trench digger,

Results tend to contradict this.

I think it's more about finding the appropriate race and on what date it falls.

A half fit horse - there'd be no point in grinding it down in such a small space of time. To get a horse fit takes patience in it's preparation.

7 days indicates the horse is in peak form (generally) and ready to win.

There are far more last start winners in 7 days than last start unplaced within 7 days.

Some of these 7 days horses have run the fastest sectional times of their career last start.