Bragging rights have always been based on how much weight you can lift. But how well can you lower a weight?
There are three phases to any muscle action, or contraction: concentric, isometric, and eccentric. I often refer to this as "lift, hold, and lower." Lifting heavy weights makes you feel great both physically and psychologically. Yet many don't take into consideration the two other phases of movement: holding and lowering.
A concentric contraction is the muscle shortening, which results in the actual load being lifted. Biomechanically, the force generated by the muscle(s) is greater than the load, therefore the load is moved. During a squat, this is displayed as going from the deep squatting position to a standing position. During a bench press, this is the action of moving the bar away from your body.
Isometric contractions result in a muscle staying at a constant length or tension. In this instance, the force generated by the muscle is equal to that of the load placed upon it; therefore, the weight is held statically. Imagine holding a barbell an inch off your chest for a two-second pause before pressing it up. This phase is commonly known as an isometric hold.
An eccentric contraction refers to the lowering portion of a lift. The muscle groups used to lift the weight are now being slowly lengthened in a controlled manner because they are producing just slightly less force than that which would be required to push the weight. Imagine the muscle resembling a large rubber band being lengthened slowly. Accumulating potential energy, the muscle absorbs force prior to rapidly shortening back to its normal size.
The last phase, the eccentric contraction, is proven to produce as much as 50 percent more force than the concentric phase. In other words, a given individual can control a lowering of approximately 50 percent more weight than they can lift. Therefore, focusing more on the eccentric phase of a particular exercise will improve your strength in all three phases of movement. Overtime, a better lifting economy is established, requiring less work and resulting in lower metabolic stress. What was once a very strenuous movement will begin to come with relative ease. Eccentric-focused training has also been well-studied in the role of preventing muscle strains and other related injuries that could potentially interfere with activity.
How to incorporate more eccentric intent into your training
The most practical application for a healthy individual is to modify your lifting tempo. The eccentric phase should generally last two to four seconds — a longer time frame hasn't demonstrated any further benefit. The isometric phase can often be nearly absent with a rapid change of direction, ranging from one to two seconds, to further create tension and facilitate neuromuscular control. Finally, the concentric aspect should always be performed quickly, but only to the extent that the individual can effectively control.
Revisiting the squat example, try descending slowly over the course of four seconds, pausing for one second at the bottom, then rising quickly to the top. This tempo would be documented as 4-1-1. These numbers can be altered in each block of your training.
Another way to train with eccentric intent? Try an overload strategy. This training technique requires heavier loads as you are performing only the lowering portion of an exercise.
For example, do only the "negative" phase of a pull-up. Step up onto a box or bench, grab the pull-up bar while you're at the top of the movement, then step off. Slowly lower down over the course of two to four seconds. At the bottom of the movement, simply step up onto the box again and let go.
This is an excellent way to overcome a difficult movement or gain more efficiency in certain motor patterns. Be prepared for sore muscles after trying this strategy, as eccentric overload does result in greater levels of muscular disturbance.
Both of these strategies are safe and effective ways to overcome stale training periods and help prevent muscular strains. It's important that these techniques are purposefully periodized into a training program, as excessive overload and poor technique could negatively impact performance. If you have an injury or a history of injuries, a health-care professional well-versed in strength and conditioning should be contacted.