Exercise is a function of movement, and movement is a skill that must be developed over time. Therefore, changing your clients’ exercises with every workout is not a good long-term business strategy. For clients to improve their movement skills and coordination, there must be some consistency in the exercises selected for their workouts. This can be a tough situation for trainers, who need to provide their clients with both variety (to make workouts interesting) and consistency (to facilitate a sense of achievement). 

You can create added value for your services by using the science of periodization to provide a systematic way to constantly change the volume and intensity of exercise. Periodization calls for alternating phases (periods) of training based on volume, intensity and movement complexity. The greatest benefit of periodization is that it uses rest as a means of allowing for adaptation to the physically demanding stresses of training. Structured, consistent changes to exercise programs can adjust for training complexity, intensity and volume. It’s also an effective strategy for helping clients achieve desired goals, which can lead to long-term retention. 

Here are seven compelling reasons to apply the science of periodization to develop long-term programs that are dynamic, challenging and fun for your clients: 

1. The purpose of periodization is to manage the application of physical stress applied to the body by manipulating training volume, intensity and movement complexity. When training intensity is low, the volume (the number of reps and sets) can be high; as training intensity or movement complexity becomes more challenging, the volume can be reduced. The goal of periodization is to manipulate the training stimulus to focus on creating metabolic fatigue, mechanical overload or a combination of the two to allow optimal adaptations over an extended length of time. 

2. The basic exercise movements can be consistent to provide for efficient learning; however, the acute variables of exercise program design (exercise selection, intensity, repetitions, rest interval, sets, tempo) can be applied in a progressively challenging manner to gradually increase the level of difficulty, which is essential for achieving results. It is well established that physical adaptations to exercise, including muscle growth and definition, depend on the application of these By systematically changing the acute variables, you become more important to your clients because you're providing them long-term exercise program solutions to help them achieve all of their fitness goals. 

3. Resistance training causes two specific types of stress on muscle tissue: metabolic and mechanical, both of which can provide the necessary stimulus for muscle growth. However, the research is undecided on which type of stress provides the greater benefit. A properly periodized program can alternate between phases of heavy weight for low reps to create mechanical stress and phases of light-to-moderate weight for high reps to induce metabolic stress. 

4. The acute variables of exercise program design most closely related to creating metabolic or mechanical stress are exercise selection, intensity, repetitions and tempo. By creating both types of stress, properly designed and periodized training programs can stimulate muscle growth, improve definition and promote long-term client retention. 

5. In a linear periodization scheme, volume, intensity and movement complexity are inversely related; as the intensity or complexity of movement gradually increase over the course of the training cycle, the volume should decrease. A linear program can be organized into various components based on length of time for each training phase and should include occasional periods of off-loading or active rest for optimal adaptation to the training stimulus. In a linear periodization program, segments of time can be organized into short (microcycles), intermediate (mesocycles) and long-term (macrocycles) time frames. 

6. The non-linear model organizes adjustments to the acute variables on either a week-to-week or a training-session-to-training-session basis. Non-linear models apply varying levels of training stress, which can induce metabolic challenges while allowing for rapid neuro-endocrine adaptations. Non-linear periodization changes the intensity and volume of exercise on a more frequent basis. This allows clients to complete two to three high-intensity training sessions per week, along with lower-intensity workouts on other days. This makes it possible for clients who feel they must exercise every day to reduce their risk of overtraining.

7. Linear models of program design are structured to peak for a single event or competitive season. Non-linear models allow clients to train for multiple events or recreational activities throughout a year. For example, in a linear program a client may use the same weight for the same movements over the course of a two-week microcycle. In a non-linear program, a client can use the same exercise movements with each workout, but apply the acute variables to do a strength workout with heavy loads for four to six reps on Monday, followed by a metabolic conditioning workout using lighter loads for 10 to 12 reps on Thursday, and then a power-based workout with moderate weights for six to eight reps in a small-group workout on Saturday. 

While non-linear models allow for more frequent variations in training stimulus, they are designed for individuals with more training experience and higher fitness levels. Consequently, it might be a better idea to start clients on linear models to gradually enhance strength, improve coordination and increase fitness levels over an extended period of time. You can then transition the client to a non-linear model to allow for more frequent changes to the training stimulus. 

Understanding how to apply periodization for a systematic and progressive application of the variables of exercise program design gives you the ability to change the volume, intensity and complexity of a program at specific intervals to maximize performance while allowing appropriate levels of rest and recovery as a critical strategy. Clients who don't like to exercise will definitely appreciate the fact that you make rest a part of your long-term plan, while the clients who love to exercise will need to be coached on the benefits of rest to allow the optimal adaptations to the exercise stimulus.