Honors Theses

Date of Award


Document Type

Undergraduate Thesis


Health, Exercise Science, and Recreation Management

First Advisor

John Garner

Relational Format



The use of a performance mouthpiece may cause notable performance changes in an isometric mid-thigh clean pull (iMTCP) due to altered muscular force production. The purpose of this study was to examine the effects of wearing various mouthpieces coupled with a clenching of the jaw on iMTCP force production. Three recreationally trained college-aged males (Age: 26.67 ± 2.89) volunteered to participate in three testing sessions separated by one week each. In the three sessions, the subject performed repetitions of an iMTCP under the following conditions: performance mouthpiece with jaw clenched (PMP-JC), performance mouthpiece with no clench (PMP-NC), traditional mouthpiece with jaw clenched (TMP-JC), traditional mouthpiece with no clench (TMP-NC), no mouthpiece with jaw clenched (NoMP-JC), and no mouthpiece with no clench (NoMP-NC). The iMTCP assessment was measured using a Jones Machine® with a modified fixed bar allowing the subject's strength to be transferred onto a force plate via ground reaction force. The force plate analyzed the subject's clean pull trials as the collected data was used to calculate the subject's peak force (Fz), normalized peak force (nFz), and rate of force development (RFD). There were no significant differences (p > .05) or interactions found in Fz between the test trials. Similarly, for nFz and RFD, no significant differences (p >.05) or interactions were found between conditions. Therefore, the subjects' iMTCP assessments showed no overall interactions or improvements between conditions for this study. This goes to show that there is no overall benefit to wearing any sort of performance mouthpiece in hopes of generating a larger force production.

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