First you have to understand the purpose of a plyometric exercises and what is to be gain from this kind of training. While these may be good training exercises they are not true plyometric training. The goal of plyometric training is to get the athlete to reduce contact time with the ground. The idea is the force of each movement(with the help of gravity) increases the force of the next movement as well as reduce the contact time with the ground. Once contact time increases the exercise must stop. Exsample if jumping three 24 inch hurdles the athlete’s ground time increases after 2 hurdles, either jump only 2 hurdles or reduce high to 21 inches. I believe you start simple and work up. I think the best is skipping it a great starting point and yet can be a challenge for even professional athletes.