Thanks for the reply martn76,
With the step ups, would you say it is the lifting of the foot up on to the box, or the pushing yourself upwards, that best trains the psoas?
As the person lifts their foot up on to box, their obviously working hip flexion, including the psoas, expecially if it is a high box. (as you know)
But when the person actually pushes up their body in the step up (contracting glutes / hip extensors, and quads) , the psoas may act as a stabilizer of the spine. So which part of the step up move would you suggest gives the greater stimulus to the psoas major?
Anyone?