Squash and basketball players, runners and other athletes often wear knee braces for injuries during workouts and competitions. Sometimes the braces are worn after injuries or surgery to limit and control movement at the knee and protect the knee from further damage; on other occasions, the sport braces may simply assist or provide stability for unsteady knees. Lots of athletes with knee troubles report that running feels easier and more sustainable when they are wearing a brace
However, it's not clear to what extent a knee brace actually affects performance. Because they tend to limit and control movement at the knee, can they slow athletes down significantly?
Unfortunately, scientific research concerning the effects of knee braces has been rather slim. One study determined that when the quadriceps muscles of one leg were considerably weaker than the quads of the other leg, wearing a knee brace on the weaker leg improved running velocity considerably. Another investigation carried out with injured athletes showed that as long as the quads in each leg were about equally strong, wearing a knee brace had no impact on performance
However, some studies have found that athletes wearing knee braces perform more poorly during demanding exertions. Additional research has linked knee braces with higher lactate levels during exercise, suggesting that knee braces may interfere with blood flow to the leg muscles. Another study determined that heart rate and oxygen consumption were higher when athletes wore knee braces while running on a treadmill, indicating that knee braces actually increased the energy 'cost' of exercise