Trunk muscle activity during spine stabilization exercises performed in a pool

Objectives: To compare trunk muscle activity levels among a variety of therapeutic aquatic exercises designed for patients with low back pain.

Study design: Quantitative observational laboratory study.

Setting: Sports medicine clinic housed in a University.

Participants: Eleven physically active males aged 25.7 ± 5.53 years.

Main outcome measures: Surface electromyographic (EMG) data from muscles rectus abdominis (RA), external oblique (EO), lower abdominals (LA), multifidus (MT), and erector spinae (ES) were recorded and then normalized to a maximal voluntary contraction.

Results: EMG values during abdominal bracing and Swiss ball exercises for muscles RA, EO, LA, and ES were significantly greater than most other exercises tested that included pelvic tilt, marching, hip abduction, and alternating arm exercises (P = .04-.001). EMG values of muscle LA were also greater for the abdominal hollowing exercise, whereas muscle MT displayed the greatest EMG values during the hip abduction exercise when compared to most other exercises tested (P = .02-.001).

Conclusions: The aquatic exercises that maximize trunk muscle activity in the healthy males studied are abdominal bracing and Swiss ball exercises. Some muscles were selectively activated during abdominal hollowing (LA) and hip abduction (MT) exercises when compared to most other exercises.