Understanding progressive overload

As part of our Biohacking Masterclass Series, we will explore a number of different techniques and practices to improve your daily performance. This series will range from obvious subjects like exercise and nutrition to fringe subjects like breathing techniques and sleep hygiene. Consult your physician before implementing any of these topics. We are not your physician. Note: This post may contain affiliate links to the products we use. 


The words “work”, “work capacity”, and “progressive overload” are frequently thrown around in fitness settings. Not only are these terms somewhat ambiguous to many gym-goers, but they are also often misused. In this article, we’re going to clearly break these down so you don’t have to guess. Furthermore, we’ll leave you with a few tips on improving your work capacity using these concepts. 

While it is abstractly thrown around in the weight room, work is a physical equation stemming from the product of force and distance (W = F x D). In the gym, force is calculated from mass (the mass of the barbell) and acceleration (the rate of velocity change through the lift). Distance is the cumulative total of all repetitions together. As a simplified example, 5 repetitions of back squat where each repetition is 1 m makes D = 5 m. 

Work capacity is more obviously the amount of work your body is capable of performing. The intensity and duration of the work (i.e. high intensity/short-duration or low-intensity/long-duration), will determine the exact work capacity for your body. For example, high-intensity anaerobic exercises rely on the phosphagen and glycolytic (from carbohydrate) energy systems, and these systems are limited by certain parameters of energy production. Further, the specific types of muscle fibers an athlete has will determine how well they perform under the energy system constraints created by anaerobic training. Alternatively, athletes performing low-intensity aerobic exercises use different energy systems. These systems are optimized to perform with predominately type-I slow-twitch muscle fibers that use oxygen efficiently. 

Finally, progressive overload is the process of subjecting your body to ever-increasing amounts of stress. By deliberately increasing the amount of work your body performs, your muscles and nervous system can adapt and improve over time. The process of progressive overload is depicted in the myth surrounding Milo of Croton. When a calf was born near Milo’s home, the wrestler lifted and carried the animal on his shoulders. Each day, Milo repeated the process. 4 years later, Milo was no longer lifting a small animal, but a full grown 4 year old bull. The same process can be applied to training.

We’ve discussed the principle of progressive overload with anaerobic training. Typically, this falls into a few categories: 

  1. Adding more sets - if you can squat 3 sets of 3 at 300 pounds, add one more set and perform 1, 2, or 3 repetitions until you can do 4x3 at 300 pounds. Eventually, build to 5-8 sets of 3. 
  2. Adding more reps - Using the same set structure as above, if you’ve reached a point where you can do 5 sets of 3 reps at 300 pounds, begin adding reps to your sets until you can do 5 sets of 4 reps, and eventually 5 sets of 5 reps.
  3. Adding more workouts - This option is self explanatory. You can increase your work capacity by working out more frequently. Importantly, this option can also subject your body to a greater amount of stress.

But what about aerobic work capacity? 

While we are certainly more versed in high-intensity resistance training, the same principle applies to aerobic training. Using the same format as our anaerobic list above, progressive overload under aerobic conditions could look something like: 

  1. Interval training with 400-800m runs. For example, starting with 4 800 m runs and progressively increasing to 5, 6, 7, etc. 
  2. Continuing with the running example, if you can only perform 5 rounds of 400 m runs, begin adding in longer 600 or 800 runs one round at a time. 
  3. Increasing the frequency of your anaerobic training. Simply workout more often.