National Study Identifies
Baseline For Lower Body Power

A requirement for success in many sporting activities is explosive power. Power refers to the athlete's ability to apply maximal force in the shortest possible period of time. Lower body power is probably best measured by the vertical jump. During a vertical jump, the muscle about the knees, ankles and hips act rapidly together with maximal force. This produces the greatest possible velocity of the body as it leaves the ground.

In most sports, the muscles of the lower body are important not only for the activities that involve the legs - jumping, running and kicking but also for initiating forceful upper body activities like throwing, pulling and lifting.

Based on a study performed by the National Athletic Testing Program (NATP) examining improvements and trending results of high school students, the vertical jump of athletes vs. non-athletes were examined. Those who participated in an organized sport program were classified as an athlete and those who only participated strictly in physical education were classified as non-athletes. The vertical jump was measured with a Vertec with the subjects using a stationary two foot jump. The scores in Table 1 and 2 are the averages for both the vertical jump and weight for each grade by the two classifications. The vertical jump was recorded in inches and the weight in pounds. A total of 52,939 subjects were used in the study.

The male athletes improved an average of 5.00% from 9th to 12th grade. Male non-athletes improved on average 4.73% per year. The female athletes improved 1.93% from 9th grade to 12th grade. The female non-athletes improved on average 0.58% per year. The largest improvement for both the male and females athletes occurred between 10th and 11th grades (5.78% and 4.24% respectively). The largest improvement for both the male and female non-athletes occurred between 9th and 10th grades (6.84% and 1.09% respectively). An important fact when examining this information is that male athletes weighed more than the non-athletes for each grade but female athletes weighed less than the non-athletes for each grade.

Similar to previous NATP studies, athletes improve at a faster rate than non-athletes. Although both improve at similar rates from year to year, it is more difficult to improve the vertical jump as it increases. One possible explanation of why the male athletes improve at a faster rate than any other classification could be attributed to the emphasis of a strength and conditioning program. In reviewing this study one should consider that some of the improvement from year to year for all high school students can be attributed to physical and mental maturity.

Traditional weight training to improve strength will only increase the vertical jump in athletes who exhibit a lower initial strength. If an athlete is already strong, training should be concentrated on improving force development and muscle power output. This is best achieved through explosive training with light loads and with the use of plyometrics.

By improving the leg strength through weight training and plyometrics, explosive leg power and jumping ability will be improved. The stronger the legs, the more protection they will provide to the ligaments and enhance the stability and function of the knee. Also, the stronger the legs, the more you will be able to increase the speed and power. It will also take longer for the leg muscles to fatigue thus helping improve overall performance.