Adding mechanical vibration to a half squat with different ballasts and rhythms increases movement variability.

Area of Science:

• Biomechanics
• Exercise Physiology
• Motor Control

Background:

• Movement variability is crucial for motor control and adaptability.
• Whole body vibration (WBV) is used in training to enhance neuromuscular responses.
• Entropy measures complexity and unpredictability in dynamic systems, applicable to movement analysis.

Purpose of the Study:

• To investigate if whole body vibration (WBV) alters movement variability during half squats.
• To examine the influence of different ballast types (weighted vest, dumbbells, bar) and squat rhythms (40 and 60 bpm) on movement variability under WBV.
• To quantify changes in movement variability using sample entropy.

Main Methods:

• Twelve male athletes performed half squats with 15% body mass ballast (weighted vest, dumbbells, bar) under static and whole body vibration conditions.
• Squat rhythms were set at 40 bpm and 60 bpm.
• Movement variability was assessed via sample entropy of waist-mounted accelerometer data.

Main Results:

• Whole body vibration significantly increased movement variability compared to no vibration.
• Higher sample entropy was observed with weighted vest and dumbbells compared to the bar, and at 40 bpm compared to 60 bpm.
• No significant differences in movement variability were found without vibration across ballast types or rhythms.

Conclusions:

• Mechanical vibration during half squats non-proportionally increases movement variability.
• The increase in variability is more pronounced when ballast is applied to the upper limbs and during slower squat rhythms.
• Findings suggest WBV can modulate motor control strategies during resistance exercises.