Effects of 8 week oral splint usage on body flexibility and muscle strength-endurance performance in Pilates practitioners.

Purpose We investigated the acute and chronic effects of oral splint on muscle strength-endurance performance and body flexibility. Methods Twelve Pilates practitioners (age 49.5 ± 5.8 years; mass 58.6 ± 6.5 kg) were evaluated with (OS) and without (CTRL) oral splint. Before (PRE) and after (POST) 8 weeks of oral splint usage during Pilates activity, muscle strengthendurance and body flexibility were evaluated through a frontal plank exercise and a Toe-touch test in OS and CTRL. Before each test, the highest electrical activation (EMG) of masseter and temporal muscles during maximal occlusion was determined. During frontal plank, the time-to-exhaustion, the maximum voluntary activation of masticatory muscles and the time of muscles activation have been determined. Results No OS vs CTRL and PRE vs POST differences were found in the maximum voluntary activation of temporal and masseter muscles. The time-to-exhaustion in OS was longer than CTRL in both PRE (P = 0.049) and POST sessions (P = 0.043). Time of masticatory muscles activation during plank was moderately greater in OS at PRE (P = 0.020) and POST (P = 0.022), while no difference between PRE and POST emerged in both conditions. Higher muscular activation was found in OS than CTRL at PRE (P = 0.031) and POST (P = 0.031), whereas no difference between PRE and POST appeared. No effect on flexibility emerged neither acutely nor chronically. Conclusion Acute and chronic oral splint usage improved strength-endurance performance but not body flexibility. These findings suggest biomechanical and neural mechanisms influencing the muscle length and the concurrent activation potentiation, but not muscle tone and stiffness.