Why lifting with bent knees hurts more later
Joint angle-specific neuromuscular time course of recovery after isometric resistance exercise at shorter and longer muscle lengths
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When you push hard with your knee almost fully bent, your muscles work way harder inside—even if the outside force feels the same as when your knee is less bent. This makes your muscles weaker and less active for up to two days after, even if you don’t feel sore or have high blood markers.
Surprising Findings
Neuromuscular fatigue was worse at the untrained joint angle (50°) than at the trained angle (90°) after deep-bend exercise.
Common belief: training at one angle only affects that angle. This shows training deep can impair function at shallower angles more—like your muscles got 'stretched out' and lost efficiency.
Practical Takeaways
If you train with deep knee flexion (e.g., full squats, deep leg presses), wait at least 48 hours before training legs again—even if you don’t feel sore.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When you push hard with your knee almost fully bent, your muscles work way harder inside—even if the outside force feels the same as when your knee is less bent. This makes your muscles weaker and less active for up to two days after, even if you don’t feel sore or have high blood markers.
Surprising Findings
Neuromuscular fatigue was worse at the untrained joint angle (50°) than at the trained angle (90°) after deep-bend exercise.
Common belief: training at one angle only affects that angle. This shows training deep can impair function at shallower angles more—like your muscles got 'stretched out' and lost efficiency.
Practical Takeaways
If you train with deep knee flexion (e.g., full squats, deep leg presses), wait at least 48 hours before training legs again—even if you don’t feel sore.
Publication
Journal
Journal of Applied Physiology
Year
2024
Authors
Gerard McMahon, Gladys Onambele-Pearson
Related Content
Claims (6)
Doing strength exercises with your knee bent further back makes your muscles weaker and harder to activate for up to two days afterward—even when you’re testing them at different knee angles—compared to doing the same exercise with your knee less bent.
Exercises that position biarticulate muscles at longer lengths (via joint angle manipulation) produce greater hypertrophy in those biarticulate muscle heads compared to exercises that place them at shorter lengths.
Even though your muscles feel just as sore and your blood shows similar signs of damage after doing leg exercises with your knee bent far back or only slightly bent, your muscles are actually weaker and harder to activate for longer after the deep bend version.
When you push hard with your knee bent all the way back, your thigh muscles have to work much harder internally than when your knee is only slightly bent—even if you’re pushing with the same force on the machine.
After doing leg exercises with your knee bent all the way back, your muscles are weaker not just at that angle—but even more so when you try to use them with your knee only slightly bent, as if your muscle fibers got stretched out and lost their normal power.