A single exercise bout and locomotor learning after stroke: physiological, behavioural, and computational outcomes

Abstract

Acute high-intensity exercise coupled with motor practice improves the retention of motor learning in neurologically intact adults. However, whether exercise could improve the retention of locomotor learning after stroke is still unknown. Here, we investigated the effect of exercise intensity and timing on the retention of a novel locomotor learning task (i.e. split-belt treadmill walking) after stroke. Thirty-seven people post stroke participated in two sessions, 24 h apart, and were allocated to active control (CON), treadmill walking (TMW), or total body exercise on a cycle ergometer (TBE). In session 1, all groups exercised for a short bout (∼5 min) at low (CON) or high (TMW and TBE) intensity and before (CON and TMW) or after (TBE) the locomotor learning task. In both sessions, the locomotor learning task was to walk on a split-belt treadmill in a 2:1 speed ratio (100% and 50% fast-comfortable walking speed) for 15 min. To test the effect of exercise on 24 h retention, we applied behavioural and computational analyses. Behavioural data showed that neither high-intensity group showed greater 24 h retention compared to CON, and computational data showed that 24 h retention was attributable to a slow learning process for sensorimotor adaptation. Our findings demonstrated that acute exercise coupled with a locomotor adaptation task, regardless of its intensity and timing, does not improve retention of the novel locomotor task after stroke. We postulate that exercise effects on motor learning may be context specific (e.g. type of motor learning and/or task) and interact with the presence of genetic variant (BDNF Val66Met).

A Short Bout of High-intensity Exercise Alters Ipsilesional Motor Cortical Excitability Post-stroke

“…Also, it is important to note that we do not know whether the positive motor cortical excitability changes we found would be associated with gains in motor performance or learning. Nepveu et al 17 did find better retention of a time-on-target upper extremity motor task after high-intensity interval training in people with stroke, but other work using a different learning paradigm suggests this effect may be very task-specific 53 . It remains to be investigated whether our exercise priming protocol can enhance motor performance or learning in people with stroke.…”

Acute cardiovascular exercise does not enhance locomotor learning in people with stroke

“…Given the differences in the intensity and duration of the exercise protocols, the specific reasons for the discrepancies between the study by Charalambous et al . () and Nepveu et al . () are difficult to ascertain.…”

“…Charalambous et al . () investigated whether a single bout of exercise could improve the retention of a novel locomotor task in people with chronic stroke. The potential mediating effects of exercise intensity and timing were also investigated.…”

“…In light of these results, Charalambous et al . () concluded that the effects that acute exercise has been shown to have on motor memory might be task‐specific. When complex locomotor tasks are involved, acute exercise does not appear to enhance retention.…”

“…The study by Charalambous et al . () also explored the potential role of brain‐derived neurotrophic factor (BDNF) genotype in mediating the response to acute exercise on the capacity to retain the locomotor task. BDNF is a neurotrophin that regulates rehabilitation‐induced recovery after stroke (Ploughman et al .…”