Arm span

Arm span, also known as reach, is a measurement of the length from one fingertip to the other when a person's arms are stretched out to the sides parallel to the ground. This measurement is often very close to a person's actual height. It can be useful when someone cannot stand up straight to have their height measured because of back or leg problems, like scoliosis or osteoporosis.

Arm span helps health experts estimate a person's height in situations where traditional methods aren't possible. Other ways to measure height include looking at knee length or measuring someone lying down.

Sometimes, if the arm span is much larger compared to the person's height, it might suggest health issues affecting height, such as changes in the spine from aging or certain spinal conditions.

Arm span in sports

Having longer arms can be very helpful in many sports. For example, in basketball, tennis, and swimming, a longer reach helps athletes perform better. Famous boxers and fighters, like Sonny Liston and Jon Jones, used their extra-long arms to keep their opponents at a distance while they attacked. However, having very long arms can make some activities, like weightlifting, a bit more challenging.

Procedure

The easiest way to measure someone’s arm span is by using what’s called the demi-span. You can use a tape measure to find the distance from the center of the person’s chest, near the breastbone, to the tip of their middle finger when their arm is stretched out to the side. Then, you simply double that number to get the full arm span. This method is helpful because measuring from fingertip to fingertip usually needs help from another person or markings on a wall.

In situations where a person can’t easily stand up, such as when they are lying in bed, their arm span can be used to guess their height. On average, a person’s arm span is very close to their height, so measuring the arm span can give a good idea of how tall they are.