Resting mechanomyography before and after resistance exercise

Abstract

A number of mechanisms have been proposed to explain the elevation in oxygen consumption following exercise. Biochemical processes that return muscle to its pre-exercise state do not account for all of the extra oxygen consumed after exercise (excess post-exercise oxygen consumption, EPOC). Muscle at rest after aerobic exercise produces mechanomyographic (MMG) activity of increased amplitude, compared to the pre-exercise state, which declines exponentially with the same time constant as EPOC. The purpose of this study was to determine how the resting MMG is affected by resistance exercise, and whether any change is related to oxygen consumption (VO(2)). Ten young male subjects (22.9 years) performed 30 min of resistance exercise consisting of one set of 10 repetitions at 50% 1-repetition maximum (1-RM) followed by five sets of eight repetitions at 75% of 1-RM for leg press and leg (knee) extension, with 1 min rest between sets. Oxygen consumption was measured by indirect calorimetry, MMG by an accelerometer placed over the rectus femoris, and surface electromyogram (EMG) with electrodes placed distal to the accelerometer. Recordings were made before exercise and for 5.5 h after exercise. MMG activity, expressed as mean absolute acceleration, was significantly elevated after exercise (P = 0.0006), as was EMG activity expressed as root-mean-square voltage (P = 0.03). MMG and VO(2) demonstrated exponential decay after exercise with similar time constants of 7.5 +/- 2.2 and 7.2 +/- 1.0 min, respectively. We conclude that resting muscle is more mechanically active following resistance exercise and that this may contribute to an elevated VO(2).

Mechanomyogram for Muscle Function Assessment: A Review

“…Another study [31] included muscle balance investigation of quadriceps muscles. Seven studies [7], [22], [33], [62]–[65] involved muscle activities of movements from different muscles, and the rest nine [8], [37]–[39], [44], [66]–[69] were related to investigation of MFs of diverse exercises from quadriceps muscles.…”

“…Nine studies [8], [37]–[39], [44], [66]–[69] reported MMG measurements of exercise. Table 7 depicts an overview of MMG effects examined for exercises.…”

“…This result suggested that less stretched muscles could more freely oscillate, producing higher MMG amplitudes [39]. Again, McKay et al [69] examined MMG signals from resting muscles before and after resistance exercises. They found that resting MMG amplitudes increased about threefold after vigorous resistance exercise, and that the increase decayed exponentially over time.…”

Effects of spinal anesthesia on resting metabolic rate and quadriceps mechanomyography

“…Exercising muscle results in increased MMG activity and increased oxygen uptake (Stout 1997). Resting muscle also produces MMG activity, and resting-muscle MMG activity is increased after exercise and is associated with the increase in oxygen uptake (VO 2 ) after exercise (McKay et al 1998(McKay et al , 2004(McKay et al , 2006(McKay et al , 2007. Post-exercise MMG activity may therefore contribute to excess post-exercise oxygen consumption, and elevated metabolic rate.…”

Bulk movement included in multi-channel mechanomyography: Similarity between mechanomyography of resting muscle and that of contracting muscle

“…Furthermore, vibrations detected in the MMG measured on a muscle in the rest state (resting MMG) (McKay et al, 2007(McKay et al, , 1998 are expected to reflect mechanical deformation characteristics similarly to myotonometry because both the resting MMG and myotonometry record free damped vibration, which is generated in the soft tissue below the skin surface, as a reaction to the mechanical impact: arterial pulsations of the resting MMG, and a device-created force impulse of myotonometry. The detection of arterial pulsations in the resting MMG has been reported for the biceps brachii, forearm (McKay et al, 1998), and femoris muscle (McKay et al, 2007). However, those studies removed arterial pulsations from the MMG to avoid interruption in the detection of small muscle contraction activity during the resting state.…”