2008 Volume 53 Issue 2 Pages 287-295
The purposes of this study were to examine the effect of teeth clenching on isokinetic muscle strength during isokinetic elbow (60, 120 degrees per second) and knee (60, 180 degrees per second) extension and flexion using a BIODEX isokinetic dynamometer. Twenty-five American football players (19.6±1.3 years) with normal occlusion served as subjects. Isokinetic muscle strength of the elbow and knee, extension and flexion strength were measured during tooth clenching (Bite), biting with a soft biteplate (Soft), biting with a hard biteplate (Hard), and without tooth clenching (No-bite). Analysis of the peak torque per body weight and the time to peak torque yielded the following results:
1) The peak torque per body weight of elbow extension with Soft was significantly higher than with Bite and No-bite (120 deg/s, p<0.05).
2) The time to peak torque of elbow extension with Hard was significantly slower than that with No-bite and Soft (60 deg/s, p<0.05), and those with Bite and Hard were significantly slower than that with No-bite (120 deg/s, p<0.05).
3) The peak torque per unit body weight of knee flexion with Bite and Hard were significantly lower than that with No-bite (60 deg/s, p<0.05), and that with Bite was significantly lower than that with No-bite (180 deg/s, p<0.05).
4) The time to peak torque of knee flexion with Soft and Hard were significantly slower than that with No-bite (60 deg/s, p<0.05), and that with Bite, Soft and Hard were significantly slower than that with No-bite (180 deg/s, p<0.05).
These findings suggest that tooth clenching and the materials of the biteplate are factors that lead to increased isokinetic muscle strength of elbow extension and to decreased isokinetic muscle strength of knee flexion. Thus it appears that tooth clenching and the materials of the bite-plate do not influence isokinetic elbow flexion muscle strength or knee extension muscle strength.
