OBJECTIVETo investigate the use of surface electromyography (sEMG) and electrocardiogram (ECG) in evaluation of dynamic workload.

METHODSThrough controlling the speed and gradient, 8 subjects ran on the treadmill power machine to simulate the dynamic work. The sEMG signal of anterior tibial muscle (AT) and gastrocnemius muscle (GC) of right lower limb and ECG signal were recorded. The root mean square value (RMS), median frequency (MF), mean power frequency (MPF), heart rate (HR), standard deviation of all normal to normal intervals (SDNN) and Borg scores were analyzed.

RESULTSIn the five sports, with the speed increasing, all the values of RMS increased in the AT and GC (P < 0.01). With the gradient increasing, the values of RMS increased in the GC (P < 0.01) while the values of RMS of AT had a trend of decrease (P > 0.05). In all five sports, both the values of MF and MPF in AT and GC were lowest in B sports. Compared to A sport, most of the values of MF and MPF increased in C, D, E sports (P < 0.01), with a highest value in the D sport. Compared with A sport, the HR of B, C, D, E sports significantly increased (P < 0.01), and the highest heart rate was found in B sport, however, the values of SDNN significantly decreased. With the increased speed and gradient, the scores of Borg scale significantly increased.

CONCLUSIONIn the evaluation of dynamic workload, RMS and HR appear to be good indexes. However, in terms of stress reaction to dynamic workload, MF and MPF are more sensitive.