Eccentric exercises are also referred to as negative training or negative work. They benefit muscles by absorbing the mechanical energy exerted by the heavy workload. That energy is then released with what is called elastic recoil, essentially a spring-like actions that facilitates the next muscle movement.
Eccentric muscle contraction was originally called excentric by Danish researcher Erling Asmussen in 1953 to describe the movement away ("ex-") from the center ("-centric") of a muscle. Other examples of eccentric contraction include:
- • Lowering a weight during a shoulder press
- • The downward motion of squatting
- • The downward motion of a push-up
- • Lowering the body during a crunch
- • Lowering the body during a pull-up
Sports physiologists believe that eccentric training can build muscle size and strength better than standard concentric-eccentric movements. By focusing solely on the downward force exerted on a muscle, you can enlist heavier weights than you might otherwise be able to lift.
As a result, you may see improvements in the weight room faster. Eccentric training can help you get stronger in certain movements.
By working on the negative phase of a pull-up, pushup, squat, or any exercise, you get more proficient in that movement.
There may also be benefits for those trying to lose weight. While an eccentric contraction uses less energy and oxygen than a concentric contraction, the negative movement actually creates more force. This not only enhances muscle growth but also increases the rate of metabolism (the conversion of calories and oxygen into energy), promoting weight loss.
According to research from Wayne State University, a full-body eccentric workout increases the resting metabolism in athletes by 9% and for no less than three hours following the exercise.
Eccentric training often involves a partner who aids in the lifting of weight (the concentric movement) and stabilizes you as you lower the weight on your own (the eccentric movement). Alternately, you can focus on the eccentric movement by lifting a weight or body part quickly (say, within a second) and lowering it slowly (over three to five seconds).
Eccentric exercise is also commonly used for physical therapy and rehabilitation. Because eccentric contractions create more force with less energy, it is less likely to overtax injured joints and muscles. This can be especially valuable for elderly people who haven't the physical capacity for traditional eccentric-concentric exercises.
Anterior cruciate ligament (ACL) injuries are typically treated with eccentric exercise. The downward movement is less likely to compromise the stabilizing ligaments of the knee. Concentric movement, by contrast, places extreme stress on the joint as it is forced to simultaneously lift and stabilize the weight.
Other medical conditions for which eccentric training may be helpful include:1
- • Patellar tendonitis, also known as "jumper's knee"
- • Muscle-tendon injuries
- • Osteopenia diminished bone mineral density
- • Sarcopenia, muscle wasting related to aging
- • Tendinosis and other repetitive stress injuries
Side Effects and Risks
While beneficial, eccentric contractions are not without risks and side effects. The downward force exerted on muscle can protect against injury but will likely increase the risk of delayed onset muscle soreness (DOMS).
This is due to micro-tears that develop as a contracted muscle lengthens, causing soreness and pain 24 to 72 hours after the exercise. Repeated training can help reduce much, if not all, of the post-exercise soreness.
Eccentric contractions may also pose a health hazard if you lift weights larger than your maximum capacity. With something as simple as biceps curl, the lowering of excessively heavy weight can cause wrist sprain, elbow strain, and shoulder injury. To avoid this, you need to determine what your ideal lifting weight is.
Your ideal lifting weight is between 50 and 70 percent of your one-repetition-maximum (1-RM). This is the maximum amount of weight you can lift with proper form. If your 1-RM is 50 pounds, you should lift no more than 25 to 35 pounds.