Winter treadmill training: the route to road success

The shorter days and inclement weather in winter forces many athletes to train more indoors. The good news for runners is that this can actually be turned into an advantage…

Winter is here.  Not only is it dark, the very short days for northern latitude dwellers are accompanied by worsening weather conditions, which at best make running and cycling a chore and at worst (when it’s icy or foggy) downright dangerous. Moreover, when the roads are wet or the pavements are icy, it’s that much harder to put in high quality sessions. And for lone women, safety and security issues (particularly on dark winter evenings) can also be a concern.

Indoor options

For most athletes, maintaining decent levels of aerobic fitness remains important during the dark winter evenings, and there are various indoors training options available. Cycle training can be performed on rollers or a training turbo, both of which can provide a good training substitute for the real thing and are relatively inexpensive. Rowing training is another great option, although decent indoors rowers tend to be a bit pricier. Maintaining running fitness while training indoors however is more of a challenge.

While it’s possible to purchase a fairly decent cycling turbo-trainer for $300-400 whereas a decent treadmill is going to set you back nearer a grand - and probably more for one that’s robust and reliable. Then there’s the issue of space; turbo trainers or rollers are easily stashed upright and out of the way but even the most compact folding treadmill comes with a significant footprint. For that reason, many athletes who need to perform high-quality running sessions when outdoors running is tricky choose not to invest in a home treadmill, but instead use a commercial grade treadmill at the gym. Of course, that involves the extra expense of travelling to and from the gym, as well as membership costs. Despite these drawbacks however, there’s good evidence that performing at least some running sessions on a treadmill could be worthwhile.

Treadmill benefits

The biggest challenge of treadmill training is without doubt monotony and boredom. That’s why treadmill sessions ideally need to be structured in such a way to create variety and interest (see later). However, putting these issues aside, there are distinct benefits provided by indoors treadmill training. For starters, there’s no need to worry about finding well lit, traffic and pollution-free routes, nor are there safety issues for women training alone during dark winter evenings. There’s also the advantage of being able to control gradient at will and (on many treadmills) the ability to use treadmill-controlled heart rate training.

Another benefit concerns injury risk, or rather the potential for reduced injury risk when substituting treadmill running into a program. Studies on athletes undertaking regular running training have reported a one-year injury prevalence of over 50%, and of these, an incidence of musculoskeletal injuries approaching 80%^(1,2). The cause of running-related injury is usually related to repeated musculoskeletal trauma, which can be attributed to various risk factors. One of the most important of these is cumulative ground-reaction impact forces, which occur when the foot strikes the ground.

For example, a 2016 study examined 240 runners over a two-year period and reported that impact loads were greater in those runners who experienced a running injury compared to non-injured runners⁽³⁾. Meanwhile, in the same year, a systematic review looked at combined data from 18 studies on impact loading during running and found that runners with higher loading rates were more likely to have injuries than those with lower rates⁽⁴⁾.

Reducing impact

Of course, good running shoes and running technique can significantly reduce footstrike impact, but the training surface plays a major role too – and this is where treadmills can provide a real benefit. For example, two studies on this topic found that running on hard surfaces such as concrete and tarmac typically give rise to impact forces in the foot that are up to 18% higher than those produced on more yielding surfaces such as grass, and the deck of a treadmill^(5,6).

Meanwhile a study carried out last year compared the shock absorbing characteristics of tarmac, a tartan track and a treadmill deck⁽⁷⁾. Ten experienced male endurance runners performed a 40-minute running bout at their preferred constant speed on the three different surfaces, each trial separated by seven days. The shock absorption, vertical deformation, and energy return properties were measured for each surface. The key finding was that shock absorption/impact reduction was vastly better on the treadmill (0.0% on asphalt, 37.4% on tartan and 71.3% on the treadmill. The downside (as you might expect) was that the excellent shock absorption characteristics meant that energy return on the rebound was much lower on the treadmill (90.8% tarmac, 62.6% tartan, and 37.0% treadmill). While this drop in energy return reduces running efficiency (steady-state speed per litre of oxygen consumed), since treadmills are used for training rather than racing, this is not really an issue!

