The Effect of Fatigue on Knee Flexor’s Activation Following Prolonged-run

Abstract

Peripheral fatigue following prolonged runs has been studied extensively using sEMG. Still, most studies did not normalise the exercise intensity, making their findings' reliability elusive. Further, knee flexor (KF) and planter flexor (PF) activation are rarely studied. Therefore, we aimed to normalise the exercise intensity at 25% ∆ to monitor the effect of a 90-minute run on KF and PF activation. Four male runners [age: 22.00 ± 2.18 years; weight: 66.96 ± 7.03 kg; height: 1.75 ± 0.07 m] were evaluated immediately before and after 90 mins run, sEMG sensors were used to record KF ( HAM1; HAM2) and PF (GAS). The EMG data were analysed using Visual3D software to calculate the root mean square (RMS) values over ten gait cycles. Concerning HAM1, HAM2 and GAS, results from ANOVA found no statistically significant interaction between the muscles and time on EMG amplitude, F (2, 9) = 4.2565, p = .096, partial η2 = .406. Furthermore, no significant main effect in the mean RMS (P > 0.05) was found for condition (pre- and post-90 mins run), F (1, 2) = 18.513, p = .253, partial η2 = .142. Similarly, the main effect of Muscle showed no statistically significant difference in the mean RMS between the three muscles, F (2, 9) = 2.253, p = .161, partial η2 = .343. The result indicates that a 90-minute run at 25% ∆ did not induce significant alterations in KF and PF activation.