While training Jiu Jitsu you will spend a lot of time in positions where your hip flexors will be in a contracted position. It is important to open up your hips to prevent any muscular imbalances from developing.
Your primary hip flexors include your psoas, iliacus, rectus femoris. Secondary hip flexors include sartorius, tensor fasciae latae and adductor (groin) muscles.
Here are some strategies to mobilize your hips:
1) Self myofascial release: Foam rolling to address any fascial restrictions. I suggest peforming this prior to stretching. For general work use a foam roller but for more specific locations you can switch to a lacrosse ball. Spend 30-60 seconds on an area. Attack the front of the hip and the groin muscles.
2) Hip flexor stretch: This stretch hits many different areas: psoas, iliacus, rectus femoris. The leg down favors the iliopsoas while the leg up favors the rectus femoris (quadriceps).
3) Active Motion: Following a stretch make sure to move the leg in the new range or the gains will be temporary. Make sure you have the motor activation of the muscle fibers to actively move into that new range.
4) Gluteal exercises: While sustained time in a flexed position (also consider how often you sit in your daily life) your gluteal muscles may be in a lengthened position and at a mechanical disadvantage to perform their job. Make sure to include strengthening exercises to improve muscle activation and/or strength. Exercises include: bridging, hip thrusts, squats, deadlifts and kettlebell swings.
Make sure to take care of yourself so your body can handle the rigors of hard training.
Dr. Mike Piekarski, DPT
BJJ Brown Belt
Former MMA Fighter