Once again I must apologize for the long gaps between posts. I’ve got a backlog of topics I want to write on (running shoes, periodization, and strength training, to name but a few pressing ones), but it seems there is never time. My coaching colleague, Jim Vance, and I are currently working on a book which has turned out to be a bigger task than either of us expected. I’ll fill you in on more of that as we get closer to the publication date.
In the past 4 years I’ve reviewed the scientific literature on compression garments, especially stockings, several times. The research does not provide overwhelming evidence that they do anything for performance or recovery. (You can visit those posts again here, here and here). But with their increasing use, especially by triathletes and runners, the research seems to be increasing. So what I’d like to do here is to update you on the most recent research to see if there is anything new. (If you click on the study’s link it will take you to the abstract on PubMed and you can read the details should you want a bit more information.)
Duffield, R., J. Edge, R. Merrells, E. Hawke, M. Barnes, D. Simcock, N. Gill. 2008. The effects of compression garments on intermittent exercise performance and recovery on consecutive days. Int J Sports Physiol Perform, 3(4):454-68.
This is an earlier study which I overlooked when writing on this topic previously. It’s a pretty good one for giving us some idea of how effective compression garments (CG) might be for recovery, which is a commonly cited reason for use. In this study 14 male rugby players did 80-minute, high-intensity exercise circuits. They did this on 2 consecutive days and then 2 weeks later repeated the 2 days of 80-minute, challenging circuit training. One of these pairs of days was done while wearing CG; for the other CG was not worn. Among the 14 subjects the use of CG was random—some used them for the first such pair of days and others for the second pairing.
Comparing CG and non-CG, there were no differences in performance, heart rate, body temperature (measured in the ear), changes in body weight, lactate or creatine kinase (a marker of cell damage) accumulation. Skin temperature was higher with CG. So it would seem there was no benefit in wearing CG. However, the subjects reported lower levels of muscle soreness in the 48 hours post-exercise when CG were worn.
So what does this mean for endurance athletes? First of all, the obvious question is can we draw conclusions from a sport that primarily emphasizes power with endurance being much less of a factor in performance and recovery? That’s an unanswered question. Secondly, nearly all studies utilizing CG have a common problem: you know when you are wearing them and when you aren’t. That provides fuel for those who would say that the placebo effect is likely what caused the subjects to experience less muscle soreness. Some studies have tried to get around this by having the subjects wear tight stockings or other tight clothing that weren’t CG. But even then it’s possible to tell the difference. This is the same sort of problem researchers run into when studying massage, periodization, diets, and strength training. Placebo will always be a major issue in such studies when the subjects are aware of the differences.
Goh, S.S., P.B. Laursen, B. Dascombe, K. Nosaka. 2011. Effect of lower body compression garments on submaximal running performance in cold (10⁰ C) and hot (32⁰ C) environments. Eur J Appl Physiol, 111(5):819-26.
I see more CG, especially stockings, at Ironman Hawaii than at any other races I attend. And I’ve often wondered about how the heat of Kona may affect those wearing CG. If the skin isn’t exposed to the air then it would seem that cooling through sweat evaporation is reduced. In Kona the temperature on the afternoon of race day when many athletes are out running in the lava fields is around 32⁰ C (90⁰ F). It’s unbelievably hot, especially for running a marathon. Would the athletes’ CG compromise cooling and harm performance?
Ten male runners who averaged 29 years of age and had a VO2max of about 59 ran on 4 occasions with the temperature and CG-use varying. Each run started with 20 minutes of moderate-effort. Then each would run at a very high intensity until exhaustion. The 4 conditions were: A) 10⁰ C (50⁰ F) with CG, B) 10⁰ C without CG, C) 32⁰ C with CG, and D) 32⁰ C without CG. The 10 subjects did these in random order.
The average run time to exhaustion was slightly better but insignificant with CG (10⁰ C: 158 seconds with CG and 148 seconds without; 32⁰ C: 115 seconds with CG and 97 seconds without). The subjects’ Rating of Perceived Exertion (RPE) was lower during the submaximal, 20-minute bout with CG at 32⁰ C than without (13.8 vs. 14.5 on 6-20 scale). At 32⁰ C there was no measured adverse affect when wearing CG.
Here we go again. Can a 20-minute, moderate-effort run in the heat followed by a less-than-2-minute run to exhaustion give us a good idea of what to expect in an Ironman or any other longer-distance endurance event such as even a 5-km running race? Could the subjects’ knowing that they were wearing CG cause the placebo effect to affect results? We’re back into the realm of opinion. I’d love to see what hot conditions while wearing CG may mean for athletes. I’m afraid this study isn’t of much help for us in this regard.
MacRae, B.A., R.M. Laing, B.E. Niven, J.D. Cotter. 2011. Pressure and coverage effects of sporting compression garments on cardiovascular function, thermoregulatory function, and exercise performance. Eur J Apply Physiol, (epublished ahead of print).
Can CG shorts improve cycling performance? I haven’t noticed these in any races yet but that may be because they are hard to detect. I know they are made because a manufacturer sent me some to try. I saw no obvious benefit from wearing them, but there was a lot of discomfort on long rides. But maybe it’s just me and they really are beneficial.
In this study a group of trained cyclists did three, 6-km time trials on 3 occasions: A) while wearing traditional bike shorts, B) while wearing properly fitted, whole-body CG, and C) while wearing loose-fitting, whole-body CG.
Condition B produced a slightly increased heart rate with a 5% increase in cardiac output. Also in B skin temperature, but not core body temperature, increased. There was no significant difference in mean power outputs or time trial performances among the 3 conditions.
The increased heart rate may well be due to the heart having to work harder against the mechanical load provided by wearing a compression garment. That’s typically not seen as a good thing, but then full-body CG are not popular with athletes anyway. So there’s unfortunately not much to glean from this study either.
This recent review of the scientific literature points out the problem I have been seeing as I’ve followed this topic for the last 4 years: CG research design is all over the place. Just in this post we’ve seen subjects who were endurance-sport athletes and power-sport athletes. The variables measured were performance, muscle soreness and physiological effects. When it comes to performance, one of the major reasons given by users for wearing CG, the standards vary from a few seconds to 80 minutes. If you read over my previous posts since 2007 mentioned above you’ll find an even greater spread of performance measures, subjects and protocols. There is so much variety that it’s really not possible to draw solid conclusions.
The bottom line from 4 years of following this topic is that each athlete must decide whether or not to wear CG based strictly on personal experience or the shared experiences of friends. The marketing for these products continues to make claims about performance-enhancement and recovery. Pro athletes, who are supported financially or with free products by such companies, make it seem that their success is, in large part, due to the use of CG. I’d suggest being very skeptical of such claims for as you’ve seen here there really is no solid evidence to support their use. If you try a product and believe it helps in some way then that’s about as good as it can get—at least for now. I’ll continue to watch and periodically report on what I find. Let’s hope that the research becomes more focused.