Active hip flexor strengthening and flexibility at the same time. Important if you want to unlock performance in your lower body!
The hip flexor exercises demonstrated here will stretch and strengthen the hip flexors which include the muscles rectus femoris, iliopsoas, tensor fasciae latae and some other muscles.
Although the hip flexors will get work done with many lower body exercises and abdominal exercises, it's common to have tight and weak hip flexors which can limit and hinder your progress in strength, muscle and overall performance.
Stretching and strengthening your hip flexors is also good for your posture and hip position.
If any of the muscles in the hips are overly weak or tight, it can affect how you stand and how you walk. And these two things affect almost everything you do.
Strengthening other parts of the legs:
When you combine these hip flexor drills with our other active leg flexibility exercises, you can produce great results in your lower body in strength and mobility.
It's also possible they will alleviate knee and lower back problems.
Single Leg Sissy Squat

This is what we call the "single leg sissy squat". The normal sissy squat is a bodyweight exercise for quads.
You bend backwards supporting with the rear leg. The front leg stays straight or relatively straight the entire duration of the exercise.
You should feel this very nicely in the hip flexors of the rear leg.
Leaning back is already an effective way to strengthen and stretch the hip flexors, but to make it complete, you push yourself up to build strength in that range of motion.
You can do this exercise for 5-10 repetitions per set for 3-5 sets.
Low Lunge Position

The low lunge position is a phenomenal way to strengthen the hip flexors which is why we like to heavily utilize it with our clients. It's also one of the strengthening drills of Movement 20XX.
You just stay in the low lunge position for 15 to 60 seconds. Knee isn't touching the floor.
People easily overlook this exercise and think they are stronger than they actually are. In reality, most people cannot stay in this position for longer than 15 seconds without feeling uncomfortable, shaky and having hard time with their balance.
This is because of the weaknesses in the hip flexors and stabilizer muscles of the legs. This is why becoming comfortable and strong with the low lunge can produce great results.
What's even better about this is that you can easily adjust the distance of your legs, your hip position (tuck your butt!) and even the angles of your legs.
Train hard, stay safe.