Study Design
Randomised crossover trial.
Background
Swimming is often recommended for individuals with chronic low back pain, but different swimming strokes involve unique movement patterns and the impact of each stroke on pain and spinal biomechanics has not been investigated.
Objective
To compare pain intensity and spinal biomechanics across different swim strokes in individuals with chronic low back pain.
Methods
Thirty adults with chronic low back pain swam 100 metres of freestyle, breaststroke, and backstroke, in a randomised sequence. Pain intensity was assessed using a 0–10 Numeric Pain Rating Scale. Spinal biomechanics were measured using inertial measurement units placed at the thoracic spine and sacrum. Intersensor range of motion was calculated to reflect spinal movement. A mixed-effects model was used to compare outcomes.
Results
Pain intensity differed between strokes. Backstroke was associated with the least pain compared to breaststroke (mean difference (MD) -1.10; 95% CI [-1.77 to -0.43]), while differences with freestyle were not statistically significant (MD -0.60; 95% CI [-1.27 to 0.07]).
Biomechanical analysis revealed stroke-specific movement patterns. Breaststroke produced the greatest sagittal plane motion (flexion/extension), followed by freestyle and backstroke (MD 3.6; 95% CI [-2.1 to 9.2] and 8.8; 95% CI [3.2 to 14.5], respectively). Freestyle generated the most frontal and transverse plane motion (lateral flexion and rotation), followed by backstroke and breaststroke (lateral flexion: MD 6.7; 95% CI [1.2 to 12.2] and MD 25.2; 95% CI [19.7 to 30.7]; rotation: MD 2.6; 95% CI [-6.5 to 11.6] and MD 27.1; 95% CI [18.1 to 36.1], respectively).
Conclusion
Backstroke was the least painful stroke during swimming, particularly when compared to breaststroke. Freestyle produced the most spinal rotation and lateral flexion, while breaststroke produced the most flexion/extension. Stroke selection should be considered when prescribing swimming for individuals with chronic low back pain.