One of the most common areas of confusion for bodybuilders and other athletes engaged in resistance training is the question of the appropriate or optimal number of reps and sets for any given workout session or cycle.

This confusion is exacerbated by the common observation that strength and power athletes (weightlifters, throwers, and powerlifters) achieve impressive gains in lean body mass using multiple sets of low (generally 1-3) reps,(1) whereas bodybuilders more commonly employ a smaller number of sets using higher repetition schemes.(2,3) Additionally, numerous books and articles by a host of training experts have advocated a wide assortment of set/rep schemes, all of which have worked well for those who have used them.

All of the above leads to the following questions:

1) Is there an "optimal" set/rep scheme for the acquisition
of lean body mass?

2) Or, is there a better question? In other words, does focusing on
set/rep schemes lead us away from the answers, instead of bringing
us closer to them?

Here are a few possible questions that may bring us closer to the answers
we seek:

1) If you're learning a new scale on the piano, how many times should
you repeat that scale during any given practice session? Do prominent
pianists and/or piano teachers advocate various "optimal" practice
schemes, such as "25 repetitions per session" in musical
trade publications?

2) If you're practicing the tennis serve, how many times should you
repeat that technique during any given practice session? Do expert
tennis players and/or coaches advocate various "optimal" practice
schemes, such as "50 serves per practice session" in the
tennis magazines and journals?

3) If you're a 100 meter sprinter practicing the start from the blocks,
how many times should you repeat this skill during any given practice
session? Do track coaches advocate various "optimal" practice
schemes, such as "30 starts per training session?"

In the case of the above questions, are we looking for an arbitrary
number of repetitions, or is there an underlying principle or concept
which would lead us to the appropriate number of repetitions or attempts?
The answer to this question, I believe, lies in the relationship between volume and intensity.

We all recognize that intensity and volume are inversely related, but
how often do we apply that knowledge? Let's explore this for a
bit

You're out on the tennis court practicing your serve (if you can't relate
to tennis, please substitute your favorite sporting skill). You perform
your first serve (read: rep). The serve was absolutely horrible — in
fact, you missed the ball, and quickly surveyed your surroundings to
ensure that no one else witnessed the blunder. Hopefully, you mentally
rehearse the serve prior to doing another one, searching for clues as
to what went wrong. Suddenly, you remember a time-honored maxim that
your old high school tennis coach loved to quote: "Keep your eye
on the ball!" So on your second serve, you do just that. Amazingly,
it works — you manage to hit the ball, and you now realize that
your second rep is clearly better than your first.

Despite this revelation, there's no time for self-congratulation: even
though you hit the ball, it flew straight into the trees on the other
side of the court. So now you replay the serve in your mind, and realize
that you'll need to slightly modify the angle of your racquet at the
moment it contacts the ball on the next serve in order to get the ball
into the far side of the court. So on your third serve, you apply this
new concept, and sure enough, the ball goes where you want it to go.

Using the scenario above, can we find a way to quantify the quality
(read: intensity) of each serve in the practice session, and rank them
in order of effectiveness? The answer is "yes." Although the
tennis serve has a significant qualitative component, we can translate
your skill level on each serve into a quantitative measurement by having
10 highly skilled tennis coaches watch and assign a score to each serve
you perform. Then we'll drop the highest and lowest score, and average
the remaining scores.

So, let's say you executed 12 serves, and you receive the following
scores (the higher the number, the better the serve):

Serve #1: 2.0
Serve #2: 3.0
Serve #3: 4.5
Serve #4: 5.0
Serve #5: 5.5
Serve #6: 6.0
Serve #7: 5.0
Serve #8: 4.0
Serve #9: 4.0
Serve #10: 3.5
Serve #11: 3.0
Serve #12: 2.5

Next question: How many repetitions would have been optimal? There's
no exact answer — we're just looking at the principles involved.
And in principle, if we can accept the notion that only perfect
practice makes perfect, then we might suggest that you should have stopped
after the seventh or eighth repetition, because your skill levels began
to decline significantly after that point.

OK, How on Earth Does This Relate to Lifting?!

All of the above scenarios involve motor skill acquisition. And I believe
it's very useful to view resistance training for what it is: a motor
skill!

Not a believer? Have you ever trained a complete resistance training
beginner for an extended period of time? If you have, you'll have noticed
a commonly recognized phenomenon: on his first day or training, Tom can
barely bench press the empty bar for 4 repetitions.

