Claire asks: Currently, I am using a treadmill for all of my running. I am thinking of signing up for my first half marathon this autumn, so can I continue to train using only the treadmill?
It is great that you are taking on running and challenging yourself with a half marathon! While the treadmill has its benefits, you will need to find a way to hit the road for some of your miles because treadmill running and road miles are not quite the same.
When training for a race, the goal is to simulate the conditions of your event as much as possible. This includes things like elevation changes, weather conditions and start time. Then you will want to incorporate those parameters into your training to best prepare you for the demands of your half marathon.
There are several important differences between running on the road versus on the treadmill. First, the energy demands of treadmill running are less than those of running outside. One reason for this lower energy demand is that the treadmill belt assists with leg turnover rate, making it slightly easier for you to run. Because of this assistance, runners typically find that their run pace on the treadmill feels faster than their outdoor run pace.
Along with pace differences, run stride on and off the treadmill is often different. Ideally, you want to train the specific muscles and all their fibres in the same way as you are going to use them in the race. In addition, when running outdoors there can be obstacles you may encounter, like curbs, rough pavement or offroad sections, so it's best to be prepared to encounter them and their increased energy demands.
Another difference between treadmill running and road running is the amount of conditioning required of soft tissue - the muscles, tendons, ligaments, connective tissue and fascia of the body. It may seem obvious, but it’s good to know there is a difference because the road is a harder surface than the treadmill. The treadmill base plate gives when your feet strike it and, as hard as it may seem, it is more forgiving than the pavement.
The body’s soft tissue responds to this resistance by toughening up. Since road running puts up more resistance, the soft tissue adapts, or “toughens up,” to a greater degree than when treadmill running. This conditioning process is somewhat similar to the calluses we develop on our hands or feet from frequent use.
Another huge factor is adapting and acclimatising to running in outdoor weather conditions like heat, humidity, wind, rain or cold. While inconvenient at the time, it is the only way to get used to running outdoors in weather conditions similar to your race.
This is not intended to bash treadmill running. Treadmill running has its own merits and is a valuable training tool. The key is knowing when and how to use the treadmill to your advantage, especially if you are going to be racing on the road.
The treadmill provides a welcome respite from inclement weather that is impossible to go out in (like excessive snow or a thunderstorm), so there is no need to miss a run because of bad weather. It is also convenient and safe, especially if you are running solo early in the mornings or late at night.
Do you live in a flat area and your race is hilly? The treadmill gives runners the ability to set the incline for some hill training and the pace for speedwork, too. And many treadmills have an option that allows you to program a specific course, making it possible to set up a training run that mimics your race. So the treadmill offers many training benefits, too.
The bottom line is that races are outside, so if you want to do a road race, I suggest that you begin gradually shifting some of your runs to the outdoors. Continue your current treadmill regimen, but begin by shifting one or two shorter runs to the road each week. Then, every three weeks increase your outdoor mileage to the point where you have shifted about half of your weekly mileage to the outdoors, including your long weekly run.
This will allow you to gain road conditioning, adapt to the climate and work on your outdoor pace while still having the flexibility to use the treadmill. When using the treadmill, always elevate it by 1 to 2 percent to better simulate the energy demands of running outdoors. (This slight incline creates a greater energy demand and helps recruit muscles in a pattern that better simulates running outside.)
Try adding even more incline for hill training and play with the speed since it is right there at your fingertips. All of these changes will increase the intensity of your treadmill runs, and by doing so, will better prepare you for running outside.