# Do Training Load Metrics Agree? A Comparison of Session Rate of Perceived Exertion, Physiological and Biomechanical Load in Outdoor Running

## TL;DR

This study compares different ways to measure training load in runners and finds that perceived exertion is a better indicator than physiological or biomechanical measures.

## Contribution

First study comparing physiological, biomechanical, and subjective load metrics in outdoor running sessions.

## Key findings

- sRPE significantly distinguished between session types, while TRIMP and biomechanical load did not.
- Correlations between sRPE and TRIMP were moderate, but cumulative biomechanical load showed weak correlations.
- Objective metrics may not fully capture perceived exertion across different training sessions.

## Abstract

Monitoring training load is an important aspect of optimizing performance and preventing overuse injuries in runners. This is the first study comparing physiological, biomechanical and subjective load between typical outdoor training sessions, contributing to the transfer of methodologies from the gait laboratory to real-world conditions with the final goal of improving athlete monitoring.

Twelve experienced runners participated in distinct sessions: an endurance run, a submaximal effort, and interval training, which varied in perceived exertion. Using heart rate monitors, inertial measurement units and questionnaires, estimated cumulative load and its correlation with session Rate of Perceived Exertion (sRPE) and physiological load calculated via Training Impulse (TRIMP) were analysed.

sRPE significantly distinguished between session types, while TRIMP and cumulative biomechanical load did not. Furthermore, correlations between the three training load metrics were weak to moderate (sRPE vs. TRIMP: r = 0.49; sRPE vs. weighted cumulative load: r = 0.25; weighted cumulative load vs. TRIMP: r = 0.35), where only sRPE and TRIMP correlated significantly (p < 0.05). This suggests that the different measures capture different aspects of load or that the measures could be inadequate to capture load.

Objective physiological and biomechanical metrics alone may not adequately reflect athletes’ perceived exertion when training includes different session types. This highlights the importance of using a multifactorial approach to training load monitoring in running.

In contrast to TRIMP and biomechanical load, sRPE distinguished between typical running sessions in recreational runners.TRIMP and sRPE showed moderate correlation over various training sessions, while cumulative load was not significantly correlated with the other load metrics.

In contrast to TRIMP and biomechanical load, sRPE distinguished between typical running sessions in recreational runners.

TRIMP and sRPE showed moderate correlation over various training sessions, while cumulative load was not significantly correlated with the other load metrics.