Content area
Background
This study investigates the effects of a fatiguing exercise on lower limb electro-myographic activities and co-contraction in overweight females compared with normal weight females during running.
Methods
Forty-eight females were divided into two groups. The first group included individuals with a normal body-mass-index. The second group comprised individuals classified as overweight/obese based on body-mass-index. Electromyography data from the tibialis anterior, gastrocnemius medialis, vastus lateralis, vastus medialis, rectus femoris, biceps femoris, and semitendinosus muscles were collected during running at constant speed using a surface electromyography system before and after a running induced fatigue.
Findings
The results indicated significant main effects of the “Group” on tibialis anterior muscle activities during the loading phase (P = 0.040). Furthermore, the results showed significant main effects of “Fatigue” on rectus femoris (P = 0.028) and semitendinosus (P = 0.007) muscle activities during the loading phase. Paired-wise comparison demonstrated significantly greater rectus femoris and semitendinosus activities during the loading phase after the fatigue protocol. The results demonstrated significant main effects of “Fatigue” for general knee muscular co-contraction during early stance phase (P < 0.001). Paired-wise comparison demonstrated significantly greater general knee muscular co-contraction during early stance phase at post-test compared with pre-test. No significant main effect of “Group” and group-by-fatigue interactions were found for general and direct knee co-contraction during early stance phase (P > 0.05).
Interpretation
Overall, our findings indicate that both fatigue and being overweight result in running pattern differences, but these occur through different mechanisms at a neuromuscular level. Neuromuscular responses to fatigue during running in overweight adults and in normal weight adults can be evaluated together, in order to optimize the modality of treatment and rehabilitation processes in overweight adults to reduce and/or prevent the risk of running related injury.
