Comparison of hard and soft surfaces during maximal vertical jumps in a depth jump plyometric exercise
Abstract
The purpose of this study was to examine how landing surfaces used in a depth jumping
(DJ) plyometric exercise affected kinematic and kinetic variables. Sixteen male and
female college students, who were involved in recreational activities, performed 5 DJ
onto a force platform alone (hard landing surface) and a 2.35cm thick mat placed onto the
force platform (soft landing surface). The maximum angular position and angular
velocity measurements were recorded and analyzed for the trunk segment and knee joint
at the greatest point of knee flexion during landing using a video camera and an Ariel
Performance Analysis System (APAS). Contact and flight times were established using
data collected by a Bertec force platform. The vertical ground reaction forces and the
rate at which these forces were generated were collected and analyzed between surface
conditions. An alpha level of 0.05 was used in all statistical tests. A t-test was used for
all statistical analyses. Results indicated no significant differences in the maximum
angular positions of knee and trunk segments at landing (p = 0.424 and 0.266,
respectively). Angular velocities of the knee and trunk segment at landing were not
significant (p = 0.153 and 0.243, respectively). The contact and flight times were found
to be nonsignificant (p = 0.263 and 0.397, respectively). The time to peak vertical
ground reaction force was also found to be nonsignificant (p = 0.224). From the results,
it can be concluded that a soft landing surface, 2.35cm thick, would be as effective at
eliciting the desired traits (decreased joint flexion, decreased contact time, and increased
flight time) of the DJ exercise as a hard landing surface.
Subject
Plyometrics
Jumping - Physiological aspects