The Claim

Modifying knee joint angle from full extension to flexion (30 or 60 degrees) directly alters lower leg muscle activation patterns during ankle plantarflexion by decreasing medial gastrocnemius activity and increasing soleus activity, thereby shifting the mechanical workload distribution between the biarticular gastrocnemius and the monoarticular soleus.

Source: Electromyogram patterns during plantarflexions at various angular velocities and knee angles in human triceps surae muscles

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
26score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

Bending your knee changes which calf muscle does more work when you push off the ground. Straight legs make the outer calf muscle work harder, while bent knees shift the effort to the deeper calf muscle.

See the scientific wording

Increasing the knee angle from full extension to flexed positions (30 or 60 degrees) significantly decreases activation in the medial gastrocnemius while simultaneously increasing activation in the soleus muscle during ankle plantarflexions, regardless of movement speed. This demonstrates that knee positioning directly shifts the workload distribution between the two-joint gastrocnemius and the one-joint soleus.

What the research says

1 study
  1. Study: Electromyogram patterns during plantarflexions at various angular velocities and knee angles in human triceps surae muscles

    Bending your knee while pushing off with your foot shifts the work from the upper calf muscle to the deeper calf muscle, and this happens no matter how fast you move.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.