Strength differences between trained and untrained pre-pubertal children: stretch shortening cycle of muscle contractions

Abstract

This study investigated jumping performance in pre-pubertal children with respect to age, gender and trained level and their ability to use the stretch-shortening cycle (SSC). One hundred and twenty-seven (n=127) children participated in this study that included 66 from a basketball academy (age: 9.88±1.38 years) and 61 sedentary schoolchildren (age: 9.93±1.55 years). Neuromuscular variables, such as the Squat Jump (SJ), the Counter Movement Jump (CMJ), the Drop Jump (DJ) and the Standing Long Jump (SLJ) were measured. There were no significant differences between boys and girls in all the jumps for the basketball group. In the sedentary group, boys exhibit higher scores in DJ-40cm than the girls. The trained group achieves better scores in several jumps than the sedentary group. Significant differences between the sedentary and trained groups in relation to different age groups are found in all the jumps. High scores on the DJ-40cm and SLJ are a risk factor for trained status. Pre-pubertal children exhibit considerable trainability in relation to explosive leg strength; however, there is an inability to use the stretch-shortening cycle to vertical jumping performance.

Keywords: Strength; Children; Trainability; Jump performance