The Effect of a Single Bout of Exercise on the Motor Learning of a Drop Vertical Jump Landing Strategy

Abstract

PURPOSE: A single bout of cardiovascular exercise improves cognitive learning, but effects on motor learning have been scarcely researched with mixed results. Key questions remain, including the intensity of exercise required to achieve behavioral effects. The purpose of this study is to test the effect of moderate intensity exercise (ModEx) on the retention of a drop vertical jump (DVJ) landing strategy. METHODS: 40 healthy females (mean age: 20.1, range: 18-22) with no history of leg injury in the past 12 months attended a 1 hour session, first performing 2 DVJs to gather baseline data. Peak vertical ground reaction forces (PVGRF) and hip flexion (HF) angles at the deepest point of landing were measured with a force plate and 2D motion capture software. Next they performed 30 DVJs with feedback for enhanced “soft” landing mechanics. Individuals were then randomized to the ModEx group (n=20), to perform 30 minutes of biking at 55-65% heart rate reserve, or the control (C) group (n=20) for 30 minutes of sham electrical stimulation. After 1 week, a retention session was performed to assess PVGRF and HF during 2 DVJs. RESULTS: Baseline performance did not differ between groups (C: mean PVGRF=48 N/kg, (SD=12), ModEx PVGRF=45 N/kg (12), p=0.84; C: HF angle=96° (23), ModEx: HF angle=94° (24), p=0.62). Both groups reduced PVGRF and HF angles after training (C:PVGRF=38.5 N/kg (11.5), 56°(14), ModEx: PVGRF= 39 N/kg (10), 62° (14), p<0.01) and at retention (C:PVGRF=42 N/kg (10), 58°(15), ModEx: PVGRF= 41 N/kg (8), 60° (15), p<0.01). There was a group by time interaction effect on relative retention (percent change from training to retention) for PVGRF (d=0.21) and HF (d=0.31), which failed to reach statistical significance (p>0.05). CONCLUSION: Training methods were sufficient to induce motor learning, however the effect of ModEx on retention of the skill was small, and these results fail to statistically support the hypothesis that ModEx enhances motor learning of landing strategies. Recommendations for use of ModEx to enhance motor learning cannot be made on the basis of these results. Due to substantial variability, further study with a larger sample will strengthen conclusions. Other considerations for further investigation include exercise timing and dosage, motor skill complexity, and length of the retention period.