Q. How fast (or slow) should I perform the
reps in my sets?
Should you lift fast or… Superslow?
A.
Just so we all understand, “reps” is short for repetitions, or the movement
you make from point A to point B and back again, when doing an exercise. A
“set” is what we call a series of repetitions done with little or no rest between
them. So when doing your “reps” should you lift and lower the weight fast,
slowly, or some combination like lift up fast and lower slowly?
Believe it or not, there are different groups that champion every one of these
styles and everything in between! So it is no wonder that people become
confused on what to do. Nevertheless, while people will always have their
beliefs, good science, study and experimentation have revealed a sound
prescription for most people which I will outline below:
Fast or “Explosive” Reps…Why You Should “Just Say No”
The folks who believe in doing their reps fast or even “explosively” do so on the
basis that the most responsive muscle cells or “fibers” for weight training are
called “fast twitch fibers.” Every individual’s muscles have a combination of
both slow and fast twitch fibers, and it is generally understood that the slow twitch
fibers are thinner, used for fine motor activities, and have good endurance. Fast
twitch fibers are thicker, and can therefore produce more force, but they fatigue
quicker.
The “type 1” fiber is slow twitch and “type 2” are fast twitch.
Notice how much bigger the type 2a and 2b fibers are.
Stereotypically, therefore, an individual with a preponderance of fast twitch fiber
would be more muscular and be better at short term activities like sprinting and
stop-and-go sports (like football, baseball, basketball, etc). An individual with
more slow twitch fiber would be thinner, and better at endurance activities like
long distance running or biking.
A physique with more slow twitch fiber and one with more fast twitch fiber
It has also been understood, that it takes more force to accelerate an object than
it does to move it slowly. Therefore, on the basis of two facts of science:
1. The existence of “fast-twitch” fibers
2. The ability to recruit them with faster movements…
…it has become a foregone conclusion with some that if you are not trying to lift
weights as fast as possible (without compromising good form) you are not
training as effectively as possible.
That conclusion in the vast majority of cases is wrong.
For starters, the terms “fast twitch” and “slow twitch” refer to how fast the muscle
fibers reach maximum tension –NOT the speed of movement the fiber is capable
of producing. So called “slow twitch” fibers can actually move very fast! As a
matter of fact, the difference in twitch speed between the “slow” and “fast” twitch
muscle fibers is less than 1/10th of a second! Science actually measures these
fiber’s characteristics in milliseconds! So the idea that you should lift fast to
better work your “fast twitch” muscle fibers is false from the outset.
What can be worse about fast reps, if your purpose is to thoroughly stimulate
your muscles, is that fast reps actually only generate more tension on the
muscles in the initial thrust of the movement. After that, the level of tension on
the muscles actually falls off greatly because outside forces (kinetic energy or
what some mistakenly call “momentum”) are helping complete the lift. So with
fast reps you are actually only working the muscle hard in the beginning of the
movement, where the muscle is most susceptible to injury! And of course, the
same problem comes in when you seek to decelerate the lift. The ends of the
muscle and the joints take a beating seeking to slow down the excess forces
created by acceleration.
The best way to increase force and engage the fast twitch muscle fibers is
not to accelerate, but to simply use a heavier weight. As long as there is
adequate resistance, like any weight you couldn’t keep lifting for much more than
a minute, you will engage every muscle fiber by the time you reach the final five
reps or so, and sometimes even sooner. The fibers are recruited sequentially by
their size to lift the load, with the thinner “slow twitch fibers” always working first,
and the thicker “fast twitch” fibers being added as the set goes on to keep moving
the load. If the weight is very heavy (approx. 80-85% of what you could lift one
time) you will recruit every muscle fiber you voluntarily can right from the first rep,
no matter how fast or slow you lift it. In fact, the movement will be somewhat
slower just because the weight is so heavy—you can’t move it fast.
So the real truth about “slow and fast twitch” muscle fibers is that socalled “slow twitch” fibers can actually move very fast, and “fast twitch”
fibers can be activated with slow movements, and even no movement (with
isometric exercise), as long as the resistance is adequate.
Why SuperSlow is Just Unnecessary
As a backlash against the improper interpretation of science, and as a means of
reaching a wider audience with the benefits of weight training—a number of
groups have sprung up over the years espousing very slow repetition speeds for
meeting all your fitness needs. These have included the SuperSlow Guild,
SuperSlow Zone, and Slow Burn, among others. Many books have also come
out on the market in recent years, also promoting the benefits of slow repetition
weight lifting for maximum fitness in minimum time.
Slow reps are promoted as the best way in some modern fitness books
If performing reps fast is potentially dangerous because of the higher forces
being placed on the body, and inefficient because of the wildly varying level of
resistance being experienced by the muscles—than moving slower, but with a
still adequate load is definitely better. The question is, how slow?
