The effects of compression clothing during training and sports
In endurance sports, compression is almost part of the basic equipment of ambitious athletes. In marathons, a large proportion of participants run with the distinctive socks. Footballers, handball players and athletes
in many other sports also use compression clothing. But what is actually involved? How does compression clothing work? Can compression garments also support training in the gym? Can the improved training effects be scientifically proven?
F&G and asked one of Germany's most renowned experts: Prof. Dr. Billy Sperlich, head of the Integrative and Experimental Training Science department at the University of Würzburg.
F&G: How does compression clothing affect the human body?
Prof. Dr. Billy Sperlich: You have to distinguish between medical compression and the hoped-for effects in competitive sports.
In the case of a person with venous insufficiency, i.e. someone whose veins are really unphysiologically wide, compression clothing makes perfect sense in order to support the venous valve function in such a way that the venous return flow is facilitated.
But these are pathological conditions and mostly these people are inactive or postoperative or bedridden. So the muscle is not moving enough or not moving at all. As soon as movement comes into play, there is a trick: the so-called muscle pump, i.e., the muscle contracts and then the pressure exerted by the muscle is significantly higher than that exerted by the compression garment. Compression can only work at all when muscles are less contracted or not contracted at all, for example in the flight phase of jogging. Therefore, compression can work for athletes under certain circumstances, probably best in phases without muscle tension, i.e. during recovery.
F&G: Why has compression clothing become so popular in recent years, especially among endurance athletes?
Prof. Dr. Billy Sperlich: The running scene is hoping for a physiological effect: if venous return is facilitated, the heart would fill up more, and with each heartbeat it would therefore eject more blood and thus transport more oxygen. This is the basic reasoning.
But, these assumptions were not confirmed in our studies. Nothing happened, oxygen uptake was not affected in our studies. There was no increased venous return in the heart.
F&G: What exactly is the difference between this and "classic" thrombosis stockings?
Prof. Dr. Billy Sperlich: In the case of people on an airplane, in hospital, postoperatively, etc., there is no movement involved, so there is no muscle tone. That's a completely different process physiologically.
F&G: How did you come to deal scientifically with the subject of compression in sports?
Prof. Dr. Billy Sperlich: Many companies became aware of us after the 2008 Olympics and wanted us to test their products.
Our research group started by reading up on everything that compression can do to promote regeneration and performance in sports. These are parameters such as oxygen uptake, lactate values, muscle inflammation markers etc. For each study, however, you will also find counter-studies.
Then we looked: What are the expected performance-enhancing effects? Is it sprint times, jump heights, power output or, in cycling, maximum performance values such as time trials?
F&G: Have you been able to demonstrate any benefits from wearing compression garments in your studies?
Prof. Dr. Billy Sperlich: According to my current knowledge, I can conclude that if an endurance athlete feels comfortable with compression clothing and decides to wear such clothing, I would not advise him or her to do so, unless the pressure is very high, but I would also not say it is a must.
And: there is another possible benefit of compression garments that we can't quite grasp at this time. Let's take Achilles tendon or joint pain. The doctor may prescribe bandages, which is also a kind of compression. Surveys show that 50% find this compression comfortable and supportive, while the other half do not. However, the performance-enhancing effect of compression-induced pain reduction is also not measurable.
In terms of regeneration, however, compression is again more promising, because here we find a resting muscle. Swollen muscles with micro-injuries, are in rest mode after training. Muscle degradation markers show an accelerated degradation process when compression garments are applied. This also matches the subjective feeling of exertion of many respondents who said: Yes, the muscle feels better.
The increased muscle temperature when wearing compression garments also seems to promote recovery. When the muscle is warmer, biomechanical processes run better, not necessarily because of the compression, but because of the warmth. We don't know yet exactly which effect is primarily responsible for the faster recovery, maybe it's both.
F&G: And what is your personal conclusion?
Prof. Dr. Billy Sperlich: First of all, my conclusion is that, as things stand, I would see compression more in terms of regenerative aspects than in terms of performance-enhancing aspects. However, one could also conclude that a faster regeneration in turn leads to an increase in performance. However, this has not yet been properly understood.
I have not yet been able to prove the effect of facilitated return transport of the blood in healthy veins through compression in various studies.
F&G: Is it already possible to formulate recommendations for the targeted use of compression garments?
Prof. Dr. Billy Sperlich: You can't simply polarize the topic. It always depends on what you want to achieve.
In the case of skiers, for example, who had a lot of tension on the muscle, the downhill squat was about ten degrees lower with compression over a period of three minutes than without compression. Here, compression is also a slight mechanical support, depending on the material. Compression is definitely recommended for skiers, but maybe not for a 5,000 m runner. For marathon runners, whose muscles get tired after tens of kilometers, perhaps more so.
However, compression is definitely recommended for recovery after a run; the likelihood of faster recovery is given.
We tested compression garments in sprinting. Women sprinted 30 x 30 meters almost a tenth faster with compression. But the effect only occurred after the 25th sprint, when the muscle was already properly fatigued. Perhaps these are more biomechanical processes, longer stride length or neurological feedback through compression probably helps additionally.
F&G: So compression is more a topic for competitive athletes?
Prof. Dr. Billy Sperlich: No. It does not necessarily depend on the performance level. There are many influencing factors: What is the vein situation, upright or lying position?
For loads with muscle oscillations, such as skiing or, mountain biking, compression would be recommended. From a preventive point of view, I could imagine - but we have never studied this - that mechanical support can also help. Doctors do nothing else by prescribing bandages.
I could also imagine that in overweight people a body toning effect occurs, in that they feel better and like to wear compression garments.
However, I see a disadvantage in heat regulation: when large parts of the body are under pressure, less heat is exchanged and sweat production is increased. The biomechanical processes then run at full speed and the body is strongly heated. Some manufacturers therefore offer net-shaped clothing. In regeneration, however, the warming is positive again.
F&G: What about strength training?
Prof. Dr. Billy Sperlich: For strength training with compression garments, there is a positive effect, but this has not yet been proven, but targeted studies are planned: I could imagine inducing mini-hypoxia through high compression during bench presses or leg extensions. But one would have to wear the compression garments chronically.
With the pure occlusion training, it is like tying off the limbs so much that the blood flow is reduced. In that case, however, the compression has to be really tight. With simultaneous training, the muscle is then hypoxic, i.e. undersupplied with oxygen - which is the case with strength training anyway - and can then achieve the hypertrophy effect and intensify the training effect.
Compression garments might be a compromise. You could also wear them longer. We will explore this in the future, with sports students as test subjects: one leg with and one leg without occlusion or even compression, the own body as a control comparison.
The training effects of occlusion training have been proven for the strength area, but those of compression clothing have not yet been proven.
F&G: What is your summary of the current state of science?
Prof. Dr. Billy Sperlich: A lot of research is being done, but there is still no consensus.
Another problem for exact investigations is that there are only standard sizes. But that is not very helpful. Above all, it has not been proven which pressure is actually achieved.
F&G: Thank you very much for your assessment and the interesting discussion.
Source: F&G
Published on: 27 March 2015