Effect of shoe insole density on impact characteristics and performance during a jump-landing task

Abstract

The purpose of this study was to examine the effect of shoe insole densities on impact shock attenuation, lower extremity biomechanics and performance during a jump-landing activity. Fifteen healthy male college athletes performed three trials of jump-landings during three test conditions (soft, hard and medium insoles). Ground reaction forces (GRFs) and sagittal plane lower extremity kinematic data were sampled simultaneously. A repeated measure analysis of variance was performed on kinematic and GRF variables. The use of soft cushioned insoles during jump-landing significantly increased the mean jump height after first landing phase followed by take-off compared with medium insoles (p = 0.04). The mean vertical GRF loading rate was significantly lower with the hard cushioned insoles (p = 0.027). However, there was significantly greater knee flexion angle at initial contact in hard cushioned insoles compared with soft and medium insoles (p = 0.04). Softer shoe inserts may facilitate jump height, but, adversely increase vertical GRF loading rate. Vertical GRF loading rate decreased significantly with the use of hard cushioned insoles. These findings indicate that hard insole may provide greater cushioning during first landing followed by take-off and jumping. Results of this study support the use of hard cushioned insoles to reduce loading rates during first landing phase of a jump-landing task. Their ability to reduce landing-related injuries, however, remains in question.