You scratch your head thinking "How is this possible?" After
all, you can bench six times that much weight for 10 reps. But your novice
lifter improves by leaps and bounds, adding 1-2 reps per set on every
single session. Within 6 weeks, Tom can manage 6 reps with 135 pounds.

Quite an improvement, yet, there's no noticeable change in his body.
This is because his rapidly improving strength isn't due to muscle enlargement,
but rather, neural processes — specifically, the
ability of the motor cortex of the brain to recruit greater numbers of
motor units, and particularly, greater numbers of high threshold motor
units (For a more detailed look at the neural processes involved in force
production, please see Table 1).

Table 1:
The Neural Processes Involved in Force Production

1) Motor unit recruitment (intramuscular coordination): All muscle fibers
are one component of what physiologists call "motor units" (MU). An MU
is defined as a motor neuron (or nerve cell) and all the muscle fibers
it innervates or "recruits." There are several essential facts that athletes
should further understand about the functioning of MUs:

• All the fibers of a MU tend to have the same characteristics. When
all the fibers are type II, the motor unit is said to be a high threshold
or "fast" MU. If the fibers are Type I, it's a low threshold or "slow" MU.

• The all or none principle: When an action potential (the command
from the nervous system) is sent from the nerve cell to the muscle
fibers, one of two events will occur. If the action potential is strong
enough, all the fibers of that motor unit will contract maximally.
If the action potential is not strong enough, nothing will happen.
In a nutshell, muscle fibers either contract all the way, or not at
all. When the body needs to apply more force, it simply recruits more
MUs, increases the firing rate of those MUs (see "rate coding" below),
or both. Generally, untrained people have limited ability to recruit
high threshold MUs because their bodies are unfamiliar with high-tension
efforts.

• The size principle: When contracting a muscle to overcome a resistance,
the MUs involved are recruited in order of size, small to large. This
explains why people can use the muscle to pick up something light (a
pencil) or heavy (a dumbbell). As resistance increases, the body recruits
more MUs.

2) Intermuscular Coordination: This is the ability of different muscles
to cooperate during the performance of a motor task. Muscles can function
in several different ways depending on the task at hand.

3) Rate Coding: The nervous system can vary the strength of a muscular
contraction not only by varying the number of MUs recruited, but also
by varying the firing rate of each MU. This is known as rate coding.
The tension that a MU develops in response to a single action potential
from the nervous system is called a "twitch." As the stimulus from the
nervous system becomes stronger and stronger, the twitches per millisecond
become more and more frequent until they begin to overlap, causing greater
amounts of tension to be generated by the muscle fiber. The mechanism
behind rate coding is very similar to the way in which increased vibrational
frequency of a sound increases its pitch.

As an example, a muscle comprising 100 MUs would have 100 graded increments
available to it. In addition, each MU can vary its force output over
about a tenfold range by varying its firing rate (e.g., from ten to fifty
impulses per second). For any set of conditions, the force of contraction
is greatest when all MUs have been recruited and all are firing at the
optimal rate for force production.

The size of a given muscle may in part determine the relative contribution
of rate coding to total muscular force development.(4) In small muscles,
most MUs are recruited at a level of force less than 50% of maximal force
capacity. Forces that require greater tensions are generated primarily
through rate coding. In large proximal muscles (such as the pectorals
and lats), the recruitment of additional MUs appears to be the main mechanism
for increasing force development up to 80% of absolute strength and even
higher. In the force range between 80% and 100% of absolute strength,
force is increased almost exclusively by intensification of the MU firing
rate.

Muscle Fiber Types and Recruitment

By "high threshold", I'm referring to the fact that the recruitment
of fast muscle fiber requires more intramuscular tension than what's
required to recruit slow muscle fiber.

Note: The traditional classification scheme for muscle fiber types
assigns all fibers as either type IIb, type IIa, and type I. However,
I've always felt it was more instructive to simply think of all fibers
as belonging to a continuum.

A useful way to envision this spectrum is to remember the volume indicator
that was commonly used on older models of stereo equipment — it
consisted of a vertical column of small lights, and when you increased
the volume, the lights lit up from bottom to top, depending on how much
you turned the volume control knob.

