By Krista Scott-Dixon |
When you see the phrase “eccentric training,” you might think of your peculiar great-aunt Tillie pumping iron, or one of Britain’s famed oddballs such as Lloyd Scott, who in 2002 “ran” the London Marathon wearing an antique deep-sea diving suit weighing 120 pounds (it took him five days). Yet we do eccentric movements every day: when we walk down stairs, lower a child into a booster seat or sit down in a chair. Done strategically, such movements can help build muscle mass, add variety to your workout routine, prevent or help speed recovery from injuries, and put more explosive power in your movements.
But what is an eccentric (generally pronounced “EK-sentric,” but you may hear “EE-sentric” in some regions) movement, exactly? In a nutshell, it’s the lowering of weight.
Imagine, for example, the two parts of a biceps curl. You begin by holding a weight in your hand, with your arm straight by your side. You bend your elbow, flex the biceps and bring the weight up toward your shoulder, working against gravity to move the weight. This is the concentric portion of the rep (sometimes called the “positive” portion), which occurs when you have to exert the most force to move the weight against resistance.
Afterward, you lower it slowly to the starting position. This is the eccentric portion of the rep (sometimes called the “negative” portion), which occurs when you resist the weight’s downward pull. During the eccentric phase, the muscle fibers still activate to resist the weight’s pull, but the muscle lengthens and doesn’t provide enough force to move the weight in the other direction.
Eccentrics also play a part in movements such as jumping. As you prepare for liftoff, you instinctively squat down a bit (an eccentric move that gathers stored elastic energy) before leaping up (a concentric movement). This quick eccentric-concentric combo is known as the stretch-shortening cycle. And you can jump higher when you do that dip than you can when starting from a standing position, so it makes sense to use eccentrics.
Not everyone agrees on a precise definition of what qualifies as eccentric training. According to Brach Poston, MS, and Thorsten Rudroff, PhD, both of the Department of Integrative Physiology at the University of Colorado at Boulder, it can involve three things:
- Making the eccentric component of an exercise more difficult than the concentric (for example, performing the concentric portion with two arms or legs, but performing the slow, eccentric decline with only one)
The Positive Side of Negatives
Including eccentric (negative) movements as part of a well-rounded training program enhances performance. Poston and Rudroff list several reasons to train eccentrically:
- Eccentric movements provide variety in your resistance-training program: You can mix and match eccentric movements to modify familiar exercises and give your muscles a new challenge, or change the intensity of a weight set. See below for three ideas.
How to Be Eccentric
1. Make two (or five) negatives equal a positive. In some scenarios, “negative” reps can prepare you to eventually perform a “positive” rep on your own (that too-heavy bench press or a chin-up, for example). Negatives typically involve a partner helping with the concentric portion of the exercise and then doing the slow, eccentric portion on your own. For example, you may ask your partner to provide assistance in pushing the chest-press bar up, and then you resist the bar on its way down. If you prefer to work alone, you can skip the concentric portion of the exercise altogether during exercises like chin-ups (see description below). With a little practice, you’ll soon be able to do both portions on your own. But be cautious – too much of this type of work, particularly with smaller isolation lifts such as biceps curls or triceps extensions, can irritate joints.
Suggested Exercise: Negative Chin-UpsTo do a negative chin-up, find a low bar, or push a bench underneath the chin-up bar at the gym. Grab the bar, stand or jump so that your head is above it and your feet are off the floor. Hold steady. That’s your start position. Then slowly – as slooowly as possible – lower yourself down. Initially, focus on lowering yourself with an increasing measure of control. Once you can do five slow, controlled negatives, you can probably do a full chin-up.
2. Get airborne with explosive plyometics. Think about the squat-jump combo mentioned earlier. During the concentric jump portion, your knees, hips and ankle extensor muscles work against gravity and exert as much force as possible to push upward. During the pre-jump eccentric squat and during the landing, your lower-body muscles resist the downward pull of gravity to help you land under control. Otherwise, you would collapse under your own weight after each jump. But aside from helping to prevent you from sprawling in a clumsy pile, the eccentric portion also has another function: to maximize the available power of the muscles during the concentric phase that immediately follows (translation: more height in the subsequent jump). Practicing the stretch-shortening cycle with plyometric types of movements can help put power into your game, zing in your punches and height in your verticals.
Suggested Exercise: Clapping PushupsBegin in the same start position as you would for a regular pushup: body straight and rigid, palms on floor. Lower your body under control, then rebound upward as explosively and rapidly as possible. You should push yourself up high enough that you can quickly clap your hands together underneath your chest before your palms (and more important, your face) hit the floor. This exercise helps improve punching, pressing and throwing power.
3. Employ eccentrics to avoid and heal injuries. When included as part of physical therapy, a well-designed eccentric training program can encourage more rapid recovery from injuries. Eccentric training can also be part of an injury-prevention routine: Practicing plyometric exercises such as one-legged jumps, for example, can help reduce the risk of knee injuries by strengthening the connective tissues in the joint.
Suggested Exercise: Heel LoweringThis exercise can be helpful as part of a rehabilitation and strengthening program for Achilles’ tendon injuries (common in sports that involve running). Stand with the balls of your feet on a stair step and let your heels hang off the edge. Use the uninjured leg to push upward so that you are on the toes of both your feet. Then, shift your weight over to your injured leg and slowly lower your heel down as far as you can stretch it.
Risks of Eccentric Training
While eccentric training can be a powerful tool in your fitness toolbox, you should use it with care. For one thing, eccentric training can result in some surprisingly intense cases of delayed onset muscle soreness (DOMS). (Learn about DOMS in “Sore Winner,” in the January/ February 2006 online archive at lifetimefitness.com/ magazine.) Thus, eccentric training should be incorporated gradually into a workout program, and beginners should avoid doing heavy eccentrics.
People with cardiovascular disease and those at high risk of developing it should also be careful. You know that eye-popping, red-faced feeling of half-holding your breath and making that strangled “unngghhh” sound as you strain through a movement? That’s the Valsalva maneuver, and while it can temporarily give you the abs of steel necessary to help you carry a heavy couch up the stairs, it can also sharply increase your blood pressure. The combination of holding your breath and the exertion of weighted eccentric reps can be troublesome for people at high risk.
Although taking little breaths while lowering the weight can decrease this effect, such breathing can also make the movement less stable (compare how sturdy your midsection feels when you hold your breath versus when you breathe out). If you have any concerns about your cardiovascular status, get evaluated by a qualified healthcare professional before you start eccentric training.
Finally, remember to make eccentrics just a part of a complete fitness regimen. During the eccentric portion of the rep, you merely have to resist and slow the weight’s pull, so your muscles can move 120 to 160 percent more weight than they can concentrically. As gratifying as this might be to the ego, a workout plan consisting exclusively of eccentrics would be a little like a diet consisting of a single food. The food itself might be good for you, but there’s no way it can supply all the nutrients your body needs.
By using eccentrics carefully, though, especially in combination with a variety of other strength-building tactics, you may be astonished at how effectively you turn this kind of “negative energy” into positive fitness results.
Want to add some eccentricity to your weightlifting routine? Here are a few tips to help you make the most of your negatives: