Cycling causes your pelvis to tilt forward, pulling your glutes out of alignment and forcing you to rely too much on your hamstrings, quadriceps, and lower back. Since your hips act as a brace for your lower back, your back compensates by flexing, extending, and rotating. Release your tight hip flexors and retrain your glutes by performing these lower-body exercises twice a week. For each move, do 10 reps per side.
ACTIVE HIP-FLEXOR STRETCH (side-lying) Lie on your left side with your heels near your butt and your knees at waist level. Place your left hand on your left knee. Grab your right ankle, flex your foot toward your knee, then rotate your right leg downward. Pause, return, and repeat for 10 reps. Switch sides.
BACK LUNGE (with side bend) From a standing position, step back with your left foot and bend your knees 90 degrees. At the same time, reach overhead with your left hand and bend your torso to your right. Then push back up.
GLUTE BRIDGE (single leg) Lie on your back, knees bent 90 degrees and feet on the floor. Lift one leg off the floor and straighten it. Squeeze your glutes to lift your hips. Lower them.
Here’s a video from BJ Gaddour Showing You How To Improve Your Bridging