Accelometry has been widely used to measure physical activity. Even if there is research showing inaccuracy of accelometry, there is not much comparison research with muscle activity (surface electromyography, EMG). University of Jyväskylä has concluded three years program about children’s physical activity. Research highlighted the accuracy of Myontec Mbody shorts to measure physical activity over accelometry especially in the assessment of low intensity physical activity and in short-lasting sporadic activity bouts.
Studies have been showing earlier that measuring muscle activity using EMG may provide more direct information on sedentary behavior and physical activity than accelerometry (Hamilton et al., 2007; Hamilton, 2017). Furthermore, previous studies have determined EMG thresholds for sedentary activities using Mbody data derived from adults (Tikkanen et al., 2013, 2014; Pesola et al., 2016).
When comparing results in physical activity found that accelometry counts and EMG amplitude showed marked differences in swinging, trampoline jumping, crawling, static squat, single leg hops, standing long jump and jump for height, the difference being over 170% when signals were normalized to that during walking. Furthermore, in walking, swinging, trampoline jumping, stair negotiation and crawling ACC classified over 60% of the time as vigorous-intensity activity, while EMG indicated primarily light- and moderate-intensity activities.
Proportion of time in sedentary, light, moderate and vigorous activity intensity level in various tasks compared with accelerometry (ACC) and electromyography (EMG). Source Gao et al. 2018.
Duration of light, moderate and vigorous activity varied considerably between the methods especially during walking, stair negotiation, crawling, swinging and trampoline jumping.
Findings were part of the three years research program, CHIPASE - Children’s physical activity spectrum: daily variations in physical activity and sedentary patterns related to school indoor physical environment, made in University of Jyväskylä.
Gao Y, Melin M, Mäkäräinen K, Rantalainen T, Pesola AJ, Laukkanen A, Sääkslahti A, Finni T. (2018) Children’s physical activity and sedentary time compared using assessments of accelerometry counts and muscle activity level. PeerJ 6:e5437.
Haapala EA, Gao Y, Vanhala A, Rantalainen T, Finni T (2020). Validity of traditional physical activity intensity calibration methods and the feasibility of self-paced walking and running on individualised calibration of physical activity intensity in children. Scientific reports, 10, 11031.
Haapala EA, Associations of age, body size, and maturation with physical activity intensity in different laboratory tasks in children. Journal of Sports Sciences, 2021, published online.
Pesola AJ, Laukkanen A, Tikkanen O, Sipilä S, Kainulainen H, Finni T. (2015) Muscle inactivity is adversely associated with biomarkers in physically active adults. Med Sci Sports Exerc 47 (6), 1188-1196.
Pesola AJ, Laukkanen A, Haakana P, Havu M, Sääkslahti A, Sipilä S, Finni T. (2014) Muscle inactivity and activity patterns after sedentary-time targeted Randomized Controlled Trial. Med. Sci. Sports Exerc. 46, 11, 2122–2131.