One of the most popular training methods to improve speed, power and jumping ability is plyometrics. For high school and college athletes, most coaches use lower and upper body plyometrics. But to give athletes a head start, many coaches are using plyometrics with kids in middle school and grade school. Is this wise?
Before answering that question, let’s first look at the big picture and examine how our physical education system is doing in improving the physical and athletic fitness of our young people. The picture isn’t pretty: The number of injuries that occurred in physical education classes between 1977 and 2007 increased by 150 percent, according to a study published in the September 2009 issue of Pediatrics
. What’s more, 52 percent of those injuries happened to middle school children – in fact, the number of head injuries doubled in children of ages 5-10 years!
One of the primary purposes of physical education is to learn basic movement skills such as running and jumping. From these general skills, the individual can move to more complex and specific skills that occur in sports. The failure of the schools to teach these skills is indicated by the aforementioned study, which reported that 70 percent of the injuries occurred in the major sports such as basketball, football and soccer. For parents who are thinking of giving their son a head start on an NFL career by signing him up for peewee football, a better idea is to help him develop into an athlete first.
Physical education should be approached like the study of mathematics – you must master one skill before proceeding to the next. This means that PE teachers must avoid the temptation to allow students to skip basic skill sets as they move through the curriculum. As with a math student needing extra tutoring to master a skill set, coaches should give these kids the extra attention they need to learn how to properly run, jump, tumble, kick and throw.
Making this problem increasingly difficult to fix is the situation that schools are facing with budget cuts. With less money, administrators often force PE teachers to deal with classes larger than they can adequately supervise; they may resort to reducing the length and number of PE classes and to allowing emergency certifications that enable them to hire coaches who are not as qualified as certified PE teachers but who will work for less. Let me give you an example.
One of my colleagues did volunteer work as a strength coach for a local school in his area that was having financial difficulties. Each weight training class had only one instructor, but the principal said that the minimum number of kids in each class had to be 65 students. Having only one PE teacher for 65 young men and women is absurd. To make a bad situation worse, the weightroom was only about 800 square feet – an accident just waiting to happen! If these are the conditions young people are forced to deal with, parents need to band together to find ways to increase funding for the school to have adequate facilities and supervision.
With that background, let’s take a closer look at the risks versus benefits of having young athletes perform plyometrics.
Coming to Terms with Plyometrics
The person who popularized plyometric training to improve sports performance is the late Yuri Verkhoshansky of Russia. Professor Verkhoshansky, an exercise scientist, was also a track coach who specialized in the jumping events. During the winter when his athletes trained indoors, he was looking for ways to duplicate the stress on the body during the takeoffs for the jump (stress that could reach up to 600 pounds/300 kilos) other than overloading the spine with heavy partial squats. The result was plyometrics, also known as “classical plyometrics” and “shock training.” As proof of the effectiveness of Verkhoshansky’s methods, 12 of his athletes achieved the prestigious level of “Master of Sport.”
Verkhoshansky’s first article on plyometrics was published in 1964. Because of his pioneering work in this field, Verkhoshansky is called “The Father of Plyometrics.” Unfortunately, much of his early work was translated into textbooks that are extremely difficult to understand. However, in the ’90s Verkhoshansky co-authored a much more readable textbook in English with the late Dr. Mel Siff. Their book, Supertraining, discusses his plyometric training methods in great detail – and their sixth edition includes detailed 6- and 12-week plyometric programs that show a practical application of Verkhoshansky’s training methods.
So what is plyometrics? Many coaches describe plyometrics as any activity that involves a rapid stretching of a muscle (eccentric phase) immediately followed by a rapid shortening of that muscle (concentric phase). The delay between the phases needs to be short, no longer than .25 seconds to use the energy stored during the eccentric phase. To achieve this effect, plyometrics requires a mechanical shock stimulation that stimulates the muscles to produce the highest levels of muscle tension as rapidly as possible. The dynamic nature of shock training creates two processes: 1) a reflex increase in muscle tension and 2) the release of elastic energy stored in the muscles and tendons.
One example of a lower body plyometric exercise is a depth jump. Stepping off a low platform and immediately rebounding upward upon landing is considered an example of a shock training exercise for the lower body. The Marine Corps push-up, in which a trainee claps their hands between repetitions, is an example of an upper body shock training exercise. Along with these descriptions, Verkhoshansky would add that in both of these activities, prior to the feet or hands making contact with the floor, the muscles should be as relaxed as possible.
As for very young athletes, my opinion is that they should probably avoid the types of plyometric exercises that Verkhoshansky developed – such exercises are simply too stressful on the bones and connective tissues of prepubescent individuals. Also, consider that athletes mature at different rates – in a class of 13-year-olds some may have the physical maturity of an 11-year-old and others may have the physical maturity of a 15-year-old. As such, a qualified coach needs to assess each child individually to determine if they are ready for plyometrics; this assessment should also take into account the child’s level of maturity, as plyometrics are high-stress exercises that require discipline to perform safely and effectively.
In the meantime, however, young athletes can perform what Verkhoshansky would call preparatory plyometrics
. Jumping rope, skipping, hopping, jumping onto boxes, and training-age-appropriate weight training exercises such as squats and power cleans are considered preparatory plyometrics. Therefore, these are the types of activities that PE instructors should be emphasizing in elementary and middle school.
When a young athlete is ready to perform plyometrics, they should be gradually introduced to each training cycle – and during the highest-intensity phases an athlete may only need to perform 20-40 depth jumps, twice a week, for maximum benefit. In the 12-week program that Verkhoshansky provided in Supertraining
, he did not prescribe any jumps until the fourth week, and he waited until the sixth week before prescribing depth jumps. Further, I would have athletes stop performing plyometrics during growth spurts, because they are especially susceptible to stress fractures during this period.
Plyometrics are effective as an individual training tool, but consider that they are even more effective when used in conjunction with a sound weight training program. For example, in 1992 the published a paper on the results of a six-week study on how squats and plyometrics could influence vertical jump performance. The subjects who had performed only the squat increased their vertical jump 1.3 inches (3.3 centimeters). The subjects who did both squats and plyometrics increased their vertical jump 4.2 inches (10.7 centimeters)!
There’s no doubt that plyometrics can be a great training method to help develop powerful athletes who can run faster and jump higher, but when it comes to younger athletes, there are special prerequisites. With kids, as always, safety comes first.