Plyometric workout: don't add reps til you can get through the whole workout, then add in 5s.

Warm up:
deep knee bends - 20-30 stretch hamstrings and calves
step ups on step - do 20 starting R foot and 20 starting L foot
lunges onto step (watch knee angle)
stretch hams, quads, calves 

Plyometrics: (rest for 1 minute between sets)

set 1:
Forward jump-ups onto step - start with 5 (start facing forward and jump with both feet onto step, landing facing forward, then jump backwards off the step)

set 2:
Quarter-rotation jump-up turns onto and off step- start facing sideways on the floor & jump and turn onto the step, landing on both feet facing forward, then jump off landing in the starting position - 5 each direction (don't "wind up" upper body)

set 3:
Straddle jacks onto step (straddle start, no double bouncing) - do 2 sets of 5

set 4 (superset): (rest for 1 minute between supersets)
Slalom jumps - side to side over step - count to 10 (5 ea direction), do 3 sets alternating with:
Walking jump overs - step L on floor, step R onto step. spring off step, land on R foot - repeat going back the other way starting with the other foot

set 5:
Backward 1 foot jumpbacks to landing position - do 10 each foot and then repeat (concentrate on core body position, and keep knee over toe when landing, land on ball of foot and flatten to whole foot on ground)
Press-ups - stand on step with one foot, weight on the ball of the foot. Press up (straighten knee) and bring foot on floor to a landing position free leg. Keep pressing knee aligned over big toe. 10-20/foot. (These develop the inner knee muscles)

Set 6:
Jump drills: (if you notice lower back pain while or after doing these, lower numbers done by half and re-assess, rest as needed - this is technique work, not cardio) 

Air Turns:
2 feet to 2 feet
          half rotation - 10
          full rotation - 10
2 feet to 1 foot
          half rotation - 10
          full rotation - 10
1 foot to 1 foot (loop jump) (advanced)
          half rotation - 10
          full rotation - 10

Specific jumps on floor:
waltz jumps and/or axels on floor - 10
flight position jump-offs from step (advanced - lesson needed) 

Stretch hams, quads and calves again, and stretch lower back