Effect of Whole Body Vibration Conditions on Lower Limb Muscles during Sling Exercise

Abstract

Exercising in an unstable environment, such as with the use of a sling, improves neuromuscular adaptation by providing effective training stimuli. Moreover, whole body vibration has been used to restore the physical function of patients with nervous system and musculoskeletal disorders. However, there have been few studies on the most appropriate exercise method of combining unstable surface and WBV. The purpose of this study was to investigate the effect of a sling and sonic vibration stimulation on muscle activation while performing a Bulgarian split squat (BSS). Twenty male subjects (age 25.95 ± 2.42 years old, height: 172.59 ± 5.56 cm, weight: 77.74 ± 10.82 kg) participated in the study. The participants randomly performed five types of BS using a sling and sonic vibration (BSS-0 Hz, BSS-4 Hz, BSS-8 Hz, BSS-12 Hz, BSS-20 Hz, and BSS-30 Hz). Each condition was repeated five times. A 60-s break was given for each condition to minimize muscle fatigue. We measured the muscular activities in the gluteus medius, biceps femoris, rectus femoris, vastus medialis, and vastus lateralis. It was observed that muscle activation increased during exercise conditions that provided a sling and sonic vibration in all muscles. In particular, the highest activation appeared in the condition wherein a vibration of 30 Hz was provided. Our results show that the sling exercise combined with a sonic vibration of 30 Hz during the BSS has positive effects on lower limb muscle activity.