2014 Volume 7 Issue 6 Pages 332-336
A surface electromyogram (sEMG) is a time-related and spatial aggregate of the action potentials of a muscle's motor units. A mechano-myogram (MMG) directly reflects the mechanical contraction function of a muscle. A displacement-MMG is useful to examine the characteristics of muscle contraction. To evaluate muscle contraction, it is necessary to measure both EMG and MMG signals (EMG: input to muscles that will contract, MMG: resulting output from contraction). The authors developed a wireless MMG/EMG hybrid transducer (45L × 16W × 12mmH, 2.5g) composed of a small photo-reflector, two EMG electrodes, and a wireless transmission module. It can measure both EMG and MMG signals simultaneously. The authors applied the transducer to the measurement of displacement-MMG/EMG signals during subjects' squatting-jumping, ergometer pedaling and running on a treadmill. The authors also examined the relationship between the MMG and EMG signals recorded.