Predictors of Initial Acceleration and Maximum Speed Phases of Sprint Running in Children and Adolescents

Abstract

Sprint capacity is a key factor to succeed in many sports modalities and to identify successful predictors must be relevant to optimize speed training and talent detection. Jump tests, muscle strength, and anthropometric variables have been widely associated with sprint performance in adults. However, seeking the best sprinters among young individuals must be influenced by other variables such as sports training, body size, and maturation. Thus, the potential of jump and strength tests to explain sprinting phases (acceleration and maximum speed) might be affected during developmental ages. PURPOSE: To examine relations between the phases of sprinting performance (30m) and body composition (BC), maturation, strength, and jump tests in children and adolescents. METHODS: A database of 456 measures of participants aged 8-18y was analyzed (244 boys, age=14.8±2.3y, BMI=21.6±3.9kg/m2). Photoelectrical cells were used to measure sprint times (S30m, S0-15m, and S15-30m). An electronic mat read flight time to calculate vertical height after squat jump (SJ), counter-movement jump (CMJ), and CMJ with arms (CMJA); the difference between SJ and CMJ was also calculated (VJ- d). Lower limbs strength was tested with a portable dynamometer (LLS). Fat-free mass (FFM) was assessed by anthropometry and bioelectrical impedance analysis. Sports participation (SP) was recorded by questionnaire. A stepwise regression analysis was used to explore the relationship between sprint phases and BC, SP, jump and strength. RESULTS: CMJA was the best predictor of S30m speed (R2=0.724, P<0.001) and acceleration phase (S0-15m, R2=0.566, P<0.001). Maximum speed phase was best explained by SJ (S15-30m, R2=0.530, P<0.001). The model including FFM, gender, VJ-d, and maturity predicted S30m (R2=0.780, SEE=0.28m/s) and S15-30m (R2=0.698, SEE=0.51m/s). For S0-15m, the predictors were CMJA, impedance index, and SP (R2=0.610, SEE=0.36m/s). CONCLUSION: In accordance with other studies, sprinting performance was partially dependent on FFM and maturity. As expected, participation in organized sports seems to affect positively S30m and acceleration performance but did not explain maximal speed phase. Overall, the results highlight the relevance of BC and jump tests as a plausible model to track sprint performance in children and adolescents.