Most dynamic prone plank exercises are designed to have the upper extremity raised out front (flexing the shoulder). But a better way is to extend the upper extremity (extending the shoulder) while extending the opposite side lower extremity (extending the hip).
The start position would be lying face down on elbows and toes with the trunk/back straight.
Raise the left leg so the left foot is approximately 6 inches off the ground and extend the right shoulder so that the hand moves just past the hip, hold for 2 seconds.
Return to start position, then repeat with the opposite sides.
Alternate sides.
It is vital that the abdominals stay tight and the low back does not sag throughout the exercise. If this occurs, stop because the muscles have been pushed to fatigue. Extending the shoulder versus flexing it is more functional because it imitates normal human movement. It is best to train our neuromuscular system in the way we intend to use it.
