KinX Learning

Digital Products in the Kinesiology of Exercise

Back Extension on a Back Extension Machine

Major Muscles and Actions Involved

Back Extension on a Back Extension MachineThe erector spinae is contracted isometrically to stabilize the spine. In the hip joint the gluteus maximus and the upper hamstrings are involved in hip joint extension. In this action the trunk moves backward with the axis in the hip joint. 

Sports Uses

Stabilization of the spine is very important in most lifting exercises. When the spine is stabilized, it is held in its proper alignment while some activity such as execution of an exercise or sports skill, takes place. An example of this is executing a jump, squat or overhead press with the spine held in place. 

Did you know...

  • In seated back machine exercises, the main action is in your hip joint. Your lower back remains basically rigid to push the resistance bar or pad backward. Because of this, the erector spinae muscles of your back remain under isometric contraction in their stabilizing action.
  • Your gluteus maximus and upper hamstrings are, however, dynamically contracting to move your trunk backwards. Thus, in this exercise the back muscles are developed with the trunk held in basically the anatomical position.