Injury prevention: Warm up, roll out, build up, manage volume and intensity appropriately, cool down, rest, and recover. I have two recovery days per week where I don't train, just play or walk.
Weight training: I lift twice a week. Basic lifts: squat, deadlift, presses, chin-ups, rows, and core exercises. I lift after sprinting or the day after sprinting. I jump and throw 5 days a week before training.
Programming: I'll just provide a general overview of what I do personally and what my athletes do.
One day is dedicated to longer sprints, slightly longer than race distance. Relatively low intensity with 2-3 sets of 3-4 reps. I usually increase the distance of each set. Rest periods are moderate (2-3 minutes). Sometimes we use a 1:1 recovery for conditioning work. 100 runners might top at 200/300, 200 runners at 400/500, and 400 runners might run 800s.
One day focuses on race distance and 85-95% intensity. 3-4 sets, 2-3 reps. If my 200 goal is 25 seconds, I would run 2-3 hundreds at 13.5-15, 2-3 150s at 20-22.5, and then run 2-3 200s at 27-30. Close to full recovery. Good technique day.
One day focuses on building top speed. Short distances, (30m-60m), 90-95% intensity. Full recovery. I work on starts here also, 5m-20m max with short rest (don't need much).
I rest between each of those days. The fourth day, done the day after top speed day, is a recovery run day. 2-3 800s up to 2-3 1600s (rarely, but for some athletes). Very low intensity.
I work in 3-4 week blocks. Building intensity up throughout. Rest weeks are scheduled so I don't need them or based on the competition schedule.
This all varies based on several factors. Personally, while my goals are almost completely speed based, I enjoy weight training so much that I schedule my training with that in mind. My athletes will have different plans than me but they follow the same general ideas.