Validating the Nike+ Wireless Sport Kit for estimating pace, distance, and energy expenditure during treadmill walking and running

PURPOSE: To validate the accuracy of the Nike+ Wireless Sport Kit to estimate pace (min/km), distance (km), energy expenditure (EE) (kcal/min) during treadmill walking and running, and for two different sensor configurations. METHODS: Nine male and nine female moderately endurance trained volunteers (mean ± 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) a maximal oxygen consumption test and b) an accelerometer validation protocol including level treadmill walking (53.6, 80.4, and 107.2 m/min); and level treadmill running (134.0, 160.8, 187.6, and 214.0 m/min). RESULTS: Each subsequent treadmill speed elicited a significant increase in pace (p ≤ 0.037), distance (p \u3c 0.001), and EE (p ≤ 0.020). The Nike+ significantly overestimated pace and distance at walking speeds (53.6 and 80.4 m/min) by 23% and 9%, respectively; and significantly underestimated pace and distance at higher running speeds (160.8, 187.6, and 214.0 m/min) by 6% (pace only – laces), 10% and 15%, respectively. The Nike+ underestimated EE at each of the seven treadmill speeds; significantly by 24%, 10%, and 12% for 107.2, 187.6 and 214.0 m/min, respectively. There appears to be no marked difference between the laces and midsole sensor configurations for pace, distance, or EE. CONCLUSION: Compared to actual, estimates of EE were most accurate; speculating that the device\u27s prediction equation is more suited for estimating EE. The sensor configuration affixed to the laces is a viable alternative to that of purchasing a Nike+ compatible shoe