Table 6. VO_2max prediction equations for runners.

Model’s category	Multiple linear regression equation	R2	Derivation group performance		Validation group performance
			RMSE	MAE	RMSE	MAE
AT	VO2max = 19.78 + 1.05 * rVO2AT + 0.94 * SPEEDAT - 0.12 * FFM - 0.06 * VEAT - 0.07 * HRAT	0.775	3.43	2.61	3.60	2.74
RCP	VO2max = 1.98 + 1.03 * rVO2RCP + 0.23 * SPEEDRCP	0.899	2.0	1.58	2.08	1.60
AT+RCP	VO2max = 1.98 + 1.03 * rVO2RCP + 0.23 * SPEEDRCP	0.899	2.0	1.58	2.08	1.60
SOM	VO2max = 72.37–0.77 * BF - 0.19 * Age	0.35	5.53	4.36	5.54	4.37

AT, equation based on anaerobic threshold; RCP, equation based on respiratory compensation point; SOM, equation based on somatic variables only; R², adjusted R²; RMSE, root mean square error; MAE, mean absolute error (mL·min^–1·kg^–1); VO_2max, maximal oxygen uptake relative to body mass (mL·min^–1·kg^–1); rVO_2AT, oxygen uptake at anaerobic threshold relative to body mass (mL·min^–1·kg^–1); SPEED_AT, velocity at anaerobic threshold (km·h^–1); FFM, fat free mass (kg); VE_AT, pulmonary ventilation at anaerobic threshold (L·min^–1); HR_AT, heart rate at anaerobic threshold (beats·min^–1); BF, body fat (%); rVO_2RCP, oxygen uptake at respiratory compensation point relative to body mass (mL·min^–1·kg^–1); SPEED_RCP, velocity at respiratory compensation point (km·h^–1).