Scientists used a new study which measured the difference in effort runners expended on motorized versus self-powered treadmills. Their conclusion proves that you will work harder on a curved treadmill, than a flat treadmill.
Self-powered treadmills like the NOHrD Sprintbok, Woodway Curve Trainer and Technogym SkillMill Connect are cleverly curved to help you power your run. In order for the running belt to move, these treadmills use your bodyweight along with the friction of your foot running action to replace the need for a motor. How fast you move depends on how far up the front of the curve you step, and the resistance of the belt is adjusted using a knob placed on the front of the machine.
Many first-time users of a self-powered treadmill experienced shortened breath and a quickened heart rate much quicker than they would usually on a motorized treadmill. This has led many to question if curved treadmills were designed to make them work harder.
The answer is yes, according to the Journal of Science and Medicine in Sport’s recently published study.
The University of Essex School of Sport Rehabilitation and Exercise Science recruited 13 male runners for this study. All 13 had 5K PRs of 20 minutes or better. Over the duration of two weeks, the runners completed four treadmill runs. To define baselines for each individual runner’s maximum heart rate, oxygen uptake and velocity, the first run was a voluntary run to exhaustion. This was completed on a motorized treadmill with the gradient set at 1 percent.
The curved treadmill was familiarized by the runners on the second run. This was done by practising the protocol which they would be following on the final two experimental runs: 4 minutes of running at 5 different velocities, between each interval, there would be 3 minutes of passive recovery. The 5 different velocities were set at 40, 50, 60, 70 and 80 percent of their personal maximum velocity.
During the third and final runs, the participants completed the intervals which they had practised on the second run on motorized treadmill and a curved one. The researchers measured the runners’ cadence, respiratory exchange ratio, heart rate and oxygen uptake during the last minute of each interval as well as asking the runners to rate their perceived effort.
Similar to the manufacturer’s claims, the researchers found that runners do work approximately 30 percent harder on the self-powered curved treadmill. The runners perceived to work an average of 27 percent harder on the non-motorized treadmill. Physiologically, their symptoms matched as they had 2.5 percent higher running cadence, 16 percent higher heart rates, consumed an average of 32 percent more oxygen and 38 percent worse running economy in comparison to when they ran at equivalent speeds on the motorized treadmill.
The study’s first author, Patrick Schoenmakers pointed out that in spite of the intimidating statistics, curved treadmills have marked advantages. He said that, “every step you take affects what the (curved) treadmill does”. This means that in contrast to a motorized treadmill, the curved treadmill allows runners to self-regulate every footfall in the same way they would if they were running outside. Whereas, a motorized treadmill requires you to make conscious decisions to speed up and slow down as you use buttons to generate the speed you wish to run at. For runners who don’t wish to think about their pace either before or during a run, the curved treadmill provides a better alternative. Furthermore, scientists also benefit from the curved treadmills for studies regarding how athletes will react naturally to stimuli such as hearing “run faster or harder”.
Schoenmakers also noted that for athletes who live in flat areas but wish to train for hill running, the curved treadmill provides a useful tool. This is because the self-powered machines give an effective workout to the posterior chain muscles: hamstrings, glutes, calves. Along with his co-author, Kate Reed, Schoenmakers is working on a study to show that curved treadmills represent the same as an 8 percent gradient on a standard motorized treadmill.
Apart from working on the posterior chain muscles, Schoenmakers says that people should choose whatever method of running they prefer as outdoor running, curved and motorized treadmill running interchangeable. What should be noted is that even when people have become comfortable operating curved treadmills, as they can feel awkward at first, they should keep in mind at least 20 percent difference in pace.
Schoenmaker wrote in an email that, ‘runners can be advised to lower their speeds.” He explained that for example, “if they usually run 4:00 minute per kilometre reps) in their training, a speed of 12 kilometres per hour will mimic that.” This conversion factor may also be used for both tempo runs as well as long distance runs.