Which Calf Is Bigger?

Notice any difference in the picture above? If you look closely, you'll notice that the left calf is slightly bigger than the right. Upon palpation my patient's left calf does feel more "meaty" compared to his right.

This is surprising as my patient says that his right leg is his dominant leg. Usually the dominant leg is bigger and stronger than the non dominant leg.

Now, this patient, who is an ultra marathoner came in to see me yesterday after a 35 km training run in the morning. He said that his right calf muscle often cramps after about 35 km.

Even after an easy run, his right calf and hamstrings often feel more tired and fatigued compared to his left. He also felt that it required more effort to bend his left knee compared to his right.

My patient also does not have any numbness, pins and needles down his right leg or other neurological signs. After checking his back as well, I explained to my patient that the reason for his muscle cramping in his right calf muscle is simply due to muscular fatigue.

Since his left calf is bigger, it will also be stronger than his right calf. This means that after running a certain distance his right calf will work harder than the left calf and will fatigue faster too.

I explained that muscle cramping is not due to sodium (or salt) loss, dehydration, electrolyte or fluid loss. I've explained this in a bit more detail before in another post, have a read here please if you're keen.

We then discussed how he could do some isolated (right) leg training to make his right calf stronger to avoid cramping eventually.

Here in his case, size does matter.

Reference

Schwellnus MP, Nichol J, Laubscher T and Noakes T. (2004). Serum Electrolytes Concentrations And Hydration Status Are Not Associated With Exercise Associated Muscle Cramping (EAMC) In Distance Runners. BJSM. 38: 488-492. DOI: 10.1136/bjsm.2003.007021.