As the nights get darker and colder, thoughts of some runners and walkers turn to treadmill training. Dr Brian Hanley considers whether it is a good idea
Treadmills are useful for endurance athletes for a number of reasons: a fast and even pace can be maintained, adverse weather conditions avoided and technique or pace monitored carefully by athlete and coach. While athletes can use treadmills for interval-style training sessions where the pace varies, they are more commonly used to maintain a constant speed over a prolonged period.
But does technique change on a treadmill? Is your body forced to adopt a style it wouldn’t assume on the track or road? We recently conducted two studies at Leeds Beckett University that were published in the Journal of Strength and Conditioning Research. Each looked separately at changes in distance running and race walking biomechanics over the course of a fast 10km session on a treadmill. So what did we find?
For the study on running, 15 male competitive distance runners took part. Their best times over 10km ranged from 30-35 minutes and the athletes specialised over distances from 5km to the marathon. For the race walking study, 14 international race walkers took part, of whom nine were men and five were women. Eight of the race walkers had competed at the Olympic Games or World Championships. All of the volunteers were frequent treadmill users, particularly those race walkers from northern European nations such as Finland and Sweden where the winters are particularly inhospitable.
The athletes were tested on a specially constructed treadmill with two force plates embedded that were used to measure important variables such as impact force and contact time. High-speed video recordings at 250 frames per second were made of the athletes and biomechanical variables were measured at multiple distances during testing to observe any changes with fatigue. All athletes completed their run or race walk at 103% of their season’s best time. For example, an athlete whose best time for 10km was 30:00 ran the distance on a treadmill in 30:54.
What we saw
For both runners and race walkers, there were very small increases in step length and a corresponding decrease in step frequency with the distance completed, although these changes were so small that they were practically meaningless (they might be just caused by normal variations in how people run or race walk). Indeed, the changes for the distance runners occurred so early that they might have been due to a warm-up effect rather than because of fatigue. Overall, very few technical changes were noted for either group and it would therefore appear that endurance athletes maintain their gait biomechanics throughout a physically demanding treadmill session. Our findings suggest that, contrary to what some coaches and athletes think, using a treadmill is a valuable way to develop a consistent movement pattern with low variations in how the legs are stressed, and can be useful in learning even-speed pacing before racing.
One important change that occurred was an increase in flight time. The opposite normally happens in competition, with the result that the athlete slows because of shorter steps. While longer flight times are generally associated with faster speeds in running, and to a lesser extent in race walking, it is possible that during this fatiguing treadmill test the increase in flight time was a means of coping with the demands of the continuous fast pace.
When using a treadmill, an athlete makes repeated, yet brief contact with a moving belt (rather than pushing against a stationary surface) and the athletes in these particular studies might have increased flight time so that more of the belt passed beneath them while they were airborne. This can often lead to the athlete “drifting” backwards on the belt so they then need to quickly adjust their position to avoid falling off. While this response to fatigue is not normal or beneficial during “overground” locomotion, it is not particularly problematic for the distance runner.
By contrast, race walkers should be wary of using treadmills extensively in training in case it leads to the development of non-legal technique. The coach should observe such treadmill sessions to ensure that visible loss of contact does not occur as fatigue sets in. Such an eventuality might be more common in physically demanding training sessions where the athlete is determined to complete the session within a planned time, and legal technique is sacrificed for speed.
What it means for you
Our latest findings show that there is little material change in biomechanics during physically demanding 10km treadmill sessions, so athletes who use treadmills for training can be confident that will remain consistent. Contrast this with overground training and the changes that occur because of weather, changes in direction, or variations in terrain and the attraction of switching to an indoor belt for some sessions becomes obvious.
For race walkers, this coaching benefit should not be merely considered a potential bonus, but actually adopted as an integral part of any treadmill session as it permits continuous judgement of legal technique. This is particularly important for monitoring any visible loss of contact, rather than for knee infringements which weren’t found to occur with fatigue in our study.
Some previous research has suggested that treadmill and overground gait differ slightly, but it is possible that these opposing findings were down to the quality and nature of the equipment used. Find a good-quality treadmill and use it when the surfaces used in competition such as road and athletics tracks are inaccessible.
» Dr Brian Hanley is a senior lecturer in sport and exercise biomechanics at Leeds Beckett University and a Level-2 endurance coach