Changes in Shoulder Girdle Muscle Activity and Ratio During Pilates-Based Exercises

Area of Science:

• Biomechanics
• Exercise Physiology
• Rehabilitation Science

Background:

• Pilates-based exercises, specifically modified side-arm (MSA) and modified high-five (MHF), are frequently utilized for shoulder strengthening and rehabilitation.
• Understanding muscle activation patterns and their ratios during these exercises is crucial for optimizing therapeutic outcomes.

Purpose of the Study:

• To investigate and compare shoulder girdle muscle activity and muscle ratios between the MSA and MHF exercises.
• To analyze the effects of varying spring intensities (low, medium, high) on muscle engagement during these Pilates movements.

Main Methods:

• Twenty-two healthy males participated, performing MSA and MHF exercises with low (yellow), medium (blue), and high (red) resistance springs.
• Surface electromyography (EMG) recorded activity in the serratus anterior (SA), lower trapezius (LT), levator scapulae (LS), upper trapezius (UT), and middle deltoid (MD).
• Muscle ratios (LS/SA, LS/LT, UT/LT) were calculated across concentric, isometric, and eccentric phases.

Main Results:

• The MHF generally elicited higher muscle activity than the MSA across all spring intensities.
• Increased spring intensity proportionally enhanced muscle activity for both exercises, with SA and LT activity plateauing in the MHF at higher intensities.
• Significantly higher muscle ratios were observed with the high-intensity spring in the MHF, indicating greater stabilization demands.

Conclusions:

• The MHF exercise provides greater stimulation to the shoulder girdle muscles compared to the MSA.
• Progressively increasing spring intensity for the MSA can enhance shoulder girdle muscle engagement.
• The MHF demonstrates an optimal spring intensity for targeting shoulder stabilization, with excessive intensity potentially leading to compensatory movements.