By Therese Iknoian
For the complete story, see GearTrends® Fitness 2007, p. 38, "Take the A-Train"
No published, peer-reviewed studies exist that fully analyze the energy expenditure and biomechanics of any single A-Trainer, nor are there any comparative studies available. The equipment is just too new for those kinds of studies to exist.
However, a number of manufacturers have done or sponsored their own studies, usually by accredited sport scientists. GearTrends® can’t verify they are accurate, since we have only been given summaries and weren't able to truly assess methodology. In addition, the true marker of a research study is peer review, which allows a study’s entire protocol to be reviewed by a committee of scientific peers for bias, as well as testing and statistical accuracy. That's why those that finally end up in print in a journal, like the British Journal of Sports Medicine or the American College of Sport Medicine's Medicine and Science in Sports & Exercise, can be considered mostly more quotable and reliable. In addition, studies are commonly "replicated" in the research world, meaning other researchers do a study after the first one or more that is the same or very similar in methodology to try to come up with the same results, thereby helping to prove the first study was accurate and performed correctly.
The research summaries we have gleaned from Cybex, Lamar, Life Fitness and Matrix mostly have taken a look at stride and a user's biomechanics, sometimes comparing their own equipment to others. Our request to review a copy of the study commissioned by Precor on its new AMT equipment was declined, with company representatives in late spring 2007 saying it was still being fine-tuned. None of the studies or information presented below have been peer-reviewed or replicated.
>> Cybex Arc Trainer -- A few years ago a study on the Arc Trainer was done out of Florida by Paul Juris, who since has become executive director of Cybex's training arm, the Cybex Institute. He and his colleague compared the gait of users on two machines, the Arc Trainer and the Precor EFX 546. It concluded that the Arc Trainer was safer due to a user's more vertical position, degree of knee flexion and magnitude of ground reaction forces, as well as the sharing of the work between hip and knee on the Arc Trainer instead of the knee being forced to do all the work on the Precor.
>> Lamar Fitness Hiker -- Its study, done last year, compared caloric use in three different training modes -- hiking, gliding and elliptical-like -- on the Lamar "Hiker." Using male and female subjects that ranged in age from 17 to 49, with weights ranging from 128 to 270, the study analyzed caloric use of each of three modes, which the subjects did for five minutes, one after the other. It found that subjects who were in a steady aerobic state used on average 9.68 calories per minute when in glider mode, 10.86 when in elliptical mode and 11.91 when in hiking mode. It was concluded that this increase with increased vertical motion was consistent with current research. The study also noted that although not directly measured, the study compared results to other caloric-expenditure studies and found that the climbing motion had a similar energy use as did treadmill exercise.
>> Life Fitness Summit Trainer -- GearTrends® was only able to look at a short summary that give recommendations for movement and did not present any scientific data. It concludes simply that incline training "provides users with a new challenge." The addition of such training, it goes on to say, is that it provides "greater muscular loading of the leg." It also states that it promotes greater hip flexion but because of that needs to be balanced by hip extension and gluteal activation and discusses features the company says a machine should have, which happen to correspond to features of the Summit Trainer. We can't judge the research behind this at this point.
>> Matrix Fitness Ascent Trainer -- Of the companies that had studies, Matrix was the most open, sharing the study's charts and graphs, as well as allowing us to interview those who coordinated and performed it. It compared three machines -- the new Matrix Ascent Trainer, another with an "arcuate" path, and another called a "variable inclining elliptical." The company did not release the brands of the other two, but we can pretty wisely note that the "arcuate" one is the Cybex Arc Trainer (since it is the only arc-mode machine on the market) and the elliptical is the Precor (since it is still considered the market leader and is the one that everybody is aiming to knock over). The study compared the paths of the three modes (including stride length and step-over height) and caloric expenditure. Subjects were eight men and three women, with an average age of 31 and an average weight of 165.3. Perhaps not surprisingly, the research showed the Ascent Trainer resulted in subjects with lower heart rates (average, 5 percent), but higher caloric expenditures (average, 6 percent). This resulted in about 16 to 20 additional calories used over 30 minutes. GearTrends® isn't sure how significant 16 calories are, but Matrix researches note that they'll add up over time. The company also notes that more research is needed.
We hope no retailer will use singular, company-provided, non-peer-reviewed and non-replicated study results to promote a particular machine, let alone cite the statistics on gait and calories based on small user groups used by these studies to date.
Don't miss the full story, "Take the A-Train," in the GearTrends® Fitness 2007 issue. To download the full issue, go to www.geartrends.com/magazines.