The Overrated Rep
You probably think the number of reps per set is the most important element in your program design. People will ask, "How many reps per set do you do?" more frequently than any other question.
My answer? Something like, "Do anywhere from 1 to 30."
In reality, people place too much importance on the number of reps. I'm not saying reps ranges aren't relevant. They are, but the number itself doesn't mean much. Let's take a scenario using a set of 5 reps:
- Lifter A lowers the weight in 2 seconds and lifts it in 1 second.
- Lifter B lowers the weight in 5 seconds and lifts it in 2 seconds.
Do you think both lifters will get the same results? For one thing, lifter A will be able to use around 20-25% more weight than lifter B. But lifter B puts his muscles under tension for a lot longer.
In the first case let's say the lifter does 5 reps in 15 seconds with 300 pounds. And in the second case, the lifter does 5 reps in 35 seconds with 240 pounds.
It should be pretty obvious that both sets will have different physiological and neurological effects. The first approach should give you a bit more strength gains while the second one will give you a little bit more size gains.
And if you were to do 5 reps with even less weight, like 200 pounds, but lift as fast as you can, then that whole set might last 7 seconds or so. This would give you less size and strength gains than the other two, but might increase strength-speed (power) to a greater extent.
This is fairly superficial, but it illustrates how the number of reps isn't the be-all end-all of program design. In the examples above, doing 5 reps of the same exercise could lead to three different outcomes!
Where TUT Comes In
A lot of top coaches talk about time under tension or time under load (TUT or TUL). This has a lot of merit when trying to evaluate the effect of a set.
A longer TUT (if enough resistance is used) will lead to greater muscle fiber fatigue, more lactate production, and growth factor release. All of these contribute to stimulating muscle growth.
Maximizing lactate will stimulate hypertrophy by increasing follistatin, which inhibits myostatin, increasing growth potential. This will stimulate the release of IGF-1, the most anabolic hormone.
And by causing a more thorough muscle fiber fatigue, you'll stimulate more growth. As Professor Zatsiosrky wrote in Science and Practice of Strength Training, "A muscle fiber that was recruited, but not fatigued, was not trained."
If the set is too long, you might be forced to use a very small force production and thus produce less lactate. That's why the optimal lactic zone when training is between 40-70 seconds. Every time you lift a non-trivial amount of weight, while accumulating a certain amount of fatigue, you'll gain both strength and size (to various extents).
Most people understand that when you produce more force in a set, you'll trigger more strength gains (due to neurological adaptations). But if the force is too high, it might come at the expense of muscle growth due to insufficient time under load.
On the other end of the spectrum, a very long time under load to muscle failure might be successful at stimulating muscle growth, but if the force produced was super low, then strength gains will be minimal.
That's why the duration of a set, as well as the weight used, is important when deciding what kind of adaptations you want.
The Effects Of Time Under Tension
There are exceptions, but you can generally think of TUT like this:
- Less than a 10-second set = Highest strength gains relative to muscle growth
- 10-20 second set = High strength gains with moderate muscle growth
- 20-30 second set = Fairly equal ratio of strength and size gains
- 30-40 second set = High muscle growth with moderate strength gains
- 40-70 second set = Highest muscle growth relative to strength gains
- More than a 70 second set = Moderate muscle growth and minimal strength gains
I first got the idea of timed sets from Dave Tate. The premise is simple: set a timer for the duration you want to do (according to the table) and stay under tension for that whole duration.
You can use any means you want to reach the time limit: slow eccentrics, slow concentrics, isometric holds at various positions, going from slow reps to fast reps, it doesn't matter as long as your muscles are contracting the whole time.
For example, you could start with slow reps, maybe with a 4 second eccentric and 2 seconds concentric, then if you can't do that anymore after 25 seconds, you switch to faster reps because you have 10 more seconds in you. Then maybe you can keep doing partials for 7 seconds, and then hold 8 seconds, for a total of 50 seconds.
Any rep style will work with this method: slow, fast, partials, isometric holds, negatives, etc.
The 40-30-5 Method
A great approach is the 40-30-5 method. It's simple. Use an interval timer – you can find them for free in the app store – and program a work duration (set length) of 40 seconds, a rest time of 30 seconds, and 5 intervals (sets).
Pick a weight around 60-65% of your maximum and do 5 work sets of 40 seconds with 30 seconds of rest.
At first you might be able to get to 40 seconds using only controlled reps. But because of the short rest intervals you'll quickly have to resort to using holds, partials, and fast reps to get to the end.
The result? At the end of 5 sets you'll have the biggest pump in the history of mankind, a huge lactate accumulation, and growth factor release. It's a great way to stimulate growth if you can tolerate the pain.
While this can be done with any exercise, I recommend not using it with the big basics. Chances are that technique breakdown will be too great, increasing the risk of injury.
Use exercises lower on the neurological scale:
- Multi-joint exercises on cable/pulley station
- Multi-joint exercises on machines
- Isolation exercises with free-weights
- Isolation exercises with machines/cable
This method is hard because it hurts, but it's actually really easy to recover from because the growth doesn't come from muscle damage, but from the accumulation of lactate and growth factors. You could very easily train that same muscle again in the week and your performance won't be affected.
This is just a new way to look at your training, to change things around, and trigger more growth.
Bonus: What About Tempo Prescriptions?
To achieve the proper TUT a lot of coaches use tempo prescriptions. A tempo prescription consists of four digits, like 4010. Each digit represents one phase of the rep:
- First digit = Eccentric (lowering) duration in seconds
- Second digit = Transition time between the eccentric and concentric phase, often the stretch position or bottom of the rep
- Third digit = Concentric (lifting) duration in seconds
- Fourth digit = Transition time before the next rep OR hold in peak contraction
Using this approach it's fairly easy to program according to the optimal TUT for each goal. Just do the math for your goal.
For instance, 10 reps using a 4010 tempo will last 50 seconds and put you in the highest muscle growth relative to strength gains category.
Problems With Tempo Prescription
It does have some issues. First, focusing on counting might not be optimal when either lifting a big weight or trying to get the best mind-muscle connection. Then there's the issue of people who count too fast, or speed up the count at the end of the set.
And finally what to do if you can't do any more reps with the prescribed tempo (let's say 4020) but you could get 2-3 more by going faster. Do you do it or not?
I still think tempo prescription is a good tool, but one that needs to be used more as a way to understand what kind of rep style we want, rather than an exact time prescription to follow.