Why It’s Bad: The muscle that feels tight or hurts is often not the muscle that you need to unwind. For instance, hip flexors (which are often tight and overworked in cyclists) can cause a lot of discomfort elsewhere, says Reavy. “The hip flexors cross eight joints and when they become too tight, they limit the mobility in all of these joints,” he says. Plus, tight hip flexors pull your pelvis forward, which leads to sticking out your butt and decreasing the effectiveness of the abs and glutes. When your glutes and abs aren’t firing up correctly, it puts extra strain on your quads while you ride.