How Many Reps Should
You Be Doing?
Provided
by American
Council on Exercise
You’ve
undoubtedly heard the standard gym myth that training for size or strength
requires using heavy weights for just a few reps, while training to improve
muscle definition requires using lighter weights for a high number of
repetitions. While there is some degree of truth to these claims, it is
important to understand that the number of reps you do for each exercise has a
significant influence on the results you get from your workout program.
Today,
many popular programs encourage participants to do high numbers of reps for
ballistic exercises, such as barbell cleans or jumps. Unfortunately, doing too
many reps may actually cause injury and limit your ability to train. To make
sure you’re maximizing the efficiency of your time in the gym, here are seven
things to consider when determining how many repetitions you should do based on
your personal fitness goals.
1.
A repetition is a single, individual action of the muscles responsible for
creating movement at a joint or series of joints. Each repetition involves
three specific phases of muscle action: lengthening, a momentary pause and
shortening.
2.
Regardless of your specific fitness goals, the number of repetitions you do is
not nearly as important as whether those repetitions are performed to a moment
of muscular fatigue. Achieving fatigue in a muscle means that it is not capable
of performing one more rep and ensures that all of the muscle
fibers responsible
for moving that muscle have been engaged. If your goal is to improve definition
and you feel capable of performing a few more reps at the end of a given set,
you have not fatigued all of the type II fibers that are responsible for
creating definition. This means you have wasted your time because you will not
be training in the most efficient manner possible for your goal.
3.
In general, the number of reps you do for an exercise is inversely related to
the amount of weight you use. As the amount of weight goes up, the number of
repetitions you are able to perform decreases. Therefore, higher-intensity
loads can only be performed for a few repetitions, while lower-intensity loads
can be moved for a relatively high number of repetitions before fatigue sets
in.
4.
Training for strength requires using heavier loads, which subsequently limits
the number of reps that can be performed. A heavier weight will automatically
recruit more type II fibers in the involved muscles. Type II fibers rely on
anaerobic metabolism, which provides only a limited amount of energy. This is
another reason why heavy weights can only be moved for a few reps at a time—the
muscle simply runs out of available energy. If your goal is to improve
strength, use weights that cause fatigue after no more than six
repetitions.
5.
Training for definition can be achieved by a couple of different rep ranges.
The number of reps isn’t as important as the length of time during which the
muscle stays under tension. The type II fibers responsible for strength are
also responsible for creating the appearance of muscle definition. Definition
comes from a muscle maintaining a state of semi-contraction, which is achieved
by keeping a muscle under tension for a longer period of time. A higher numbers
of reps performed at a slower movement speed can facilitate the tension needed
to increase definition. No matter how many reps you decide to use, to achieve
definition you must reach a state of momentary fatigue, which means you’re not
capable of performing another rep.
6.
If you are a runner, cyclist, swimmer or other type of endurance athlete, you
are probably more interested in using strength training to support the specific
training necessary to achieve success in your sport. In this case, your
strength-training program should focus on activating the type I muscle fibers
that rely on aerobic metabolism, which requires performing as many as 20 or 30
reps. Endurance athletes need to be as aerobically efficient as possible, so
performing strength-training exercises with light weights for a high number of
reps will help muscles develop the mitochondrial density and aerobic efficiency
necessary to support endurance-training efforts. In this case, working until
fatigue is not necessary, because you’re not trying to add muscle mass; in
fact, you want to avoid working to fatigue. However, your rest intervals should
be kept relatively short to ensure that your workout creates the necessary stimulus
to engage your aerobic metabolism.
7.
Power, which is the ability to generate a significant amount of muscle force in
the shortest amount of time possible, is a skill that requires specific
programming to achieve. Power training can provide a number of important
benefits and is completely safe if the appropriate number of reps is used.
However, thanks to the popularity of high-intensity workout programs, it is
often performed in an unsafe manner. Training for muscular power places
tremendous metabolic and mechanical demands on muscle tissue and can rapidly
fatigue the nervous system responsible for maintaining proper joint mechanics.
When doing technical power-based lifts like the barbell snatch, clean-and-jerk,
push press or hang clean, the focus should be on the quality of
movement and not the quantity of reps performed. For safe, effective
power training, the rep range should focus on the maximum force output for one
or two reps and be limited to no more than four or five. The same is true for
medicine ball throws or jumps—the emphasis should be on the quality of movement
and not the number of repetitions performed. Jumps and throws should focus on
technique and be performed for no more than six to eight reps at a time; doing
more reps could cause fatigue, which significantly increases the risk of
injury. Like endurance training, the goal of power training is NOT to go to
fatigue, but to do the assigned number of reps with the best form possible.
Recommended
Rep Ranges to Achieve Specific Goals
|
Training Goal |
Repetitions |
|
Endurance |
≥ 12 |
|
Muscle Definition |
8-15* |
|
Maximum Strength |
≤ 6* |
|
Power
|
|
|
* For best results, the last rep should achieve momentary fatigue. |
|
AUTHOR
Pete McCall
Pete
McCall, MS, CSCS, is an ACE Certified Personal Trainer and long-time player in
the fitness industry. He has been featured as an expert in the Washington Post, The New York Times, Los Angeles Times, Runner's World and Self. He holds a master's
degree in exercise science and health promotion, and several advanced
certifications and specializations with NSCA and NASM.