In this study, landing strategies of gymnasts were hypothesized to change with different landing surfaces. This hypothesis was tested by comparing the kinematics and reaction force-time characteristics of two-foot competition-style drop landings performed by male and female collegiate gymnasts onto three surfaces (soft mat, stiff mat, no mat). Significantly lower peak vertical forces, longer landing phase times, and greater knee and hip flexion were observed between the no mat condition and the mat conditions. Knee flexion and peak knee flexion velocities were also observed to be significantly greater for landings on the stiff mat than those on the soft mat. These results indicate that the gymnasts in this study modulated total body stiffness in response to changes in landing surface conditions by using a multi joint solution. In addition, the presence of a mat may reduce the need for joint flexion and may alter the vertical impulse characteristics experienced during landing.
Jill McNitt-Gray, Takashi Yokoi, and Carl Millward are with the Biomechanics Research Laboratory, Department of Exercise Sciences, University of Southern California, Los Angeles, CA 90089-0652.