If you've been strength training for a while, you've likely heard of eccentric or "negative" reps. But are you taking full advantage of this powerful muscle-building technique? Recent research suggests that emphasizing the eccentric (lowering) phase of exercises can lead to greater muscle hypertrophy compared to traditional concentric-focused training. Let's dive into the science behind eccentric training and how you can implement it for maximum muscle gains.
The Basics of Eccentric Contractions
Before we get into the benefits, let's quickly review what eccentric contractions are. During a typical resistance exercise, you have three phases:
1. Concentric: The "lifting" phase where the muscle shortens (e.g., curling a dumbbell up)
2. Isometric: Brief pause at the top of the movement
3. Eccentric: The "lowering" phase where the muscle lengthens under tension (e.g., lowering the dumbbell back down)
While most people focus on the concentric lift, research shows that the eccentric phase may be even more important for muscle growth.
The Hypertrophy Advantage of Eccentric Training
Several studies have demonstrated that emphasizing eccentric contractions leads to greater muscle hypertrophy compared to concentric-only or traditional training:
- A study by Farthing and Chilibeck found that eccentric-only training of the elbow flexors resulted in greater muscle hypertrophy than concentric-only training, even when matched for total work [1].
- Research by Franchi et al. showed that 10 weeks of eccentric-only leg press training led to significantly greater increases in quadriceps muscle volume compared to concentric-only training [2].
- A meta-analysis by Schoenfeld et al. concluded that incorporating eccentric overload into resistance training programs appears to produce superior hypertrophic adaptations compared to traditional loading paradigms [3].
But why exactly is eccentric training so effective for building muscle? There are several key mechanisms at play:
1. Greater Muscle Tension
Eccentric contractions allow muscles to generate about 20-60% more force compared to concentric actions [4]. This increased tension is a primary driver of muscle growth.
2. Increased Muscle Damage
The high forces involved in eccentric contractions cause greater micro-damage to muscle fibers. While this leads to temporary soreness, it also triggers a robust repair and growth response [5].
3. Unique Neuromuscular Activation
Eccentric actions involve a distinct pattern of motor unit recruitment compared to concentric contractions. Research by Enoka found that fewer motor units are activated during eccentric contractions, placing greater stress on individual muscle fibers [6].
4. Metabolic Stress
Despite lower energy requirements, eccentric training still produces significant metabolic stress in muscle tissue. This metabolic accumulation appears to play a role in stimulating hypertrophy [7].
Implementing Eccentric Training for Muscle Growth
Now that we understand the benefits, how can you incorporate more eccentric focus into your training? Here are some effective strategies:
1. Slow Eccentrics
Simply slowing down the eccentric portion of each rep to 3-5 seconds can increase time under tension and muscle activation. A study by Pereira et al. found that slow eccentrics led to greater hypertrophy than traditional tempos [8].
2. Supramaximal Eccentrics
Use a weight that's 10-30% heavier than your 1RM for the eccentric portion, then have a partner help you return it to the starting position. This allows you to overload the eccentric phase beyond what you could normally handle.
3. Two-Up/One-Down Method
Perform the concentric portion of an exercise with both limbs, then lower the weight with only one limb. This doubles the eccentric load on the working side.
4. Eccentric-Only Sets
Occasionally perform sets focusing solely on the eccentric portion with very heavy loads. Use a partner or machines to return the weight to the starting position.
5. Accentuated Eccentric Training
Use specialized equipment like weight releasers to overload just the eccentric phase of a movement. Research by Walker et al. showed this method produced superior strength and size gains compared to traditional training [9].
Programming Considerations
While eccentric training is highly effective, it also places greater demands on the body. Keep these tips in mind when incorporating eccentric-focused work:
- Start conservatively: Begin with 1-2 eccentric-focused exercises per workout and gradually increase volume over time.
- Allow for extra recovery: The muscle damage from eccentric training requires additional rest between sessions.
- Cycle intensity: Don't perform maximally intense eccentric work every session. Alternate between heavy and moderate loads.
- Monitor soreness: Excessive muscle soreness can interfere with subsequent training. Adjust volume and frequency as needed.
Conclusion
Eccentric training offers a potent stimulus for muscle growth that shouldn't be overlooked in your hypertrophy program. By strategically emphasizing the eccentric portion of exercises, you can maximize tension, muscle damage, and metabolic stress—key factors in stimulating new muscle growth. Experiment with the techniques outlined above to take your muscle-building efforts to the next level. Just remember to start slowly and listen to your body as you harness the power of eccentric training.
References:
1. 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.
2. Franchi, M. V., Atherton, P. J., Reeves, N. D., Flück, M., Williams, J., Mitchell, W. K., ... & Narici, M. V. (2014). Architectural, functional and molecular responses to concentric and eccentric loading in human skeletal muscle. Acta Physiologica, 210(3), 642-654.
3. Schoenfeld, B. J., Ogborn, D. I., Vigotsky, A. D., Franchi, M. V., & Krieger, J. W. (2017). Hypertrophic effects of concentric vs. eccentric muscle actions: a systematic review and meta-analysis. Journal of strength and conditioning research, 31(9), 2599-2608.
4. Roig, M., O'Brien, K., Kirk, G., Murray, R., McKinnon, P., Shadgan, B., & Reid, W. D. (2009). 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.
5. Hyldahl, R. D., & Hubal, M. J. (2014). Lengthening our perspective: morphological, cellular, and molecular responses to eccentric exercise. Muscle & nerve, 49(2), 155-170.
6. Enoka, R. M. (1996). Eccentric contractions require unique activation strategies by the nervous system. Journal of applied physiology, 81(6), 2339-2346.
7. Schoenfeld, B. J. (2013). Potential mechanisms for a role of metabolic stress in hypertrophic adaptations to resistance training. Sports medicine, 43(3), 179-194.
8. Pereira, P. E. A., Motoyama, Y. L., Esteves, G. J., Quinelato, W. C., Botter, L., Tanaka, K. H., & Azevedo, P. (2016). Resistance training with slow speed of movement is better for hypertrophy and muscle strength gains than fast speed of movement. International journal of applied exercise physiology, 5(2), 37-43.
9. Walker, S., Blazevich, A. J., Haff, G. G., Tufano, J. J., Newton, R. U., & Häkkinen, K. (2016). Greater strength gains after training with accentuated eccentric than traditional isoinertial loads in already strength-trained men. Frontiers in physiology, 7, 149.
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