RESUMO
It was investigated whether the activity of lower limb musculature shows any interlateral asymmetry during a vertical jump, namely the countermovement and impulsion phase, the flight phase, and the landing phase,were considered. These stages were represented by an initial burst of electromyographic activity, a between-bursts interval, and the first component of a final burst of electromyographic activity. Right-handed volunteers (6 male and 6 female), that practiced exercise irregularly, were tested. Electrodes were fixed over the motor point and a reference point of muscle vastus lateralis and of muscie soleus. These electrodes were connected to a standard electrophysiological recording system. The subjects performed three blocks of 1O lumps each. Individual electromyographic activity was bandpass filtered (30 to 1000 Hz) and sampled at a frequency of 3.12 5 Hz. This activity was subsequently rectified. The duration of each stage of the lump and the magnitude of each burst of activity were evaluated. These data were submitted to an ANOVA and a Newman-Keuls test, with significance level set at 0.05. Only the final burst of electromyographic activity showed interlateral differences. The duration of the first component of this activity was longer on the right side than on the left side for both the vastus lateralis muscle and the soleus muscle. The magnitude of this activity was also larger for the right side than for the left side for the vastus lateralis muscle and the soleus muscle. There is thus an asymmetric pattern of muscle activity in the inferior limb during the landing stage of a vertical jump. The right leg may be more involved in supporting the weight of the body when landing from a jump than the left leg.