A comparison of workload quantification methods in relation to physiological responses to resistance exercise

Area of Science:

• Exercise Physiology
• Sports Science
• Biomedical Engineering

Background:

• Accurate internal load estimation is crucial for optimizing resistance exercise (RE) programming.
• Traditional measures like volume load (VL) and session rate of perceived exertion (SRPE) have limitations in reflecting physiological stress.
• Understanding the interplay between external load metrics and physiological responses (e.g., blood lactate, cortisol) is essential for training monitoring.

Purpose of the Study:

• To evaluate the efficacy of VL, SRPE, RPE load (RPEL), and a modified RPEL (RPEL-2) in estimating internal load during RE.
• To investigate the relationships between SRPE, VL, and RE intensity.
• To correlate these training load measures with changes in blood lactate and salivary cortisol levels.

Main Methods:

• Twelve healthy men performed RE at 55%, 70%, and 85% of their 1-repetition maximum (1RM).
• VL, SRPE, RPEL, and RPEL-2 were calculated for each session.
• Changes in blood lactate and salivary cortisol were measured and correlated with the training load variables.

Main Results:

• All training load measures increased with decreasing %1RM intensity.
• Greater increases in blood lactate and cortisol were observed at 55% 1RM compared to 70% and 85% 1RM.
• VL showed moderate correlation with blood lactate, while SRPE and RPEL showed small correlations; correlations with cortisol were generally small across measures.

Conclusions:

• Volume load (VL) may be a superior indicator of internal load in RE, particularly when assessed via blood lactate.
• RPEL-2 provides a comprehensive measure for overall training load assessment.
• Session RPE (SRPE) appears more closely aligned with VL than with %1RM intensity, suggesting its utility in conjunction with VL.