In men, muscle mass and strength are often described as being associated with increased testosterone levels. Testosterone plays a large role in the muscle hypertrophy and strength gained resulting from resistance exercise. If you don’t think testosterone is essential for muscle growth, take a look at this study. One study documented that without testosterone, you can expect impaired strength gains from a heavy resistance training protocol. In the study, young men performed several weeks of performing a resistance training program while receiving a medication that turn blunts the production of testosterone. The strength-training period of eight weeks included exercises for all major muscles (three to four sets per exercise x six to 10 repetitions) and one-minute rest periods between sets.
The protocol was designed to cause acute increases in testosterone, which has been validated by previous investigations. The subjects who received the testosterone suppression medication had a decrease in testosterone that was 10 percent lower than that of healthy males, whereas testosterone remained constant in the placebo group. So here is where the importance of testosterone becomes apparent for muscle strength and weight loss. The group that received the testosterone-suppressing medication showed no changes in strength after training, whereas the placebo group had increased strength gains. Body fat mass increased in the testosterone suppression group while it decreased by 1.3 pounds in the normal group. The testosterone blunting medication group made a small gain in lean mass, but not as much as the placebo group. So this study demonstrates that maintaining or increasing testosterone levels are essential for strength gains.
Factors Affecting Testosterone Concentrations During Exercise
Resistance exercise has been shown to increase acutely total testosterone concentrations during high-intensity exercise. The magnitude of elevation in testosterone has been shown to be affected by the muscle mass involved (i.e. exercise selection), exercise intensity and volume, nutritional intake. Large muscle mass exercises such as the deadlifts, squats, and jump squats have been shown to produce substantial elevations in testosterone compared with small muscle mass exercises. Although most people would rather perform a bench press than jump under a squat bar, the bench press is not going to increase testosterone production like a squat. For example, researchers investigated the effects of 5 sets of 10 repetitions of bench press versus five sets of 10 repetition jump squats, with 2 minutes rest between sets in 12 resistance trained men. Testosterone was raised higher following the jump squat (15 %) than the bench press (7%). This suggests that exercises which recruit the most substantial amounts of muscle tissue will cause the greatest increases in testosterone.
For example, squats have been shown to increase testosterone levels more than single joint exercises such as leg extensions. If you are looking to put on size and strength, walk right past that leg extension to the squat rack. Testosterone levels did not increase from pre to post exercise for younger and older men to upper and lower body isolation-type (leg extension) resistance training on a Nautilus machine consisting of 3 sets of 10-repetitions. Contrary to these finding, significant increases in testosterone responses of older and younger men in response to high-intensity large muscle mass squat (large muscle mass) protocol.
It’s not the Weight, but the Intensity
Testosterone responses to resistance exercise in men are less with powerlifting type resistance training protocols than those that use bodybuilding type protocols. One study compared testosterone responses to two protocols, which utilized different intensities of squats, front squats, and leg extensions yet workload remained constant.
-One protocol was a moderate intensity, bodybuilding type protocol (70% of a 1-RM) and the other protocol was
-A powerlifting type workout (100% of a 6-RM).
Testosterone responses were higher during and one hour after the 70% protocol compared to the 100% protocol. So now you understand that training intensity should be at least 70% or more to stimulate sufficient rises in testosterone production. Another study compared bodybuilders and powerlifters of the same age, size, and experience to an intense resistance training protocol, which shorten rest periods. The experimental sessions consisted of 3 sets of 10 repetitions of 10 exercises with 10-second rest periods between sets and 30 to 60 second rest periods between exercises. Testosterone increased in both groups, but regardless of previous training experience, both bodybuilders and powerlifters had similar increases in testosterone concentrations.
In 2006, researchers reported that novice men could boost their testosterone levels by 40% with a three days a week routine. Subjects were assigned to a 4-week sub-maximal strength training routine, which was to be conducted on three days of the week (Monday, Wednesday, and Friday). All of the exercises were done in 3 sets of 10 reps, with 3 min recovery in-between the sets, and with a weight that was 70-75% of the trainees one-rep max (1-RM). The resistance training routine itself consisted of 7 basic exercises in the following order: bench press, seated-pulley, knee extension, behind the neck press, leg press, bicep curls, and triceps pull-downs. At the end of the study, there was a 40% increase in resting testosterone in just four weeks of training.
More Exercise or More Fat Loss? Which Enhances Testosterone the Most
Obesity has reached epidemic proportions worldwide. Obesity results in reduced serum testosterone levels, which causes many disorders in men. Lifestyle modifications (increased physical activity and calorie restriction) can increase serum testosterone levels. Epidemiological studies support an adverse correlation between serum testosterone and obesity. It has been reported that obesity suppresses SHBG (i.e. testosterone carrier protein) and, as a result, total testosterone concentrations decrease. One study reported that the serum testosterone levels in obese males were lower than those In age-matched nonobese men. Researchers just reported in the Asian Journal of Sports Medicine that a resistance exercise program increased testosterone levels and boosted the insulin sensitivity hormone adiponectin in conjunction with a loss of body fat.
Researchers investigated which lifestyle modification, increased physical activity or calorie restriction, had a greater effect on increasing serum testosterone levels. They measured serum testosterone levels, the number of steps taken per day, and the total energy intake for overweight and obese men before and after a 12-week lifestyle modification program. All participants were tested before and after a 12-week lifestyle modification program that included aerobic exercise training and dietary modification. The participants were broken down into two groups:
Study 1: Participants were divided into two groups based on the average change in the number of steps taken per day after the lifestyle modification program (average: 3,579 steps/day) into a low physical activity group (1,110–3,579 steps/day) and a high physical activity group (3,586–10,486 steps/day).
Study 2: Participants were divided into two groups based on the median change in total energy intake after the lifestyle modification program (median: –494 kcal/day) into a low-calorie restriction group (LCR; range: –189 to –494 kcal/day) and a high-calorie restriction group (–539 to –2,735 kcal/day).
At the end of the study, serum testosterone levels were significantly increased after the 12-week lifestyle modification program. Also, as shown in Study 1, serum testosterone levels were significantly increased only in the high physical activity group. The changes in serum testosterone levels were also positively correlated with the total number of steps taken per day and independent of age, smoking, medication use, and changes in body mass after the 12-week lifestyle modification.
In contrast, as shown in Study 2, there were no significant changes in serum testosterone levels in the groups that were based on the calorie restriction levels. These results suggest that an increase in physical activity levels have a greater effect on increasing serum testosterone levels in overweight and obese men during this 12- week lifestyle modification program.