Here is a workout done by Seb Coe.
[Better Training for Distance Runners, p. 273]
"Half-Squats: Ranging from two sets of 5x 200 reps to two sets of 500 each; recovery equal to the duration of the set."
To put this workout in context, Peter Coe was writing about how a strength training workout can be done without nearby facilities and/or equipment.
I really like doing half squats [with no weights]. But physiologically speaking, what does this accomplish? Surely, a runner like Seb and a coach like Peter wouldn't waste time on exercises with little benefit.