Lead Hook->Low Rear Round Kick

Lead Hook to Rear Low Round Kick

A couple of points regarding this solid combination:
1) High line to low line - attacking high causes your opponent to focus on protecting their head and distracts their attention away from their lower body.
2) Shifting opponents weight - the idea is to hit hard enough with the hook (whether it lands or he blocks) to shift the opponents weight onto his lead leg. This in turn makes it more difficult for the opponent to defend against the on coming round kick.

As leading with a hook is riskier, it may be a good idea to precede the combo with a feint. Another option is to use it as part of a larger combination such as Jab->Cross->Hook->Low Rear Leg Round Kick.

Dane Sky