Estimation of maximal oxygen uptake using the heart rate ratio method in male recreational football players

Maximal oxygen uptake (VO_2max) is associated with cardiovascular and metabolic health in the general population. The heart rate (HR) ratio method (HR_ratio) is a valid, easy and accessible method for estimating VO_2max in well-trained subjects. This study examined the validity of using the HR_ratio to estimate VO_2max in recreational football players in the untrained and trained states. Sixty-six participants (age 39.3 ± 5.8 years) were tested pre-training and 28 after 12 weeks, for VO_2max assessment, running on a treadmill alternating speed (1 km h⁻¹) and inclination (1%) increments every 30 s until exhaustion. Maximal HR (HR_max) was assessed directly with a multiple approach and estimated with selected equations. Resting HR (HR_rest) was measured in supine position, after 15 min of rest. The HR_ratio method considers the product of HR_max/HR_rest ratio by a theoretical proportionality factor (15 ml kg⁻¹ min⁻¹, TPF) to estimate VO_2max. This population-specific proportionality factor (SPF) was 14.6 ± 2.6 ml kg⁻¹ min⁻¹. In the untrained state (n = 66), participants’ actual VO_2max (41.3 ± 6.2 ml kg⁻¹ min⁻¹) was moderately lower (~ 2 ml kg⁻¹ min⁻¹) than the estimated VO_2max using the TPF. A nonsignificant difference (0.7 ml kg⁻¹ min⁻¹) was found when the VO_2max was estimated using the SPF. When using HR_max equations and the TPF, a small nonsignificant difference (~ 1.5 ml kg⁻¹ min⁻¹) was reported between actual and estimated VO_2max. In the trained state (n = 28), the estimated VO_2max values were not significantly different from the actual VO_2max (44.2 ± 5.2 ml kg⁻¹ min⁻¹), with large effect sizes when considering TPF and estimated HR_max. The results of this study provide evidence of the applicability of HR_ratio in estimating VO_2max in male adult/middle-aged recreational football players.