, the factors influencing the production of peak power (PP) in middle childhood are still unclear. PURPOSE: To assess the production of PP generated in a vertical jump during middle childhood and to identify potential limiting factors. METHODS: Forty-two participants (24 boys and 18 girls; 6.3 + .48 years of age), were assessed in 1st grade and for the next two consecutive years. Counter-movement vertical jump height was determined using an electronic platform and converted to PP (W) using the following equation: (65.1 x jump height (cm)) + (25.8 x weight (kg)) x 21,413.1 (Canavan & Vescovi, 2004). Participation in extracurricular sports was determined in a questionnaire. Height, weight and skinfolds (triceps and calf) were also measured. Repeated measures ANOVA were performed to determine differences by year of study and Pearson correlations to evaluate relationships between peak power and body composition variables. Independent sample t-test was used to detect differences between gender and extracurricular sports participation. RESULTS: Jump height and PP (W) increased with age (PP = 1080 ± 329, 1196± 261, 1411 ± 316 W for the 1st, 2nd, and 3rd year respectively, p<.05). No differences were found in PP between boys and girls per year (1069 + 383 vs 1093 + 250, 1191+ 292 vs 1201 + 221 and 1441 + 343 vs 1371 + 282 W, respectively). A negative correlation was found between sum of skinfolds (SSF) and jump height (r= -.41, -47, -.58, for years 1 to 3 respectively p<.0001), as well as between sum of skinfolds and relative PP (W/kg) (r = -.54, -.65, -.73, for years 1 to 3 respectively, p<.0001). No significant differences were found in PP between extracurricular sports participants vs. non participants for the 2nd and 3rd year (1214 ± 296 vs 1165 ± 196 W, p=.56; and 1468 ± 348 vs 1297± 208 W, p=.10, respectively). CONCLUSION: These results suggest that during middle childhood jump height and PP increase with age, are negatively influenced by body fat accumulation and are not affected by gender or extracurricular sports participation. Further studies addressing potential limiting factors of muscle peak power production during middle childhood are needed. Funded by the University of PR - FIPI Institutional Grant