Treadmill running is quite often a contentious topic amongst runners. Some hate it, while some love it. A common phrase used is that “it’s not the same as running outside”, and this is true. A treadmill belt has more give in it than the road, so they can be more ‘forgiving’ to run on. The belt can also assist leg turnover which can allow runners to go a bit faster. There are no weather conditions to contend with while running indoors either and you won’t face any headwinds.
However, treadmill running presents other obstacles. The same wind that may slow you down isn’t cooling you down anymore. The speed is constant and there’s no let up so you have to stay focused. Time passes by slower as there’s nothing to look at. These obstacles present opportunity. Running on a treadmill can be very beneficial for a number of reasons and can enable you to work on certain weaknesses or specific areas in a more focused way than running outside.
Benefits of treadmill running
Running indoors on a treadmill puts you in different environmental conditions than running outside. The main differences are that it’s hotter and there’s no moving air to cool you down and move sweat away. Fortunately, there’s multiple benefits of running on a treadmill in the heat.
Increase in plasma volume
An acute response to exercise is an increase in plasma volume. Plasma in blood carries oxygen to working muscles and moves blood to the skin to assist with thermoregulation. An increase in plasma volume improves a runner’s ability to exercise at a given intensity with less effort.
Running in hot conditions stimulates a rise in plasma volume. This is mainly due to the fact that it’s hotter and there’s greater demands placed on our ability to regulate our temperature. So, running on a treadmill can improve our performance when we race or run outside, as we can in theory run at the same intensity with a lower heart rate due to a rise in plasma volume.
Improved body thermo-adaptation
Training in hot conditions also improves our ability to thermoregulate and improves our overall thermo-adaptation. New evidence is showing this type of training may improve performance in cold weather as well (1).
Training in the heat can result in reduced blood lactate at a given intensity in cool weather and improve ventricular compliance along with other similar adaptations. Essentially this teaches the body to manage thermo-stress better and improves its ability to react to extremes in temperature. Running on a treadmill indoors has the potential to improve performance in both hot and cool environments.
The two components of speed are stride length and stride frequency. Improving leg speed is an easy way to improve the capability to run at faster paces. As already mentioned, a treadmill belt assists leg turnover. For many, maintaining a high leg turnover is a limiting factor in their ability to move more quickly. Running on a treadmill can help improve leg speed due to the way it makes you run. This can translate into an improved ability to maintain better form at faster paces outside.
Pace yourself better
Many runners find it hard to run at set paces. One of the major benefits of running on a treadmill is that you don’t have to control the pace. This can be very beneficial for runners who struggle to do interval and tempo runs at the right pace. It’s also easier to construct interval sessions as the pace, time and incline can be controlled.
Treadmill running workouts
There’s an abundance of sessions that can be done on the treadmill but I think it’s best to use it for focused work. I recommend the following types of sessions for treadmill running.
Leg Speed Session
As mentioned before, the way a treadmill belt works is a great way to increase leg speed. I like to do some shorter distance reps at a fast pace to help increase turnover. This type of session has multiple fitness benefits including an improved ability to tolerate high levels of lactic acid. An example of this session would be:
- Warm Up: 10mins easy running at a relaxed pace, gradually building the intensity
- Main Set: 10x1minute at fast speed (I would aim to do these about 20secs faster than my 5km min/km average pace)
- 1-2mins rest/easy jogging between
- Cool Down: 10mins easy jogging letting the heart rate drop down
Hill Rep Session
Running up-hill works muscles in a different way from running on the flat and requires more leg strength. Performing hill reps will improve your ability to run up-hill but it will also improve your performance in the later stages of runs. This type of session places a similar type of fatigue on your legs that you'll experience at the end of a run when muscles are simply fatigued from the repetitive strain. Doing hill reps on a treadmill is much more convenient than doing it outside and can be more conducive to eliciting the most beneficial adaptations as the gradient, speed and rest time are totally within your control. I always find hill rep sessions outside can take ages because running back down takes too long. Below is one of my favourite sessions, it’s called “5’s”:
- Warm Up: 10mins easy running with a few 10-15second surges in pace
- Main Set: 5x5mins at a 5% incline at about half marathon race pace with 3mins rest in between (of course you could start off with 2 or 3 reps and keep the pace easier than that)
- Cool Down: 5-10mins easy jogging
This is a session I’ll specifically do in the lead up to a race. The aim of the session is to build the pace over a set period of time so the last part of the main set in the run is at the fastest pace. This pace will be a bit faster than the targeted race pace. By building the intensity and doing the hardest bit at the end, it again mimics the demands of the race. The treadmill makes it easy to control the pace and boosts performance for racing as a result of the mechanisms discussed earlier. Here’s my example build run:
- Warm Up: 5mins easy just getting the legs moving
- Main Set: 4x15mins building the pace every 15min block by reducing min/km pace by 10-15secs.
- Start at a steady pace and make the last 15mins at least 10-15secs faster than target race pace.
- Cool Down: 10mins very easy jogging
This session doesn’t have to be as long. Doing 3x5mins as build could work equally as well. The length of reps is dependent on the length of race.
Top tips for running on a treadmill
You may sweat more running indoors on the treadmill and lose more electrolytes as a result. It’s important to replace these during your session and immediately once you’ve finished. Sodium is the main electrolyte to replace. Always drink an electrolyte drink during treadmill sessions. There is a variety of energy and recovery drinks available on the Run4It website in our Nutrition category.
Wear the right clothing
The most important element in being able to exercise in hotter conditions is your perception of temperature. Studies have shown that performance is worsened in hot conditions when participants think they’re too warm.
Wearing lightweight, breathable and fast-drying clothing can help make you feel better than clothing that isn’t as technical. Your actual core temperature won’t be much different but you’ll feel more comfortable and that will improve performance.
Wear a heart-rate monitor to gauge your effort
There’s an idea that running on a treadmill is easier because the same outside pace would feel a bit harder. While some may find this to be the case, most people will find that their heart rate will be higher for that pace on the treadmill because of the temperature. So, the physiological strain is actually higher. Wearing a heart-rate monitor will help you gauge your effort more appropriately than just pace.
It’s widely accepted in the sports science world that running at an incline of 1% will mimic the demands of running outside more closely. I always approach this cautiously though as running at a constant incline could lead to overloading certain tendons and muscles. The additional heat stress of running inside means this isn’t really necessary.
The treadmill can be a valuable tool to improve your running
The topic of treadmill running will always be debated amongst runners. There is definitely no substitute for running outside in the fresh air and enjoying the outdoor freedom. However, there are many benefits of running on the treadmill and whether or not you incorporate it into your training is dependent on your motives. If your goal is to improve your performance and run to the best of your ability, then it should be a tool that you consider utilising. Whether that’s to improve your ability to race in the heat or execute an interval session effectively.
Balance is key and there’s no best way to do anything. Hopefully this article gives you an idea about how you can use treadmill running in your plan and what sessions you should do.
- Lorenzo S, Halliwill JR, Sawka MN, Minson CT. Heat acclimation improves exercise performance. Journal of applied physiology: 109(4), 1140-1147, 2010.