@alejandromatias674: If you sit a lot, strengthen your hip flexors. Sit up straight with your legs in front of you and use your hands for support. Set up two obstacles and lift your leg over and back for 20 reps. If that’s too difficult, remove the obstacles and simply lift your leg up and down. You can also bend your knees to shorten the range of motion. You’re still strengthening your hip flexors either way. Then finish with a runner’s lunge to stretch the hip flexors you just strengthened. Sit here, breathe, and relax into the stretch. Strengthen them, then stretch them.