ARE ECCENTRIC OVERLOADING EXERCISES BETTER FOR MUSCLE GROWTH KEY POINTS?
- Eccentric Overload causes muscle damage, but the muscle damage becomes less over time due to the repeated bout effect, but muscle growth still occurs.
- Excess muscle damage can reduce muscle growth.
- When using the same amount of weight, concentric contractions (lifting the weight) are highly fatiguing, whereas eccentric contractions (lowering the weight) are relatively fatigue-resistant.
- There is no superiority of eccentric contractions compared to concentric contractions when high levels of effort or the sets are taken to failure.
- Muscle growth can occur with both heavy and light weight, independent of the load.
Introduction to Eccentric Overloading
Many have suggested that heavy eccentric exercises are more effective for increasing strength and muscle size. Eccentric strength (i.e., lowering the weight) is about 20–40% greater than concentric strength (lifting the weight), so naturally, this results in a greater amount of tension overload for the eccentric portion.
Eccentric Overloading Studies
In studies that compare eccentric exercise to concentric exercise, there is greater muscle growth from eccentric exercise (10%) than concentric exercise (6.8%) due to a greater tension placed on the muscle through an eccentric contraction. Remember, you can handle a greater weight by lowering the weight than lifting. There is also evidence of greater type II muscle fiber growth during eccentric overloading exercise. One of the most impressive studies comparing traditional exercise to eccentric overload was a study performed on hockey players, which found that eccentric overload resulted in an 8.9% increase in quad muscle growth. In contrast, the traditional resistance exercise group gained 2.1%.
Eccentric Overloading Machine
Most gyms don’t have accentuated eccentric overload machines, so lifters often create their own methods of eccentric overload. The most common method is lifting with two arms and lowering with one arm (i.e., pulling down with a v bar handle with both hands and slowly lowering the weight with one arm). The same concept can be used with the legs, where you lift the weight with both legs and lower with one leg. Eccentric overload has been suggested to be a superior way of gaining muscle because of the greater tension overload; more muscle growth can occur.
ARE ECCENTRIC EXERCISES SUPERIOR FOR MUSCLE GROWTH?
Some, but not all studies, have found that eccentric overload will increase muscle growth. Some studies have found that muscle growth is similar despite using an eccentric overload. One study found that the eccentric overload group had greater strength gains than traditional resistance exercise; however, muscle growth increased the same in both groups, despite the concentric/eccentric overload group using a 40% greater workload on the eccentric component. The concentric training volume was similar for both groups, but the total training volume was greater for the eccentric overload group because they used a heavier eccentric contraction. It was also stated that once they reached muscular failure in the traditional training group, the load was reduced the next set.
Training to Failure
So based on this, the traditional training group was training with failure during some sets and used a high level of effort. So how is it that you can overload eccentric muscle contractions and not produce more muscle growth? Muscle hypertrophy is more about a high level of effort or high exertion levels than the actual weight being used. [4,5] Effort levels determines how much muscle activation is occurring and the level of motor unit recruitment. Studies have found that both heavy and light weight can cause similar levels of muscle growth when trained to failure. If the traditional exercise group is training to failure, then full muscle activation is occurring, which could be why the traditional training group gained a similar amount of muscle despite using a lighter weight for the eccentric component. Similar to the studies showing equal muscle growth with heavier and light weight exercise taken to failure.
CONCENTRIC AND ECCENTRIC STUDIES
Another study had subjects perform one leg using concentric and the other leg using eccentric contractions of the quadriceps muscle for 20 weeks. The eccentric contractions used a 35% higher loading regimen than the concentric training routine. Despite the higher loading of eccentric contractions, the groups’ muscle growth was the same. The last study to be discussed had subjects train one leg with concentric contractions (80% 1-RM, 2 – 3 s per repetition) and the other leg with eccentric contractions (145% 1-RM, 2 – 3 s per repetition) on a leg extension machine. Both groups had similar increases in muscle mass.
ECCENTRIC VS CONCENTRIC CONTRACTIONS PERFORMED WITH THE SAME WEIGHT
What if you equate the concentric and eccentric workloads so they were equal? One study measured arm size and strength changes in response to groups that used a normal concentric contraction with an eccentric overload compared to a traditional resistance exercise program. Because eccentric overload uses a heavier weight, the researchers had the subjects in the traditional exercise group do an added set to create an even total workload. The regular training groups did 4 sets of 75% of a 1 RM with concentric and eccentric contractions.
The eccentric overload group did 3 sets of 75% a concentric 1RM and eccentric contractions with 120% of 1RM. There was no difference in muscle growth even though both groups increased muscle strength at the end of the study. The author suggested that the lack of changes in muscle could have been because of the advanced training status of the subjects, or longer than 9 weeks of training could have resulted in changes in muscle size. A review on accentuated eccentric overloading suggested that changes in muscle size from accentuated eccentric loading may take longer than 12 weeks to occur, as many of the studies so far have been less than 12 weeks.
ECCENTRIC OVERLOADING CAUSE MORE MUSCLE DAMAGE AT FIRST
Another study had subjects use 5 sets of eccentric exercises with 110% of their 1-RM. The researchers measured the biceps circumference with MRI imaging. After the intense eccentric exercise, the subjects experienced soreness and elevated markers of muscle damage. Still, the most shocking finding was that arm volume or size decreased on three separate occasions at weeks 2, 3, and 8 weeks after exercise.
The authors suspected the loss of arm volume was due to intense damage caused by eccentric exercise. Again, this points to extreme muscle damage that can result in impaired muscle gains in the early phases of exercise, with muscle damage exceeding the body’s ability to recuperate and grow. However, the body becomes more resilient to muscle damage due to the repeated bout effect. Also, keep in mind that heavy eccentric exercise that causes muscle damage will reduce the muscle’s ability to store glycogen. Thus, athletes will have impaired recuperation following intense eccentric exercise.
CONCENTRIC AND ECCENTRIC EXERCISES RESULT IN DIFFERENT TYPES OF MUSCLE GROWTH
It’s important to note that concentric and eccentric muscle contractions result in different types of muscle growth, achieved through contraction-specific modalities. The concentric portion or muscle shortening will increase muscle size diameter or cross-sectional area. Eccentric contractions stretch the muscle, which causes an increase in muscle growth by increasing fascicle length.
Studies have found that eccentric-only contractions cause muscle growth at the distal or furthest end of the muscle, whereas concentric contractions cause muscle growth in the middle region. This suggests that you need a combination of concentric and eccentric exercises for maximal muscle growth because each contraction causes different types of muscle growth. Just keep in mind, always think how much damage you occur during exercise will determine when you can retrain that muscle, so if you are planning to add some eccentric overload partner-assisted contractions, plan for increased recovery time.
Summary: All muscle contractions are equally important for muscle growth. Overloading the eccentric component results in more muscle damage and soreness at first. The muscle then protects itself from further damage through the repeated bout effect. After that, muscle damage and soreness are diminished. If you incorporate heavy eccentric exercise into your routine, you will probably need to reduce your workout frequency to accommodate the excess muscle damage and soreness.
Key Points of Eccentric Overloading:
- · Muscle damage becomes less over time due to the repeated bout effect, but muscle growth still occurs.
- · Excess muscle damage can reduce muscle growth.
- · When using the same amount of weight, concentric contractions (lifting the weight) are highly fatiguing, whereas eccentric contractions (lowering the weight) are relatively fatigue-resistant.
- · There is no superiority of eccentric contractions compared to concentric contractions when high levels of effort or the sets are taken to failure.
- · Muscle growth can occur with both heavy and light weight, independent of the load.
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