The Modified Pike
This modified version of the classic pike enables better execution and better stimulates the rectus abdominis. What you will do is put your elbows on a bench and bend your knees a bit.
First, let's take a look at the wrong approach:
Modified Pike: Incorrect  Now the Right Way:
Modified Pike: Correct
Setup and Execution
Position yourself with your elbows on a standard bench, the lower legs (shins) on a stability ball. Push yourself into a plank to get to the starting position.
Begin by circling your back and harnessing the coccyx. Bend your abs without moving your weight forward over the bench and push your lower back up to the ceiling while gently bending your knees as they move toward the chest.
It is very important that your focus is on steering back, DO NOT actively pull the knees to the chest. This makes the contraction stronger in the abdominals and less in the hip flexors.
When you are in full flexion, lower your body back to the starting position. Think about stretching your spine to neutral and not pressing your legs. Stop at Neutral and repeat the exercise.
- This exercise from the ground is a good option, but may be too advanced for some lifters. If you intend to exercise your rectus abdominis, you should first keep the movement outside the hips. Maintaining a stable position in the pelvis gives your abdominal muscles a point of anchorage for pulling and flexing the spine and for keeping legs and hip flexors out.
- Moving less far allows you to have better control and focus throughout the set. When an exercise is difficult to do, most of the focus shifts from the muscles being worked to the movement. This results in "everything being done, no matter what". The intention is as important as the movement itself. If you can not feel how the muscle works, you miss the point.
- Perform a slight rocking movement at the bottom of the repetition, moving your weight back toward your feet to make sure you're concentrating on your abdominals, not the shoulders. This shift of weight into your feet will brighten your core.
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