Neural conduction and excitability following a simple warm up

Objective: This study examined the effect of a generic, active warm up on neural and muscular conduction time.

Design: Single group, pre-post design.

Methods: Central and peripheral neuromuscular conduction time was quantified in the abductor pollicis brevis (APB) and gastrocnemius muscles of 18 healthy participants (mean age 25.9 ± 5.8 years, 12 males) using transcranial magnetic stimulation (TMS) and M-wave techniques, prior to and immediately following an active warm up consisting of 5 min running at 65% of maximum heart rate. Neural conduction time, for both TMS and M-wave, was quantified as the time between stimulus artefact and deflection of the wave form, whilst muscle conduction time for TMS and M-wave, was quantified from the stimulus artefact to the absolute peak twitch response.

Results: Following the warm up protocol, a significant reduction in muscle conduction time was found in both TMS and M-wave of 0.43 ms (P = 0.02) and 0.30 ms (P = 0.001) for the APB; and 0.29 ms (P < 0.001) and 0.87 ms (P = 0.003) for the gastrocnemius, respectively. No change was found in neural conduction using either TMS or M-wave techniques.

Conclusions: These findings support previous data which demonstrate an improvement in muscular conduction time and subsequent improvement in athletic performance post warm up. The data also make evident that changes in muscular conduction time are a global response to warm up and are not directly related to muscular activity. In contrast, neural conduction time did not change and should not be confused with changes in muscular conduction time in the literature.