A well-constructed scrum machine will encourage the forwards to improve the timing of their scrum. It doesn’t matter how much weight you have packing into the scrum, if your engagement timing is off, you will struggle to win scrums!
Coaches tell us it is overwhelmingly noticeable to see the difference between the power a scrum can achieve when the timing is right, compared to when the timing is off. When I say ‘timing’, I am meaning the ability of all 8 players in the scrum to engage and drive at the same time, in a straight line. It really allows you to work on your timing as a unit and make sure you’re ready to go once the team hits the field.
So a major function of the scrum machine is predominantly as a timing device. The forward pack can exert their energy at the same time, while being closely observed by the forward’s coach. Ultimately you want all 8 forwards to be giving their maximum input in order to overcome the opposition’s scrum. A scrum machine allows you to practice that time and time again and monitor the pack. This isn’t a luxury you have in a live scrum situation.