Effect of running speed on temporal and frequency indicators from wearable MEMS accelerometers

Amplified by the development of new technologies, the interest in personal performance has been growing over the last years. Acceleration has proved to be an easy variable to collect, and was addressed in several works. However, few of them evaluate the effect of running speed on relevant indicators. The influence of the sensors location on the measurement is rarely studied as well. This study is dedicated to investigating the effect of running speed on acceleration measured at three different positions on 18 volunteers. All participants were equipped with three inertial measurement units: on the dorsal surface of the right foot (Fo), at the centre of gravity of the tibia (Ti), at the L4-L5 lumbar (Lu). The test was performed on a treadmill at nine randomised speeds between 8 and 18 km/h. Ten accelerometric variables were calculated. Linear regressions were used to calculate speed from the indicators calculated on (Lu), (Ti), (Fo). Indicators associated to signal energy were highly correlated with speed ( r 2 > 0.90 ). Median frequency appears to be affected by the frequency resolution. Finally, the measurement points closest to the impact zone result in the most correlated indicators

Whole-Body Cryostimulation: New Insights in Thermo-Aeraulic Fields inside Chambers

(1) Background: This article presents a study that aims to provide a precise understanding of the temperature distribution within a whole-body cryostimulation (WBC) chamber, whether it is empty or occupied by one or several individuals; (2) Methods: The study employs a mixed numerical and experimental approach, utilizing simplified computational fluid dynamics (CFD) simulations and experimental analysis; (3) Results: The results reveal a non-negligible temperature difference between the setpoint and actual temperature in the middle of the cryochamber. Furthermore, it is shown that the presence of individuals inside the chamber results in both an average temperature rise and a more heterogeneous thermal behavior associated with the number of individuals present. As the number of occupants in the cryochamber increases, the magnitude of the thermal gradient (up to 10 °C) and temperature heterogeneity (up to 13%) also increase; (4) Conclusions: The results suggest that when the cryotherapy chamber is occupied by three people, it becomes necessary to extend the duration of cold exposure to obtain a dose/effect ratio and analgesic threshold equivalent to those obtained when only one person is present. The findings of this study emphasize the need for further research to establish temperature guidelines and standardize measurement methods for effective WBC treatment