Aerobic Exercise Intensity: A Dose-Response Effect on Motor Adaptation and Learning

Acute aerobic exercise (AEX) can enhance motor learning. While AEX intensity likely plays a key role, there is mixed evidence for AEX-enhanced motor skill acquisition and learning across a spectrum of exercise intensities. This may stem, in part, from inconsistent AEX parameters (i.e., intensity, structure, and duration) employed within and across studies. Additionally, evidence suggests that AEX can enhance a specific form of motor learning, namely motor adaptation. Moderate- and high-intensity AEX can increase motor adaptation, but evidence remains limited and inconsistent. Hence, the impact of AEX intensity on motor adaptation remains unclear. Here, we investigated the influence of AEX intensity on motor adaptation, while controlling for AEX structure and duration. Eighty young adults were assigned to four cycling AEX/Rest groups (n=20/group): 20 min of light (LIIT), moderate (MIIT), or high (HIIT) intensity interval training, or Rest (control). AEX consisted of four 3-min cycling intervals (LIIT, 35% heart rate reserve [HRR]; MIIT, 55%HRR; HIIT, 80%HRR) and 2-min active recovery (25%HRR). Participants practiced a visuomotor rotation task immediately after AEX/Rest (adaptation) and at a no-AEX 24 h retention test (motor learning). We found that: (1) all AEX intensities enhanced motor learning compared to Rest, and (2) HIIT enhanced motor adaptation and learning to the greatest extent, followed by MIIT then LIIT. This is the first study to demonstrate a dose-response effect of AEX intensity on motor adaptation and learning. Our results highlight the importance of considering intensity when prescribing AEX in sports and clinical contexts to promote motor learning.