If you're looking for a strength training method that not only maximizes power and size but also corrects form and function, it's time to incorporate eccentric isometrics into your training routine. Eccentric isometrics involve lowering a load slowly (3 or 4 seconds), pausing in the bottom position for an additional 2 to 7 seconds, then powerfully driving the weight up.
Having used this method with my athletes and clients, I've found nothing more effective for improving lifting mechanics, muscle function, mobility, stability, strength, hypertrophy and power. Besides the fact that eccentric exercises have been shown to be highly effective for producing strength and muscle mass, there are additional reasons why eccentric isometrics enhance performance.
Muscles contain numerous sensory receptors known as muscles spindles. These proprioceptive mechanisms respond to stretching and provide internal feedback relating to body positioning and mechanics. The greater the stretch, the more feedback they provide. Because eccentric isometrics emphasize a controlled stretch, they essentially increase sensory feedback, allowing the lifter to fine-tune, modify and perfect his or her technique and body mechanics.
In my research performed at the University of Georgia, we found eccentric isometrics improved measures of both upper- and lower-body stability. This is most likely due to improved motor control and increased motor unit recruitment resulting from the deliberate eccentric motions. Besides improving strength training mechanics, this can have a profound impact on athletic performance, since the athlete will have greater control and awareness of his or her body on the playing field.
We also found eccentric isometrics to be highly effective for improving symmetrical loading (percent of load supported by left vs. right side). In essence, eccentric isometrics help eliminate uneven distribution between the sides of the body. The practical application for any athlete is significant, since eliminating imbalances and improving symmetry are critical for injury prevention.
Finally, eccentric isometrics are incredibly effective at inducing post-activation potentiation (PAP). This is fancy term for an immediate, albeit temporary, increase in power, speed, torque and force production.
Although there are several complex scientific explanations as to why this occurs, much of it comes down to improved neuromuscular efficiency and increased activation of available muscle fibers. The take-home point is that performing eccentric isometrics several minutes prior to an explosive event (jumping, sprinting, throwing or hitting) significantly enhances power, speed, force and movement mechanics. When performed near the beginning of a workout, it allows you to increase the amount of load you can handle on subsequent sets, ultimately producing greater gains in strength and muscle mass.
Tips for Performing Eccentric Isometrics
Rather than letting the weight press you down, focus on using your opposing muscles to pull the load into proper position. For example, during a Chest Press, squeeze your lats and use your upper back to pull the weight down, essentially turning the eccentric movement into a Row.
Don't collapse at the bottom. The goal is optimal and natural range of motion, not excessive range of motion.
Stay tight and keep your spine rigid throughout.
Don't breathe heavily during the actual repetition or you'll lose tightness and collapse. Think about sipping air through a straw, and take deep breaths between reps rather than during.
Go barefoot or minimalist. The feet provide plenty of sensory feedback for movement modification, but bulky shoes or inhibited feet can blunt the response.
Don't use the mirror. Focus on feeling your way through the movement rather than watching your way through. You may even want to try closing your eyes.