Suppressed Arm Swing While Running: No Change In Sagittal Plane Joint Kinetics

Arm swing contributes positively to the metabolic cost of running and can be easily manipulated in clinical settings. When arm swing is suppressed, the body adapts by altering whole-body motion. Removing arm swing during running may facilitate a compensatory increase in lower extremity joint contributions throughout the gait cycle. PURPOSE: 1) To compare the steady state VO2 consumption between arm swing and no arm swing conditions. 2) To compare lower extremity joint kinetics between arm swing and no arm swing conditions via statistical parametric mapping. METHODS: Highly trained female runners (n = 11, training: 37.7 ± 15.2 miles/week, VO2 Peak: 60.9 ± 6.6 mL·kg-1·min-1, age: 21 ± 3 years, weight: 58.5 ± 3.6 kg, height: 1.69 ± 0.05 m) were recruited to complete a single session of running. This protocol included a self-paced 10-minute warm-up and two six-minute conditions, counterbalanced between participants. Both arm swing and no arm swing conditions were completed at 3.5 m·s-1 on level grade and included the collection of steady-state VO2 consumption. During no arm swing conditions, participants were asked to maintain both hands over their naval, clasped together. An instrumented treadmill (1000 Hz) and motion capture system (100 Hz) were used to derive joint kinetics during the final minute of each condition. Time-normalized data from the first five strides were used to impute an ensemble average for each participant. Ensemble time series were then analyzed via statistical parametric mapping, using a paired t-test statistical test to assess for statistical significance (α = 0.05). Steady state VO2 was compared by a paired t-test (α = 0.05). RESULTS: Despite a statistically significant increase (p = 0.03) in oxygen consumption during no arm swing conditions (No Arm Swing VO2: 48.9 ± 4.2 mL·kg-1·min-1; Arm Swing VO2: 47.7 ± 4.3 mL·kg-1·min-1), no significant differences were noted for joint angles, moments, and powers at the ankle, knee, or hip between arm swing and no arm swing conditions (p > 0.05). CONCLUSIONS: The present findings suggest suppression of arm swing during running results in no systematic compensatory strategy, where one joint assumes the added conditional demand. Furthermore, our findings support the hypothesis that removing arm swing is metabolically detrimental to running.