A resistance band looped around both feet lets you strengthen hip flexors with a crane kick movement. Keep your knee low and your lower back neutral to avoid rounding your spine. Hold each side, then switch.
Chapters
Do you want to strengthen your hip flexors? I need you to look like the Karate Kid. What you're going to do is take a band and put it around your feet, just like so. You're going to put your arms out like you're going to crane kick, raise up and hold in alignment just like this, and then slowly lower. Then alternate sides. As you're doing this, don't go too high with the knee. You will round your lower back. We don't want to do that. We want to create stability through the lower back. Keep it nice and neutral. Hands out like a crane. Hold. Slowly transition to the next side and slowly lower. That way you can strengthen the hip flexors while keeping a neutral spine and fixing your back. Ha!