Movement like a cat

this is an old one.

what they mean is to have a flexible spine and to move from the scapulae/spine, not from the front of the shoulder.

when we discuss 'what is an arm?' we are left with the understanding that the arm begins at the spine. the arm itself, shoulder, pectorals, scapula, trapezius and lattimus are what constitutes your arm.

so lets keep it simple

1 relax
2 'punch'(read reach) from your spine and sternum. use your whole arm
3 relax some more. especially your back.

the scapulae should never rise towards the neck