Though the hip flexors are the primary movers in the GHD sit-up, the abs play a strong role in stabilizing the torso to prevent hyperextension of the spine. This is, in our opinion, a more functional role for the abs than trunk flexion. Carefully introduced and practiced, the GHD sit-up is a potent tool for reeducating the athlete to use the hip flexors more efficaciously and safely.
7 GHD Machine Exercises for Glutes, Hamstrings & Back - Steel Supplements
The Ultimate Guide to GHD Sit-Ups: Benefits, Technique, and Variations
Body Solid Glute & Ham Machine, SGH500
EliteFTS
Glute Ham Developer
Adjustable Floor Glute & Hamstring Developer (GHD) - Cross Training Workout Lifting Equipment in Home and Commercial Gym
The Ultimate Guide to GHD Sit-Ups: Benefits, Technique, and Variations
GHD Hip Extension - FITNESS INSTITUTE
Glute Ham Developer – Torque Fitness - Commercial
How to Use the Glute-Ham Developer (GHD)
CrossFit The Glute-Ham Developer Sit-Up
Tip: The Most Misused Machine in the Gym
CrossFit The Glute-Ham Developer Sit-Up
