I’m often asked whether it is ok to run on a treadmill rather than outside. My answer usually differs to each person because it depends why they are asking me the question but there are pros and cons for each. So here are my general thoughts on the subject:
Running outside may be better than running on a treadmill when:
You plan to do or have entered a running event
If you are aiming to do an event running outside then you need to get used to running outside. A treadmill helps you run since there is a continual ‘pawing back’ motion through the belt. Effectively part of the running motion is done for you therefore you do not develop the strength through this section. You will over-develop some muscles relative to others which will make it feel increasingly harder for you to run outside if you get too used to a treadmill. It can be easy to convince yourself not to run outside when it is, say, raining hard or blowing a gale. But if you train for weeks or even months for one event only to wake up on that day and discover a downpour then what are you going to do?
When the session you want to do is a long endurance one
Whether a long run for you is 30 minutes or 3 hours it can be really boring doing it on a treadmill. Running outside tends to pass quicker since you have a variety of views and terrain to keep you occupied. In addition, usually our longer runs are a training session for some kind of distance event so I refer back to the last point! Also consider long training runs for half or full marathons where you need to learn to drink and / or eat on the run. If you’re going to have to carry things in the event then the place to work out what is best for you is on a training run in similar conditions.
When you want to consolidate your running
I usually include in my clients training programmes a regular ‘run as you feel’ run. This allows you to pull all your running training together. It may mean pushing hard up a hill because you feel strong or really letting the run stretch out on the flats because you feel flexible. Or it may even mean easing back the pace just becasue you feel a little tired that day. It lets your body respond to its muscles and your fitness while allowing you to just enjoy running (which should be the number one reason we all do it!) with no fixed agenda or target. This is much harder to do on a treadmill as your legs respond to the pace of the machine, rather than your pace being a response of your mind and body.
When you plan to run an off-road event
A treadmill has a flat, smooth and bouncy surface. It doesn’t ‘feel’ the same as grass, sand, gravel or mud under your feet. If you are planning an event on non-road surfaces then you need to get used to running on these surfaces. It is good practice to run on various surfaces anyway since the differences in terrain gives your lower limbs a better strength and stability workout. This means all the supporting, smaller muscles around your ankles and knees are worked more, making them stronger and keeping you more resistant to injury.
When the weather is nice and you have spent all day inside
Speaks for itself really! Why would you want to stay cooped up inside with lots of other sweaty bodies when you could be outside in the fresh air?
Running on a treadmill may be better than running outside when:
You are returning from an injury and want to try your running out
Running outside to some extent will strengthen your muscles up but from time to time we can suffer from injuries and niggles. If you have had a set back then it is may be worth building your running back up on a treadmill, especially if the injury has been caused by the impact of running. Treadmills nowadays all have shock absorbers to lessen the impact. In addition it is easier to just stop the session completely, if needs be, when you are on a treadmill than if you are outside and discover you can’t run anymore when you are 3 miles from home!
When you only want to include a little bit of running in your overall workout
If you run mainly for fitness or you do a lot of cross training then you may want to just include a short running section within an overall cardiovascular workout. Logistically it makes much more common sense to just do 10-15 minutes on the treadmill so you can then move to another piece of equipment as easily and quickly as possible.
When you just cannot seem to get your speed up outside
This for me is the best reason to use a treadmill. Most of us start out running at one speed, which we find hard to vary. Then we develop to 2 paces; our normal pace and flat out. As we develop as runners we find we can vary our paces considerably depending on the session. However, there can come a point where we struggle to increase our ‘pure speed’; the flat out pace. Interval training on a treadmill can really help here as your legs are ‘forced’ to go to a faster pace until they learn to do it on their own.
When it’s icy outside
Save yourself a broken leg and use the treadmill instead!
When you are trying new trainers out
Most good running shops will allow you to bring their trainers back after a test run as long as you don’t use them outside. Proper trainers are the best running investment you can make so be sure that they feel right for you.
I am a fan of treadmill running when there is a specific purpose to it. I include one treadmill session a fortnight in my own programme, but given I am doing 5 or 6 running sessions a week the proportion of treadmill running is quite small. Since my clients in general don't have the need to do so many sessions I tend to discourage them from using treadmills often, for the reasons I have stated above. However, at this time of year it can be hard to motivate yourself to go out in the cold and dark. And as women we have to question the safety of running alone in the dark. So, when all is said and done, if it’s a case of a treadmill run or no run then I’d pick a treadmill one every time!