Effect of trunk muscles fatigue on plantar pressure distribution in novice runners.

During running, trunk muscles act to sufficiently contribute to the energy generation and transmission of the body parts. Improper function of trunk muscles affects running mechanics adversely and could result in altered lower limb energetics. The aim of this study was to examine the effects of trunk muscles fatigue on plantar pressure distribution in novice runners. 46 novice heel-to-toe runners (26 female and 20 male) ran in 3.3 m/s before and after the trunk muscles fatigue along the plantar pressure measuring device. Then, participants performed trunk muscles fatigue protocol. Trunk muscles fatigue protocol consisted of four consecutive cycles of seven exercises (1) rotating trunk with a medicine ball in sitting position, 2) prone static torso extension with a medicine ball, 3) rotate lower torso with a medicine ball in supine position, 4) incline sit-ups with a weight plate, 5) lateral side binding with a weight plate, 6) rotating lumbar extension with weighted plate, and 7) standing trunk rotation with weighted pulley resistant. After trunk muscles fatigue, increases in loading of lesser toes (p = 0.001, ES = 0.379), fourth (p = 0.001, ES = 0.474) and fifth metatarsals (p = 0.004, ES = 0.173) and medial and lateral heel (p = 0.018,0.001, ES = 0.118,0.427) were observed. Also, foot progression angle (p = 0.001, ES = 392) and relative time of initial contact phase (p = 0.003, ES = 0.182) decreased. The trunk muscles fatigue could alter the plantar pressure distribution pattern. Novice runners should consider strengthening of the trunk region muscles to avoid trunk muscles strength reduction-related changes in running mechanics.