Hi. Thanks for a good explanation of the knots. Since they are there for a long time as you say, not painful nor tender. There has to be no worry. But once you have noticed then and there has to be a reason for them and it is always better to get them diagnosed. These can be intramuscular lipomas.. I would advise such lumps to be checked by a Surgeon and get the FNAC ( fine needle aspiration cytology), ultrasonography done. Since you are an ardent exercise man. it is always better to get them removed. The lumps (dis-ease) is removed and you get the tissue diagnosis.