Compress, perform, recover
The science of compression wear
A glance around the gym floor confirms the transition of compression clothing from athletic niche to the mainstream fitness market. Kyle Earnshaw looks at the science behind compression wear to evaluate whether the claimed benefits are supported by research.
The past few years have witnessed a huge growth in the popularity of compression garments among practitioners of all sports and fitness activities, from recreational to elite level. But what training advantage can such clothing claim to produce – and is it backed up by science? Let’s take a look at the history behind compression wear and the recent research into its benefits.
Over 60 years ago, patients suffering from venous disorders (including deep-vein thrombosis) were given compression treatment for the first time, the aim being to enhance circulation, reduce blood pooling and increase deep-tissue oxygenation. Compression has also been shown to achieve positive results in individuals with blood clotting, chronic swelling and lymphoedema.
Fast-forward three decades and researchers turned their attention to whether compression could help athletes receive the same circulatory benefits as patients. Study results published in the American Journal of Physical Medicine in 1987 showed that after intense exercise, athletes who wore compression socks exhibited lower blood-lactate levels. It is theorised that the garments help transport more blood deep down to venous calf muscle pumps, which reduces incidence of swelling and pooling, and reduces lactate1. It would be natural to draw the conclusion that if compression garments were applied to other areas of the body then a similar response could be expected.
With initial studies focusing on the post-operative improvements in venous blood flow in the lower extremities, scientists began looking into the effects of compression clothing on athletic performance, with a focus on power production in explosive activity. Studies were conducted on athletes’ maximal vertical jump height, and sprint times over 60 metres. Improvements in maintenance of jump height were noted along with an increased frequency of stride in sprinting for those wearing compression shorts2. This gives rise to the question of how a compression garment could have an effect on power. It seems that compression wear can improve proprioception and reduce muscle oscillation, thereby improving muscle efficiency. If this is the case, then it could be concluded that this improved efficiency of movement would lead to the enhanced performances.
In a recent two-part study, six trained runners ran continuously for 15 minutes at 80 per cent of VO2 max. The first part of the study measured oxygen-cost when running in compression shorts, and the second part gauged cost when wearing conventional running shorts. The results showed a significant reduction in oxygen consumption (up to 26 per cent) in comparison to conventional running shorts3. As with the initial studies on power development, researchers concluded that the positive effect of compression clothing may improve movement efficiency by improved proprioception and muscle coordination. This therefore reduces the amount of oxygen required for a set intensity and points to the use of compression wear as a performance aid in competition, or recovery aid when lower intensity training is desired.
Blood lactate levels
With the beneficial effect of compression wear on circulation established, scientists looked further into the effect of improved venous return on the removal of blood lactate from working muscles. Testing study subjects at 110 per cent of VO2 max on both treadmill and bicycle ergometer, researchers found that there was a decrease in post-exercise blood lactate concentration when the compression tights were worn4. The conclusion was that the compression tights were increasing the amount of lactate held within the muscles, therefore reducing the amount released into the blood.
In a recent New Zealand study, the effect of compression wear on muscle damage recovery – as gauged by creatine kinase levels – was measured. Twenty-three elite male rugby players were randomly assigned to complete one of four post-match recovery strategies: passive recovery; active cool down; contrast water therapy; and compression tights. As expected, the passive recovery method showed the highest levels of creatine kinase at all recorded time intervals. It was interesting to note that there was no significant difference among the three other methods5, meaning that compression was just as effective as active recovery and contrast water therapy.
In another study, two groups of untrained men and women performed two sets of 50 arm curls using an isokinetic dynamometer. Within this test a maximal eccentric contraction was imposed every fourth repetition. Participants who wore a compression sleeve for five days after the test showed a reduction in swelling and perceived pain, and reduced impact to elbow joint range of motion. Additionally, they displayed a significantly lower circulatory creatine kinase concentration6.
Individuals will vary in their ability to handle different stressors and the regeneration of normal metabolic reserves should be a priority for all active people from the elite to the recreational. This selection of research suggests that compression wear may be both a performance and recovery aid through improved circulation, enhanced proprioception and reduced muscle oscillation.
As fitness professionals we know that the practices to promote recovery should commence immediately post-training or competition. We also know, however, that adequate cool down is often neglected. Compression wear may be a way of ensuring a greater number of exercisers recover faster and can train harder. Its ease of application, and ability to be worn in transit, thereby enabling recovery to continue after leaving the training setting or sports arena, make it an appealing option to aid in post-exercise recovery.
1. (Tawnee Prazak, Triathlete.com) http://triathlon.competitor.com/2011/08/gear-tech/under-pressure-does-compression-apparel-work_32884/2
2. J Sport Sci 2003; 21:601-610
3. Int J Sports Med 2006; 27:373-378
4. Am J Physical Med 1987; 66:121-132
5. Br J Spts Med 2006; 40:260-263
6. J Sports Rehab 2001; 10:11-23
With a background in exercise physiology, Kyle studied exercise and health in New Zealand. He has worked as a health consultant, exercise physiologist, personal trainer and sports conditioner. Kyle is currently the brand manager for CW-X Conditioning Wear. Network members receive a 20 per cent discount on conditioning wear purchased at www.cw-x.com.au when entering the code AFNPT at the checkout.