Leg raise

The leg raise is a strength training exercise which targets the iliopsoas (the anterior hip flexors).

They can also be performed on other apparatuses such as dip bars and captain's chairs, which also involve the torso being suspended in the air, except that the stress through the arms is different.

It is generally the more difficult variation for the abdominal muscles due to having to support the pelvic weight as opposed to simply stabilizing its alignment.

Alongside this however, it is also potentially the easiest to use bad form on, because users may use a swinging motion to 'cheat' by building up momentum.

If the abs are not properly engaged, the spine can easily hyperextend and go into anterior pelvic tilt.

Extending the knee joint (often called a straight leg raise)[4] increases the demands of leverage on both hip and spine flexors.

Others do partial range repetitions to focus on more difficult portions of the exercise (generally when the leg is parallel with the ground).

Both ab muscles (rectus and transversus abdominis) are used to isometrically stabilize the spine to resist extension and posterior pelvic tilt that would otherwise occur with the legs lifted in front.

When the lumbar spine flexes, the rectus abdominis is worked dynamically instead of isometrically, increasing its activity, but lessening the stabilizing effect of the TA.