Utility of Portable Electromyography for Quantifying Muscle Activity during Daily Use

Abstract

Background: Mobility has been studied using performance, questionnaire, pedometer and accelerometer measures, but these tools do not provide information about muscle activity. To better understand mechanisms associated with movement impairment as they relate to function, it is valuable to quantify muscle activity during everyday activities. Objective: This report presents electromyography (EMG) during daily activities from the affected and unaffected limbs of a 74-year-old man who survived a stroke 12 years ago, compared to 7 older healthy men who had not experienced a stroke. Methods: The biceps brachii, triceps brachii, quadriceps and hamstring muscles were recorded continuously for one 8-hour session in the unaffected limbs of the stroke survivor and control subjects. On a second day, EMG from these same muscles of the affected side was recorded for 4 h. Bursts (amplitude >2% maximum effort, duration >0.1 s) and gaps (amplitude <1% maximum effort, duration >0.1 s) of EMG were quantified for the number of times they occurred, mean event duration (seconds), mean peak amplitude (percent maximum voluntary efforts) and rate of activity (event activity/second). Results: Burst and gap patterns of the unaffected limb muscles were similar between the stroke survivor and controls. Increased numbers of bursts (approx. 40%) and gaps (approx. 44%) were seen in the subject’s lower limb muscles of his affected versus unaffected side. Biceps brachii burst activity of the affected limb was increased, whereas triceps brachii burst activity was decreased. These muscle activity changes in the affected limb suggest that the triceps brachii was relatively inactive and the biceps brachii and lower limb muscles were active in an ‘on’ and ‘off’ pattern. Conclusion: Muscle activity in the unaffected limb of the stroke survivor was similar compared to control subjects, but the affected limb differed from the unaffected after stroke. Portable EMG to monitor muscle activity for prolonged periods was not reported to be an impediment by the case or control subjects. Using this technology, EMG bursts and gaps can be recorded and used to describe muscle activity. Future work may consider the feasibility of this technique to monitor rehabilitation progression or long-term plasticity of muscle activity.

Age-Related Increase in Electromyography Burst Activity in Males and Females

“…Long-term EMG was recorded using surface electrodes (20 mm interelectrode distance) placed on the long head of the BB and the lateral head of the TB as well as the VL and BF as previously described [8–11, 24, 25]. BB and TB are the principle elbow flexors and extensors, respectively, and are the primary contributors to reaching in order to execute functional upper limb movements.…”

“…Laboratory studies using electromyography (EMG) have provided considerable understanding of age-related changes in muscle activity for simple isometric and anisometric contractions [3–5], gait [6], and discrete tasks [7] executed under experimental constraints. With the advancement of technology, portable EMG devices now offer a means to characterize muscle activity (bursts) and quiescence (gaps) over long durations outside the laboratory, enabling discrete measurement of neuromuscular control within the environmental context of daily life [8, 9]. …”

“…For a discrete task when the EMG is quantified through bursts, muscle activity increases in old adults relative to young adults and is also greater in women [8, 11]. Together, measurement of bursts and gaps for a discrete task, such as carrying a bag of groceries, suggests that muscles are active more often and “rest” less in older adults and women.…”

Age- and sex-related differences for electromyography gaps during daily activity and a discrete task

“…Electromyography (EMG) directly quantifies muscle activity. To explore fatigue and injury in the workplace [7][8][9], and daily activity [10][11][12][13], quantification of periods of muscle activation (bursts) and intervals of muscle quiescence (gaps) has been employed to study the activation of specific muscle groups over long durations.…”

Electromyographic audio biofeedback for telerehabilitation in hospital

“…In this context, surface electromyography is considered valuable for quantitative evaluation of muscle activity. 1,2 We have investigated the use of surface electromyography with biofeedback for telerehabilitation. The aim of the study was to investigate the therapist's point of view.…”