Compression suits: do they have any real benefits?

THE use of compression suits in racehorses is in its infancy and almost all of the reports so far have been positive, although most of them are within advertorials. Two racehorse trainers in South Africa, Justin Snaith and Brett Crawford, have bought compression suits chiefly for long distance travel. There is solid evidence that the suits are medically useful to humans in this regard. One manufacturer claims that its suit keeps muscle temperature warm in cold weather and cool in hot weather, and this is backed up by Her chiropractor Michael Bryant, who traveled with her, reported no sign of sweating in a testimonial within a compression suit advertorial article. Black Caviar also wears her compression suit immediately after exercise, as there have been good reports that the suit aids in recovery, injury prevention, and fatigue management. Her trainer Peter Moody has reportedly said that she visibly relaxes after it has been zipped on. The first racehorse to ever wear a compression suit was the Australian sprinter Hay List, winner of three Group 1s and runner- up to Black Caviar in four Group 1s. Trainer John McNair bought the suit due to Hay List’s injury problems and the horse wore it for the first time two weeks before the Group 1 Newmarket Handicap, which was his second run after a long injury-enforced layoff. He duly won under top weight and the public witnessed him in the suit after the race. McNair said the suits greatest advantage was for travel as the horse “recovers from the journey so much quicker.” Ed Dunlop used a compression suit on Melbourne Cup runner up Red Cadeaux’s return trip to England. Dunlop added, "We've been using it pre-exercise and it seems to help warm him up and get his muscles more supple as a result." Compression garments originated as medical devices for humans. Graduated medical advertorial testimonials. However, Snaith’s experience contradicted this. He reported that during hot weather travel, the suit caused an increase in sweating, and consequently his horses only wear it when traveling in cold or cool conditions. On the other hand, Black Caviar’s body temperature was monitored on her three-legged journey from Melbourne to London and it did not alter significantly throughout. She also only lost 8kg in weight – an acceptable amount for such a long journey – and her distal limbs had no evidence of swelling and were cool on palpation.  compression garments place the greatest pressure on the part of the limb farthest from the heart, with gradually reduced pressure closest to the heart. They have been shown to improve peripheral circulation, increase venous return (blood flow from the veins back to the heart), and reduce swelling. Garments of varying types are used post- surgery to encourage resolution of swelling and bruising, to facilitate skin retraction, and to flush the body of potentially harmful fluids. They are also used to aid in the healing of burns and to prevent or treat muscle strains and low blood pressure, and can be worn on long haul flights to prevent deep vein thrombosis. Perceived advantages of compression sportswear are that it speeds recovery from fatigue; reduces muscle soreness; improves ability to maintain performance levels when worn between exercise; removes post-exercise metabolic waste products from the blood, such as lactate, more quickly; encourages a more rapid return to pre-exercise creatine kinase (CK) levels (CK is a marker of muscle damage); as well as improves performance and maintains correct body temperature. The theory is that when compression is applied to specific body parts in a balanced way, it accelerates blood flow and this gets more oxygen to the working muscles, thereby boosting performance. Better blood flow also helps rid the system of lactic acid and other metabolic waste products, which helps an athlete work at a higher rate for longer. Furthermore, improved oxygenation reduces the effects of delayed onset muscle soreness and accelerates muscle repair. The way it works is explained well by Adam Trewin, a BSc honours graduate in Exercise Science. He said, “The circulatory system is comprised of both arterial and venous blood flow. Arterial blood is pumped from the heart/lungs, is oxygenated and flows at a high pressure. Correct fitting compression garments will not significantly impede this arterial blood flow. However, venous blood, which is deoxygenated having done its metabolic job of passing through the capillaries and offloading oxygen and nutrients to the active muscle, flows at a much lower pressure. These veins have special venous ‘one-way’ valves built in which allows blood to go back towards the heart, but not the other way. Muscle contractions squeeze the blood back to the heart and this is the main mechanism for venous return. Compression garments utilise this same mechanism.” Studies done on whether compression garments can enhance performance have been inconclusive, while evidence showing that they enhance recovery is more substantial. The use of compression suits in the Sharks Rugby team, a major professional franchise who play out of Durban in South Africa, provides a practical guideline, for at this level no quarter is spared in getting the best out of each player. Dr Glen Hagemann, the managing director of Sharks Medical and the President of the South African Sports Medicine Association, revealed that the majority of players only wore their c ompression garments after exercise. He reckoned the chief benefit of wearing the suit during play would probably be as an anti-chafe measure, as it wicks away sweat. He confirmed that the reason for use after the game was for recovery, injury prevention, and fatigue management, although he admitted that evidence even in this regard was still mainly anecdotal. The long-term benefit of the post-match use of compression garments is to maintain or improve subsequent performance. Marnie Oberer, a nutrionist, athlete, and television presenter in New Zealand, pointed out, “Recovery is a key component for any athlete wanting to make gains in their