When “System Overload” is a Good Thing

I will never forget one elementary school field trip in particular.

We went to Playland, where before me loomed the iconic wooden roller coaster, its rickety rails trembling beneath a flying capsule of screaming fanatics. Upon initial observation, the terror appeared to outweigh the fun.

My friend Jacob saw things differently. I got into the lineup, my mind swirling with fear, anxiety, and doubt. 

Scared of heights, I strapped in for the ride, my eyes shut the entire time, knuckles white on the bar at my sternum. It was a nerve-wracking experience… the first time.

Each time I returned, my eyes stayed open longer; my hands gripped the bar less tightly; the butterflies in my stomach transformed from ones of terror to ones of excitement and joy. 

Eventually that coaster became almost boring. I took to bungee jumping and skydiving. A kid who had convinced himself he was scared of heights was, in fact, an adrenaline junkie.

In a previous column we discussed one of four principles of sports training: Specificity. Now let’s discuss an equally important one—Overload.

The principle of overload states that, in order to become stronger and more efficient at movement, we must expose our systems to stresses above what they normally experience. This allows for specific adaptations, such as improved strength on a lift or improved endurance on a paced run.

Nobody ups and completes marathon without any training, right? We build ourselves up to such milestones, and we do so through overloading our system—not dramatically or all at once, but consistently over time.

You first jog couple of kilometres. Each jog is either a little longer or a little faster, and thus a new stress for the system to adapt to. If you only ever jog two kilometres at the same pace, finishing a marathon remains out of reach.

How about squatting 200 pounds? First you have to be able to squat your own weight, then work up to added weight. By the time you can squat 200 pounds just once, squatting 100 pounds for several reps feels incredibly easy. This gives athletes a valuable sense of progress—and because it is relative to one’s own strength and abilities, this principle is works for everyone.

As fitness consultant Chris Goulet wrote for Bodybuilding.com:

The main reason you may be failing is most likely because you’re no longer challenging yourself. If you don’t progressively overload the muscles by forcing them to do more than they’re accustomed to, they have no reason to make further adaptations.

The two typical ways to implement overload is through intensity and volume. Intensity overload tends to build strength, while volume overloading works toward endurance adaptions. Both methods can contribute to size gains, depending on implementation.

In the gym, intensity means adding weight to the bar, while volume means adding an extra rep or set. On the track, intensity means faster speeds at distances you’ve completed; volume means adding mileage at a familiar pace.


Your system can only handle loads slightly above its current maximum. Excess is adding more to risk of injury than potential gains. Adding five to ten extra pounds to a compound movement or half a kilometre for an overload session is plenty, especially for novice and recreational athletes. Overloading demands generous recovery, too, something to discuss in a future column.

In a nutshell, operating outside of your comfort zone is integral to developing as an athlete, no matter the goal. Your system must be pushed to its limit in order to adapt and overcome. Applied methodically, the overload principle will send you soaring to new heights—even if you have to close your eyes the first time.

A version of this article originally appeared in The Progress.