Muscles often tighten up because your body is trying to create stability where it's lacking. For instance, you might think your hamstrings are tight, but the underlying issue could be an unstable core. So if you simply improve the flexibility of a tight muscle, you may actually be removing your body's point of stability. As a result, your body can become more unstable, increasing your risk for injury.
In the case of your hamstrings, instead of only using traditional stretch-and-hold techniques, try performing dynamic movements that boost flexibility and challenge your stability at the same time. An active stretch like the Inverted Hamstring Stretch (see below) will lengthen your hamstrings while training the muscles around your hips and torso to keep you balanced. Add the Inverted Hamstring Stretch to your warm-up, and include Romanian Deadlifts in your strength routine to improve strength, stability, and flexibility.
Inverted Hamstring Stretch
Stand on your left leg with your arms raised out at your sides. Keeping your back flat, slowly bend forward at your waist while reaching your right heel back and toward the sky. Pause when you feel a stretch in the back of the upper thigh of your down leg, then return to the starting position and repeat. Do 4-5 repetitions on each leg. Watch this video to see how it's done.
Single-leg Romanian Deadlift
This movement is similar to the Inverted Hamstring Stretch, but hold a pair of dumbbells in front of your thighs with straight arms. Do 2-3 sets of 8 to 12 repetitions with each leg. Watch the video for proper technique.
– Sue Falsone