Differences in Jump Landing Mechanics, Strength, and Vertical Jump Height Between Obese and Non-Obese Children

Abstract

It has been reported that overweight and obese children display increased joint loading, higher impact loading and decreased joint ROM during walking and running. There is limited research examining the movement mechanics of other high impact activities in children. PURPOSE: To compare jumping mechanics, strength, and max vertical jump between healthy weight children and children classified as overweight or obese. METHODS: 42 children (22 males, ages 11.1±1.6 yrs; 20 females, ages10.9±1.3 yrs) were divided into 2 groups based on the CDCP’s BMI percentile for children. 24 children were classified as healthy weight (HW) (n=13 males, 11 females; BMI percentile 44.8±25.8) and 18 children were classified as overweight/obese (OW/OB) (n=9 males, 9 females; BMI percentile 95.6±3.9). Participants completed 2 testing session approximately 1 week apart. During the first session age, height, mass, and leg strength were collected. Max torque created during isokinetic knee extensions at 90 degrees/s was used to determine leg strength. For the second visit participants completed a max vertical jump test and 5-10 drop jump trials. For jump trials, participants jumped off a 20 cm platform onto 2 force plates and immediately jumped up to a target set at 60% of their max jump height. Ground reaction forces (1000Hz) and joint kinematics (200Hz) were captured for each trial. One way ANOVAs (α=0.05) were used to determine group differences for each of the variables of interest listed in Table 1. RESULTS: Results can be found in Table 1. CONCLUSION: There appear to be no group differences in leg strength, max vertical jump height, or max landing force. However, similar to other studies, HW children displayed greater ROM during landings than children classified as OW/OB. Increased joint ROM while landing from a jump has typically been thought to decrease vertical loading, however our data suggests significantly greater ROM does not always result in increased vertical loading.Table 1: Summary of means, p-values and effect sizes for variables of interest