Often in weight training programs, one will recognize the verbiage of their trainer at some point saying, “Hey Team, time to bring some eccentric focus to these ____(exercise)! Slow it down!” Manipulating exercise tempos is one of the many variables trainers and coaches implement into their program design to elicit strength gains, solid biomechanics, and muscle hypertrophy.
Concentric and eccentric muscle contractions are both forms of isotonic contraction, when muscle changes length. Concentric contractions involve the muscle shortening while generating force (such as taking more time on the way up on a trapbar deadlift or pushing weights up during a chest press); occurs when the force generated by the muscle overcomes the external resistance.
Eccentric contractions involve the muscle lengthening under tension (such as taking more time on the way down on a trapbar deadlift or lowering the weights on a chest press); occurs when the external resistance is greater than the force generated by the muscle, causing it to lengthen while still contracting.
Creating emphasis in both eccentric or concentric tempos throughout various exercises help individuals to build strong foundational biomechanics that lead to more efficient performative movement patterns. We tend to see more focus on eccentric than concentric patterns in training because while both can be effective pathways to building impactful strength, there are a few key differences that support eccentric contraction as slightly more beneficial for maximal gains. Eccentric contractions tend to yield slightly greater benefits when compared to concentric contractions when it comes to:
- Muscle fiber recruitment and damage, which is necessary for muscle hypertrophy and increase in muscle growth and mass. This is, in part, due to the ability for more weight to be lowered in eccentric than lifted in concentric for most people.
- Particularly effective at strengthening tendons and ligaments as they lengthen under load which reduces the risk of injury for the athlete and keeps them moving!
- Tend to be more specific to the velocity and mode of contraction used during training, leading to a slightly higher performative turnover from training to sport/activity.
Pros of concentric contractions include effective muscle fiber recruitment, can increase muscle fiber diameter, and are generally easier to perform especially with bodyweight exercises.
In summary, while both eccentric and concentric contractions are important for a well-rounded training program, eccentric tend to yield slightly higher gains when it comes to muscle growth, tendon/ligament strengthening, injury prevention and performance specificity. However, variety is the spice of life and the ideal approach to training involves a combination of both to result in the maximum range of adaptation, strength and resiliency of the body to handle different movement patterns.
p.s. If you’re wondering about where isometric contractions come into play, I’m going to dedicate an entire article on that topic soon and how we have seen them be effective with clients we get the privilege of working with!
