If you’ve ever put in consistent effort into your gym sessions and still felt like you were going nowhere, progressive overload might be the missing piece. It’s not complicated, but once you understand this fundamental concept, it changes how you approach every single workout.

You hear the term thrown around the gym floor constantly. However, progressive overload is not just gym jargon. It remains the single most important principle behind every result you get from your strength training. If you want your body to keep changing and growing stronger, you have to give it a reason to adapt.

We sat down with One Playground’s Head of Coaching, Matt Duncan, to break down what progressive overload is and explore how it can be used to maximise strength gains and optimise muscle building in the gym, all while safeguarding against overtraining.

What is Progressive Overload?

Progressive overload involves gradually increasing the demand placed on the body during exercise to create a specific adaptation, whether that’s gaining muscle, increasing strength or improving fitness. Simply put, if you want to continue seeing progress, you need to find ways to keep challenging your body. The routine that got you to your current fitness level will not necessarily push you to the next one.

As Matt explains, “This is an example of the SAID principle (which stands for Specific Adaptations to Imposed Demands), the body’s remarkable ability to adapt to the specific stresses placed upon it during training.”

You can gradually overload your body by increasing the demands placed on your muscles through higher intensity, greater volume, or longer exercise duration. In response to these increased physical demands, your body adapts by becoming stronger, increasing muscle mass, or enhancing a specific fitness element.

How Strength Training Builds Muscle

To understand how the challenge of progressive overload leads to real progression, we need to look at how the body actually builds muscle.

Hypertrophy represents an increase in muscle size. This growth happens through three primary mechanisms: mechanical tension, metabolic stress, and muscular damage. You can achieve all three of these through consistent resistance training.

1. Mechanical Tension

“Mechanical tension refers to the load that is dispersed through the muscle, and many researchers believe this is the primary stimulus for hypertrophy,” Matt explains.

During strength training, your muscles experience physical force as they contract and lengthen. The muscle detects this force and signals a chemical response that stimulates the muscle fibres and leads to an increase in size.

You need a substantial load to trigger this reaction. “These sensors are called mechanosensors,” Matt notes. “However, these mechanosensors are highly tuned in and sensitive to how long the muscle is loaded for, and how much load is placed on the muscle. A cheeky squeeze of your biceps holding your coffee cup at your desk is unlikely to do the job.”

2. Metabolic Stress

During the process of anaerobic glycolysis (that’s the process of using glycogen for fuel in the absence of oxygen; this system is typically utilised in activities that last up to three minutes), your body produces by-products known as metabolites, creating an acidic environment in the tissue. This build-up creates metabolic stress, believed to be a key factor that helps develop muscle size.

Matt explains, “These reps are easy to recognise, they’re the ones that really ‘burn’.

“A common misconception is that the burning sensation is ‘lactic acid’ being produced. Yes, the environment is acidic, but humans do not produce lactic acid. We do produce lactate, however. This is your body’s response to the acidity; it aims to buffer us from it, but it’s not the cause. In fact, the production of lactate has been shown to have positive benefits on heart, liver and brain function”.

3. Muscular Damage

It’s believed that micro-trauma to the muscle, sustained during resistance training exercises, can enhance the hypertrophy process. The type of muscle contraction heavily influences the amount of damage that occurs.

“Eccentric” contractions (where the loaded muscle lengthens) have been shown to create a greater amount of micro-damage than “concentric” contractions (where the loaded muscle shortens) or “isometric” contractions (where the muscle remains at the same length under load).

“For a visual reference, picture a person about to squat,” Matt says. “They begin by bending at the knees and hips and lowering the weight. Here, the target muscles, the quads and glutes, lengthen, making this the eccentric portion. If the individual pauses halfway down, their muscles work to hold them still, creating an isometric contraction. As the person returns to a standing position, the target muscles shorten, making this a concentric contraction.”

While exercise-induced muscular damage contributes to muscle building, too much damage impedes your progress. Aim to work to a minimal effective dose during your sessions. You want just enough stimulus to drive adaptation, but not so much that you cannot recover in time to train again within a few days.

A good place to start is to aim for 10% of your reps having that horrible burning feeling. This would mean that if you did 4 sets of 10 reps, the last 4 reps of the last set should be a genuine grind.

Because these three mechanisms occur simultaneously during strength training, accommodating all of them within your programming yields the best results. Always prioritise mechanical tension and the core fitness principles of progressive overload.

How to Apply Progressive Overload to Your Workouts

The frequency and size of the progression you need depend on your individual fitness level, specific goals, and overall training experience.

As a general guideline, increments should be introduced gradually, typically ranging from 2-10% increases per week, while allowing sufficient time for adaptation between workouts.

This increase can be done in a number of ways:

• Load: How much weight you’re lifting is one of the most important factors in stimulating hypertrophy. If prioritising load, and in week 1 you achieved 10 reps with 100kg, the next week you would aim to use between 102 kg and 110 kg for the same 10 reps.
• Reps: An increase in the number of repetitions performed during a set. For example, if you achieve 100 kg for 10 reps in week 1, you would aim for 11 reps with 100 kg in week 2.
• Sets: Adding another set to the same exercise. More suited to beginners, who have the ability to make more progress at the start of their training journey, increasing the number of sets is a great way to develop work capacity. That would look like 2 sets of 10 reps in week 1, then 3 sets in week 2, and so on.
• Tempo: Slowing down the eccentric part of the movement. This is a great option if you’re not quite ready to add more weight to the exercise. You may perform the eccentric (lowering) portion of the movement 1 second slower each week, or perhaps introduce pauses before the concentric (shortening) portion.

Essential Fitness Principles for Muscle Growth

“While progressive overload reigns supreme,” Matt explains, “other factors play pivotal roles in driving progress in resistance training.”

To see the best results, you must focus on proper form and technique. Excellent form maximises muscle recruitment and minimises your risk of injury. You must also train with enough intensity to actually stimulate adaptation. Finally, maintain a balanced, nutritious diet to fuel your growth, and prioritise high-quality sleep to optimise recovery.

and minimise the risk of injury, training with enough intensity to stimulate an adaptation (your body needs a good reason to improve), maintaining a balanced and nutritious diet that fuels training and growth and prioritising adequate rest and sleep to allow for optimal recovery and muscle repair”.

How to Prevent Overtraining

To avoid the pitfalls of overtraining, Matt notes how it’s crucial to strike a delicate balance between enough volume and intensity to provide a stimulus and enough rest and recovery to promote an adaptation.

“Listen to your body and adjust your training intensity accordingly,” Matt advises. “Incorporate rest days into your routine, and prioritise sleep and nutrition. Additionally, implementing deload weeks helps mitigate the risk of burnout and injury, allowing for sustained progress over the long term.”

Final Thoughts

In the pursuit of gaining strength and muscle, progressive overload stands as a guiding principle, which allows for sustained progress over time. However, it’s essential to approach training with structure and accurately record adjustments.

The aim is to train consistently over long periods of time, using the minimum effective dose. This will always outperform training extremely hard for a few weeks or months and then stopping.

Stress management, good sleep and nutrition will allow your body to respond effectively to the demands placed on it in the gym, but striking this balance can be a difficult thing to do, as we often have a hard time viewing our efforts objectively.

Working with a coach or using biometric data can help offset some of the emotional decisions made about training. It’s always best to have a plan, and (mostly) stick to it.