Finish Workout with High Reps?

My football coach tells us to do “10-8-6” or “5-3-1” (whatever the days workout was) and then take the weight way down and crank out about 10-20 reps of a low weight until we go to failure and that is the best way to get big and strong fastest.

Is there a lot of truth to that? and is that how you work out?

depends.

depends on the exercise. depends on the muscle. depends on the weight. depends on the form.

for instance with cable rear delts I would never do LESS than 10 reps and often 20+. For Quads high reps can be good but you should never be using anything resembling “light weight”. Heavy and High reps definately equals growth.