Validating the Nike+ Wireless Sport Kit for Estimating Pace, Distance, and Energy Expenditure during Treadmill Walking and Running

The use of accelerometry based physical activity monitors among recreational athletes to meet or exceed recommended physical activity guidelines has grown in popularity. In the interest of capitalizing on this demand, Adidas developed the miCoach Pacer System which allows the user to observe pace, distance, and energy expenditure during walking or running. Purpose. To validate the accuracy of the Adidas miCoach activity monitor in estimating energy expenditure (EE) (kcal/min), pace (min/km), and distance (km) during treadmill walking and running, and for two different sensor configurations. Methods. Nine male and 9 female moderately endurance trained volunteers (mean ± SD age: 28.83 ± 1.90 y; height: 168.72 ± 1.86 cm; body mass: 62.19 ± 2.58 kg; VO2max: 54.36 ± 1.15 mL/kg/min) completed a maximal oxygen consumption test, and the miCoach validation protocol comprised of level treadmill walking at 53.6, 80.4, and 107.2 m/min, and level treadmill running at 134.0, 160.8, 187.6, and 214.0 m/min. A miCoach unit was attached to the right shoelaces (Laces) and a second unit was placed within the right midsole of a modified shoe (Midsole). MiCoach estimated pace, distance, and EE were compared to actual values determined by criterion methods (Actual). Data were analyzed using a repeated-measures ANCOVA (EE), or a repeated-measures ANOVA (pace, distance). Results. There was a significant increase in EE (P ≤ 0.003), pace (P ≤ 0.001), and distance (P \u3c 0.001) with each subsequent treadmill speed. The Adidas miCoach significantly overestimated actual EE for the midsole at 53.6 m/min (P = 0.045), and for both laces and midsole at 80.4 and 107.2 m/min (P ≤ 0.036). The Adidas miCoach significantly underestimated actual pace for the midsole at 160.8 m/min (P = 0.05). No significant differences were observed for laces or midsole EE compared to actual EE at any running speeds. Further, no significant differences were observed for estimated pace of laces or distance of laces or midsole compared to actual values. Conclusion. The Adidas miCoach device appears to accurately estimate pace and distance across a range of treadmill walking and running speeds and accurately estimate EE during treadmill running. Additionally, these results suggest that either laces or midsole sensor configuration provides similar values. Partial support for this study was provided by UTEP CHS Graduate Enhancement Funds