Get to know the science behind eccentric training and how it can be a secret superpower for crushing new PRs.
What goes up, must come down—that’s the beauty of gravity. But when it comes to traditional strength training, letting gravity take over and do the work for you on the lowering phase of an exercise might mean you’re leaving gains on the table.
That’s why eccentric training is so valuable. Research shows that this method can add strength and build more muscle. Lifting weights up will definitely get you stronger, but adding resistance and pace to the “negative” portion can also yield big-time benefits. Here’s how it works.
What Is Eccentric Training?
Lifts happen in two parts: The concentric phase occurs when you lift the weight up and muscles shorten. You’ll feel yourself flexing, like during the “up” phase of a biceps curl. The eccentric phase is when you lower the weight down, and the muscles lengthen or are “on stretch.”
Eccentric training loads the muscle with more tension when the muscle is lengthened during the eccentric phase of a movement. “Using an accentuated eccentric [phase] might stimulate muscle building through another pathway that you wouldn’t necessarily get during traditional training,” notes hypertrophy expert and Tonal Advisory Board member, Brad Schoenfeld, PhD.
You can create overload in the eccentric phase by adding more weight during that phase or slowing down the movement to get back to starting position. On a biceps curl machine, this might look like curling up with both arms, and returning the same weight down with only one—increasing the tension only on the eccentric phase.
What Are the Benefits of Eccentric Training?
Research confirms you can get major performance boosts with eccentric training. Several studies show improvements in muscle strength and size (hypertrophy) when you increase demands on the eccentric phase of the muscle contraction. Researchers also saw improvements in hypertrophy at the end of muscles, like at the heads of the quadriceps near the knee, which increases overall muscle mass and thus performance.
Eccentric training also helps you move more efficiently and prevent injury. Your body uses eccentric contractions as a braking mechanism to decelerate and keep you from falling down, whether it’s a sudden change of direction in a basketball game or simply walking down a flight of stairs.
What’s the Science Behind Eccentric Training?
Researchers know that eccentric training improves strength and hypertrophy, but there are different theories about why based on the whole body of literature. Here are some of the most commonly-accepted theories:
- Eccentric contractions create more damage to the muscle in the form of microscopic tears, which is a good thing because it stimulates more muscle growth, explains Schoenfeld.
- Eccentric overload may also specifically target type-II, or “fast-twitch,” muscle fibers, which are larger and more powerful. Fast-twitch muscle fibers are the ones you use for sprinting, jumping, and strength training.
- On a cellular level, your body responds differently to eccentric overload than it does to concentric, sparking muscle-building processes as soon as you start loading that phase.
- Eccentric training can also improve flexibility so muscles are longer at rest. Longer muscles generate more force, translating to increased power, speed, and jump performance. The more force you can produce, the faster and more agile you can move.
How Can You Incorporate Eccentric Training into Your Routine?
If you’re just starting out with eccentric training, you can focus on slowing down the eccentric phase–counting to five as you lower down and coming up on the concentric in one count. You can also try bodyweight exercises like performing a single-leg squat onto a bench and then standing up with both legs. Once you start adding free weights to create eccentric overload, you’d have to get a spotter to assist you on the concentric phase (lifting portion), and there are limitations to how many machines you can perform it on, explains Schoenfeld.
The good news is: “Tonal makes it easy and efficient to include eccentric overload in your workout,” he adds. Eccentric Mode on Tonal allows you to add digital weight on the eccentric phase automatically—meaning you don’t have to do anything but toggle on the mode before your set. The weight will increase on its own during the eccentric phase and decrease during the concentric phase during every rep.
You can also leverage Spotter, which will sense when you’re struggling and kick in to reduce the weight so you can get across the finish line. That means you can safely add weight without the fear of injury, even when you’re lifting alone. Adding these dynamic weight modes will give you the benefit of eccentric overload on any exercise you perform without needing a spotting pal or any extra equipment.