Jumping, skipping, running, etc are all plyometric activities, I totally agree with that. I read more in the question then was asked. I read what are good plyometric exercises that would best improve a basketball players plyometric abilities. As someone who has been in the field over 28 years and been involved in some very high level training(USA Track and Field Level 3 Endurance Coach, Level 2 Sprints/Hurdles(with several Level 3 classes), Level 1 School Instructor, as well as attended many USATF High Performance Podium Projects/Summits) I look at everything as a problem that must be solved with maximal results without wasting a second. In that case you must view this from a neuromuscular viewpoint with a emphasis on the neuro aspect. While a vertical jump can be an excellent exercise. If you do just one it is not very effective but doing 10 may be as bad if the athlete begins to increase ground time after 3 jumps. Then setsf 3 jumps with long recovery would be best. Many years ago Bill Bowerman(Nike,Pre, University of Oregon) observed a coach doing plyometrics with his athletes. He asked the coach how many sets and reps? The coach responded that he had no idea, he just watchs and that how he knows when to stop them. That is the essence of coaching/training observe and adjust.