What is Progressive Overload?

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In the realm of resistance training, where building strength and gaining muscle are the ultimate goals, one concept stands as the cornerstone of progress: progressive overload. This fundamental principle forms the bedrock of effective training programs, allowing individuals to see continued improvements over time.


We caught up with One Playground’s Head of Coaching, Matt Duncan, to explain the essence of progressive overload, explore its significance, and unveil the key considerations for maximising it as a strategy in the gym, all while safeguarding against overtraining.


What is ‘Progressive Overload’?


Progressive overload entails gradually increasing the demand placed on the body during exercise in order to create a specific adaptation, whether that’s gaining muscle, increasing strength or improving fitness. Simply put, if you want to continue to see progress, you need to find a way to continue to challenge the body. What got you to where you are, won’t always lead to you getting better. 


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.”


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


What makes the body build muscle?


To understand how the new challenge of overload leads to progression, we must understand how the body builds muscle. 


Hypertrophy is the term given to an increase in muscle size and happens through three primary ways: mechanical tension, metabolic stress and muscular damage. You can achieve all three of these through 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 resistance training, muscles experience 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.


In order for this reaction to happen, you do need a substantial load. “These sensors are called Mechanosensors,” Matt notes, ”however, these mechanosensors are fairly 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), by-products known as “metabolites” are produced, creating an acidic environment. This build-up is referred to as metabolic stress and is believed to contribute to developing 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 adaptation. How much damage occurs is influenced by the type of muscle contraction. “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 of different contraction types, picture a person about to squat, 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 was to pause halfway down, their quads, glutes and hamstrings would be working to hold them still, this would be an isometric contraction. As the person returns from the bottom of the squat to and standing position, the target muscles shorten, making this a concentric contraction”.


Although it seems likely that exercise-induced muscular damage does contribute to hypertrophy, too much damage can certainly impede it, the target for most sessions should be to work to a minimal effective dose, just enough stimulus to drive an adaptation but not too 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.


It’s hard to determine exactly how much each method contributes as they occur alongside mechanical tension and it’s difficult to study them in isolation. The most productive approach would be to accommodate all three within your programming while prioritising mechanical tension and the principle of progressive overload.


How to ensure you are overloading effectively: how much and how often

The frequency and magnitude of progression in resistance training that’s needed for progressive overload depends on various factors, including individual fitness levels, goals, and 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.


Are there any other considerations?

“While progressive overload reigns supreme,” Matt explains, “other factors play pivotal roles in driving progress in resistance training. These include ensuring proper form and technique are utilised to maximise the recruitment of muscle 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. 


“This entails listening to your body and adjusting training intensity and volume accordingly, incorporating rest days into your routine, and prioritising adequate sleep and nutrition. Additionally, implementing deload weeks can help 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.

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