Co-contracting the Abs and Glutes in
Leg Pull Front IMAGE 1
As we evolved from quadrupeds (walking on all fours) to erect bipeds, the spine has transitioned from a suspension bridge type of structure, using tension/ compression relationships, to a weight-bearing column. This change exposed the various structures of the spine to different potential stressors. For example, the lordotic posture results from a weak abdominal core, and tight hip flexor muscles.
IMAGE 2
If we imagine the pelvis like a wheel, this combination of tightness and weakness produces a forward or “anterior” roll, and potential shearing stressors (Image 1). For this reason, back rehabilitation programs always incorporate abdominal strengthening exercises. Conditioning the front so that it acts like a retaining wall helps to protect the back. See image two for an example of the retaining wall effect of rectus abdominus and the external obliques.
IMAGE 3
The Leg Pull Front (Image 3) represents an exercise that can be used to develop and condition the abdominals and to stabilize the lumbar spine. Practiced properly, it reproduces the quadruped position and temporarily
relieves the biped stress on the spine. At the same time, it strengthens the supportive abdominal muscles. The tendency when performing the Leg Pull Front is to hyperextend the lumbar spine (rolling the wheel forwards) and lift the tailbone into the air. This arises primarily from tightness in the hip flexors (including the
psoas) which, when the leg lifts, is stretched and tilts the pelvis forward (“anterior tilt”) extending the lumbar spine (refer to image one again for illustration). This tendency can be balanced and corrected by stretching the hip flexors and learning to co-activate the Gluteus Maximus and Rectus Abdominis during the exercise.