Building muscles without testosterone

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If you’ve got no testosterone in your body you can’t build up muscles, say the textbooks. Not so, say sports scientists at the University of Maryland in the United States. They discovered that men with prostate cancer who are taking drugs that block the effects of testosterone can still build up muscle mass and strength by doing strength training.

Study
Nearly all men, if they live long enough, develop prostate cancer. Doctors usually start by treating prostate cancer with medicines that prevent testosterone or other androgens from interacting with the androgen receptor. They often combine the anti-androgens with other drugs that block the brain’s secretion of regulatory hormones such as LH and FSH. Without those hormones the testes don’t produce testosterone.

Anti-androgen therapy inhibits the growth of many prostate cancer tumours, but side effects include muscle mass decrease, loss of strength, increased bodyweight and increasing difficulty in performing everyday activities. The researchers wanted to see whether strength training could help change this.

The researchers performed experiments with 17 men all of whom had prostate cancer, were receiving anti-androgen therapy and, with an average fat percentage of 31.4%, were overweight. Their average age was 67.

For a period of 12 weeks the researchers got the men to train three times a week using resistance machines to exercise their main muscle groups. They did unilateral knee extensions, chest press, seated rows, seated hamstring curls, abdominal crunches and leg presses.

After warming up, the men did 4-5 reps using a weight with which they could just manage 5 reps. After that the weight was reduced and without resting they did another 1-2 reps to failure. After that the weight was reduced again and they did another 1-2 reps to failure, and so on and so on. For each exercise the men did a total of 15 reps.

Results
Despite the fact that the men had virtually no testosterone in their bodies, they still managed to build up over 1.5 kg muscle mass. Their fat percentage went down from 31.4 percent to 30.7 percent.

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Their maximal strength increased for knee extensions, chest press and leg press.

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At the end of 12 weeks of doing strength training, the men were finding everyday activities easier. They could get up and sit down again on a chair more times in a short time span [Chair Stands], they could climb stairs faster and took less time to cover a distance of 400 metres.

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Strength training improved their quality of life. The men’s score for the Brief Fatigue Inventory went down – showing that they had more energy. In addition, the men considered that they were functioning better socially, emotionally and physically.

Conclusion
“Contrary to the commonly accepted role of testosterone in strength training-induced muscle hypertrophy and within the limitations of this study, we present preliminary evidence that near optimal muscle adaptations can occur in older hypogonadal men”, the researchers wrote. “The observed gains in muscle mass and strength are associated with improved functional independence and quality of life in these men.”

“A better understanding […] the mechanisms responsible for the increases in muscle hypertrophy, strength, and physical function in the absence of testosterone could help prevent the mobility limitations, weakness, fatigue, and poor quality of life common in men with prostate cancer receiving androgen deprivation therapy.”

Strength training induces muscle hypertrophy and functional gains in black prostate cancer patients despite androgen deprivation therapy.

Abstract

BACKGROUND:
Androgen deprivation therapy (ADT) for prostate cancer (PCa) is associated with weakness, fatigue, sarcopenia, and reduced quality of life (QoL). Black men have a higher incidence and mortality from PCa than Caucasians. We hypothesized that despite ADT, strength training (ST) would increase muscle power and size, thereby improving body composition, physical function, fatigue levels, and QoL in older black men with PCa.

METHODS:
Muscle mass, power, strength, endurance, physical function, fatigue perception, and QoL were measured in 17 black men with PCa on ADT before and after 12 weeks of ST. Within-group differences were determined using t tests and regression models.

RESULTS:
ST significantly increased total body muscle mass (2.7%), thigh muscle volume (6.4%), power (17%), and strength (28%). There were significant increases in functional performance (20%), muscle endurance (110%), and QoL scores (7%) and decreases in fatigue perception (38%). Improved muscle function was associated with higher functional performance (R (2) = 0.54) and lower fatigue perception (R (2) = 0.37), and both were associated with improved QoL (R (2) = 0.45), whereas fatigue perception tended to be associated with muscle endurance (R (2) = 0.37).

CONCLUSIONS:
ST elicits muscle hypertrophy even in the absence of testosterone and is effective in counteracting the adverse functional consequences of ADT in older black men with PCa. These improvements are associated with reduced fatigue perception, enhanced physical performance, and improved QoL. Thus, ST may be a safe and well-tolerated therapy to prevent the loss of muscle mass, strength, and power commonly observed during ADT.

PMID: 23089339 PMCID: PMC3593619 DOI: 10.1093/gerona/gls206 [PubMed – indexed for MEDLINE]

Source: http://www.ncbi.nlm.nih.gov/pubmed/23089339 

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