Running shorts are a specialized form of shorts

Shorts

Shorts are a bifurcated garment worn by both men and women over their pelvic area, circling the waist, and covering the upper part of the legs, sometimes extending down to or even below the knee, but not covering the entire length of the leg. They are called "shorts" because they are a shortened...

 worn by runners

Running

Running is a means of terrestrial locomotion allowing humans and other animals to move rapidly on foot. It is simply defined in athletics terms as a gait in which at regular points during the running cycle both feet are off the ground...

.

Materials

Running shorts are designed to facilitate comfort and free movement during exercise. Their materials are lightweight and hard-wearing. Many running shorts include an inner lining that acts as underwear, so you don't have to wear underwear with running shorts. Polyester

Polyester

Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...

 is a common fabric in running shorts.

Variants

Many running shorts have a seam cut up the side of each leg to enable freer movement. Manufacturers define running shorts according to the length of the leg which is not cut. For example, a 3/4 seam means that 1/4 of the length is cut.

• 1/2 split seam shorts are the shortest
• 3/4 split seam shorts are short, but not as short as 1/2 split seam shorts
• Square leg shorts have no split at all

Longer shorts are not ideal for running. A runner's stride may pull up the fabric of his or her shorts, which can cause discomfort. Nonetheless, some runners prefer longer shorts because they cover a greater portion of their legs.

Some runners use athletic hot pants as running shorts. Like 1/2 split seam shorts, hot pants do not encumber leg movement.

Lycra running shorts are an alternative to conventional, polyester-based shorts. In most cases, lycra running shorts reach the mid-thigh area. They are skin-tight, so they allow for more flexible, unencumbered movement.