Most of the work done in traditional resistance training exercise emphasizes the concentric phase of muscle contractions. This is the shortening of the muscles as they act against a resisting force, such as the upward push of a bench press, the standing portion of squats, or the lifting of your arms when doing bicep curls. Previous studies have indicated that concentric training leads to the largest strength gains overall, but according to a new study, eccentric training may lead to better size gains.
A team of researchers conducted a meta-analysis and systematic review of randomized controlled trials that analyzed the results of concentric and eccentric training on muscle hypertrophy among healthy adults. All the studies evaluated had to include:
- A minimum of six weeks of testing time
- Direct comparison of concentric and eccentric actions
- Measurements of morphologic changes to the muscles
- Healthy, injury-free participants
Fifteen studies met the inclusion criteria, and the researchers analyzed the data from these studies thoroughly. They compared the various morphologic measurements (MRI, ultrasound, computerized tomography, etc.) to see whether eccentric or concentric training proved more effective regarding muscle growth.
According to their data, they found that eccentric training yielded better results than concentric training. The mean muscle growth change across all the studies was 10.0% for eccentric training, but just 6.8% for concentric training. However, the researchers stated that the “results did not reach statistical significance.”
Simply said: eccentric training is just as important for muscle growth as concentric training.
In previous studies, concentric training has been proven the more efficient type of training for specific strength gains. Eccentric training tends to produce eccentric-focused strength, which accounts for the lowering portion of the exercise. However, this new study indicates that more visible changes in size can be brought about by including eccentric training into your workout.
Your workouts should, therefore, be composed of both concentric and eccentric training. If your goal is to build serious strength, you can spend up to 75% of your workout on concentric training, with 25% of eccentric training mixed in. If, however, you plan to see visible muscle growth, the hypertrophic effects of eccentric training mean you can include up to 50% of your resistance training workouts in the form of eccentric exercises. Ultimately, the process is not cookie-cutter. Every individual will go through his or her own process of experimentation and evaluation before arriving at their own preferred conclusion. The important thing is that you keep fine tuning your training to get the best results for you individually.
Reference:
1. Schoenfeld, BJ, Ogborn, DI, Vigotsky, AD, Franchi, MV, and Krieger, JW. ‘Hypertrophic effects of concentric vs. eccentric muscle actions: A systematic review and meta-analysis.” J Strength Cond Res 31(9): 2599–2608, 2017.
