Sudden weakness in any athlete is cause for concern. When a 15-year old girl developed severe weakness in both arms after swimming, a medical exam was needed. There weren’t any problems at rest, just during swimming or weight-training.
The weakness was bad enough that she was forced to stop swimming. Tenderness was present in both arms when pressure was applied to the back of the elbow on the lateral (outside) surface. X-rays for fractures and nerve testing (called nerve conduction studies) were normal.
Doctors thought the problem was the radial nerve where it passes in a groove in the lower part of the upper arm. When the triceps muscle on the back of the upper arm contracts, it presses on this nerve. A special testing machine was used to prove this was the problem. The test wasn’t for the strength of the muscle, but to see if the weakness occurred when the muscle contracted against the nerve.
A loss of 45 percent power in the swimmer’s arms supported the idea that the radial nerve was getting pinched. This is called nerve entrapment. Since it only happened when the arms were used for heavy and repeated activity, it was further labeled a “functional” entrapment.
The treatment in this case was surgery to release the nerve. This was done in two parts, first on the left and then on the right. When the doctors opened the area up, they were able to see that the muscle did indeed trap the nerve.
This girl was able to return to swimming after 10 weeks of recovery. And six months after surgery she won a silver medal at the Swiss National Championships.