i tried using squats to stimulate myself for jumping but it didn't seem to have an effect and took a lot of time. starting with a few max effort SVJs and then progressively increasing effort on jumps did the trick better than anything. that's for jumps.
for squats i wouldn't even do a walk-out like coolcolj suggested, although it's not a bad idea. i'd just warm up normally until i got close-ish to my goal single, and then do a few progressively heavier singles until i got to the target. so like: bar x 10, 60 x 5, 100 x 3, 120 x 2, 140 x 1, 150 x 1, goal weight: 160 x 1. lots of visualization along the way, while resting, and if it was a true max then i'd hype myself up before the goal weight by slapping my legs and cursing a lot and kind of quietly yelling at myself, if that makes sense.
for sprints, dunno. i was never very good at them.