Calculating Load and Intensity Using Muscle Oxygen Saturation Data | JoVE Visualize

Area of Science:

Exercise Physiology
Sports Science
Biomedical Engineering

Background:

Accurate quantification of training intensity and load is crucial for optimizing athletic performance and preventing overtraining.
Muscle oxygen saturation (SmO2) offers a non-invasive method to assess muscle metabolic responses during exercise.
Previous research has explored SmO2 in various exercise contexts, but its application in differentiating training loads across distinct protocols requires further investigation.

Purpose of the Study:

To calculate training intensity and load using muscle oxygen saturation (SmO2) as an internal load indicator during two distinct physical tasks: a 40-m Maximal Shuttle Run Test (MST) and a 3000-m time trial run.
To compare the external load (EL), internal load (IL), training load, and efficiency index (Eff_index) between the MST and the 3000-m time trial.
To validate the use of SmO2-derived metrics (muscle oxygen extraction [∇%SmO2] and cardio-muscle oxygen index [CMOI]) in quantifying training demands.

Main Methods:

Twenty-nine university athletes performed a 40-m MST (10 × 40-m sprints with 30s recovery) and a 3000-m time trial.
External load (EL) was determined by distance and time.
Internal load indicators included %HR_MAX, ∇%SmO2, and CMOI (∇%SmO2 ÷ %HR_MAX). Training load and Eff_index were calculated using speed, IL, and SmO2 variables. Bayesian factor analysis (student t test) was employed for statistical comparisons.

Main Results:

Significant differences were observed in EL between the 40-m MST (331 ± 22.8) and 3000-m trials (222 ± 56.8) [BF¹⁰ = 6.25e⁺⁶; p <0.001].
Internal load, specifically CMOI, was higher during the 40-m MST (39.20 ± 15.44) compared to the 3000-m run (30.51 ± 8.67) [BF¹⁰ = 1.70; p = 0.039].
Training load and Eff_index were substantially greater in the 40-m MST across both SmO2-derived metrics (∇%SmO2 and CMOI) compared to the 3000-m trial (all p <0.035).

Conclusions:

Muscle oxygen saturation (SmO2) effectively serves as an internal load indicator, complementing speed-based external load measures.
The study successfully demonstrated the calculation of training intensity and load using SmO2 during distinct exercise protocols.
These findings support the utility of SmO2 monitoring for a more comprehensive understanding of physiological strain during different types of athletic training.