How Many Repetitions are YOU Doing?

To follow up on last week’s strength series I felt that it would be appropriate to discuss different rep ranges, and why we do the set number of reps that we do. Like everything in the strength and conditioning world, repetition ranges are chosen to elicit a desired response. Also like everything else in the strength world, science is the basis for why a repetition range is utilized. Rep ranges follow two rules; complete fatigue of the appropriate muscle fiber type, and working within the appropriate energy system. Luckily for us, these two rules work hand in hand. However, it is important to understand both to truly understand rep ranges.

FATIGUING THE APPROPRIATE MUSCLE FIBER

Here’s a quick anatomy lesson for you. There are two main types of muscles fibers in the body, type I and type II. These two types of muscles fibers can be broken down into other fibers such as, type IIa, type IIx, type IIb, and various others. For simplicity sake, we will limit this discussion to type I and type II fibers. Type I fibers are the slow twitch muscle fibers in the body, meaning they are not very powerful, but are not fatigued easily. These fibers are the body’s primary endurance fibers. The type II fibers are much stronger and more powerful than the type I fibers, but fatigue very easily. Type II fibers are the body’s primary means of power production. Rapid, powerful movements, and movements requiring high amounts of strength rely on type II fibers. These two types of fibers work at all times to produce all the movements that we make with our body. When strength training, speed training, or conditioning is engaged in, the muscular adaptation is occurring in the type I and type II muscle fibers. In order for adaptation to occur, the muscle fiber must be completed fatigued.

WORKING THE APPROPRIATE ENERGY SYSTEM

The second rule of repetition ranges is working the appropriate energy system. Energy systems, like muscle fibers, are responsible for the movements we make. The human body produces energy two ways, with oxygen (aerobic) and without oxygen (anaerobic). In general, it can be said that the aerobic energy system works in conjunction with the type I muscle fibers and the anaerobic energy system runs with the type II muscle fibers. Energy systems run on a continuum, where the percentage of energy contribution relies on the intensity of the exercise. With low intensity endurance exercise, the contribution of the aerobic energy system is much greater than the anaerobic energy system. When exercise intensity is very high, almost all of the energy is coming from the anaerobic energy system. Training energy systems is different from muscle fibers, and is a discussion we (you I) do not want to get into today.

Behold – the scale of all scales

High Rep Range – 12+ Reps

The high repetition range builds muscular endurance. It may seem obvious why, and it is. Doing high reps of an exercise makes it difficult to use heavy weights, therefore the primary focus is the type I fibers and the aerobic energy system. Engaging in muscular endurance training requires fatiguing the type I muscle fibers. For this reason, the range is left at 12 and above. Anything below 12 will likely result in a weight being used that is too heavy to focus on the type I fibers. The light loads used in muscular endurance training allow for minimal muscle breakdown and minimal neural fatigue, allowing for muscular endurance training to be engaged in more often that other types.

Moderate Rep Range – 6-12 Reps

The moderate rep range is everybody’s favorite rep range, and probably the most common rep range used in gyms. Everyone from elite Olympic athletes to your casual weekend warriors use a moderate repetition range. The claim to fame of the moderate rep range is the all-beloved muscular hypertrophy. A moderate rep range, especially 8-10 reps causes an enormous amount of muscle breakdown (if appropriate weight is used, of course), and therefore leads to muscular hypertrophy. The problem in athletics is that for many sports, hypertrophy training is not high on the list of performance variables. There are plenty of people who could benefit from gaining weight, but for the most part gaining strength is more important than gaining weight. Moderate rep ranges break down both type II and type I fibers, and place a decent amount of stress on the nervous system. Multiple days of recovery are usually required after a hypertrophy training session.

Low Rep Range – 3-6 Reps

The low rep range is important in increasing strength and power. The nervous system is the primary beneficiary of using low repetitions, although there is still a good amount of muscle breakdown when performing 6 repetitions of an exercise. The low rep range taxes the nervous system to a great degree, causing it to adapt and strength to build. Use of the low rep range is essential for extending power capacity, making it useful in building top end speed. Recovery typically only takes a day with low rep range workouts.

Very Low Rep Range – 1-3 Reps

The very low rep range is the primary means of increasing strength and power. Strength is increased by completing very low reps because the weight used is very close to a 1RM, fatiguing the appropriate fibers. Power is increased through the fatiguing of the appropriate fibers, as well as the initial anaerobic energy pool. Using very low reps to train power is effective because the highest power outputs typically can only be sustained for a very short amount of time; training past that time becomes ineffective. The very low rep range is the primary range used (and should be the only range used) for Olympic lifting. Very low reps are advantageous for increasing strength and power, but are not as safe as using a low rep range. Due to the extremely high demand on the nervous system, a recovery period of 2 days is typical in after a very low rep range workout.

The next time you go to the gym to workout think about these rep ranges and what you are trying to accomplish. After all, you don’t want to end up like this guy

Okay, so maybe you do. But then again, it won’t be conducive to your sports career.


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