We have become an ‘on demand’ society that wants what we want when we want it, which is usually NOW. This is especially true when it comes to getting results from exercise and workout programs. No one likes wasting time yet when it comes to their fitness programs I see a LOT of people not making the most out of their time in the gym because they may be using the wrong number of repetitions for their specific fitness goals.
The number of reps assigned for an exercise indicate the number of times to perform that particular movement. You’ve no doubt heard the standard gym myth that training for size or strength requires heavy weight for few reps while training to improve muscle definition or ‘toning up’ requires using lighter weights for a number of repetitions. While there is some degree of truthiness to these claims it is important to understand that the number of reps you do for each exercise has a significant influence on getting the results you want from your workout program. When it comes to doing high intensity strength or power exercises some popular programs encourage participants to do high numbers of reps for ballistic exercises like barbell cleans or jumps and in cases like this doing too many reps could actually cause injury and limit your ability to train. To make sure that you’re maximizing the efficiency of your time toiling in the gym here are 7 things you should know about the number of repetitions that you should be doing for your fitness goals.
- 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.
- Regardless of your specific fitness goals the number of repetitions performed 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 finish a set capable of performing a few more reps you have not fatigued all of the type II fibers that are responsible for creating definition meaning that you have wasted your time because you will not be training in the most efficient manner possible for your goal.
- In general, the number of reps you do for an exercise has an inverse relationship with the amount of weight used. As the amount of weight goes up, the number of repetitions able to be performed decreases. Higher-intensity loads can only be performed for a few repetitions while lower intensity loads are can be moved for a relatively high number of repetitions before fatigue sets in.
- Training for strength, the ability to produce force, requires using heavier loads which subsequently restricts 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 and 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 then you should be using weights that cause fatigue by no more than six repetitions.
- 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 in 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. Higher numbers of reps performed at a slower movement speed can apply the tension necessary to increase definition. That is why you will generally see eight-to-twelve or twelve-to-fifteen reps as the target ranges in many magazines that focus on bodybuilding or figure competitions. To achieve definition no matter how many reps you decide to use, it is important to reach a state of momentary fatigue meaning that you are not capable of performing another rep.
- If you are a runner, cyclist, swimmer or other type of endurance athlete then 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 and you should be doing upwards of twenty or thirty reps. Endurance athletes need to be as aerobically efficient as possible, doing strength training exercises with light weights for high reps will help your muscles develop the mitochondrial density and aerobic efficiency necessary to support your 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.
- Power is the ability to generate a significant amount of muscle force in the shortest amount of time possible and is a skill that requires specific programming to achieve. Power training can provide a number of important benefits and it is completely safe IF the appropriate number of reps are 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, the clean-and-jerk, the push press or the 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, at the most, 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 movements performed. Jumps and throws should focus on technique and be performed for no more than six or eight reps at a time; doing more could cause fatigue which significantly increases the risk of injury. Like endurance training when power training the goal 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
Increase Strength: 2-6 reps
Increase Size/definition: 8-15 reps
Improve Endurance: 12-30+ reps
Increase Power: 1-8 reps with EXCELLENT form!
For best results – the last rep should be incredibly difficult!
Heavy loads apply a mechanical stress to muscle while performing a high number of repetitions creates a significant metabolic stress both of which can stimulate desired physiological reactions like muscle growth or definition. Whether it is by the amount of weight used or performing reps to fatigue the demand on the involved muscles should be sufficient to initiate the neurological or structural adaptations to achieve your desired goals.