Many people have adequate knee flexion flexibility, but have limited control and strength over that flexibility. And that’s not optimal! So here’s an amazing exercise to work on controlling that flexibility and strengthening your hamstrings at their endrange. Enter knee flexion passive-range holds!
Start in a half-kneeling position and really pressurize and brace your core so you minimize movement from occurring in your lower back. If you have something to hold on to and drive into the ground to create tension, grab it and use it. You can always use the wall as seen in the video.
With one hand, grab around your foot and pull your heel towards your butt into maximal knee flexion. Again, make sure you’re not extending through your lower back. From here, slowly start to let go of your foot, trying to not let your foot fall to the ground. Really use your hamstrings to hold that foot in the air for 2-3 seconds! Repeat this for 10-15 repetitions for a few sets.
Ideally, you shouldn’t lose much range of motion when you let go with your hand (like Dr. Ryan did). As with all strength training though, your control and strength will improve, decreasing the deficit.