Muscle Inactivity and Activity Patterns after Sedentary Time-Targeted Randomized Controlled Trial

Abstract

A simple tailored counseling was able to reduce muscle inactivity time by 33 min, which was reallocated to 21 min of light muscle activity. During work time, average EMG amplitude increased by 13%, reaching an average of 1.8% of EMG MVC. If maintained, this observed short-term effect may have health-benefiting consequences.

Muscle activity patterns and spinal shrinkage in office workers using a sit–stand workstation versus a sit workstation

“…These EMG shorts have been tested previously for validity, repeatability and feasibility, and a detailed description of the recording devices has been reported (Finni et al 2007). Adequate repeatability and consistency of EMG signals, both day-to-day and within-day, have been tested in our laboratory and reported in previous studies (Tikkanen et al, 2013;Pesola et al, 2014).…”

“…In order to reflect the overall inactivity and activity periods, normalized data were averaged to produce mean thigh muscle EMG. The inactivity threshold was set individually at 90% of the mean EMG amplitude measured during quiet standing for 10s, in accordance with our previous studies (Tikkanen et al 2013;Pesola et al 2014). The threshold for light and moderate-to-vigorous intensity was defined individually as the mean EMG value during normal walking.…”

“…The normalized, averaged, artifact-free EMG data were further processed using a custom-made Matlab script (MATLAB, MathWorks, Massachusetts). Based on the thresholds, signals were analyzed for total muscle inactivity duration (min), total muscle activity duration (min), light and moderate-to-vigorous muscle activity duration (min), duration of the five longest continuous inactivity periods (min), and number of activity bursts throughout the workday, as described previously (Tikkanen et al 2013;Pesola et al 2014). …”

“…In normal daily life the thigh muscles are inactive for over 65% of the day (Tikkanen et al 2013) and over 78% of work time, even in physically active office workers (Pesola et al 2014). In the current study, the activity patterns of quadriceps and hamstring muscles showed 15% less inactivity and 11% more light activity in workers using sit-stand workstations compared to users of traditional sit workstations.…”

“…Office work exposes people to high amounts of sedentary time, consisting of long periods of sitting with minimal muscle activity (Pesola et al 2014). Too much sitting is adversely associated with cardio-metabolic (Wilmot et al 2012) and increased risks of musculoskeletal symptoms (Lis et al 2007).…”