During this year’s World Cup, one scene repeats itself game after game: several players take the field with holes in the calves of their socks. Social media is rife with theories about the supposed competitive advantage that this might give them. But science has yet to find evidence that it improves performance.

Professional soccer socks are, by design, form-fitting. In addition to holding shin guards in place, they provide support to the ankle, the arch of the foot, and the calf; they help manage moisture and reduce foot movement inside the cleat to improve stability. This design principle has been used in professional soccer for decades. Although materials have evolved to become lighter and more durable, they are still primarily based on synthetic fibers such as polyester, nylon, and spandex.

But quite a few players have complained that the socks are too tight and cause a tingling and numb sensation in the calf area. The discomfort is so great that halfway through a game, they cut several holes in the calf area to “release tension” and run better. There is a biomechanical component to this sensation: during a sprint or change of direction, the largest muscle in the calf contracts and increases in thickness to generate force.

Over time, the practice of cutting holes in socks has taken on an almost intuitive explanation among players themselves: splitting open the fabric allows the muscle to “breathe,” relieving pressure. However, specialists in sports medicine and recovery point out that there are no studies demonstrating that cutting holes in socks provides any benefit. In fact, much of the research on compression garments concludes that when properly designed and fitted, they can help limit muscle inflammation after intense exertion.

Despite the lack of evidence regarding physiological benefits, the practice continues to spread among professional soccer players. Today, it is considered primarily an anecdotal phenomenon, based on each player’s personal experience rather than scientific evidence. Furthermore, the rules of the game do not prohibit modifying socks as long as equipment remains safe and the shin guards remain properly covered.