I’ve never seen people do workouts like that… Closest I’ve ever seen was what Jim Ryun did prepping for 4:00 mile, where he’d do 15x400m at race pace with 60-90″ rest – but even that was probably less than 80% and he’s not a high school girl.
I’d say: Rest. and Tech.
If she’s survived those kinds of workouts, she has plenty of fitness. For 300 hurdles, the race is over quick enough, that stride pattern is everything, especially for girls. I’d suggest doing stride pattern work twice leading into the meet. A few drills that did wonders for me and helped me go from 40.4 to 38.4 my senior year w/out improving 400m speed significantly:
1. Starts to first hurdle – 2-4 of them. These should be done at close to 100% effort. On one of them, try to get there in 2 less steps (ie for a girl – 26 steps vs. 28 – that’s just a guess).
2. Tempo work on hurdles 2-4 around the curve:
– space the hurdles 2m close and try to do it in 2 less strides – that should be very difficult, but doable.
– mess up the hurdle spacing – ie – hurdle 2= 2 hurdles in; hurdle 3= 1 hurdle out; hurdle 4=spaced correctly – this will help prepare mentally for the inevitable missing of steps, or too quick of a start, too slow of a start, etc.