In the same way, imagine that we arbitrarily assign all muscle fibers
into a vertical column of say, 15 categories, or "lights." When
you curl a 5 pound dumbbell, only the bottom 2 lights turn on; i.e.,
the bottom 2 categories are recruited. But if you curl a 35 pound dumbbell,
the bottom 6 categories are recruited, and so on.

The importance of targeting fast muscle fibers (even if you speculate
that you're a "slow-twitcher") is that a number of studies
show that fast fibers have significantly better capacity to hypertrophy
than slow fibers.(5,6) Other studies strongly suggest that intermediate
muscle fibers can convert "downward," (i.e., taking on characteristics
of slow-twitch muscle fibers) when training involves low to moderate
resistances for prolonged durations, or "upward" (taking on
characteristics of fast twitch muscle fibers) when training involves
high tension efforts.(7)

If your goal is to get bigger, you need to gain access to the heavy
hitters — the high threshold, fast motor units, because you can't
train them until your brain learns to recruit them in the first place.

The Bottom Line:
What Causes Hypertrophy Anyway,
And What's The Best way to Achieve it?

There have been a number of possible mechanisms proposed for the hypertrophy
process. These include the muscle hypoxia hypothesis (a deficiency of
blood, and therefore oxygen to the muscles stimulates protein synthesis),
the blood circulation hypothesis (blood circulation to working muscle
provides the stimulus for growth), and the ATP debt hypothesis (ATP concentrations
decline during training, which supposedly stimulates muscle growth).(8)

However, the theory which seems to hold the most promise suggests that
energy distribution (or lack thereof) creates the stimulus for muscular
hypertrophy. The idea is that during rest, muscular energy is distributed
between mechanical work and protein synthesis (protein synthesis is a
24-hour a day process, however, it is greatly accelerated by heavy training).

So for example, when you're standing in line at the supermarket, a small
amount of energy is used to keep you standing upright, and the rest is
diverted toward protein synthesis. However, during a hard training session,
a large proportion of available energy is expended for the mechanical
work involved in lifting, which leaves relatively little for protein
synthesis. It's proposed that this energy deficit is the trigger for
hypertrophy of the working muscles.(9)

This hypothesis corresponds well to Selye's general adaptation syndrome
(GAS) theory, where, upon being subjected to a stressor, the organism
first experiences an alarm stage (here, the energy deficit), and then
later, a supercompensation stage (hypertrophy).(10)

If the above hypothesis is correct, we can then say that hypertrophy
is a function of how much mechanical work is performed per unit of
time. For example, imagine that today's back and triceps workout
resulted in a volume of 23,250 pounds performed in a 50-minute time
frame. If during the next back and triceps workout you manage to lift
23,320 pounds in 55 minutes or less, you'd have provided the necessary
stimulus for muscle growth. Do sets and reps matter? I think they do,
but not in the way that you might think. Table 2 illustrates two workouts
that both result in the same training volume:

Table 2: Comparison of Volume Versus Intensity-based Approaches
Workout One		Workout Two
A-1:	Chins: 245 (3x10)	A-1:	A-1: Chins: 245 (10x3)
A-2:	Close-grip bench: 225 (3x10)	A-2:	A-2: Close-grip bench: 225 (10x3)
B-1:	Bent Rows: 205 (3x10)	B-1:	Bent Rows: 205 (6x5)
B-2:	French Press: 100 (3x10)	B-2:	French Press: 100 (6x5)
Volume:	23,250 pounds	Volume:	23,250 pounds
Duration:	55 minutes	Duration:	55 minutes

From this information, you might conclude that the way you arrange your
sets and reps will have no bearing on the outcome. After all, the training
duration, volume, and even density are identical in both cases. Even
the intensity is the same, since the same weights are used in both cases.
But wait: is intramuscular tension (the key to accessing, and
therefore, training, fast muscle fibers) simply a matter of how much
weight you use?

If you answer "Yes," let me propose an experiment: I'd like
to place a 25 pound plate gently on top of your foot, and determine your
reaction to the load. Then, I'd like you to drop the same plate from
6 feet in the air on your foot. Sounds Okay? The weight is the same in
both cases, right? So the outcome should be identical! Of course the
outcome will NOT be identical, because the plate which is dropped from
a height picks up acceleration as it falls.

In much the same way, accelerating a weightload results in greater tensions
on the target muscles than moving the same weight slowly. Further, many
sets of low reps facilitate acceleration more efficiently than few sets
of many reps (which is the norm in gyms and weightrooms today).

