Every club has wrestlers at different levels of physical condition.
What is too much for one athlete may be too little for another. Some kids have more drive and desire to reach their potential. The best exercises are plyometrics like squat jumping, knee up jumps, box jumping, leaping, and the medicine ball. 30-60 seconds of work, equal amount of rest. Another tip is to have them jump rope before the session starts, this lets them run a little harder because they are already warm-up.