Multivariate Analysis of the Relationships among Muscle Strength, Muscle Endurance, and Muscle Oxygenation Dynamics During Incremental Exercise.

OBJECTIVE

We aimed to clarify whether having both high leg muscle strength (MS) and leg muscle endurance (ME) contributes to optimal muscle oxygenation dynamics during incremental exercise, regardless of related factors.

DESIGN

A prospective cross-sectional study. Thirty healthy young individuals were categorized into low leg MS (Low-MS group: n=15), high leg MS but low leg ME (High-MS/Low-ME group: n=8), and both high leg MS and leg ME (High-MS/High-ME group: n=7) groups. Muscle oxygen saturation (SmO2) at the vastus lateralis was measured during incremental exercise. Whole-body oxygen uptake (VO2), total hemoglobin (THb) at the vastus lateralis, sex, leg muscle mass, and adipose tissue thickness (ATT) were considered related factors.

RESULTS

The multivariate mixed regression model, with SmO2 change from rest to 30-100% peak VO2 as the dependent variable; individual as a random effect; and sex, group, leg muscle mass, ATT, THb change from rest to 30-100% peak VO2, and peak VO2 as fixed effects, revealed that group (High-MS/High-ME group vs. High-MS/Low-ME group) significantly predicted SmO2 change from rest to 30-100% peak VO2 (estimates=26.2, P<0.001).

CONCLUSION

Having both high leg MS and ME may contribute to optimal leg muscle oxygenation dynamics during incremental exercise, regardless of related factors.