Author(s): WYSS, C., NASROLLAHZADEH, N.1,2, CHOUKROUN, R.2, BROOME, M.2, PIOLETTI, D.1, Institution: INSTITUTE OF BIOENGINEERING, EPFL, Country: SWITZERLAND, Abstract-ID: 210

INTRODUCTION:
Jaw clenching has been proposed to influence neuromuscular performance through mechanisms such as concurrent activation potentiation and enhanced central drive. While mouthguards are primarily used for dental protection, their potential effect on muscular performance remains debated. This study investigated whether the use of a mouthguard designed to facilitate comfortable and stable jaw clenching could increase maximal voluntary contraction (MVC) in different muscle groups.
METHODS:
Three trained athletes (male and female) performed a series of maximal strength tests across multiple muscle groups, including upper body (horizontal pull, seated press, shoulder press), trunk (lumbar extension, trunk rotation), and lower body (leg extension, leg curl, leg press). Each test was repeated under several randomized conditions: without mouthguard and with different types of commercially available mouthguards, including custom-fitted and boil-and-bite models. For each condition, three maximal trials were recorded using standardized resistance machines. Athletes were blinded to force output values during testing. Statistical analyses included repeated-measures ANOVA or non-parametric equivalents, depending on data distribution.
RESULTS:
Across participants and exercises, the presence of a mouthguard was generally associated with equal or higher MVC compared to the no-mouthguard condition. Mouthguards allowing stable and comfortable clenching consistently produced higher maximal forces in several muscle groups. In particular, one custom-designed mouthguard showed significantly higher MVC in up to 40% of tested exercises compared to no mouthguard, with no systematic decrease in performance observed in any condition. The effect was most pronounced in large muscle groups and multi-joint exercises. Inter-individual variability was observed, but the overall trend favored improved force production when jaw clenching was facilitated.
CONCLUSION:
These findings suggest that mouthguards enabling effective jaw clenching can positively influence maximal muscle force across different regions of the body. The results support the hypothesis that improved occlusal stability may enhance neuromuscular activation during maximal efforts. While the sample size was limited, the consistency of the effect across athletes and muscle groups indicates a potential performance benefit beyond dental protection.

To conclude, the use of a mouthguard that facilitates jaw clenching appears to increase maximal voluntary muscle contraction in multiple muscle groups. This highlights a potential dual role of mouthguards in both protection and performance enhancement, warranting further investigation in larger controlled studies.