The purpose of this study was to compare estimation accuracy of an accelerometer (Lifecorder Ex: LC) and a wristband type accelerometer (ViM sports memory: ViM) during non-locomotive activities. We chose fifteen activities. Fourteen young adults (7 males and 7 females) participated into 8 activities at least. An indirect calorimeter (MetaMax 3B) measured metabolic equivalent (MET) throughout all activities. Participants wore the LC on their hip and the ViM on non-dominate their wrist to estimate MET. To estimate MET, LC derivations (LC1 and LC2) were used and ViM derivations (ViM1 and ViM2) were used. Differences between MET and each estimates were analyzed by 2-way repeated ANOVA model in mixed model. Both of the LC1 and the LC2 significantly underestimated MET during most of activities (p ≤ 0.008). The ViM1 was significantly different from MET for all activities (p < 0.001), while the ViM2 showed not significant differences to MET during Dynamic stretch, Darts, Active video game (boxing), and Walking (p ≥ 0.162). These results show that the ViM can assess MET during non-locomotive activities more accurate than the LC and the LC consistently underestimates MET during all of non-locomotive activities.

Purpose: The aim of the present study was to elucidate the reliability and validity of measurement of ground reaction force (GRF) parameters during a sit-to-stand (STS) movement as a method of assessing lower limb muscle function in middle-aged and older women with knee pain. Methods: We recruited 61 women with mild to moderate knee pain and 61 healthy controls, aged 50-86 years. Five GRF parameters were measured: peak reaction force, two rate of force development parameters, and two time-related parameters. These parameters were compared on the basis of the presence or absence of knee pain. Intraclass correlation coefficients (ICC) and errors of measurement values were calculated. Partial correlation analysis adjusted for age was used to investigate the association between GRF parameters and knee extension strength, muscle power, and five physical function tests. Results: Significant differences were observed between groups in the following GRF parameters: peak reaction force and the two parameters of force development rate (Cohen’s d = 0.68-1.44). In participants with knee pain, the abovementioned three parameters had a good reproducibility (ICC = 0.88-0.93). The two parameters of force development rate were significantly correlated with knee extension torque and power (partial-r = 0.50-0.57) and five physical function tests (partial-|r| = 0.40-0.59) adjusted for age. Conclusion: These results suggested that GRF parameters in the STS movement have sufficient reliability and validity as a method of assessment of lower limb muscle function in middle-aged and older women with mild to moderate knee pain.