Estimation of submaximal exercise stroke volume of Mexican athletes supports peripheral adjustment in VO₂ max

The purpose of this study was to determine if the assumed difference in the athletes' (ATH) submaximal (Subm) exercise stroke volume (SV, mL·beat^-1) was due to an endurance adaptation of different proportion in relation to Subm heart rate (HR); absolute (VO₂ max, L·min^-1) and relative oxygen uptake (VO₂ max, mL·min^-1·kg^-1). Subjects were (N=57) 26 ± 9 yrs old, 171±6 cm of stature, and TBM of 66±9 kg. The sample was divided into non-athletes (n=11) and ATH of diverse sport specialties (n=41) who were ranked either at national or international level. The ATH were then regrouped in 5 groups: 30, (n=8 =39 mL·min-1·kg^-1), 40, (n=11, =49 mL·min-1·kg^-1) 50, (n=8, =59 mL·min-1·kg^-1), 60, (n=7, =69 mL·min-1·kg-1), and 70, (n=4, =79 mL·min-1·kg^-1) (VO₂ maxRelATH). We applied a maximum effort test using a cycle ergometer with direct measurement of VO₂ at 2240 m of altitude. The average of the SV was obtained from the relation between VO₂ and HR with a slope ?VO2/?HR and a stable value of 1/[O₂] arterial = 1/2 •10. The ergometric power max, the index of ergometric power max, VO₂ max, and SV were significantly greater in the ATH (138 mL) versus the non-athlete (86 mL). But, SV was not significantly different between the groups classified by VO₂ maxRel (VO₂ maxRelATH). The similar SV between VO₂ maxRelATH groups is explained by a probable dissociation between the central and peripheral components during the endurance adaptation (i.e., the practice of each sport specialty imposes on the athlete's VO₂ maxRelATH). The findings support the contention that SV distinguishes the differences in this variable between the ATH and nonathletes but not between the VO₂ maxRelATH groups.