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Hypertrophy: more time in tens, more gains

Nowadays, there is a growing concern to train in order to improve health, but there is also a concern with the aesthetic aspect. As for the aesthetic part, people want to develop their muscles (hypertrophy).

It is usual to see people in the gym who want to significantly increase their muscle mass but who do not follow the guidelines to achieve this goal.


The National Strenght and Conditioning Association (NSCA) defines a number of repetitions in the range of 8 to 12 repetitions for hypertrophy, with loads between 65 and 80% of a maximal repetition. When we define a goal and consequently a number of repetitions, the latter repetitions are assumed to be quite challenging in order to fatigue and stress the muscle fibers, causing them to increase in size.

Unfortunately our body does not know how to count the number of repetitions but has the ability to feel muscle tension, contraction and stretching.

When we speak of repetitions we are assuming that these repetitions are performed at a certain speed. The total number of repetitions plus the speed of each repetition gives us the time under tension (time in which one or more muscles are active in a given exercise).

For hypertrophy, the NSCA defines an interval of 4 to 7 seconds in duration of each repetition, and the eccentric phase (phase of muscle stretching in favor of gravity) should be the slowest.

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So if we do the math, for a hypertrophy goal, according to the values recommended above for each repetition, the time under tension should be above 32 seconds, and it is usual for this purpose that the time under tension should be around 40 seconds per round for 10 repetitions.

A study from the year 2012, concluded that the performance of a given exercise with a time on 6-second concentric phase tension and 6-second eccentric phase showed significant increases in protein synthesis capacity (essential process for muscle growth).

Although the time of each repetition is higher than the one mentioned above, this study has value since it proves that the time on muscular tension is an important factor in hypertrophy. The reason may be that by doing each repetition slowly and in a controlled manner, we will be stimulating different types of fibers, which also include type 1 fibers that are fibers with higher resistance and that need more time to reach the fatigue and the necessary stress to increase it.


1. Perform exercises between 8-12 repetitions

2. The load chosen should be between 65% and 80% of a maximum repetition

3. Do each repetition at a slow to moderate execution speed (4 to 6 seconds per repetition)

4. Time on muscle tension between 40 and 60 seconds per series

5. At the end of each set, we should not be able to do more than the 12 repetitions

Contact us. Do not worry about planning, let us guide you along the way to achieve your goals. Enjoy and have fun on this journey to success

Francisco Barbosa text