Consider your last workout, where you did an all-out set of 10 reps
with 225 on the front squat. How much tension (measured as pounds of
pressure on the bar) did you exert on the bar on rep number 10? If you
barely managed 10 reps, and you would have missed the 11th rep, would
you accept that you exerted just slightly more than 225 pounds of force
on the bar — perhaps 226 pounds? If so, would you also accept
that you managed slightly more force on rep number 9, and even more on
rep 8, etc., since fatigue accumulates from rep to rep? Here is a hypothetical
representation of your force output during that set of 10:

Rep One: 244 pounds
Rep Two: 242 pounds
Rep Three: 240 pounds
Rep Four: 238 pounds
Rep Five: 236 pounds
Rep Six: 234 pounds
Rep Seven: 232 pounds
Rep Eight: 230 pounds
Rep Nine: 228 pounds
Rep Ten: 226 pounds

Now bear in mind, the exact numbers may not be completely accurate,
but the trend is. The idea is simply that accumulating fatigue limits
force output from rep to rep. If we add up these numbers and divide by
10, we get 237 pounds — this represent the average force per rep.

Now let's invert the sets and reps and see what we get. Instead of using
225 pounds for 1x10, we'll use the same weight for 2x5. Now, the average
force per rep is 240 pounds, because by keeping fatigue to a minimum,
we can accelerate the bar more effectively. Yet the total volume and
density are unchanged. Given the following two alternatives, which would
you choose?:

First Scenario: 225x10
Load: 225 pounds
Volume 2250 pounds
Average Force per Rep: 237 pounds

Second Scenario: 225 (2x5)
Load: 225 pounds
Volume 2250 pounds
Average Force per Rep: 240 pounds

(Please see Table 3 for a more detailed representation of how to employ
these principles into an actual workout.)

Table 3:
Sample Chest & Back Workout Employing the Principles Discussed

"A" Series: Dips and Chins

1) Using the concepts presented in "Warming-Up
to a Great Workout — a five-stage event!," warm yourself
up by doing several easy sets of both exercises, alternating between
dips and chins.

2) Your working weights should approximate 70% of 1RM for each exercise
(this may necessitate using additional load on the dips via the use
of a weighted belt). Don't get too hung up on 70% — we're just
selecting an intensity to illustrate the principles involved.

3) Determine an appropriate lifting speed and a way to monitor it
from set to set. The speed will depend on the resistance selected and
the repetition scheme. For this example, we'll select 2 seconds OR
LESS per rep. Either have a training partner count your reps, or use
an electronic metronome to monitor your rep speed.

4) Determine a rest interval. Again, this can depend on the resistance
selected and the repetition scheme, but for this example, we'll use
60 seconds OR LESS between sets. Use a stopwatch or a partner to monitor
this parameter as you progress through your workout

5) Okay it's "Go Time!" (From Jerry Seinfeld's unsolicited and aged
personal trainer, played by Lloyd Bridges): Perform your first set
of dips, making sure to stay ahead of the 2 seconds per rep speed (this
will require maximal acceleration, but I'm not suggesting that you
sacrifice control in the process — stay tight and maintain
superb control at all times). Rest one minute or less, and perform
your first set of chins. Rest one minute or less, back to dips.

6) Continue alternating between dips and chins until you either slow
down to the point where a rep takes more than 2 seconds to perform,
and/or where you miss a rep or cannot beat the time limit between sets.
This "failure" should occur somewhere between 6 and 12 sets any more,
and the load is too light; any less, and the load is too heavy.

(REMEMBER, WE'RE SEEKING REP QUALITY, SO WE MIGHT DO MORE SETS
USING FEWER REPS.)

7) Depending on how many sets you managed, the "A" series should have
taken you between 15 and 30 minutes. Now on to "B" series

8) Your next 2 exercises: Incline dumbbell presses and Hammer rows.
Perform 1-2 warm-up sets for each exercise in order to rehearse the
motor pattern and to determine an appropriate training weight for each
exercise. For the "B" series, I'll often select a slightly reduced
load and slightly increased reps per set, for the purposes of local
muscle endurance and growth hormone secretion. For this example, we'll
use 70% of 1RM and sets of 6.

9) Perform the "B: series in the same manner as the first two exercises,
using the same speed parameters.

