Abstract
Purpose
To determine the effect of leg dominance on trunk muscle activity during bridging exercises on the floor and a gym ball.
Background
Perturbation training including bridging exercises and unstable surfaces have been shown to increase trunk activity. Trunk muscle activity increases on the contralateral side to the stabilising leg during bridging, however, no studies exist on the effect of leg dominance on trunk muscle activity during bridging exercises. This study will investigate whether trunk muscle activity differs when stabilising on the dominant versus non-dominant leg.
Method
A same subject observational design collected surface electromyography (SEMG) muscle activity for right (R) and left (L) bilateral IO and EO in 2 bridging exercises. (1) feet on the floor, (2) legs on a gym ball. 13 subjects, all right leg dominant (age, 21.53±1.50 years, height 169.38±8.33 centimetres, weight 67.91±10.60 kilograms gave informed consent. All SEMG data was normalized against maximum voluntary contractions. Data was analysed using paired t-test or Wilcoxon rank analysis.
Results
In the ball exercise lifting the dominant leg significantly increased RIO (p=0.004), in the floor exercise lifting the dominant leg significantly increased LEO (p=0.03) and RIO (p=0.05). In the ball exercise lifting the non-dominant leg significantly increased LIO p=(0.007) and LEO (p=0016). All other recordings were non-significant.
Conclusion
There was no consistency in increase in trunk muscle activity when comparing lifting the dominant and non dominant leg in the two exercise conditions. This may reflect the variability in individual trunk muscle response to perturbations.
