The glute-ham developer is a staple piece of equipment in most CrossFit boxes. It can be used for several different movements, but probably the most common being the GHD sit-up. This is an exercise that requires individuals to lower their torso past the point of extension (resulting in hyperextension) and then primarily use their hip flexors to return to a sitting position. The CrossFit community has received criticism from the fitness world for many of their ideologies, and CrossFit’s take on the sit-up is no different.
Critics of the GHD sit-up have conjured up many different arguments as to why this type of sit-up should not be performed. First of all, many have argued that the target muscles for a GHD sit-up are actually the hip flexors and therefore the movement does not recruit the use of the abdominal muscles whatsoever. However, this is not the case. Ask any athlete who has done a set of twenty plus GHD sit-ups in a workout and they will tell you that they could barely sit up to get out of bed the following morning. In fact, the GHD sit-up actually recruits the abdominal muscles in two different ways. First of all, this movement takes the trunk from hyperextension to full flexion, which recruits the use of the upper, middle and lower abdominal muscles. No other sit-up movement does that. Secondly, the abdominal muscles’ role in this exercise is to stabilize the torso from unnecessary extension, therefore playing the important role of protecting the spine from serious injury.
Many fitness professionals have also argued that the amount of hip flexor work induced by the GHD sit-up can lead to problems in the lower back. Dr. Stuart McGill, a world-renowned spinal expert and a professor of spine biomechanics at the University of Waterloo (Ontario), argues, “You can’t perform exercises with high spine power and expect it to stay healthy. When you repeat high force and velocity through collagenous disks, they will delaminate and bulge.” Dr. McGill argues that the repeated motion of moving the spine from flexion to hyperextension is causing repeated damage to one’s disks. However, CrossFit founder Greg Glassman argues that when the GHD sit-up is performed correctly – employing the full use of the hip flexors – then the lumbar spine is preserved throughout the movement, reducing the likelihood of it being injured.
Finally, those opposed to the GHD sit-up argue that the anatomical damage caused by the GHD sit-up puts the spine in a precarious position when performing the Olympic lifts, which are common movements in the CrossFit regimen. Spinal expert Dr. McGill stated in an article published by Stack.com, “Programming of the GHD sit-up is problematic when combined with other exercises that require stiff and tough collagen fibers, such as Olympic lifts.” However, this argument does not have a lot of merit because GHD sit-ups paired with heavy Olympic lifts is a rare combination in WODs (workout of the day). Furthermore, CrossFit preaches the concept of “core to extremity”, claiming that every movement starts from an individual’s core, and then extends out to the appropriate limb and musculature needed to perform that movement. CrossFit argues that by strengthening the abdominal muscles, athletes are actually improving their success in the Olympic lifts because their strong core helps them generate power throughout the movement and stabilize the barbell on the shoulders (front rack position) or overhead.
In conclusion, both parties employ convincing arguments for and against the use of the GHD sit-up. However, it is important to remember that each individual’s anatomical makeup is different, so there is no right or wrong answer as to whether GHD sit-ups should be included in a regular exercise regimen. They might be beneficial for some individuals and harmful for others. Furthermore, it is important to understand the muscles that are targeted by this movement so that when it is performed, it is done correctly. Most injuries occur when a movement is done incorrectly. Therefore, before performing an excessive amount of GHD sit-ups in a workout, ask a coach to observe your movement to determine if the correct muscles are being engaged properly.