Motor variability during resistance training: Acceleration signal as intensity indicator

Area of Science:

• Biomechanics
• Exercise Physiology
• Signal Analysis

Background:

• Physiological time series variability analysis indicates organism state.
• Complexity analysis is useful in cycling but understudied in resistance exercise.

Purpose of the Study:

• To determine if acceleration signal variability indicates intensity in squat exercises.
• Investigate the application of complexity measures in resistance training.

Main Methods:

• Seventy-two participants performed squats at 10-90% of 1RM.
• Acceleration data collected via IMU and force platform.
• Variability analyzed using Standard Deviation (SD), DFA, FuzzyEn, and SampEn.

Main Results:

• Significant effects of intensity on variability measures for both IMU and force platform (p < 0.001).
• IMU data showed increased motor complexity with higher intensity for DFA, FuzzyEn, and SampEn.
• Force platform data showed fewer differences, with DFA detecting most intensity variations.

Conclusions:

• Acceleration signal variability, particularly motor complexity, is a potential indicator of relative intensity in squat exercises.
• IMU-based complexity measures offer a promising approach for monitoring resistance training intensity.