Try this rugby drill at your peril.
Physics and all that weights and mass stuff was never our strong point at school English was obviously, duh) so we're treading thin ice here.
But even a mere mortal like us knows that weight, momentum and force all does odd things to the body.
Putting undue pressure on knee and legs often leads them to buckle under the strain.
So we're still trying to figure how how these two USA rugby Seven's training drill did not end in a trip to hospital
https://twitter.com/USASevensRugby/status/662727348555374593
