An examination of relative and absolute timing in children, adolescents, and adult vertical jumpers

Horizontal Jumping is a well studied fundamental motor skill with established developmental sequences. Surprisingly, comparatively little work has been completed concerning vertical jumping despite its use in many sport and recreational activities. The purpose of this study was to determine age related differences in vertical jump coordination and performance through the examination of kinematic variables. Twenty-eight participants in three different age groups (9 children age 4--6 yrs, 9 adolescents age 12--14 yrs, and 10 adults age 18--25 yrs) performed 5 maximum vertical jumps with countermovement. Three-dimensional data were collected with a Peak Motus Motion Analysis System. Dependent measures were angular displacement of hip, knee, and ankle joint at low point of crouch, time to peak velocity of joints and segments relative to take-off, peak displacement and time to peak displacement of joints and segments relative to take-off, timing between segments and joint angles from crouch to take-off, time from standing to crouch position of counter movement, time from crouch position to take-off, and height jumped. Segmental and joint data were analyzed across age with oneway MANOVA. Time to crouch, time to take off, and height jumped were analyzed with separate oneway ANOVA. Analyses indicated both qualitative and quantitative differences in dependent measures across age groups. Specifically, the knee and ankle joints of adults and adolescents reached peak velocity after take-off, whereas, only the ankle joint of children reached peak velocity after take-off. Also, there was greater height jumped, greater displacement of the hip joint, and greater time to take off with an increase in age. Results are discussed relative to implications for the development of control and coordination for the vertical jump.