Claims and evidence

Compression garments are marketed as base-layer garments "engineered" to improve strength, endurance, muscle recovery, and joint support. They're now popular among both elite and "weekend" athletes.

We checked out three readily available brands of compression garments:

• Skins ($180)
• Under Armour ($100)
• 2XU ($160)

We looked at 6 independent studies on compression garments and the claims made by the garment's manufacturers. We also interviewed Dr Melanie Bussey from the Otago School of Physical Education (a specialist in biomechanics and athletic injury).

The compression leggings we tried are made from a mixture of nylon, polyester, elastane or lycra.

Do the garments work?

A number of claims are made for compression garments. We investigated how strong the independent evidence is for them.

Improved performance

Skins claims that wearing its sports gear will provide a physical edge during exercise by increasing blood flow to the muscles. Under Armour and 2XU say that compression garments reduce muscle oscillation - wasteful muscle movements - thereby improving power and slowing fatigue.

The bottom line

Two studies we read said that compression garments improved physical performance. But athletes who took part in one of the studies used thicker custom-fitted garments not available on shop shelves. Athletes wearing those compression leggings jumped higher because the thick neoprene material refined technique and acted like an elastic catapult.

The other positive study investigated the effect of compression garments on long-distance runners. It concluded "wearing compression garments may enhance overall circulation". The result was that the runners fatigued more slowly.

But, overall, the science seemed mixed to us. Another study of cricket players wearing two of our branded garments (Skins and Under Armour) found no added benefits in throwing or repeat-sprint performance.

Less lactic acid

All the brands we looked at were advertised as a way to speed up recovery after hard exercise. Skins, Under Armour, and 2XU say increased blood-flow also helps reduce the build-up of waste products like lactic acid. Most athletes believe that lactic acid limits running performance and causes that burning sensation during hard exercise.

The bottom line

The studies we found concluded that muscle repair sped up when compression garments were worn during recovery. Several reports we read said that this was caused by an increased blood-flow.

The most glowing report was a New Zealand-based study of rugby players. The study found that creatine kinase (a marker of muscle damage associated with heavy impact) quickly cleared from the bloodstream if the players wore compression garments for 12 hours after exercise. The researchers concluded that compression garments were an effective tool for recovery - but only as effective as a simple low-intensity warm down.

Greater muscle support

2XU and Skins garments apparently bind muscles together to "concentrate" strength and reduce the chance of injury. Skins maintain that heightened muscle awareness limits the chance of strains, while 2XU says muscle wrapping reduces soft-tissue damage in contact sports.

The bottom line

Thick neoprene compression garments prevent muscle strains by slowing your stride just before it reaches full stretch. They also reduce soft tissue damage because the material provides extra padding.

Skins says that it's wrong to think that only "thick" neoprene garments slow your stride: "There are several ways that recoil characteristics are modified including weave density, selection of fabric, direction of cut, and degree of reduction."

Dr Mel Bussey notes that injured athletes wear compression bandages around deep bruises to reduce whole muscle vibration (jarring), as well as swelling in the muscle. Based on this idea, she believes that compression garments may help reduce jarring and improve comfort with or without injury.

Better body temperature

Under Armour and Skins are supposed to moderate body temperature (both companies sell different garments tailored for different climates). The garments keep you warmer during winter because they provide an extra base-layer and supposedly "wick" away perspiration. But in summer? The companies say that sweat transferred to the outside of the garment evaporates quickly, speeds the body's cooling process, and keeps you cool and dry.

The bottom line

Compression garments increase skin temperature. That's a plus during warm-ups and in cool conditions. A thermal insulator keeps muscles at a good active temperature, and reduces the chance of injury.

But can compression tights keep you cool in warmer weather? We didn't discover any research to support this claim (the closest we got was a report that found compression garments didn't cause additional "thermal stress"). But Under Armour cited a research article that it says proved its garments moderate body temperature.

Heightened awareness of movement

Under Armour, 2XU and Skins say their compression garments improve the body's awareness of position and movement.

The bottom line

Dr Bussey says that compression bandages are sometimes applied to damaged joints to "remind" joint position receptors in the area to keep working and protect the joint. She thinks that compression tights might help here - but she wouldn't "tell an injured athlete to rush out and buy a pair of branded compression garments on that basis".

Recovery from injury

Skins says that its garments will help aid recovery from injury through "direct compression and improved muscle oxygenation".

The bottom line

Compression garments were first used by healthcare providers to reduce peripheral swelling in vascular patients, because they assisted blood flow back to the heart.

Dr Bussey told us that compression garments are commonly used in sports medicine to treat injured athletes. But she's referring to compression bandages and tape - not branded compression tights:

"Compression bandages are usually bound around an injured joint to reduce swelling. Primarily, swelling is reduced by increasing the pressure and pushing the fluid back into the blood vessels. Secondarily, excess fluid may be forced up away from the injured area and into an area with more or larger blood vessels. Through these two mechanisms compression garments may reduce joint swelling."

Dr Bussey doubts that compression tights are as effective as compression bandages: "Bandages are bound to the point of being uncomfortable - I don't think tights give the necessary pressure. The practice also depends on fluid being forced elsewhere. It may not work if pressure is applied evenly across a large area."