What principle implies that improvements in fitness will be limited to the activities that one is performing?

The overload principle is a deceptively simple concept. To make fitness gains you have to overload the body progressively. Lift heavier weights, run longer, workout more days a week, and so on in order to provide enough stress that the body will adapt and get stronger, faster, and more powerful.

As a trainer you surely know what the overload principle is, but do you really understand it? Enough to plan the best program for each client? We’ll run through the basics of overload and provide some important tips for progressively and safely overloading your clients until they hit their goals.

What is the Overload Principle?

The overload principle is one of the seven big laws of fitness and training. Simply put, it says that you have to increase the intensity, duration, type, or time of a workout progressively in order to see adaptations. The adaptations are improvements in endurance, strength, or muscle size.

In other words, when a client first starts working out, from having been previously mostly sedentary, they will see some quick gains. But, as they get fitter, you will need to increase the intensity of their training to continue to see those gains. If they continue lifting the same weights for the same number of sets and reps, week after week, the body will have adjusted to the stress, there will be no more adaptations and they will plateau.

Issues with the Overload Principle

Overloading is necessary to make gains in fitness and athletic performance. However, there are some important issues associated with this principle, both what can happen if you don’t do it at all and if you don’t do it right.

Hitting a Plateau while Ignoring the Overload Principle

The obvious issue with ignoring the overload principle is the failure to make gains. If you continue to do the same workout or train at the same intensity and frequency, you will make gains only to a certain point. After that you are not overloading the muscles and hit a plateau with no further improvements or adaptations.

This happens because our bodies are very good at adapting to stress. Initially for your newbie client, that five-pound weight provides a good amount of stress. The client gets stronger quickly. But over time, the level of stress needed in order to make new adaptations rises so high the five-pound weights just don’t cut it.

Overreaching and Overtraining Stress

On the other hand, if you use the overload principle in the wrong way, say by increasing intensity too quickly, you get into a state of overreaching or overtraining. Overreaching is a short-term problem, a decrease in physical performance that takes days to overcome.

Overtraining is a more sustained period of excessive training stress. It can take weeks to months to recover from this state of decreased performance. Some signs of overtraining you should watch out for include:

• Increased resting heart rate.

• Increased blood pressure.

• Loss of appetite and weight loss.

• Difficulty sleeping.

• Emotional changes or mood swings.

• Fatigue.

• Chronic muscle soreness.

• Extended recovery times.

Strategies for Overloading

There are several ways you can make sure your client is overloading and not hitting a plateau. Essentially these strategies all involve increasing some factor of a workout. You can increase one, two, or more in a way that makes sense for your client’s goals. These different factors together make up what is known as the FITT principle:

• Frequency. Frequency is the number of times your client works out, usually measured per week. Increasing frequency could mean going from one to two lifting sessions per week, for instance.

• Intensity. This is how hard your client is working during a training session. For strength training you can increase intensity by using progressively heavier weights. In aerobic activities, measuring heart rate is a good way to monitor increasing intensity.

• Time. The time spent doing a particular exercise, like lifting or running, can be increased to progress and overload.

• Type. Type refers to the actual, specific exercise your client is doing. You can vary the exact type of strength exercises, for instance, to overload a particular muscle or muscle group. For instance, add leg presses to squats to overload leg muscles.

It’s important to vary the factors that you change for your client. For instance, one day you may focus on increasing intensity by using heavier weights. In the next session try to focus on another strategy, like increasing the time spent on weights.

For aerobic adaptations, for instance for a client who is a runner, work on intensity one day, using heart rate or interval training, and increase time with a long slow run on another day in the same week. Mixing up how you overload the body can help to minimize the risk of hitting a plateau on gains.

Rules for Safe and Gradual Overloading

Overloading should always be progressive and gradual. Increasing intensity, reps, frequency, and other elements of training too quickly is dangerous. It can cause injuries, lead to muscle soreness, and of course cause overtraining. Follow these guidelines when planning overload for your clients to keep it safe and progressive:

• It is essential that progression occurs gradually. You can’t go from five-pound weight bicep curls one week to 20 pounds the next without increasing the risk of injury and overreaching or overtraining. Make a careful plan for how to increase workout factors that is not too abrupt.

• For strength training, work on form before moving on to a bigger weight. A safe way to progress with weights is to start with upping time and frequency before intensity. Once your client has mastered a particular movement with safe, good form, start slowly increasing the weight for more intensity.

• Test your client’s maximums to decide on weight amounts and appropriate increases in intensity.

• It’s also important to keep a log of training sessions and how you are increasing frequency, intensity, time, and type.

• Plan for recovery time. This is when gains happen and it helps avoid overtraining and injury. Recovery can be an active rest day, with a gentle workout like a walk, but it can also involve alternating easy and hard workouts.

• Don’t let your client burnout when training. Working out to collapse or exhaustion is never healthy and is more likely to lead to overtraining.

To learn more about how to determine rest periods between high-intensity sets, check out this post on the ISSA blog.

Applying Periodization

One way to avoid overtraining from overloading is to apply periodization to your client’s workouts. To get results from overloading, you don’t actually want your client to progress linearly. It is not a good idea to simply make every workout harder, faster, or longer than the previous one. There should be more variation, which is the idea of periodization in training.

Periodization is the specific planning of training cycles. It is a necessary way to train to accommodate the overload principle. In order to progress and make gains you have to vary workouts to overload the body. But, you also need to accommodate the GAS (general adaptation syndrome) principle, which says high-intensity training needs to be followed by low-intensity training or rest.

By periodizing training, you can plan for progressive overload with cycles of more intense, frequent, longer workouts and cycles that are lower in intensity for recovery and rest. There are three types of cycles that go into a periodized training plan:

• Macrocycles. The macrocycle is a long period of training, lasting six months to a year. The macrocycle may coincide with a sports season, like summer and fall running races, or culminate in one event, like a fitness competition. Your client will have large, overarching goals for the macrocycle, like running a marathon in a certain time.

• Mesocycles. A macrocycle is divided into three to four mesocycles, lasting a couple of weeks to a month. These cycles can hit specific smaller goals, like running a 10k, then a half marathon. They may focus on specific aspects of training, like strength or hypertrophy for lifting.

• Microcycles. These shorter cycles last just about a week but maybe two weeks. Each microcycle is the detailed workouts you plan for your client, keeping the larger goals and focuses in mind.

Periodization allows you to vary your client’s overall workout and take advantage of overload with appropriate periods of rest or low intensity activities. Changing up the focus of each mesocycle and varying sessions within each microcycle provides enough overload, variation, and recovery time to help meet the overall macrocycle goals.

The overload principle is a crucial, foundational idea in fitness. If you don’t overload the body, you will never see gains in muscle strength, endurance, and size or aerobic fitness. Over-stress the body and you will over-train and see a decline in performance or even get injured.

Finding the right balance is essential for careful and effective progression. And when combined with periodization in a good training plan, you can help your clients overload the right way, making important fitness gains and hitting athletic and performance goals.

If you want to learn more about working with athletes and helping them hit their goals, check out the ISSA’s comprehensive course on Strength and Conditioning.

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