Liv a. I was thinking about your question to me, about how to know when enough is enough, while at the swimming pool this morning. It's an interesting question that's got me thinking. I used to think it's when your muscles burn, but I have found recently that if you continue past that point, the pain goes.Manila I was doing my laps I realize I go through the muscle burning, last about another 30 minutes then stop when my muscles actually stop working properly. So this morning, my weaker are stopped clearing the water and my coordination went off. If you have weakened muscles then it's important to keep the muscles nearby fit! For instance I have just developed weakness in my triceps, but all other arm muscles are stronger, so swimming is great because I use other arm muscles as well. My husband is a neurologist and he said to keep exercising especially unaffected muscles. Aly