Once you’ve been diagnosed with a hip flexor injury it’s important to rest the muscle group. Not taking the time to rest can prolong your recovery. In addition to rest, you can apply ice for 30 minutes every 4 hours or so. For more severe injuries your doctor may recommend using crutches. After the muscle has started to repair itself, then it’s a good idea to start physical therapy. A physical therapist will use a variety of techniques to help heal and strengthen the area.