Static Diagonal: isometric opposite knee to hand push
With the PBU at 30-35 mm Hg or other hand to monitor that no pressure change, slowly lift one knee towards the opposite hand and push them isometrically against each other on a diagonal line. Push for 10 seconds and repeat 10 times so long as control is maintained (no pressure change).
As soon as any pressure increase or decrease is registered the movement must stop and return to the start position. Do not stabilise with the opposite foot or allow substitution or fatigue.