How Running Differs on the Curved Treadmill
While the purpose of this post was to dig through the current literature on non-motorized curved treadmills (NMCT) and make it easily understandable, I’ll dedicate the first couple hundred words to discussing how to most effectively and safely run on one.
Understanding what the curve is trying to encourage in terms of running posture would be the first step in improving your technique on the machine. The only way to get the belt moving and remain at a consistent pace is to run with a slight forward lean, striking with mid- to fore-foot and maintain a high cadence. So to get the belt moving, assume a slight lean of the torso and start jogging. Due to the lean, you may feel most comfortable starting with your hands on the side rails but you should attempt to quickly transition to using the appropriate arm action. As your cadence (steps per minute) and knee drive increase, so should your pace.
To better understand how fast you should be running and what type of workout to perform, the following summary on the current literature should influence your decision. If you have any additional questions, reach out to us at unifiedhp@gmail.com.
A couple sessions on the Air Runner and you’ll be Eliud Kipchoge running a 2 hour marathon.
Patrick Schoenmakers and Kate Reed appear to be pioneering the most comprehensive research projects on the non-motorized curved treadmill running. The conclusions from the current research will be of no surprise to anyone who has spent any duration of time running on the Air Runner. At any given speed, an athlete will be training at a higher relative oxygen uptake (percentage of VO2 Max) than they would be if they were on a traditional treadmill. This means that despite covering the same amount of distance, it is a more demanding effort. This is also demonstrated by the heart rate response; with athletes running at a higher percentage of their max heart rate at any given speed while on a NMCT.
Running economy is a term that defines how effectively you use fuel to move at a given pace. Larger runners have lower running economies because of the amount of muscle mass that is required to oxygenate. Weather conditions, slope, and terrain all can impact running economy as well. Based on the results of Schoenmakers and Reed’s study, runners appear to have a less efficient running economy when on a non-motorized curved treadmill.
While that sounds like it would be considered a strike against running on a NMCT, it would be comparable to adding load to a squat. Yes, you require more energy and incur more muscle damage when squatting with a weight but that challenge is necessary to promote muscular adaptation. A NMCT can be used to overload the system and present a greater challenge to the athlete, which in turn should improve economy when they return to running on the road. Understand the purpose, understand the athlete, and program use of the NMCT accordingly.
Practical Applications of the Research
Since the perceived difficulty and heart rate response to a given pace is higher on the curved treadmill than it is on the traditional treadmill, the former could be a viable option for someone who is:
1. Rehabbing a running-related injury
2. Transitioning between a walk/run program and a steady state running program
3. Weight loss client that is able to achieve a higher intensity without the joint impact of running
Schoenmakers and Reed are working on a project now demonstrating how running on the curved treadmill is comparable to running on 8% incline on a traditional treadmill. This helps explain why a few minutes on the NMCT has you feeling your hamstrings, calves, and glutes in a way that is only replicated when you’re pushing the pace during a hill climb. In general, Schoenmakers recommends running at a slower pace when on the NMCT; “for instance, if they usually run 6:43 minutes per mile in their training, a pace of 8:03 [on the NMCT] will mimic that. The same conversion factor can be used for long distance and tempo runs”. This is important to note when trying to elicit a certain training effect whether you’re building an aerobic base or training in intervals at threshold pace.
References
Schoenmakers, P. P., & Reed, K. E. (2018). The physiological and perceptual demands of running on a curved non-motorised treadmill: Implications for self-paced training. Journal of Science and Medicine in Sport, 21(12), 1293-1297. doi:10.1016/j.jsams.2018.05.011
Smoliga, J. M., Hegedus, E. J., & Ford, K. R. (2015). Increased physiologic intensity during walking and running on a non-motorized, curved treadmill. Physical Therapy in Sport, 16(3), 262-267. doi:10.1016/j.ptsp.2014.09.001
Snyder, A. C., Myatt, C., Weiland, N., & Bednarek, J. (2011). Energy Expenditure While Walking on a Non-Motorized Treadmill. Journal of Strength and Conditioning Research, 25. doi:10.1097/01.jsc.0000395752.34040.25
Waldman, H. S., Heatherly, A. J., Waddell, A. F., Krings, B. M., & Oʼneal, E. K. (2018). Five-Kilometer Time Trial Reliability of a Nonmotorized Treadmill and Comparison of Physiological and Perceptual Responses vs. a Motorized Treadmill. Journal of Strength and Conditioning Research, 32(5), 1455-1461. doi:10.1519/jsc.0000000000001993