As most CrossFitters know (or learn at some point in their fitness journey), the GHD sit up is an extremely potent stimulus for the anterior chain where you are performing a ballistic type situp initiated by a lower body kick through a nearly 270 degree range of motion. This movement has been a staple of CrossFit programming since workouts were first popularized on crossfit.com in 2001 and athletes of all abilities can be seen tackling reps in the box on a daily basis or on the competition floor. With this being such a common movement programmed, why do so many people say it makes their back hurt?
Reason 1: Anterior Chain Motor Control
The full GHD sit up is standardized by the athlete touching the ground with the arms overhead as they go back into a position of global extension through the hips and spine then returning to a seated position with the hands touching the foot pads. When attempting to perform these repetitions at high intensity, it can be easy to lose control of the extension as you reach for the ground which results in increased stress on the facet joints between vertebrae of the lumbar spine. To perform this skill correctly, one must maintain tension in the abdominal muscles throughout the range of motion to properly control extension of the lumbosacral region which will reduce likelihood of increased stress on the joints of the spine in this position. There is also the matter of initiating the return to a seated position. This should be initiated with a rapid extension of the knee resulting in engagement of the rectus femoris portion of the quadriceps muscle group which is a powerful hip flexor attaching to the pelvis at the anterior inferior iliac spine. This muscle action enables the pelvis to rotate with the trunk as your return to a seated position. If the athlete does not time the rapid knee extension correctly, the hip flexion portion of the movement is dominated by the iliopsoas (iliacus and psoas major muscles). Due to the psoas major attachment on the lumbar spine, this can create an anterior shearing force which results in increased stress to the facet joints. Proper motor control is vital to the performance of GHD sit ups in a pain-free manner.
Reason 2: Mobility Limitations
The full GHD sit up involves moving the trunk through an extreme range of motion. As a result of this, mobility limitation in a number of areas can result in excess stress to the joints of the lumbosacral spine region. Any limitation in thoracic extension or shoulder flexion can be a common culprit here. If the thoracic spine does not extend well enough then more of that motion must come from the lumbar spine. If the athlete struggles with an overhead position due to shoulder flexion limitation, more motion must come from the lumbar spine to get the hands to the ground. Another area of limitation that can contribute to increased stress on the low back is a lack of hip extension. If the athlete struggles to get the femur posterior to the pelvis, the end result is more stress on the lumbar spine (this could also manifest as low back pain with activities such as running, jumping, and olympic lifting).
Reason 3: You’re Not Strong Enough!
This should be pretty self explanatory. If you have never attempted GHD sit ups and decide that it’s a good idea to go for 150 repetitions during a high intensity workout just because the coach programmed the Hero Workout “Michael”, that one is on you. Like any other exercise movement or modality, if you are not experienced and/or have not been building volume gradually over time, please scale appropriately. Just because you have done a lot of AbMat sit ups or toes to bar does not mean you are prepared for high volume GHD sit ups under metabolic stress. Don’t be that person! Recognize the error of your ways and start incorporating GHD sit ups into your accessory work so you can build tolerance to the stimulus.
Okay thanks, but what do I do now?
Great question, having an answer for why your back hurts doing GHD sit ups is nice and all but you probably want to know what needs to happen so you can crush reps WITHOUT PAIN. Makes sense to me. Step 1 is to ask your coach for help! They are the ones that see you everyday in the gym. They know your strengths and weaknesses, they know what you struggle with, they know what types of cueing you respond well to, and they have spent countless hours teaching you how to move better already. Show some humility and ask them for help!
For those of you who don’t have a trusted coach, here are some steps you can try on your own.
Step 1A: Scale the range of motion!
This is the quickest and easiest fix. Shorten the range of motion and increase over time. Place a box behind you (preferably foam) so you have a consistent target and practice controlling your range of motion to that target. Slow the movement down, maintain tension throughout the lowering portion, and work on the timing of your knee extension to initiate return. When this gets easy and pain-free, lower the target.
Step 2: Adjust the GHD
This is another quick and easy fix, especially in the athlete with requisite strength but dealing with some of the aforementioned mobility limitations. Moving the foot pad closer to the thigh pads will position the hips closer to the ground and off the edge of the thigh pad. This reduces the amount of global extension mobility required through the hip, lumbar spine, and thoracic spine to achieve the full range of motion required for “good” reps.
Step 3: See a Physical Therapist, preferably one who knows CrossFit…
Physical Therapists are uniquely qualified to perform an examination identifying any weakness, motor control impairment, and mobility limitation contributing to your experience and, most importantly, we can provide the appropriate treatment customized to your specific needs! At RISE, we pride ourselves on practicing what we preach, meaning you can find us in the gym throwing down right next to you. Need proof? Search the 2024 CrossFit Open leaderboard (Josh Davis - CrossFit Sanitas and Eli Edwards - CrossFit South Denver). Book an appointment for a thorough and comprehensive evaluation then get back out there so you can dominate your gym buddy the next time GHD sit ups show up on the whiteboard and go home without back pain.