Sam Groth's form has always interested me because of its uniqueness and because it produced the fastest serve in tennis history.
Things I've picked up on:
- He hits ball at the apex of the toss
- His tossing arm is bent
- His feet point away from the baseline when he uncoils and goes into his serve
- His body is almost facing the opposite direction of the net, and he leads with his behind
- He coils his body as he tosses