How to Select the Right Intensity and Reps for Your Clients

Do you know the movie Groundhog Day? In the film, the main character, played by Bill Murray, has to have a new experience on the same day until he finally has everything right. If you work out in a gym, you may be familiar with this phenomenon. Often times it can seem like you can run in your gym at a certain time on a given day and see the same members on the same machines doing the same exercises with the same weight. I recently went to a gym where I took group fitness classes in the early 2000s. It was early Monday through Friday night, around when I was teaching. As I walked through the facility, I felt like I was stepping back in time because I saw many of the same members on the same pieces of equipment they wore years earlier when they were there working regularly.

The overload principle of training program design states that a training stimulus must be applied with an intensity greater than that at which the body is being used in order to induce physiological changes. One of the most common challenges for the average fitness enthusiast is reaching a plateau where exercise no longer seems to have an effect and the body no longer makes physiological changes. To adjust to weight training, you need to do enough repetitions to cause temporary fatigue in the affected muscles, or resistance heavy enough to cause fatigue after just a few repetitions.

Intense, high-intensity exercise puts mechanical stress on the muscle, while a large number of repetitions creates significant metabolic stress. Both types of stress can stimulate physiological responses related to muscle growth and definition. Whether through the amount of weight used or through repetitions to the point of fatigue, the muscles involved should have enough needs to initiate both neurological and structural adjustments.

Therefore, the two program design variables most closely related to the principle of overload are intensity and repetition. Intensity is the amount of drug used and is usually expressed as a percentage of a repetition maximum (% 1-RM) for a given lift. Another way to describe intensity is to list the maximum number of reps that can be performed for a given lift. For example, if a person can press 200 pounds for a total of 10 reps and cannot do another rep, 200 is their 10RM. Any of the intensity description methods can be used to assign specific intensities for exercise in a person’s exercise program.

Repetition is a single, individual action of the muscles responsible for movement in a joint or set of joints. A rep has three phases of muscle action: an eccentric stretch, which is a short isometric pause, and a concentric shortening. The number of repetitions assigned to an exercise indicates how often a person should do that particular movement. As previously mentioned, the repetitions should be done until momentary muscle fatigue occurs to create the necessary overload to encourage specific adjustments.

Repetitions and intensity are inversely related; as intensity increases, the number of repetitions a person can perform decreases. High-intensity workouts can only be done for a few reps, while low-intensity workouts can be postponed for a relatively high number of reps before fatigue begins. It is not necessary to perform a full stress test on a client to identify their 1-MRI. The table below shows the number of repetitions that can be performed at a specific intensity for different training results.

The intensity of an exercise determines the number of repetitions that can be performed. For example, if a client wants to develop hypertrophy (the technical term for muscle definition), they should use enough intensity per exercise to do only six to 12 reps, which will be strenuous until the last rep. If a client can only do 12 reps with a given weight for one exercise, that weight is 12 RM. Once the client can do more than 12 reps, the weight should be increased so that the rep range remains between six and 12. It should be noted that exercises MUST be performed if the goal of training is to improve tone muscle or forehead definition to fatigue. This is the only way to induce congestion to create this response.

Given the popularity of high-intensity fitness programs, it’s important to consider the recommended rep ranges for specific strength exercises. Muscle strength training places enormous mechanical and metabolic demands on muscle tissue and can quickly strain the nervous system, which is responsible for maintaining proper joint mechanics. If you are using heavy weights for strength-based engineering lifts, such as popping or cleaning, the rep range should be focused on maximum power for one or two reps and limited to no more than four or five. Starting, cleaning and shaking are technically demanding lifts. If a person tries to do too much without adequate rest or rest, there is a significant risk of injury.

If a client wishes to improve muscle tone, there are two options for intensity and repetition, each of which can recruit Type II muscle fibers and motor units responsible for improving definition.

• Use a moderate intensity load (about 67-85% 1-RM) of six to 12 repetitions or

• A low-intensity exercise in which the client repeats repetitions due to fatigue (the inability to perform another repetition).

If someone hires you as a personal trainer or takes the time to attend group training sessions, they are likely to be interested in seeing the results. Adding reps or increasing intensity can make clients or participants work harder than they are alone. The overload doesn’t have to be significant, but it does have to be consistent and effective to get results!