Weights
The key to weight training for any sport is to be specific to the sport.
There is no point in just getting stronger, you need to ascertain which muscles
are required for your sport and where they need to be strong (shift large weights - regardless
of the speed of motion) or powerful (whereby the movement must be fast as well).
Sprinting requires powerful muscle movements to propel you body along a
track. However, a muscle strength must be build before the more powerful work
is done.
Good exercises for sprinters include
Bench Press
Cleans
Squats and Squat Jumps
Calf Raises
Arm Curls
At the start of a winter training regime high numbers of reps should be
done to build a base of strength. This would typically be something like
4 x 10 on many exercises. As the winter progresses you should increase the
weight and cut the reps, maybe looking for around 3 x 6 by February (this
is for a single periodised year - when you'll compete in the summer only).
The finishing touches are put to your weights by alternating high speed
low weight reps for power (say 3 x 6 on a very light weight) and very heavy
weight with low reps (3 x 3 on 90% of maximal lift).