Teeth Clenching Improves Selective Response and Shortens Reaction Time

ABSTRACT: Sugai, N, Hirabayashi, R, Okada, Y, Yoshida, Y, Okouchi, T, Yokota, H, Ishigaki, T, Komiya, M, Sakamoto, K, and Edama, M. Teeth clenching improves selective response and shortens reaction time. J Strength Cond Res XX(X): 000-000, 2026-In sports, rapid decision making and quick reactions are vital for optimal performance. Enhancing reaction time in choice to respond, task-based tasks require efficient cognitive processing and motor output. This study examined the effects of teeth clenching and clenching balance on reaction time. Teeth clenching has been shown to boost muscle activity and cognitive function; however, imbalanced clenching between the left and right sides may negatively affect performance. Twenty-two right-handed subjects with normal occlusion and 28 or more teeth completed a forward stepping task under 3 clenching conditions: no clenching without dental contact (No-CL), moderate clenching (Moderate-CL), and maximal clenching (Max-CL). Reaction time was assessed through the soleus muscle (Sol) activity, including Sol reaction time, release time, and grounding time. Results showed significantly shorter Sol reaction, release, and grounding times under Moderate-CL and Max-CL conditions than under no-CL (p < 0.05). In subjects with balanced clenching, all 3 measures improved significantly under clenching conditions (p < 0.05). However, those with clenching imbalance showed improvement only in Sol reaction time (p < 0.05). Furthermore, a significant positive correlation was found between clenching imbalance and changes in reaction time, particularly for release time and overall reaction time under clenching conditions (r > 0.37, p < 0.05). These findings suggest that clenching can enhance spinal excitability and cognitive performance through activation of the locus coeruleus, potentially improving reaction ability in sports and daily life. However, clenching imbalance may limit these benefits, highlighting the importance of considering clenching balance in future research and performance strategies.