By Chris Thibaudeau
Okay, before you get the wrong impression, this article is not about training on the "juice". It is an article on how to maximise the effects of your own serum testosterone and how to increase it naturaly.

A Little Reminder
Testosterone is known as the male hormone, It is secreted by the testes and according to the most recent research it is so in a circadian (regular cycling) manner. Still according to these studies even if each individuals have slightly differant cycles it is the general rule that testosterone levels are at their highest in the morning. So training in the morning do have a slight advantage over working out later in the day.
As you probably already know testosterone is the muscle-building hormone. By synthesising proteins it rebuild the muscle fibers damaged by resistance training.
The amount of testosterone in your body is a limitating factor because you can't build more muscle if your testosterone levels are not high enough, that's why athletes who take synthetic testosterone (steroids) experience faster muscle growth, their limitating factor just disapeared.
But without plunging in the hell of performance enhancing drugs there is a way to increase your level of testosterone naturaly.

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Effect of Weight Training on Serum Testosterone
Again, research prove, in a consistant manner, that the level of serum testosterone is higher after a bout of demanding resistance training. That increase being affected by the amount of muscle mass stimulated, the training load and the level of intensity (again intensity reffering to a %age of your 1RM).

Effect of the amount of muscle mass stimulated on serum testosterone
Findings all flood in the same direction as to say that the larger the amount of muscle mass is stimulated simultaneously, the more the testosterone level increase. You might have heard a trillion time that multi-joints exercises were better than isolation exercises to develop muscle mass and strength but without really knowing why.
Well this is one of the reasons: multi-joints exercise stimulate more testosterone production compared to single-joints movements. That's why doing heavy sets of squat will build you all around, because it shut your natural levels of testosterone through the roof!
For that reason the bulk of your program should be constituted of the basic, multi-joints movements, if you want more testosterone that is!
Yet despite that we see countless individuals doing endless hours of biceps curl, leg extension and the likes. Literaly wasting their time when they could be training productively!

Effect of the Training Load (volume) on Serum Testosterone
Most of the literature goes in the same way on this issue. Resistance exercise must be done at a sufficient volume to fully stimulate testosterone production. Too low a volume will not cause testosterone to be released a level near what higher volume do.
But that doesn't mean that you should hammer countless sets of countless exercises. Because if studies shown that an higher volume do cause more testosterone to be released those levels quickly decrease after 45 to 60 minutes. So giving that evidence I have to disgress slitghly from my original plan to include:

Effect of the Rest between Sets on Serum Testosterone
Since an higher volume lead to more testosterone but longer training time lead to less there must be a time factor somewhere that will enable us to conciliate the two. Of course it's the time of rest between your sets.
To cut a long story short, many studies researched that variable, the most significant being by Kraemer et al.
This research consisted of two groups, one performing an hypertrophy workout made of sets of 10 RM with a minute of rest between each sets.
The other one was a strength training consisting of multiple sets of 5 RM with 3 minutes between each sets.
Both group shown significant increase in serum testosterone, the earlier showing a slightly higher increase.
That indicate that hypertrophy workout do increase testosterone level more than strength training. Also shorter rest periods seem to have the same effect.
If 1 minute seem to lead to bigger increase in testosterone level than 3 minutes I wouldn't recommand going below 1 minute in hope to increase the testosterone level even more, because by doing so you would greatly impair your short-term recovery and would have to decrease your load.

Effect of Intensity on Serum Testosterone
As I just said hypertrophy training seem to bring more serum testosterone increase. But one shouldn't forget that the group performing sets of 5 RM with 3 minutes of rest also showed a significant increase. In fact for optimum testosterone increase the intensity should be kept between 5 and 10 RM with a rest time proportionate to these levels of intensity.

Effect of Time Under Tension on Serum Testosterone
If the repetition range is a good way to determine the level of intensity it might not be the best way to determine the optimum time under tension. TUT also play a big role in testosterone stimulation since it directly influence the type of training followed, and since hypertrophy showed an higher increase in serum testosterone the time under tension should be aimed toward that type of training (to maximise testosterone production at least, maximum strength is another thing). The optimum time for hypertrophy has been found to be between 40 and 70 seconds. Thus 10 reps at a tempo of 101 might be in the correct rep range but the time under tension (20 seconds) is not high enough for maximum hypertrophy, in this case it would be geared more toward neural adaptation.

Points to remember
1-You should stick with as many multi-joints exercises as you can.
2-You should use a training load high enough to fully stimulate testosterone production.
3-Keep your reps in the 5-10RM range,
4-Keep your rest between sets in the 3-1 minute(s) range according to your intensity level.
5-For maximum testosterone release keep your time under tension between 40 and 70 seconds.
6-Train early in the morning if you can. Not to worry if you can't since this don't have a huge effect.
7-Increase your post workout protein intake to take advantage of the testosterone spike.

References
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