As a marathoner, I am always trying to cover the distance at greater speeds. When you pursue endurance sport goals like this, you run into physiological limitations that impede your ability to go faster. When you start off, it’s likely that what will be limiting your gains is how capable your muscles are of firing with force for 33,000 consecutive steps (muscle endurance).

The interesting thing about the marathon puzzle is once you get your muscles firing with force over the distance, you’ll run into new physiological limitations. Here are the ones I’ve found by racing.

  • Ability to absorb oxygen in the lungs and send it to muscles (VO2max)
  • Ability to dispose of lactic acid build up in the muscles (Lactate Threshold)
  • Ability of stomach to breakdown and convert calories into fuel for muscles. (Caloric absorption)
  • Ability to train in larger and larger volumes, keep form, and ancillary muscles like glutes to continue to fire and avoid biomechanics injuries. (more muscle endurance, form improvements, efficiency)

In the pursuit of improving, it’s worth thinking about the human body as a system, and these physiological processes as just that – processes. Those processes can and do improve under very specific training stress. Through a process of stress introduction and removal, your body’s system will adapt to the load and improve the process.

When a single process is impeding your ability to improve, it’s your limiter.

Your system will always have limiters, you just need to identify them and improve the process around that limitation.