Originally Posted by RogueFLIP
Yes, as the angle of the knee enters more flexion, you'll get more soleus involvement, but it's not like the gastroc totally goes on vacation.
The gastroc is a secondary knee FLEXOR, so as the knee is bent, it's contracted, not on slack.
Playing tennis, the brain wants "all hands on deck" so to speak in terms of muscle recruitment; add the violent eccentric/concentric contractions of the muscles plus the amount of force impacted during running/stopping/split step and you can see how easily spasms/pain can occur.
I do not know the angle of knee flexion at which the Gastrocnemius can supply little force to the Achilles Tendon. I suspect that the angle of knee flexion does not have to be very large. ?
Do you have any information on that angle?
Maybe we should agree that we need to find some more information on the involvement of the Gastrocnemius vs knee flexion.
I did read somewhere that the majority of tennis calf injuries are to the Gastrocnemius but I only saw that information in one reference so far. This is an interesting issue since it would be useful to know what stresses lead to calf injuries - bent knee Soleus stresses, brief straight knee Gastroc stresses, or others?
For injury prevention, most players that I see only do straight knee stretches and its not clear what that type of stretch is doing for the Soleus, if anything. ?