The following excellent article on training comes via the Powerbar website and CTS/Carmichael Training Systems (Lance Armstrong's trainer). All of these concepts are of particular importance to ski racers.
Using Plyometrics to Gain Balance, Speed, and Power
by Renee Eastman, M.S., CTS Pro Coach
Plyometrics is a method of power training that involves jumping and hopping to utilize your own body weight to develop explosive power. Adding plyometrics to your current training program is easy, as it requires minimal equipment and can be done almost anywhere. Plyometrics is not necessarily a new method of training; coaches and athletes have been using these drills for years.
Plyometric exercises include drills like jumping in place, leaping, bounding, and even running and skipping. Plyometrics, or jump training, takes advantage of the stretch reflex in your muscles. You could equate it to stretching a rubber band, then letting it go. The more you stretch the rubber band, the more rapidly it returns and the further it travels. To illustrate how this works, consider the example of jumping from a flat-footed stance. If you try to leap in the air without first crouching down, you cannot get very high. If you instead squat down first, then leap in the air, you can get much higher. By squatting down first you actually put the muscles in your thighs into a stretched condition before you contract them. As a result, you can generate more force from them, which results in a higher leap. If you take this one step further and squat down quickly and immediately jump up, you can get even higher. This is because the faster you stretch the muscle, the quicker it snaps back, generating more power and allowing you to gain more height.
Adding plyometric exercises to your training program can improve your speed and power, as well as help you gain more neuromuscular coordination and balance. For most sports, speed and power are more important than pure strength. Strength is how much force you can generate. Power, on the other hand, is how quickly you can generate that force. Most sports do not require a person to generate maximal force (being able to lift 500 lbs), but instead require a sub-maximal force (being able to move your body (weight) through space very fast) to be generated very quickly. Plyometrics can be the finishing touch to your resistance-training program as you move towards the more specific training for your sport.
Plyometric exercises are very demanding because they involve dynamic, high-force movements through a wide range of motion. This type of training should only be included after you establish a significant base of strength and flexibility, which makes it a great addition to winter training for summer-sport athletes. Generally, an athlete would want to add these kinds of drills after a base conditioning program which not only includes aerobic training and stretching, but also several phases of resistance training. Because of the forces applied to the ligaments and tendons, these types of exercises are generally not advised for athletes with knee or back problems. And for all athletes, they are best performed on a more forgiving surface. Artificial running tracks are good for shock-absorption as well is grass, dirt, and even artificial turf playing fields. However, concrete and asphalt surfaces should be avoided, as they are too harsh for landing.
In designing a plyometrics program you should evaluate what kinds of specific movements your sport requires. Most sports involve action in various planes of movement. Sports like volleyball and basketball call for a lot of vertical (up and down) movement; while sports like running and sprinting are primarily horizontal (forward) action. Other sports like football and soccer require both vertical and horizontal movements but also quite a bit of lateral (side-to-side) movement. Don’t restrict your plyometric training to only the plane you use in your sport, however. Cyclists and runners, for instance, benefit from some lateral exercises because these are muscles and movements not typically challenged during more sport-specific workouts.
Here are a few different types of plyometric exercises.
Jumps in Place – This is a vertical jump in which the athlete takes off and lands in the same place. Primarily, the athlete leaps in the air, returns and quickly rebounds to jump again. These include squat jumps, lunge jumps and tuck jumps. These exercises are low to moderate in intensity.
Hops – A hop is a forward or lateral movement in which the athlete takes off and lands on one or two feet, but unlike a jump in place, the athlete is moving directionally. Hopping exercises can include bunny hops, two-footed hops up steps, and hopping over cones or small hurdles (either side-to-side or forward and back). Most of these exercises are moderate in intensity.
Bounding – Bounding is often done as exaggerated running type strides. They maximize time spent in the air while minimizing the time that the foot stays in contact with the ground. Examples include skipping, bounding up stairs and long running strides. These exercises are moderate to high intensity.
Medicine Ball Throws – These drills work primarily the core and upper body but also include all the stabilization muscles around the trunk. Tossing a medicine ball to a partner in front of you, or to the side, and even overhead can help develop the muscles around the trunk in a way more specific to most sports than merely doing crunches. These drills can be moderate to high in intensity.
Box Drills and Depth Jumps – These are very demanding drills because they increase the force generated by the athlete by adding an increased gravitational challenge. In depth jumps an athlete steps off a box, lands, and rebounds as high as possible. In box drills the athlete can go up and down from one box or boxes of different heights. Intensity is determined by the height of the box and the number of jumps. These exercises are high intensity, and because of the higher risk, should only be part of a supervised training program.
When planning each day’s plyometric training, you need to be careful with volume and intensity. Intensity of each workout is not just determined by the intensity of each drill, but also by how many jumps or foot contacts are performed in each workout. It would be best to start with 2-3 sets of 10 repetitions of a few low to moderate intensity exercises. Once you have mastered the easier drills, progress to harder exercises. Because these are very hard workouts, you will need to warm up with 15-20 minutes of aerobic activity and some dynamic stretching before you start your workout. Rest between sets is also important, as most drills require 2-3 minutes recovery between exercises. Allowing at least 48 hours for full recovery between workouts is also necessary to derive the best benefits from this type of training.
Adding plyometrics to your current training program can help you gain more specific speed and power for your sport. However, with this and any new training program you should consult a qualified trainer to make sure you have proper form to prevent injury and to get the best benefits from doing these types of exercises.
- Baechle, Thomas. Essentials of Strength and Conditioning. Human Kinetics, Champaign, IL. 1994.
- Chu, Donald. Jumping in to Plyometrics. Leisure Press, Champaign, IL. 1992.