Validity of sports watches when estimating energy expenditure during running

Table 2 Concurrent validity (tested device vs. criterion measure) of the three sports watches

	30% vVO_2peak	50% vVO_2peak	70% vVO_2peak	90% vVO_2peak	110% vVO_2peak
Mean difference [%]
Suunto Ambit2	38.09 ± 42.06	36.29 ± 20.57	19.16 ± 18.03	−21.62 ± 12.54	−31.85 ± 10.54
Garmin Forerunner920XT	−25.16 ± 16.09	−4.87 ± 29.34	−8.83 ± 10.50	−37.94 ± 8.82	−49.30 ± 9.18
Polar V800	12.20 ± 21.65	−3.61 ± 15.04	−4.29 ± 12.02	−29.98 ± 9.68	−39.52 ± 8.89
MAE [kcal/min]
Suunto Ambit2	1.46	2.75	2.32	4.15	7.05
Garmin Forerunner920XT	1.05	1.28	1.39	6.56	10.40
Polar V800	0.86	0.89	1.21	5.20	8.37
MAPE [%]
Suunto Ambit2	41.93	36.30	21.32	23.05	31.85
Garmin Forerunner920XT	26.28	17.59	11.54	37.94	49.30
Polar V800	22.76	11.43	10.09	29.98	39.52
RMSE [kcal/min]
Suunto Ambit2	1.82	3.27	2.74	4.88	7.81
Garmin Forerunner920XT	1.22	1.98	1.77	7.05	10.81
Polar V800	0.93	1.26	1.67	5.75	8.81

Results are expressed as mean ± standard deviation
vVO _2peak speed at maximal oxygen uptake, MAE mean absolute error, MAPE mean absolute percentage error, RMSE root mean square error

ISSN: 2052-1847