In sports, "there is a spring" refers to the movement in which tendon tissues such as the Achilles tendon and patellar tendon are stretched and contracted, but the muscles also act as springs that expand and contract.On the other hand, it is said to be "soft and good muscle", and the softness as the ease of expansion and contraction becomes a problem.However, the superiority or inferiority of the muscles that are soft and easy to expand and contract and the muscles that are hard and difficult to expand and contract was unknown.

　In the study, the vastus lateralis muscle stretches and contracts when the running exercise touches the ground, and the ratio of fast muscle fiber (white muscle) and slow muscle fiber (red muscle) (muscle fiber composition) differs greatly between short-distance athletes and long-distance athletes. Measurements were performed using (the muscles that make up the quadriceps femoris).

　As a result, it was found that the muscles of long-distance runners are stiffer than those of sprinters.Therefore, when examining the relationship between the 100m dash time of sprinters and the hardness of the muscles, it was found that the sprinters with muscles that are hard and difficult to stretch and contract have better times.On the other hand, in long-distance running (5000m), it was found that athletes with soft and easily stretchable muscles had better times.

　This study is the first time that there is a suitable combination between muscle quality (hardness / softness) and the sport for athletes to perform well, and that combination depends on the characteristics of the sport. Revealed.This indicates to athletes the need for training according to their competitive characteristics and muscle quality, and is expected to contribute to the establishment of appropriate training methods in the future.

Paper information:[Medicine & Science in Sports & Exercise] Muscle stiffness of the vastus lateralis in sprinters and long-distance runners