On my last few rides I have noticed a pain at the rear of my right knee in the two tendons? that run down from the thigh to the calf when I push hard. It feels like these tendons are being overly stretched, even though there is still a good bend in my knee at the bottom of the downstroke, and seems to leave me riding toe down rather than 'round pedalling'. Does anyone have any idea what the problem may be? Could it be related to cleat position as the saddle isn't too high and my bike position is set up as it has been for years. Or do I just need to do some stretching and try to improve flexibility in that area?