Plyometrics for speed and power.

Plyometrics, though enjoying renewed popularity these days, has been used by track and field athletes in Europe as far back as 1920. The benefits of this type of training, whether you are a sprinter or a marathoner, are numerous in part because of the running-specific nature of many of the exercises. The body is vertical, as in running, and the forces developed are similar. Here is an overview of plyometric principles, as well as exercises you can incorporate into your weekly training.

Plyometric exercises consist of hopping, skipping, bounding, and jumping to assist in developing lower-body strength, speed, and power. These exercises also improve neural response, the essential component of quickness. Plyometrics helps you maximize force while minimizing the time it takes to achieve that force, that is, it aids in explosiveness. By contrast, in weight training the focus is on the magnitude of the force; in plyometrics, the focus is on the speed of muscle contraction. The better trained you are, the less time it takes for your muscles to contract.

To help clarify the role plyometrics can play in your training, consider the three types of muscle contractions. Eccentric contraction, in which your muscles lengthen under loading, usually precedes a maximal effort, as when you cock a baseball bat the second before hitting the ball. Concentric contraction involves a shortening of the muscles under loading and is used to accelerate the body or move an object, as when you suddenly move in the opposite direction to hit the baseball. Isometric contraction occurs when muscles are loaded while stationary (e.g., two hands pushing against each other).

In effective plyometric training, an eccentric contraction is followed immediately by a concentric contraction to produce a powerful force. The rapid stretch during eccentric contraction (cocking the bat) loads the muscles with energy, and the quick switch to concentric contraction (swinging at the ball in the opposite direction) results in a powerful reflex reaction force. The two essential controlling factors for increasing power in plyometrics are: a more rapid initial stretch, which generates more power in the muscle group moving in the opposite direction in the second phase of the action; and a shorter time between eccentric and concentric contractions. There should be no hesitation. In skipping, for example, the rapid prestretch on landing and immediate change of direction generates a powerful force.

The following beginner exercises, then, will help runners of all distances achieve greater strength, ankle mobility, running economy, speed, coordination, and stride push-off, as well as better injury prevention. Sprinters, of course, will improve their explosiveness at the start. It's a good idea to have a solid weight training base before beginning a rigorous plyometric training component. But any runner with a solid mileage base and good lower-body strength can begin plyometrics. For advanced exercises like jumping from boxes and over hurdles, it's best to first be able to squat 1.5 times your body weight. We'll look at more advanced techniques in a future issue. For now, to work up to jumping from a box and springing up, you can try a stretch-and-hold routine: drop from a box and freeze, rather than continuing immediately into a jump up.

Beginning plyometrics, attempt 40 to 60 foot contacts per session (a two-legged landing counts as two contacts), with one to two minutes between sets.

Two-legged ankle hops. Standing with your feet shoulder-width apart and using only your ankles, hop up and down in one spot rapidly, trying for minimal foot contact time with the ground.

Two-legged small hops. Stand tall and move forward with small, quick hops. Move your arms together and as they move forward, hop forward. As your arms move backward, move forward again. Repeat for about 10 meters.

Two-legged big hops. With knees slightly flexed, jump forward as far as possible with a strong arm swing from behind.

Fast feet. Run in one spot on your toes with your feet barely leaving the ground. For a variation, try moving over a distance of 20 to 30 meters with very short steps and then suddenly accelerate into a fast running stride.

Sprinting itself is plyometric, which helps explain why the exercises are perfect for runners--there is a built-in sport specificity to this type of training.

Trampoline. This is a great plyometric activity that achieves high-impact benefits with low-impact forces. It is also an excellent aerobic workout, and very good for balance. Just remember to warm up and start gradually.

Rope skipping. As you become used to the feel of hopping and bounding, introduce a jump rope into your beginner plyometric regimen. This is another great aerobic workout that improves coordination and tones the upper body a bit as well.

(The Complete Guide to Running: How to be a Champion from 9 to 90 by Earl Fee, 2005, Oxford: Meyer & Meyer Sport, UK, pp. 353-359)