Muscle Oxygen Saturation of Master??s Triathletes/Duathletes Similar to that of Younger Athletes

Abstract

1411 Many current masters' endurance athletes have been exercise training for 20–30 years, longer than that of most previously studied athletes. As individuals age typically maximum oxygen uptake and heart rate decrease as does muscle mass and respiratory capacity. However, training has been shown to maintain maximum stroke volume and a-vO2 difference, while also enhancing muscle respiratory ability. PURPOSE: To determine if muscle oxygen saturation of experienced master's endurance athletes was similar to that of younger endurance trained athletes. METHODS: Six male master triathletes/duathletes (MA; mean age = 57.0 ± 2.4 years) with at least 20 years of continuous training (mean = 24.2 ± 4.9 years) were compared to 6 younger triathletes/duathletes (YA; mean age = 32.3 ± 5.7 years). All athletes performed an incremental exercise test involving five, 6-minute stages. This was followed by a maximal running test (MAX). During the tests, oxygen uptake variables, blood lactate, and muscle oxygen saturation (StO2) of the gastrocnemius through near-infrared spectroscopy (NIRS) were determined. RESULTS: Running speed at lactate breakpoint (BRK) was significantly lower for the MA (7.9 ± 0.6 mph) than for the YA (9.1 ± 1.0 mph). Both BRK and MAX oxygen uptake were similar between the two groups of subjects. BRK heart rate was significantly less for the MA (MA = 156.5 ± 14.1 bpm, YA = 168.0 ± 7.2 bpm), while lactate was significantly greater (MA = 3.9 ± 0.8 mM, YA = 3.1 ± 0.7 mM). StO2 was not different between the two groups at BRK (MA = 65.2 ± 9.4%, YA = 56.2 ± 9.4%), nor at MAX (MA = 50.1 ± 9.9%, YA = 39.5 ± 11.0%). The small sample size probably was the cause of the StO2 values not being significantly different, as all of the MA values were greater than those of the YA. CONCLUSION: The master's athletes had similar if not greater muscle oxygenation when compared to that of the younger athletes probably due to the longevity of their training. This study was funded by Hutchinson Technology Incorporated, Hutchinson, MN