Muscle oxygen saturation reflects individualized responses to exercise intensity during rowing ergometer exercise.

Area of Science:

• Exercise Physiology
• Sports Science
• Biomedical Engineering

Background:

• Precise rowing training intensity monitoring requires both systemic and local physiological indicators.
• Muscle oxygen saturation (SmO2), measured by near-infrared spectroscopy (NIRS), reflects local muscle oxygen utilization.
• SmO2 may complement traditional systemic indicators like heart rate (HR), oxygen uptake (VO2), and power output (P).

Purpose of the Study:

• To investigate SmO2 dynamics in upper (biceps brachii, BB) and lower limb (vastus lateralis, VL) muscles during rowing.
• To evaluate the practical application of SmO2 for individualized training monitoring in rowers.

Main Methods:

• Twenty-six trained male rowers underwent incremental tests, training sessions, and a 2000m race on a rowing ergometer.
• Continuous SmO2 measurements of BB and VL were taken using NIRS, alongside HR, VO2, and P.
• Linear mixed-effects models analyzed within-subject associations between SmO2 and systemic indicators.

Main Results:

• SmO2-VL decreased significantly from rest to maximal power during incremental exercise.
• Within-subject associations between SmO2-VL and VO2, HR, and P were stronger than SmO2-BB.
• SmO2-VL showed robust negative associations with HR and P during the 2000m race, reflecting exercise intensity.

Conclusions:

• SmO2 decreases progressively with increasing exercise intensity, with vastus lateralis being more sensitive than biceps brachii.
• Within-subject SmO2-VL measurements reliably indicate local muscular oxygen extraction.
• SmO2 monitoring can complement systemic variables for individualized training in rowing.