Brief Answer: Can be due to low pottasium. Detailed Answer: Dear Friend. Hi , I am Dr Anshul Varshney , I have read your query in detail , I understand your concern. Normally twitches can occur due to exercise specially when a person starts doing them, but with continuous exercise one overcomes that within a course of few days. I would like to know following things : 1. When did you start exercising? 2. Any history of weakness in your legs? 3. Any history of lower limb paralysis , that gradually recovered? If this has started recently with new exercise program , this would recover in few days as your muscles get toned. But if it is persisting since a long time , you should get your serum pottasium checked post exercise. This can be due to Hypokalemia , resulting as a result of dehydration during exercise or due to an inherited condition called as hypokalemic periodic paralysis. This is my personal opinion based on details available here. If you still have any query you may please ask me. Stay Healthy. Dr Anshul Varshney , MD

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