When looking at how many reps one should perform in a set of high intensity strength training, we must first understand that the number of reps is dependent on how the reps are performed.
Let’s go back to our barbell curl example.
The trainee should begin to curl the barbell up smoothly and slowly, without excessive bending or leaning. At the top of the movement, pause in the contracted position and flex the biceps for a second, then lower slowly under control, back to the start of the movement.
So basically, lift under control, pause briefly and contract the muscle, and finally lower slowly under control. Then pause and repeat.
I suggest a controlled 2-3 seconds for the lifting (known as the positive) portion and 3-4 seconds for the lowering (know as the negative) portion of the movement. We want to avoid any herky-jerky swinging of the weights here.
This will ensure we eliminate momentum from the movement and greatly decrease any chance of injury.
It also allows for the greatest stimulus as the targeted muscles do the lifting and lowering, not your joints or outside forces like momentum.
You don’t have to count the seconds…just make sure you’re doing the movement slowly and smoothly. This should give you a total time of about 5-7 seconds per rep.
This also results in a high degree of safety.
Look around at how others are using resistance training at your gym and you’ll see most performing reps that are much faster, and hence dangerous.
This can also wear on your tendons and joints, and we want to wear out our muscles, not the tendons and joints.
The next thing we need to look at when determining how many reps to perform is how our muscle fibers are affected during a set of intense weight training exercise.
Muscle fiber involvement is important because we want to recruit as many muscle fibers as possible during our set.
On a basic level, you have 2 muscle fiber types, slow twitch and fast twitch fibers. These names are related to the fiber’s rate of fatigue. (i.e. slower and faster to fatigue from exercise).
And not all muscles are necessarily comprised of the same fiber mix. Some people may have predominantly fast twitch fibers in their chest, but slow twitch fibers in their biceps.
Just like in our earlier bell curve example for genetic traits, most people have a mix of both fast and slow to fatigue fibers in their muscles, while there are those that are mostly fast twitch on one end of the spectrum and mostly slow twitch on the other end.
Those with a higher percentage of fast twitch fibers will excel in athletic events that involve exerting maximum force such as tackle in football or a sprinter.
Those with a higher percentage of slow twitch fibers will generally excel in just the opposite type of activities, such as a marathon or triathlon.
During a high intensity weight training exercise done to or as close as possible to failure, we want to stimulate as many of the three types of fibers as we can.
In order to do this, you must select a weight that provides sufficient intensity as this will recruit the most fibers of both types as possible.
The reason for this is that muscle recruitment takes place in a ramping up process. For the first few easier reps, more slow-twitch fibers are doing the work, with little fast twitch involvement.
As the exercise gets harder, the fast twitch fibers come into play more, and even more so toward muscular failure.
To generate sufficient intensity without turning the exercise into an endurance movement, select a weight that is approximately 70-8096 of your i rep maximum in a particular exercise.
Most will be able to complete 8-1o reps with this percentage of i rep max. With our average rep time of 5-7 seconds per rep discussed earlier, this tells us is that most people will do well to perform a high intensity weight training exercise to failure for somewhere between 4o and 70 seconds, or 8 to io repetitions.
This brings up another important point.
Your muscles don’t know how many reps you’re doing, they know how long they are under load, or experiencing the resistance.
This is known as time under load (TUL). So what we are looking for is a TUL of around 4o to 70 seconds for most people to experience maximum strength and muscle growth benefits.
But, I’ve found that counting seconds is trickier than counting reps, so as long as we are keeping our reps smooth and slow, in the 5-7 second range, we should be shooting for 8-io reps per set, done to momentary muscular failure.
This is a general recommendation that will work well for most everyone.
You may respond better to a slightly higher or lower rep range depending on your muscle fiber make-up.
Go ahead and experiment with slightly higher or lower reps and see if that boosts your results a bit. The 8-1o range is the place to start, though, and will yield impressive results!
Regardless of the number of reps, remember, what’s most important is that you work each exercise to the point of muscular failure.