Build leg strength with deadlifts, squats, lunges, leg presses and calf raises. Improve your explosive strength with box squats and box jumps. Increase jumping ability with reactive squats. Using less than 50 percent of your max weight, lower yourself halfway to a normal squat, then jump up. Jump off a box, then jump back up to perform depth jumps for improved vertical leap. Work your upper body with curls, extensions, kickbacks, rows and presses. For javelin and shotput, practice throwing much heavier and much lighter balls and javelins to train your nervous system to use more effort and to work faster, respectively.