I've been asked a few times recently what I think of treadmill running, and as it's that time of year when the weather doesn't always encourage outside running, I thought I'd explain the pros and cons of using these machines.
Easy to measure - If there's a pace or incline you need to run at, you can simply set it up and crack on. This makes treadmills very handy for speed or hill sessions and if you're travelling a lot you can effectively do the same intensity of workout anywhere.
More forgiving on joints - A belt is cushioned whilst a path or pavement is typically hard. Therefore, running on a treadmill can reduce the amount of impact on the joints. It's particularly useful during rehab as not only can it be easier on the body but also you can stop whenever you need to.
Safer option during winter - It's not ideal conditions outside currently. Pitch black evenings and ice when it turns colder can create hazards you may want to avoid. Treadmills could be a safer option to ensure you get your sessions in during the winter.
Availability - Now there's nothing more accessible than a pair of trainers and the great outdoors! However, if like me, you don't live near a track or a quiet stretch of path, treadmills can be a great alternative for your interval work. As you're never far from a gym, their easy availability can promote consistency in your speed training.
Differing muscle mechanics - Outside you're running over a still surface whilst on a treadmill there's a moving belt. This means muscles will be activating differently and some will be underused on a machine. For example, when you run outside your hamstrings will activate to bend your back knee so your heel moves towards your back side and the cycle is completed. However, on a treadmill the belt moves to take your foot back behind you and therefore does a lot of the work for the hamstrings. This is why I suggest you supplement your training with treadmill running, rather than doing it all indoors.
Potential loss of key skills - When running outside, although it may not always feel like it, you're constantly running on uneven surfaces whether it's a pavement or a trail. Your feet are therefore making slight adjustments continuously, and over time this helps to improve your agility, co-ordination and balance. As a treadmill is pancake flat, you can lose out on these possible benefits by sticking to just a machine.
It's dull - There, I said it! The repetitive nature of treadmill running and the fact that you're moving but not actually going anywhere can make it very boring. I'd suggest doing speed work rather than steady state as it's typically shorter in duration and the variety makes it more interesting. If you do need to do steady state however, my advice would be to put a lot of thought and effort into your playlist!