Elitetrack: Sport Training & Conditioning

what are the most beneficial stretches for the 110m hurdles?

Do you mean static stretches or dynamic stretches?

both. dynamic stretches for warming up, static stretches at the end of the workout.

Unless you have serious flexibility limitations, static stretching is highly overused and over-rated for hurdlers. While I don't do any hurdle specific stretches just for my hurdlers I'd guess that things like leg swings, split scissors, hurdle rollbacks, and hurdle seat exchanges would be the most specific to hurdle performance.

What are split scissors, hurdle rollbacks, and hurdle seat exchanges?

Split scissors- Laying in plough position, split legs fore-aft and to the side.

Hurdle rollbacks- Roll from plough position to modified hurdle position (alternating legs in the plough position).

Hurdle seat exchanges: Sit in hurdle stretch position (not modified version), lay back, roll to stomach, roll back to other side hurdle strength position.