Bigger Gains in Strength with 10 Weeks of Eccentric Overload Training: Back in the early 90’s, there was a book called Bigger Muscles in 42 Days by Dr. Elliot Darden. The book took a revolutionary approach to training by advocating that people needed to spend less time in the gym but more importantly to emphasize eccentric contractions. If you look at most people train in the gym lifting, they pay little attention to the eccentric or lowering phase of the lift. Lowering the weight under control brings gravity into play in another fashion. During positive work or concentric contractions, muscle fibers are shortening. During negative work or eccentric contractions, the same fibers are lengthening. Although lifting and lowering may seem like a very simple process, the physiological differences to muscle adaption are much different. Emphasizing the eccentric contraction is associated with positive changes in strength and lean muscle mass. Eccentric contractions are so important that if you remove the eccentric contraction from the lift, strength gains are reduced. In one study, researchers compared a concentric only strength training program to a concentric and eccentric program for five weeks. Subjects who performed the concentric/eccentric training had nearly twice the strength gains as those who only trained only with a concentric contraction only exercise regimen. Another study found that placing an emphasis on the eccentric overload experienced a 46 percent increase in strength in just one week! Also, eccentric exercise primarily activates the fast twitch muscle fibers are more likely to lead to greater muscle soreness and muscle growth.
Eccentric Overload Training Increases Muscle Damage
If you look at muscles under a microscope after an intense bout of eccentric exercise, it would seem like a bomb exploded in the muscles. The muscle fibers are pulled apart, and the fibers have increased growth factors at the site of injury repairing the muscle fibers. Researchers have long been aware that maximal eccentric contractions result in more muscle damage and more muscle fiber growth, but researchers wanted to compare the differences between maximal concentric contractions and maximal eccentric contractions and how they affected satellite cells. Satellite cells are essential for muscle growth and repair, without the activation of satellite cells, muscle won’t grow. Satellite cells are so important for muscle growth that if you prevent satellite cells from being activated after an intense muscle overload, there is no muscle growth despite being damaged by tension overload. Optimal repair and adaptation of skeletal muscle is facilitated by resident stem cells (satellite cells). To understand how different exercise modes influence satellite cell dynamics, researchers measured satellite cell activity in conjunction with markers of muscle damage and inflammation in human skeletal muscle following a single work- and an intensity-matched bout of eccentric or concentric contractions. Participants completed a single bout of eccentric or concentric of the knee extensors. A muscle biopsy was obtained before and 24 h after exercise. At the end of the study, peak torque decreased following eccentric exercise but not concentric exercise. The researchers found that in the eccentric group, satellite cell content per muscle fiber increased significantly (by 27%), but there was no significant increase in the concentric group. In conclusion, eccentric but not concentric results in functional and histological evidence of muscle damage that is accompanied by increased satellite cell activity 24 hours post-exercise. The research study should be a real wake-up call for those athletes that want to grow, to emphasize eccentric contractions during their weight training by lowering the weight slowly with the heaviest weight possible.
Eccentric Overload Training
10 Weeks of Eccentric Overload Training Increases Strength but not Muscle Mass
Eccentric Overload Training has been a novel method to increase strength and muscle mass. Researchers examined ten weeks of accentuated eccentric loading versus traditional resistance training in strength-trained men. Young, strength-trained men were allocated to:
– Concentric-Eccentric resistance training in the form of accentuated eccentric load (eccentric load = concentric load + 40%). Custom weight-releasers were used to add the additional eccentric load to the leg press exercise or
– Traditional resistance training, while the control group continued their normal unsupervised training program.
Both intervention groups performed three sets of 6-RM (session 1) and three sets of 10-RM (session 2) leg press and knee extension exercises per week. The eccentric overload group performed the same training as traditional but used greater loading during the eccentric phase. Immediately after resistance exercise, the groups received a whey and a small amount of carbohydrates. Muscle mass and strength was assessed before and after the study.
After training, maximum isometric force production and eccentric force increased significantly more in the eccentric overload load group than control, which was accompanied by an increase in voluntary muscle activation. Knee extension repetition-to-failure improved in the accentuated eccentric load group only (28%) compared to the traditional training group (24%). Similar increases in muscle mass occurred in both intervention groups. In summary, eccentric overload training led to greater increases in maximum force production, work capacity, and muscle activation, but not muscle hypertrophy, in strength-trained individuals.
The author of the study commented, “Accentuated eccentric loading (i.e. eccentric overload) seems to provide an additional training stimulus to increase maximum force production, as well as increasing work capacity/reducing fatigue during lifting in previously trained subjects. That the improvements in eccentric overload were greater than traditional training in the second 5-week mesocycle indicates that these changes may take several weeks to manifest in subjects accustomed to resistance training when the addition of supervision/motivation, greater loading intensities and assistance at concentric failure are made.”
Walker S, Blazevich AJ, Haff G, Tufano JJ, Newton RU and Häkkinen K(2016) Greater strength gains after training with accentuated eccentric than traditional isoinertial loading loads in already strength-trained men. Front. Physiol. 7:149.
Raeder C, Wiewelhove T, Westphal-Martinez MP, Fernandez-Fernandez J, De Paula Simola RÁ, Kellmann M, Meyer T, Pfeiffer M, Ferrauti A. Neuromuscular fatigue and physiological responses after five dynamic squat exercise protocols. J Strength Cond Res. 2015 Sep 1.
Hyldahl RD, Olson T, Welling T, Groscost L, Parcell AC. Satellite cell activity is differentially affected by contraction mode in human muscle following a work-matched bout of exercise. Front Physiol. 2014 Dec 11;5:485.
Vijayan, K, Thompson, JL, Norenberg, KM, Fitts, RH, and Riley, DA. Fiber-type susceptibility to eccentric contraction-induced damage of hindlimb-unloaded rat AL muscles. J. Appl. Physiol. 90: 770-776, 2001.
B. Schoenfeld (2012): Does exercise-induced muscle damage play a role in skeletal muscle hypertrophy?
Roig, M, O’Brien, K, Kirk, G, Murray, R, McKinnon, P, Shadgan, B, and Reid, WD. The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis. Br. J. Sports Med. 43: 556-568, 2009.