Does the operating temperature of accelerometers affect data measurement during static and dynamic conditions in sports? A randomized-control trial

This study aimed to analyse the effect of two operating temperatures (optimal vs environmental) on IMU internal temperature and accelerometry-based data in two conditions of measurement: (a) static, no movement; and (b) dynamic, a U’16 game-based training soccer session with 14 players. Each session took a 60-min duration and followed an ecological design (no intervention in environmental conditions). Fifty-six WIMU PROTM inertial devices were randomly grouped in four conditions (two operating temperatures × two measurement conditions, 14 devices in each group) and recorded IMUs’ internal temperature, resultant acceleration vector and PlayerLoad (PLRT). Devices were placed in the manufacturer’s docking station at the static condition and in a specific harness at the interscapular level at the dynamic condition. Repeated measures t-tests were employed for between-group comparisons at 1-min average sections throughout the register. Between-group differences were found in the static and dynamic conditions in IMUs internal temperature (static: 0–31 min; dynamic: 0–20 min) and resultant acceleration vector (static: 0–29 min; dynamic: 0–19 min). Instead, no differences were found in PLRT dynamics and accumulated PLRT although values in the environmental group were overestimated. In conclusion, WIMU PROTM devices must achieve the optimal operating temperature (38–39°) to avoid measurement error, regardless of the application (short or long sessions).