“Despite the apparent complexity of modern exercise programs, you really have only two options if you want to get fitter: you can train harder than you’re currently training, or you can train more. Those two variables, intensity and volume, are the basic levers that all training plans fiddle with in various ways. But let’s be honest: two variables is still too many. We all secretly want to know which one is really the master switch that controls our fitness.”-Alex Hutchinson, “Is It More Important to Run Faster or Run Longer?” Outside. August 14, 2019.
As covered in the discussion on adaptation response, there is no “master switch that controls our fitness.” If you want to be good at doing push-ups, do push-ups. If you want to swim the English Channel, then practice swimming miles at a time in cold water currents. If you want to be able to hold your breath for an extended time, then practice holding your breath. If you want to have six-pack abs, then you need to reduce your eating and increase your activity to the point that you can get your body fat below 10%. Everybody has six pack abs, it’s just that, for most of us, they are hidden behind a thick layer of fat.
Of course, goals tend to be more complex. If you want to run your first marathon, then you need to run more. You should work up to running 50 miles a week and be able to run for 20 miles straight a month before your race.
If you want to run faster than your last marathon, then you can increase your mileage up to 120 miles a week of elite runners and you can work in as much speed work as your body can handle at that volume, which will not be much unless you have been running that kind of volume for years and your body has adapted to it.
It is possible to run shorter distances fast and move up to the marathon. So, after years of adapting to a high volume of speed and middle distance running, you can start training for longer distances and increase mileage.
However, if your new to running, your goal is to run a marathon and you don’t have a decade time horizon to do it, then it’s probably easier to start with running more rather than a running program focused on running faster. Conversely, if your goal is to run a sub-20 minute 5k race, then running more than 50 miles a week will likely make you slower, not faster. Better to do intervals of 5k, a mile, a half-mile and a quarter mile with lower total mileage.
Your training has to reflect the activity you are training for. Sprinting is not the same as long distance running. Cycling isn’t the same leg exercise as doing squats and deadlifts. Our body (and mind) adapts to the training (or lack thereof) we give it.