A Manchester study finds that muscle from bodybuilders produces less force than muscle from people who do not weight train.
Individual muscle fibres of bodybuilders were found to be extraordinarily large and to be able to generate forces that far exceed those of other people.
However, when researchers tested muscle cells from bodybuilders they discovered that they produced less force per gram than muscle cells from people who did not weight train.
Excessive muscle growth from bodybuilding could cause a reduction in muscle quality thereby causing the discrepancy in cellular force, results published in Experimental Physiology suggest.
Professor Hans Degens, from Manchester Metropolitan University and lead investigator, said: “Most of us are impressed by the enormous muscle bulk of bodybuilders and think that these people must be extremely strong, like the ‘Incredible Hulk’. We found that their muscles and also their individual muscle cells are extraordinarily large, and can generate forces that far exceed those of other people.
“The surprising thing, however, was that a gram of muscle from bodybuilders produced less force than that from non-bodybuilders, and it thus seems that the ‘muscle quality’ is less in bodybuilders.
“It appears that excessive muscle growth may have detrimental effects on the quality of the muscle, and one may well be better off with normal-sized muscles than with metabolically expensive large muscles.
“We had no indication that the proteins generating force – muscle motor proteins – work less in bodybuilders, but it could be that they have fewer motor proteins per gram muscle. It would be interesting to see what aspect in the training of bodybuilders causes this decrease in muscle quality.”
Researchers took small muscle samples from the thigh of 12 male bodybuilders, six power athletes, such as sprinters, and 14 men who were physically active but did not weight train, isolating single muscle cells from the sample.
Researchers analysed the muscle cells’ contractions – resembling someone lifting suitcases of different weights – and measured the speed and force produced. From this, they were able to calculate the muscle quality.
Prof Degens added: “In power athletes, however, the muscle quality was improved. The training method seems to have an impact on muscle quality, which is of great importance for trainers and coaches interested in improving either performance or appearance of athletes.”
The study suggests that high-intensity, low-volume resistance training with aerobic exercise, as performed by power athletes, is beneficial to ‘peak power’ as opposed to bodybuilding.