Abstract
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.