The influence of maturation on sprint performance in boys over a 21-month period

Abstract

Purpose: This study examined how the characteristics of maximal overground sprint performance are affected by the period of peak height velocity (PHV) in boys. Methods: One hundred and eighty-nine school-aged boys completed two assessments of maximal sprint performance, separated by a 21-month period. Kinematic characteristics of sprint performance were collected during a 30 m sprint using a floor-level optical measurement system, with modelled force and stiffness characteristics also calculated. Participants were grouped according to maturation using a non-invasive predictive equation. Individuals whose maturity offset was <-0.5 yrs in both assessments were classed as ‘pre-PHV’ (n=67) while those whose maturity offset developed from <-0.5 to >0.5yrs in test two were classed as ‘pre-to-post-PHV’ (n=39). Participants with a maturity offset between >-0.5 and <0.5 yrs at test 2 were removed from analysis (n = 67) to ensure that the entire pre-to-post-PHV group had experienced the PHV spurt Results: The pre-to-post-PHV group experienced significantly greater increases in speed (10.4 vs. 5.6%) and relative vertical stiffness (12.1 vs. 5.6%) compared to the pre-PHV group. Step frequency declined (-2.4%) and contact time increased (2.3%) in the pre-PHV group, whilst step frequency increased (2.7%) and contact time decreased (-3.6%) in the pre-to-post-PHV group. Changes in relative measures of vertical stiffness, maximal force and leg stiffness accounted for 79% and 83% of the changes in speed between assessments for pre- and pre-to-post-PHV groups, respectively. Conclusion: As boys experience PHV there are greater increases in maximal sprint speed compared with those who remain pre-PHV. Furthermore, measures of relative stiffness and relative maximal force appear to exert an important influence on the development of maximal sprint speed in boys, regardless of maturity.