performance, yet – despite the popularity of various recovery interventions – it is an area “Black Caviar also wears her compression suit immediately after exercise, as there have been good reports that the suit aids in recovery” lacking scientific evidence. This is not to say the recovery practices of elite athletes are unwarranted, it’s possible that their anecdotal reports supersede future scientific verification.” Racehorses, if they could talk, might support this notion as all reports, although, again, chiefly advertorial, suggest that they “love” their suits. There have been no reports of horses becoming agitated after they have been zipped on. Dr Manfred Rohwer, who works for a thoroughbred veterinarian practise in South Africa, reckoned a compression suit would be of little use as a performance enhancer for an event as short as a horse race, pointing out that even rugby players only wear them after a game. Today’s racehorse, whose natural prowess as a creature of flight has been enhanced by years of select breeding, possesses a sophisticated mechanism for transporting oxygen to muscle tissue. On top of this, a third of the total red blood cells are held in reserve in the spleen and can be mobilised during the excitement phase of competition. It seems unlikely that a compression garment would enhance this process. However, there is little doubt that there is significant lactate build-up in a horse during any race. The administration of bicarbonates, otherwise known as “milkshaking,” began in the 1980s in horseracing as a method of neutralising lactate acid build-up. This has caused much controversy, and bicarbonate levels are now subject to screening limits on raceday. An American study performed on six human subjects using treadmills and bicycle ergometers showed a decrease in post-exercise lactate concentration when compression stockings had been worn during exercise. The investigators concluded that the compression stockings were increasing the lactate retained in the muscles, thereby reducing the amount released into the blood, which is contrary to other claims that the increased blood flow carries the lactate away. This was not the only study done on humans that showed reductions in post-exercise blood lactate when compression garments were used during exercise or afterwards. However, studies invariably show that compression garments cause a reduction in perceived post-exercise muscular soreness and a decreased level of creatine kinase. Studies on sportsmen have been limited by the fact that none appeared to have measured the level of compressive forces applied by the garment, and invariably there was no evidence to suggest the clothing exerted graduated compression. Furthermore, to date, there is little evidence to suggest that wearing compression clothing is more effective than other recovery interventions. A study by Gill and colleagues in 2008 tested professional rugby players with four different recovery methods after a match. They either did nothing after the match, performed light exercise on a stationary bike, immersed themselves to the hip in cold water, or wore compression garments. It was found that the latter three recovery methods were equally effective and that doing nothing resulted in greater levels of lactic acid, greater levels of creatine kinase, and greater levels of muscle soreness. Applied to racehorses, the compression suit would be the easiest and least time-consuming of the three recovery options, although more expensive than the light exercise option. “Studies invariably show that compression garments cause a reduction in perceived post-exercise muscular soreness and a decreased level of creatine kinase” One study done on university volleyball athletes showed that when wearing custom-fit compression shorts they were better able to maintain power output during repeated vertical jumps. The investigators concluded that the shorts increased the athlete’s ability to resist fatigue. In a further study done on university track athletes specialising in jump events, those wearing custom-fit compression shorts showed significant increases in countermovement jump height, plus significant reduction in muscle oscillation during landing. In this same group, 60-metre sprint times were not affected but average hip angle was reduced. Although not measured as part of the study, this suggested that stride frequency was increased. The investigators concluded that augmented proprioception (the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement) may have provided an improvement in technique, while the reported reduction in the oscillatory displacement of the muscle may have promoted enhanced neurotransmission and mechanics at the cellular and molecular level. A similar study done on six athletes on a 200 metre track suggested a reduction in the metabolic cost of running at a specific speed. The investigators suggested that the positive effect of wearing the compression clothing may arise due to an enhancement of the motion pattern brought about by an increase in proprioception and muscle coordination. They also speculated that a reduction in muscle oscillation enhanced performance and went on to suggest that wearing a lower-body compressive garment may reduce muscle fatigue by supporting more active muscles and applying pressure in such a way as to support muscle fibers in their contraction direction. Of course, there have been no studies performed yet on the effects of compression garments on racehorses, but the evidence gathered, both anecdotally and scientifically, on their benefit to humans provides plenty of food for thought. They certainly appear to cause no harm and the words of Dr Phil Conway, the director of various sports injury clinics and a runner’s clinic in Calgary, might be the best advice for racehorse trainers at this stage: “The bottom line is if you feel that compression clothing is helping

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THIS ARTICLE FIRST APPEARED IN - NORTH AMERICAN TRAINER - ISSUE 41

TRAININGWebmaster26 April 2013Black Caviar, Compression, Health, Transport