Using an Inertial Device (WIMU PRO) to Quantify Neuromuscular Load in Running: Reliability, Convergent Validity, and Influence of Type of Surface and Device Location

Gómez-Carmona C.D., Bastida-Castillo A., González-Custodio A., Olcina G., Pino-Ortega J.

Objective: This study aimed to assess the reliability and validity of WIMU PRO accelerometers in measuring PlayerLoad (PL) during running and to investigate the influence of speed, inertial device location, and type of surface on the measured load.

Participants: Twenty resistance-trained men participated in the study, with an average age of 27.32 years, height of 1.74 m, body mass of 68.96 kg, and body mass index of 22.76 kg/m².

Methodology: Over the course of 5 weeks, participants performed four progressive incremental tests on both a treadmill and an athletic track. External load variables (PL) were recorded by four WIMU PRO inertial devices placed at different locations (scapulae, center of mass, knee, and ankle). Physiological variables, including heart rate (HR) and SmO2, were measured using a GARMIN HR band and a MOXY near-infrared spectroscopy device, respectively.

Results: The study found high reliability for PL measurement on both types of surfaces, with the ankle location showing the best values (ICC = 0.99, CV = 4.65% on the treadmill; ICC = 0.96, CV = 6.54% on the track). Convergent validity was nearly perfect with HRAVG (r = 0.99) and moderate with SmO2 (r = -0.69). Significant differences in PL between surfaces were reported in all locations except the scapulae, with higher values found on the track. The ankle location consistently reported the highest PL values across all speeds and surfaces.

Conclusion: The study suggests that WIMU PRO accelerometers are reliable and valid for measuring PL during running. However, the choice of accelerometer location should be based on the specific purpose of the measurement, with the ankle location recommended for analyzing neuromuscular load in running. Additionally, individualized assessment is necessary due to the variability of gait biomechanics among subjects.