A Comparative Analysis On Aerobically- And Anaerobically-trained Individuals’ Skeletal Muscle Oxygen Saturation

Abstract

Skeletal muscle oxygen saturation (SmO2) is an important measure of how well muscles uptake oxygen from the blood and has been shown to correlate to exercise load. Maximal rate of oxygen consumption (VO2max) has been used to measure cardiorespiratory fitness which influences how much oxygen is being carried in the blood. What is not fully elucidated is if there is a difference in SmO2 and VO2max between aerobically trained individuals (runners) and anaerobically trained individuals (CrossFitters). Purpose: To determine if CrossFit-trained individuals and runners have differences in SmO2 during and after VO2 max test. Methods: Seventeen Crossfitters (n = 12 male; n = 5 female, Age 28.6 ± 7.6 years, VO2max 43.6 ± 7.2 ml/kg/min) and 18 endurance runners (n = 10 male; n = 8 female, Age 43.1 ± 12.3 years, VO2max 41.1 ± 7.6 ml/kg/min) completed a single VO2 max ramp protocol treadmill test while wearing a MOXY Sensor to assess SmO2. The MOXY Sensor was placed on the lateral-posterior belly of the gastrocnemius. The high, average, and low measures of SmO2 were obtained at baseline, during exercise, and post-exercise. In addition, total hemoglobin (THb) was also measured at all time points. The data was analyzed using a paired sample t-test to compare SmO2 measures, VO2max, THb, and time to recovery (secs). In addition, a linear regression was performed to show differences between groups. All analyses were performed using SAS (v.9.3). Results: There was a significant difference between the highest point of baseline SmO2 data between groups (p = 0.0330) with Crossfit individuals having a higher baseline SMO2. However, no significant difference was found for VO2max, THb, and time to recovery between groups. Additionally, we controlled for age and gender by running a linear regression. For gender, we did not find any statistical significance; however, we found that age had a significant effect on VO2 max (p = 0.0358). Conclusion: Analysis of the data indicated that aerobically-trained and anaerobically-trained individuals did not have a significant difference in SmO2 during the VO2 max test. Due to our disproportionate gender and age sample size, future research is needed in order to determine the full extent of whether there is a significant difference in SmO2 between anaerobically- and aerobically-trained individuals.