Any runner that has trained for any amount of time knows that as they as they develop themselves mentally and physically, they will eventually and consistently be able to take on more volume in their training at they move along. Other factors, of course, come into play such as age, lifestyle demands such as career or family and general overall health concerns unrelated to the training.
Life is not necessarily of that ilk and one must determine what their limitations are as they move through the levels of volume. Recovery from illness or pregnancy, undue focus on career issues or family responsibilities should all take precedent over higher volume, unless you are a professional athlete. Using the advice of a fitness professional can be helpful as well.
If you start the process of training from a young age, let’s say in high school, and you are focused on a part-time basis on track and field, for example, you may perhaps cover about 30 to 40 km throughout the course of the week if you are practicing daily and competing as well. If you can run the 5k in about 20 minutes likely through the course of the school year you’ll be able to shave a minute or two off that time with consistent training. Year after year, as you go through high school your distances will increase and your timing will be reduced until you are perhaps running the 5k in about 15 minutes and covering almost 60k in distance on a weekly basis.
By the time, you reach university, you are capable of running 100k over the week but then college life creates a distraction and you drop to back to your high school average and you may even abandon it all together in favour of scholastic and social demands. Don’t feel bad. We’ve all been there.
Once you’ve graduated and have started to work for a living, you may still enjoy running casually for fitness and stress reduction and you may again decide to get more serious. You’re young, you’re in shape, why not take on a marathon? So you train amply to prepare yourself for the prospect and after about 12 to 18 months, you find that you are again back to where you were when you began university and you’re feeling pretty damn good about yourself. Then work becomes more demanding and you find that you can’t dedicate as much time as you’d like to training so you slow it down a bit but keep running daily to stay fit, just with less intensity than the marathon training. By the time you reach 30, you’re still out there all the time, covering about 100k a week. Still you’re finding that you can’t increase your speed but you keep plugging away. A couple of years later, you hit your personal best in timing and complete a marathon in just under two and half hours. Look at you! You’re awesome.
Life has thrown you a few curve balls but you’ve still managed to maintain some consistency and train regularly to increase your abilities, in spite of age, commitments and injuries. Everyone has some kind of story to tell around their running development and that is only one example. The limits that life sets for you are one possibility and the limits you might create for yourself are another – lack of consistency, bad habits in nutrition or substances. It’s up to you. The basic premise, however, is to remain consistent, increasing your volume in increments to achieve personal bests at all milestones in your life.