Shoulder muscular activation during common kettlebell exercises: a randomized cross-sectional surface EMG study

Area of Science:

• Exercise Physiology
• Biomechanics
• Sports Science

Background:

• Understanding shoulder muscle activation is crucial for effective exercise programming.
• Different resistance modalities may influence muscle recruitment patterns during upper-body exercises.

Purpose of the Study:

• To compare shoulder muscle activation during functionally similar upper-body exercises using kettlebells, dumbbells, and elastic bands.
• To analyze how different resistance types affect muscle engagement in overhead pressing, rowing, and swinging movements.

Main Methods:

• Twenty healthy males performed standardized overhead pressing, rowing, and swinging exercises.
• Surface electromyography (EMG) recorded activity from seven shoulder muscles.
• EMG data were normalized, log-transformed, and analyzed using a two-way repeated-measures ANOVA.

Main Results:

• Significant differences in shoulder muscle activation were observed across exercises and muscles, with a notable interaction effect.
• The Bottoms-Up Kettlebell Overhead Press showed higher upper trapezius and infraspinatus activation compared to traditional kettlebell presses.
• Rowing with free weights resulted in greater middle and lower trapezius activation than elastic band rowing.

Conclusions:

• Kettlebell, dumbbell, and elastic band exercises produce distinct shoulder muscle activation profiles.
• Exercise selection based on resistance modality can be tailored to target specific shoulder muscles.
• Findings support informed exercise programming for task-oriented training contexts.