What happens when a runners calf fatigues?

The calf plays a substantial role in distance running. Improving calf strength, endurance, and power is a common goal in rehab and the weight room.
What happens when the calf fatigues?
Willer and colleagues answered this question in their 2021 study.
The authors examined 18 subjects (11M, 7F) who were national standard runners who completed a high-intensity run to failure, 3D gait analysis, and muscle activation tests of 8 different muscles.
What did they find?
Not to their surprise, things changed as the runner fatigued.
The authors found
1️⃣Increase in ground contact time (+4%)
2️⃣Decreased in flight time (+3%)
3️⃣Decreased peak vertical GRF (−6%)
4️⃣Decrease in plantar flexion peak moment (−9%)
In layman's terms, runners spent more time on the ground and placed more stress on the knee to maintain speed🦵.
When working with runners with knee or calf pain, it is crucial to ensure their body is ready to run and they aren't pushing to fatigue early in rehab.
Be sure to check out the full study below and I'll see you next week on #thinkingcapthursday
loom.ly/Y1HFJJ8