TORQUE TELLS YOU THE JOINT DEMAND — NOT THE WHOLE MUSCLE STORY.
- 01
Torque is rotational demand: force multiplied by the perpendicular distance from the joint axis.
- 02
External moment arms change as the body and resistance move, which is why an exercise feels harder at some joint angles.
- 03
Muscles also have internal moment arms that change with joint position, so joint torque cannot be converted directly into one muscle’s force.
- 04
Use torque analysis to understand exercise challenge, then combine it with muscle length, stability and training evidence.
DISTANCE FROM THE JOINT CHANGES THE DEMAND.
A load creates more external joint torque when its line of force is farther from the joint axis. In a dumbbell lateral raise, for example, shoulder torque rises as the arm becomes more perpendicular to gravity even though the dumbbell mass stays the same.
MUSCLES SOLVE THE DEMAND WITH THEIR OWN LEVERAGE.
Muscle force creates internal torque through an internal moment arm. That leverage changes with joint position and differs between muscles. Multiple muscles, passive tissues and co-contraction can contribute to the same measured joint torque.
THE HARDEST JOINT ANGLE IS NOT FIXED.
As external and internal moment arms change, the relationship between required joint torque and available muscle force changes. Cables, cams, bands and free weights can therefore create different resistance profiles even for similar movements.
HIGH JOINT TORQUE IS NOT A DIRECT GROWTH SCORE.
A high torque demand can indicate substantial muscular force, but it does not identify which muscle carries the demand or whether the stimulus occurs at a productive muscle length. Long-term adaptation still depends on repeated loading, volume and progression.
USE TORQUE TO EXPLAIN, NOT TO OVER-RANK.
Torque analysis is most useful when comparing where two exercise variants are hardest and whether that challenge aligns with the target. Then test the real movement for comfort, stability and progression.
DON’T EQUATE EXTERNAL LEVERAGE WITH TARGET-MUSCLE TENSION.
Common mistakes include ignoring internal moment arms, treating a longer external moment arm as automatically superior and forgetting that technique changes can redistribute demand to different joints and muscles.
READ THE EVIDENCE.
- 01Review (2026).
The interplay between muscle length, range of motion and exercise selection.
PUBMED ↗ - 02Androulakis-Korakakis et al. (2024).
Optimizing resistance-training technique for hypertrophy.
PUBMED ↗ - 03Kassiano et al. (2022).
Exercise variation and resistance-training adaptations: systematic review.
PUBMED ↗ - 04Systematic review/meta-analysis (2022).
Variable resistance training and force, velocity and power outcomes.
PUBMED ↗
Educational content only. It is not medical advice. See the Fitness Disclaimer.