Straight back,knees bent to absorb and transmit pressure, back parallel to ground means the weight will come through straight rather than up or downwardsStraight back allows weight to come through and you get this by bending knees,pushing the chest forward and raising the chin Feet are back and shoulder width apart for stability and to get legs to generate /absorb power not other parts of body
....to practise this go 1v1 and get them to alternate push and resist to allow the weight to come through then go 2v2 then 3v3...once they are comfortable pushing /resisting get them raising and lowering the scrum height..they do this by bending at the knees , keeping shoulders square , chin and head up.1v1 then 2v2 then 3v3 ...next get them moving sideways left and right by taking small steps keeping feet no closer than shoulder width apart, 1v1 then 2v2 then 3v3 ..in both these drills get them to chase the weight ie keep the pressure on the oppn or they will sacrifice stability and balance
Get the whole group of front rowers or the whole scrum to bind in a circle facing each other and calling the engagement sequence eg ;squeeze ,all squeeze binds,knees, all bend at knees, now , in unison all thrust upwards extending legs up on to toes then into air together.
In a game the contact with the oppn, forward pressure, put-in by the halfback, the hookers strike and the delivery of the ball should be part of one consecutive dynamic movement
The whole scrum.....
Assemble quickly with the front row one arm's length from the opposing front row. Form as a bound unit close to the mark as soon as the scrum has been called The tighthead prop calls the engagement and leads-in Upon contact maintain forward pressure
Hooker
Co-ordinate scrum assembly and engagement.
Bind with the loosehead before binding with the tighthead.
Bind at the armpits over the prop's shoulders.
Face the deliverer as much as tight binding allows.
Co-ordinate the put-in and the strike along with the deliverer.
Strike the ball to deflect it between the loosehead prop's legs.
Clear the ball so that it is behind the front row.
Props
Bind with the hooker at the armpit so the hooker is unrestricted in the movement of hips and lower torso.
The tighthead leads in to enable the hooker to turn towards the deliverer. The tighthead should 'call' the engagement.
Sink down into a crouch position, head up.
Drive up into engagement from the crouched position.
Make firm contact by binding and retaining the square on position.
Loosehead binds with a bent arm between the shoulder blades of the tighthead prop. For support turn the head out to rest on the upper arm.
Tighthead binds with a straight arm reaching as far down the loosehead's back as possible.
Transfer the scrum's weight to the opposition by maintaining body position with a straight back,head up, shoulders above the level of the hips and hips forward of the knees.
Maintain pressure until the ball is out by either sinking at the knees or pushing forward.