I used to ride my bike about every other day two summers ago and with school I wasn't able to get on too much this past summer. Now that the weather is getting nicer again, I am attempting to get back into the riding spirit. But, when ever I attempt to go on any kind of ride ( which consists of hills out the wazoo ) my inner thigh muscle ( I believe is the Vaste Interne) will always cramp up and bulge when I stand. The problem isn't that it cramps when I stand its that I can't get a full push with my legs when pedaling.

Is this a conditioning problem or possibly my seat may have change positions over the past year or so?