The assessment of vibromyographical signals in the time and frequency domains during a fatigue protocol

At present there appears to be a lack of data on the effects of vibration stimulation and its influence on muscular fatigue. The purpose of this study is to investigate the behaviour of the fundamental frequencies produced by the rectus femoris muscle when performing an isometric fatiguing protocol under conditions of no vibration and vibration. Sixteen recreational athletes (mean  SD) age 22 ± 4.4 years, body mass 73.2 ± 11.7 kg and height 173.1 ± 9.7 cms were recruited. Vibration stimulation was delivered at 50.42  1.16 Hz with an acceleration of 13.24  0.18ms-2 to the dominant leg of participants. A paired t-test revealed significant (p < 0.05) within condition differences between pre and post measures for peak isometric force, peak normalised EMGRMS and lactate measures for the two conditions. A one-way ANOVA revealed no significant differences between the post measures of these variables between the two conditions. An ANOVA revealed significant (p < 0.05) differences between the peak frequencies at the completion of the isometric fatiguing protocols between the non-vibrated (9.8 ± 3.5 Hz) and vibrated conditions (27.1 ± 12.2 Hz). The vibrated condition resulted in an increase in peak frequency indicating a state of less fatigue