Reliability & Validity of WIMU for measuring velocity during resistance exercises

First study to test the reliability and validity of WIMU enclosed to a Smith’s machine bar in order to measure velocity in back squat. This study had two main goals. The first was to determine the reliability of the WIMU for mean velocity measurements during resistance exercises at 40% and 80% 1 repetition maximum (maximum weight you can lift with maximum effort in a single repetition). The second was to compare the results for the WIMU to a linear encoder (gold standard) for mean velocity measurements when clipped to the bar during back squat exercises using the Smith machine.

23 trained men aged 22.3 ± 3.2 years participated in this study. At maximum velocity in the concentric phase, they performed 10 repetitions with 40% 1 repetition maximum and eight repetitions with 80% 1 repetition maximum while using the WIMU and T-Force linear encoder simultaneously to record data.

In conclusion, the findings of this study suggest that WIMU is a reliable and valid tool for the assessment of mean velocity during the back squat exercise using the Smith machine. These findings could help coaches and sport researchers evaluate athletes performing resistance exercises similar to squats with a reliable, valid and portable tool.

Infographics by José María Oliva

Trunk stability assesment using an inertial device (WIMU)

The purpose of this research was to perform a trunk strength assessment of protocols described in the literature using accelerometry, by means of CV and ApEn entropy calculations. In addition, to check differences in CV and ApEn variables depending on the type of exercise, as a secondary objective. Twenty-four male subjects who were part of a football team participating in the Third Division:

  •  Age: 23,4 ± 2,73 years
  • Height: 1,75 ± 0,09 cm
  • Weight: 74,3 ± 6,19 kg
  • -BMI (Body mass index): 21,51 ± 3,47 kg/m2)

This data was recorded by means of an inertial device located in the center of mass (L3) and their accelerometric signals were analyzed by two statistics: coefficient of variation (CV) and approximate entropy (ApEn).

Significant differences were found in the value of CV and ApEn in all exercises except between PP and PL in ApEn (p <0.05). The data were distributed in low, medium and high values of CV and ApEn of the participants. A trunk strength-stability assessment using an inertial device or multi-sensors is proposed as a practical method for strength and conditioning coaches. Also, the application of the statistics CV and ApEn for the analysis of signals in stability exercises is recommended.

infographics by José María Oliva