According to the authors above, and others in the Slow Motion exercise camps, it
should take at least 10 seconds to lift the weight, and another 5-10 seconds to
lower it, for a full 15-20 second rep. The main justification for this super slow rep
speed is safety and the elimination of momentum or any other outside force to
aid the muscle in lifting. The contention is that this will cause the fastest “inroad”
into a muscles capacity—or deep muscle fatigue in the muscles worked—and
this is seen as the primary goal of a training session.
Now you will have to answer for yourself, whether bringing about deep muscle
fatigue or “inroad” is the top purpose of your training. But the fact of the matter
is that while fatigue certainly is important in stimulating the adaptive
response from training, it is not the only, or even the most important
objective of training for most people’s goals.
Deep muscular fatigue is not a prerequisite for effective weight training
The majority of people lift weights for the purpose of increasing strength
and enhancing muscle size or shape. These goals are achieved by using
proper form in the exercises, working hard, and being progressive with the
poundages used. None of these things are dependent on bringing the muscle
to a deep level of fatigue. In fact, if the set is carried on too long it is actually
harder to work the fast twitch muscle fibers with the level of tension required to
get the optimum response. So, while moving super slow is still an option, it
necessitates doing a very minimal number of repetitions (like 3-5) to keep the
total time under tension of the set in the 30-90 second window necessary for best
results.
Furthermore, since a muscle is stronger lowering a weight than lifting it, the
muscles actually experience less effort with a longer lowering time, than a more
conventional one (like 2-4 seconds). They actually get a bit of a respite with the
long lowering time on each repetition. So, on the basis of adequate tension, and
creating more fatigue with that tension—slow lifting really is NOT better than
more typical lifting approaches.
Finally, on the claim that super slow repetitions are safer than more moderate
repetition speeds (like 2 seconds to lift and 2-4 seconds to lower)—a force gauge
study in the Journal of Exercise Physiology Online demonstrated no significant
difference between the SuperSlow 10/10 protocol and more moderate 2/2-4
repetition speeds on peak forces or safety. In fact, professional engineers
have stated that the real key to exercise safety is not speed of movement,
but proper exercise performance and smooth turnarounds at the ends of
the movement. Jerking and heaving are most definitely to be avoided!
Not Too Fast, Not Too Slow, But Just Right
(The Goldilocks Prescription for Rep Speed J)
As suggested above, a more moderate pace of repetitions affords all the benefits
with none of the potential drawbacks—as long as good form is maintained.
Rather than focusing on speed per se, the main thing that you want to
maintain is rep smoothness. You don’t have to count seconds each repetition
but you should focus on control. You should be mastering the weight, not it
mastering you. One way of determining this is what we call “the pause test.”
When doing any of your exercises you should be able to stop at any point in the
movement, hold the weight briefly, and then continue. If you find that the weight
keeps moving after you try to stop it, or it invokes unwanted body sway than you
are using too much weight and are not in control. Now, in a hard set you
probably will not be able to pause and get all the reps you want. However, the
idea is that you could pause as a demonstration of control.
As a general rule, “smooth” reps take about 3 seconds to lower, and a
couple seconds to lift—and sometimes longer as the set nears completion.
It is especially important when approaching the end of a range of movement for
speed to be smoothly reduced to zero. You can pause briefly, without relaxing
the musculature, before smoothly moving in the opposite direction. If you follow
this simple guideline, while using proper technique in your exercise form, you will
have almost zero chance of injuring yourself with your weight training.
Helping you exercise control in your choice of rep speeds,
-Tom Morrison J
Fitness Coordinator
Bradley Wellness Center
Reference Sources:
• Baye, Drew. “Q & A: Repetition Speed, Recruitment and Stimulation” article found online
at: http://baye.com/repetition-speed-confusion/
• Baye, Drew. “SuperSlow Training, Ken Hutchins, and the SuperSlow Zone” article found
at: http://baye.com/superslow-training-ken-hutchins-and-the-superslow-zone/
• Johnston BD. “Moving too rapidly in strength training will unload muscles and limit full
range strength development adaptation: A case study” Journal of Exercise Physiology
online Volume 8 Number 3 June 2005. found online at:
http://www.medxbend.com/articles/documents/rapidity_of_movemen.pdf
• Jones, Arthur. The Lumbar Spine, The Cervical Spine, and the Knee Testing and
Rehabilitation. Pg. 44 found online at:
http://www.arthurjonesexercise.com/TheLumbarSpine/RehabBook.pdf
• McRobert, Stuart. Beyond Brawn. CS Publishing, Connell, WA, 1998. pp. 224-226.
nd
• McRobert, Stuart. The Insider’s Tell-All Handbook on Weight Training Technique 2
Edition. CS Publishing, Connell, WA 2000. pg. 16.