Another treadmill benefit concerns camber – or lack of it when compared with road running. Depending on the location and peak rainfall rates in a given area, roads typically slope downwards from center to edge by around 2-5 degrees (camber angle) in order to ensure efficient water drainage off the road. However, research has found that a camber angle of less than 5 degrees to the side is sufficient to significantly alter running biomechanics in runners, altering the amount of ‘twist’ experienced around the knee joint in both the supported and unsupported leg⁽⁸⁾. You don’t have to be a biomechanics expert to understand that constant twisting at the knee joint, especially when combined with impact shock, is not a good recipe for healthy knees, which is why the perfectly flat deck of a treadmill can also help give the knees an additional break from the stresses of road running.

Finally, it’s worth adding that compared to running in the dark, treadmill running provides a well-lit smooth and hazard-free surface with no ruts, potholes or hidden obstructions to trip over. Although a trip injury might seem unlikely, a study on US army personnel found that lower extremity sprain/strain injuries were most commonly caused by falls, jumps, trips, or slips, many of which occurred while running⁽⁹⁾.

There are downsides to treadmill running of course; unless you have the luxury of one in the house, you’ll have to visit your local gym to treadmill train and you’ll find it harder to keep cool without the use of a decent fan. Then there’s the potential issue of boredom; endless hours of single-pace running staring at a wall is less inspiring than watching paint dry. The good news is that there are ways round this – see the tips box below – so maybe it’s worth getting on the deck this winter!

Practical advice

The take-home message here is that for athletes pondering whether to incorporate some treadmill running into their winter training program, there are many upsides and few downsides. The main benefits are twofold: firstly, high-quality training becomes possible when it is impossible outside, and secondly, treadmill training can give joints and ligaments a much needed break. Below are some tips for athletes wanting to add treadmill training a weekly program. For those who don’t have easy access to a gym, or have the space and funds to accommodate a treadmill in the home, there are some key points for consideration.

How to apply these findings to your own training:

• Consider scheduling one or two treadmill sessions per week into your regular winter training routine. Weekday evenings are ideal since you can perform your outdoor running at weekends;
• Make at least one of these sessions a high-quality one – for example by performing a structured interval program using variable speed, gradient or both.
• Use motivational tools such as music during training sessions to help inspire you and prevent boredom.
• Ensure adequate cooling when running. The use of a large and powerful fan trained on you is recommended, especially for longer sessions.
• Remember that while treadmill training is generally easier on the joints, you still need to ensure you warm up and cool down properly.

Key points for treadmill purchase

• Overall dimensions: Check it fits into your intended location and that you’ll have sufficient space to mount and dismount. If space is tight, consider a folding treadmill. Check too that it can be sited near a power point.
• Motor: Should be rated at least 1.5 CONTINUOUS horsepower and have good torque. At very low speeds, the belt should not slow when you step onto it (a sign of good torque). Check what sort of warranty is offered – the motor is the heart of the treadmill and expensive to put right in the event of a failure.
• Cushioning and Stability: What does the treadmill feel like to run on? A good treadmill should offer excellent cushioning, yet not shake, wobble, rattle or vibrate on each foot strike.
• Belt or Tread: While running, check that the treadmill belt is wide enough and long enough to accommodate your running style without feeling cramped. Check also that it moves smoothly across the deck.
• Maximum speed: How high is it? Treadmill motors used at near maximum speeds for long periods of time don’t last too long. Ensure it is at least 2mph higher than your regular training pace.
• Gradient control: Is there one? If there is, what is the maximum gradient? A higher maximum e.g. 12% is useful for walking workouts. Also check how quickly the gradient changes once the button is pressed!
• Handrails: These should be comfortably positioned and provide enough room to easily accommodate your running action. Make sure there are no sharp protrusions against which you could knock your hands or arms.
• Computer monitor: Should be easy to operate and the feedback comprehensive and clear. Find out what programmed options are on offer. Do they include heart rate control (very useful for beginners or those on demanding training programs)?
• Safety: Is there a safety cut-off in the event of a slip or fall?
• Noise: How noisy is the treadmill especially at higher speeds? Apart from being very irritating if you’re trying to listen to music or watch TV, quieter treadmills usually indicate a better standard of construction and motor quality.
• Construction: Is the mainframe substantially constructed? As a rule of thumb, the heavier the treadmill, the better. Is the frame welded or bolted (welds are better than bolts, which can work lose under heavy pounding)? Does the treadmill visibly yield when you step on it – this can be a sign of a flimsy build.