Previous Position

Reverse punch (Gyaku Zuki) in Front Stance (Zenkutsu Dachi)

Keep you feet in the same position but lock your Rear leg straight into Front Stance (Zenkutsu Dachi)
Punch from your hip with your Right fist.  The punch should finish directly in line with the centre of your chest towards the 10.30 clock position.  

Pull your Left fist quickly back to your hip
Push your Right hip forward and your Left hip back to give more reach to the punch
Make sure your Left knee is over your Left toes
Do not lean forward
Breathe out partially - follow on to the next move immediately