Despite what many people think, lifting weightsespecially with exercises like squats and snatchesis important to improve your jumping ability, but it's only one part of the equation. Explosive hops and jumping drills called plyometrics will help you turn the strength you develop in the weight room into raw vertical power.
Two or three times a week, add plyometric movements to your training program after your dynamic warm-up and before your weight training. Start with basic moves, such as the Drop Squat - 2 Legs or Countermovement Squat Jump.
Perform two sets of up to five repetitions for each move. Rest a minute between sets of the drop squat and two to three minutes between sets of the squat jumps. Be sure to rest at least a day between plyometric training sessions.
-- Nick Winkelman, performance specialist, Athletes' Performance