[Lauren Cowley is currently a senior at the University of Mount Olive and will graduate in May 2017. She is an Exercise Science Major, and a former NCAA DII Soccer Player. She is currently an Athletic Development Intern at Athletic Lab.]

According to the ACSM, “muscle contractions involve shortening and lengthening while the muscle is still producing force. The phase of contraction that occurs when the muscle shortens is concentric, whereas the phase of contraction that occurs as the muscle lengthens is eccentric” (Eccentric Resistance Exercise for Health and Fitness, n.d.). Throughout my education in the field of Exercise Science, I’ve always been interested in the concentric versus eccentric debate. Following a video I viewed recently, I expanded my knowledge of eccentric movement profoundly. It is essential to strengthen both concentric and eccentric phases of muscle contraction in order to sustain sport performance and prevent injury throughout the whole range of motion (Eccentric Strength Development, n.d.). It appears that recent training programs place emphasis on the eccentric phase of muscle contraction.

The benefits of eccentric resistance training appear to be copious, with one major benefit being its effect on muscular strength. It produces augmented strength in the entire range of motion of each joint, greater strength across a range of movement speeds and amplified sport performance and muscular power (Eccentric Resistance Exercise for Health and Fitness, n.d.). An article in the British Journal of Sports Medicine investigated “the effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults” with the aim to determine whether eccentric resistance exercises were superior to concentric exercises in stimulating gains in muscle strength and mass. Their findings, following meta-analyses, were that high intensity eccentric resistance exercise showed more significant increases in total strength and eccentric strength than concentric exercise, in terms of velocity and mode of contraction. Eccentric resistance training was also found to be more effective in the promotion of muscle mass measured as muscle girth at high intensities, as well as in increasing muscle cross-sectional area (Roig et al., 2008).

When investigating eccentric resistance training and muscle hypertrophy, Farthing and Chilibeck (2003) found that eccentric resistance training resulted in the greatest increases in strength compared to concentric training, and is most effective for muscle hypertrophy and strength gain (Farthing & Chilibeck, 2003). Whilst, Moore (2005) found that there were significantly greater rates of myofibrillar fractional and protein synthesis following maximal eccentric resistance training than concentric training (Moore, 2005). In other words, Farthing and Chilibeck found that eccentric training is more effective at increasing muscular strength and muscle size than concentric training, whilst Moore discovered that eccentric training results in increased muscular size and strength at a much faster rate than concentric training.

In order to maximize strength gains, eccentric resistance training is typically applied by performing movement in the eccentric phase for four to six seconds. (Eccentric Resistance Exercise for Health and Fitness, n.d.). Eccentric overload, “when the eccentric force is close to or more than concentric 1RM” (kBox Training Guide, n.d.) is commonly used for training. Eccentric overload can be applied through manual assistance and/or resistance, with a person aiding an athlete in the concentric phase of movement, or pushing down upon the weight in the eccentric phase, thus producing overload. When completing certain bilateral limb movements, an athlete can use both legs on the way up, but just one on the way down. ‘Cheating’ is another method that is frequently used, where an athlete will swing with their body or complete the concentric phase using accessory muscles, and only limited muscle groups for the eccentric phase.

Flywheel training is another popular way in which eccentric overload can be applied. Flywheel training enables athletes to produce a higher eccentric force by decelerating the flywheel in a quicker time than the acceleration phase. The flywheel appears to be common choice for eccentric overload due to its lower risk of injury, lack of ‘cheating’ in the concentric phase, and its lack of assistance required (kBox Training Guide, n.d.).

In terms of application for injury prevention, Pedersen et al (2011) found that hamstring injuries in professional football players decreased by up to 90% as a result of increasing eccentric strength through eccentric resistance training and increasing the eccentric to concentric strength ratio between the hamstrings and quadriceps (Petersen et al, 2011).  Small et al (2009) also determined that when conducted post-training, eccentric resistance training significantly reduces the effect of fatigue on hamstrings. (Small et al, 2009).

Although there are copious benefits of eccentric resistance training, they are also several considerations for its application. An adequate warm up specific to the exercise being done is essential, and muscle soreness is extremely common in the 24-48 hours following exercises due to possible increased lactate levels when compared to concentric exercises. It is also essential that an athlete completes the movements with correct form before increases in weight can take place. Maximal eccentric resistance exercises should also be used mildly, at maximum frequency of once per week (“Eccentric Resistance Exercise for Health and Fitness,” n.d.)

If you’re trying to increase an athlete’s muscular strength, consider prioritizing eccentric resistance training in order to do so. Eccentric resistance training enhances muscular strength significantly. An athlete is stronger eccentrically than concentrically, by as much as 30-50% (Duchateau & Enoka, 2016), so whilst an athlete may be able to put a heavy weight down, they may not be able to get it back up again.  An athlete is also more efficient when using the eccentric phase of movements (Kelly et al, 2015), therefore without sufficient levels of eccentric strength, swift switching from eccentric to concentric work becomes very inefficient.

References:

Duchateau, J., & Enoka, R. M. (2016). Neural control of lengthening contractions.Journal of Experimental Biology, 219(2), 197-204.

Eccentric Resistance Exercise For Health and Fitness. (n.d.). Retrieved from https://www.acsm.org/docs/brochures/eccentric-resistance-exercise.pdf

Eccentric Resistance Training and Muscle Hypertrophy. (n.d.). Retrieved from https://www.omicsonline.org/eccentric-resistance-training-and-muscle-hypertrophy-2161-0673.S1-004.pdf

Eccentric Strength Development [Video file]. (n.d.). Retrieved from https://www.youtube.com/watch?v=e5Q7X-mNUEs&list=PLOOu1kOtLwFlL-XSCwReUrUtPO-n3Xjn-&index=3

Farthing, J. P., & Chilibeck, P. D. (2003). The effects of eccentric and concentric training at different velocities on muscle hypertrophy. European Journal of Applied Physiology, 89(6), 578-586.

kBox Training Guide. (n.d.). Retrieved from http://www.gimnica.pt/filecont/kBox%20training%20guide.pdf

Kelly, S. B., Brown, L. E., Hooker, S. P., Swan, P. D., Buman, M. P., Alvar, B. A., & Black, L. E. (2015). Comparison of Concentric and Eccentric Bench Press Repetitions to Failure. Journal of Strength and Conditioning Research, 29(4), 1027-1032.

Moore, D. R. (2005). Myofibrillar and collagen protein synthesis in human skeletal muscle in young men after maximal shortening and lengthening contractions. AJP: Endocrinology and Metabolism, 288(6), E1153-E1159.

Petersen, J., Thorborg, K., Nielsen, M. B., Budtz-Jorgensen, E., & Holmich, P. (2011). Preventive Effect of Eccentric Training on Acute Hamstring Injuries in Men’s Soccer: A Cluster-Randomized Controlled Trial. The American Journal of Sports Medicine, 39(11), 2296-2303.

Roig, M., O’Brien, K., Kirk, G., Murray, R., McKinnon, P., Shadgan, B., & Reid, W. D. (2008). The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis. British Journal of Sports Medicine, 43(8), 556-568.

Small, K., McNaughton, L., Greig, M., & Lovell, R. (2009). Effect of Timing of Eccentric Hamstring Strengthening Exercises During Soccer Training: Implications for Muscle Fatigability. Journal of Strength and Conditioning Research, 23(4), 1077-1083.