CrossFit GHD (glute hamstring developer) sit ups are often a polarizing movement. When you see this on the whiteboard, you are either stoked, or bummed. GHD sit ups hammer the anterior muscle chain and require skilled sequential timing to be performed correctly and efficiently. All movements that require significant back bend rely on both mobility and stability in the hips and the spine. If your body is not prepared, this can feel like a risky move for your back, and for good reason.
Uncontrolled extreme repeated extensions of the lumbar spine can result in low back pain or injury. Strains and irritation to the low back can be very common but extremely frustrating since we rely on low back and trunk stability for so many CrossFit moves. The low back (Lumbar Spine) is a large and resilient structure that can handle tremendous forces and movement; however, the loads of activity can supersede the capacity of the low back tissue can handle. When this occurs, the irritation to the low back tissue can cause a cascade of events leading to weeks to months of WOD modifications.
To mitigate risk of low back injury, or discomfort in this movement it is vital to know which muscles to strengthen. In a movement such as the CrossFit GHD sit up, the body relies heavily on eccentric control of your quadriceps, iliopsoas, and rectus abdominis muscles to control the forces of gravity on the lumbar spine. The reliance on these muscles is further challenges when the WOD involves other moves that tax these same muscles. Integrate the following exercises into your workouts to strengthen the anterior chain and avoid lumbar collapse in GHD sit ups.
1. Anterior Hip Mobilization, followed by Eccentric Hip Flexor Strengthening
2. Anterior Chain Quadruped Sliders
3. Toes to Bar with Slow Controlled Leg lower
4. GHD Face Up Plank