Progression: Perform this workout 3-6 times (once every 4-7 days),
seeking to increase your training volume by 10% each session. On the
first workout, leave enough in reserve that you can increase volume
by 10% for at least 3 successive workouts (accomplished by adding 1-2
additional sets per session). After 3-6 workouts, create a new exercise
menu and start over.

Additional Modifications: Depending on goals, need for variation,
and so forth, a variety of loads (from 55 to 85%) and repetition schemes
(between 2 and 8 per set) are possible. The key concept is to base
the training load on performance quality rather than an arbitrarily
selected number of reps or sets.
 

I should mention that I'm taking a few liberties here to get my point
across (for example, when you perform 2x5, you'll have slightly reduced
force output on the second set due to fatigue), but I believe the concept
remains valid: breaking up your sets into smaller chunks in order to
reduce fatigue allows higher force output, and accordingly, more stimulus
to high threshold motor units.

I offer this approach not as an exclusive training method (for example,
high rep sets have their place in the development of local muscle endurance
and in the production of growth hormone, which has been postulated to
assist in fat loss), but as a method that's been successful for my own
clients, and indeed, thousands of athletes involved in Olympic weightlifting,
powerlifting, and other power events.

I urge you to explore the concept. After all, the methods which will
bring you the most success in your future training are likely to be the
methods you haven't used yet — is this one of those methods?

Conclusions and Recommendations

1) Base the number of reps per set in such a way that fatigue is minimized
as much as is practical. I say "practical," because taken
to its extreme, this would mean always doing one rep per set. But obviously,
in many instances (such as heavy dumbbell presses for example), if
you try to limit reps to 1 or 2 per set, you'll end up doing more work
setting up for the set than actually performing the set itself.

2) Base the number of sets per exercise on a) how many exercises are
on the menu (the more exercises planned for a workout, the less sets
you'll be able to perform for each exercise — this argues for
multiple daily sessions), and b) the quality of your performance from
set to set. This is best measured by monitoring rep speed, usually
assessed subjectively, or objectively, using a stopwatch or an accelerometer.

3) There are two ways to increase tension on muscles: lift heavy weights
slowly (you'll have no choice in the matter in that particular scenario),
or moderate weights acceleratively.(11) The second option is rarely
used by bodybuilders, but it offers unique advantages, including improved
speed strength and never needing a spotter.

4) Regardless of how you organize your sets and reps, seek continuous,
gradual increases in work output from session to session. Hypertrophy
is a function of how much mechanical work you do in each session, regardless
of what your set/rep scheme is. If you gradually do more and more work
with each new session, you're providing the necessary stimulus for
muscle growth.

5) Fatigue is not the goal of training, but a sometimes unavoidable
result of seeking continued progress from session to session. You'll
make more progress avoiding it than seeking it.

References

1) Zatsiorsky, V.M., Science and Practice of Strength Training (1995)
Champaign, Human Kinetics, p.p. 96.

2) Komi, P.V.(Ed.), Strength and Power in Sport (1992) London,
Blackwell Scientific Publications, p.p. 378.

3) Fleck, S.J., & Kraemer, W.J., Designing Resistance Training
Programs (1987) Champaign, Human Kinetics, p.p. 217.

4) Zatsiorsky, V.M., Science and Practice of Strength Training (1995)
Champaign, Human Kinetics, p.p. 78.

5) Komi, P.V.(Ed.), Strength and Power in Sport (1992) London,
Blackwell Scientific Publications, p.p. 231.

6) Tesch, P.A., (1998) Strength Training and Muscle Hypertrophy. International
Conference on Weightlifting and Strength Training Conference Book,
p.p.18.

7) Andersen, J.L., Schjerling, P, & Saltin,
B., (2000). Muscle, Genes, and Athletic Performance. Scientific American, Vol. 283,
Number 3. p.p. 52.

8) Zatsiorsky, V.M., Science and Practice of Strength Training (1995)
Champaign, Human Kinetics, p.p. 64.

9) Siff, M.C., & Verkhoshansky, Y.V., Supertraining:
Special Strength Training for Sporting Excellence (1993) Johannesburg,
University of Witwatersrand, p.p. 60-61 )

10) Siff, M.C., & Verkhoshansky, Y.V., Supertraining:
Special Strength Training for Sporting Excellence (1993) Johannesburg,
University of Witwatersrand, p.p. 81-82 )

11) Hartmann, J., & Tunnemann, H., Fitness and Strength Training
for All Sports (1995) Toronto, Sports Books Publishers, p.p.
27.