Sustained cycling exercise increases intracortical inhibition.

Area of Science:

• Neuroscience
• Exercise Physiology
• Motor Control

Background:

• Understanding neural adaptations to exercise is crucial for optimizing training and rehabilitation.
• Intracortical inhibition plays a key role in motor control and can be modulated by physical activity.

Purpose of the Study:

• To investigate the impact of sustained cycling exercise on intracortical inhibition.
• To measure EMG suppression induced by subthreshold TMS to assess changes in neural excitability.

Main Methods:

• Sixteen participants engaged in 30 minutes of cycling at 75% of their maximum workload (Wmax).
• Subthreshold transcranial magnetic stimulation (TMS) was applied to elicit EMG suppression in the vastus lateralis (VL) muscle.
• Control cycling bouts at different intensities (75% and 37.5% Wmax) were performed before sustained exercise.

Main Results:

• EMG suppression did not differ between control cycling workloads, despite differences in EMG amplitude.
• VL EMG amplitude remained consistent throughout the 30-minute sustained cycling bout.
• TMS-evoked EMG suppression significantly increased towards the end of the sustained cycling exercise.

Conclusions:

• Sustained cycling exercise leads to increased intracortical inhibition, indicated by greater TMS-evoked EMG suppression.
• This heightened inhibition suggests increased excitability of intracortical inhibitory interneurons during prolonged exercise.
• The neural adaptations observed during locomotor exercise are comparable to those seen during sustained single-joint contractions.