Title

Comparison of the Trunk and Pelvis Range of Motion Between Gymnasts and Non-Gymnasts

Publication Date

12-2008

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Mechanical Engineering

Department

Mechanical and Biomechanical Engineering

Major Advisor

Michelle B. Sabick

Abstract

Gymnasts have a high incidence of low back injury. For this reason it is important to quantify the range of motion of the trunk and pelvis, as well as low back muscle activity, in gymnasts while performing different trunk bending tasks. The aim of the current study was to compare the range of motion of the trunk and pelvis and the low back muscle activity between gymnasts and non-gymnasts.

Twenty healthy, young female subjects (gymnast n=10, non-gymnast n=10) performed 4 different tasks: backward bending at the hips (trunk extension), forward bending at the hips (trunk flexion), bilateral bending at the hips, and a step down from a riser. While performing these tasks, landmarks of interest were tracked using an electromagnetic motion monitor and low back muscle activity was recorded using electromyography. Trunk and pelvis ranges of motion during these tasks were quantified using Euler angles. Muscle activity was normalized to maximum voluntary isometric contraction of the subject.

Pelvis back extension angle and pelvis sagittal range of motion were significantly greater in the non-gymnasts than the gymnasts (p = 0.003 and p = 0.026, respectively). The trunk back extension angle and trunk sagittal range of motion were higher in the gymnasts than the non-gymnasts (p = 0.001 and p = 0.011, respectively). During the back extension trials, the low back muscle activity was observed to be the same between groups. During the flexion and bilateral flexion trials there were no significant differences in the trunk and pelvis angles or the low back muscle activity between the groups.

During the dynamic step down from a riser the activations left and right low back muscles were found to be significantly higher in the non-gymnasts than the gymnasts (p = 0.048 and 0.006).

This study provides an initial basis for the range of motion of the trunk and pelvis for gymnasts.

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