Calf raises to failure and numbness

Question

Last week I was doing some high-rep sets of calf raises and something odd happened. On my 5th and final set I planned to go to failure, with at least 60 reps as the goal. At about 50 reps it burned badly enough that I wasn't sure if I would get 60. But then I did and tried to keep going. At 65 I thought I would try for 5 more, and when I hit 70 it started getting easier. I finally stopped at 85 because my legs were feeling weird. That's when I noticed my lower legs were slightly numb. I could still walk and feel my feet a little bit (less than normal sensation), but it was definitely odd that there was no burning at all like there normally is after a set.

The numbness subsided after about 20 minutes or so, but another strange thing was that I was not sore at all the next day. (I'm always reminded the next day that I did calves the previous day, at least a little bit.)

I did not do calves for an entire week after that. Last night I repeated the exact same workout, but this time I stopped at exactly 60 reps on the last set with the expected amount of burn at that point. Today my calves are sore just like they normally are.

Is there any explanation for this or should I chalk it up to some sort of coincidence that I went beyond burn, which led to numbness, AND I was not sore from that workout?

Answer 1

It's not unknown. To quote the Livestrong article I linked above:

Exercise can make your leg numb due to lack of blood supply to the area .... blood flow can slow down in your legs, causing numbness and tingling sensations.

....

During exercise, you may initially feel numb in a specific area, like your thigh, hamstring or calf muscle.

It's usually relatively benign, the result of working a bit too hard combined with the foot flexion potentially cutting off blood flow (a common problem in heavy elliptical users), but there are more serious risks from falls resulting from lack of sensation to the numbness being caused by pinched nerves or an impending cardiac malady, so the recommendation is to stop immediately.

As soon as you feel some numbness and a tingling sensation in your legs, stop the exercise immediately. Lie down or sit with your legs elevated to improve blood flow to the area. Avoid moving the legs and keep stationary for 10 to 20 minutes. Apply hot compress and remove any tight clothing or pants you may be wearing. Contact an ambulance immediately if you feel more serious symptoms like nausea, difficulty breathing, severe pain in the legs and loss of consciousness.