Some muscles might respond differently to how you stretch them during exercise, depending on how they’re built.

The hypertrophic response to training at longer muscle lengths may differ between untrained and trained individuals, but current evidence is insufficient to determine this due to limited data in trained populations.

Individual hypertrophic responses to resistance training are highly variable across muscle groups and are not consistently correlated between upper and lower body musculature.

Individual hypertrophic responsiveness to resistance training exhibits moderate inter-muscle correlation, but a substantial proportion of variability is attributable to non-exercise-specific biological factors.

Total training volume, training intensity, and consistency are more significant determinants of muscle hypertrophy than the specific muscle length at which training occurs.

Some people’s muscles grow a lot with training, others don’t—but if one person’s arms grow, their legs usually grow similarly, meaning your body’s natural response is more important than which muscles you train.