The sidestroke is a swimming stroke, so named because the swimmer lies on one side and it is helpful as a lifesaving technique and is often used for long-distance swimming

Long-distance swimming

The distances that distinguish long distance swimming from ordinary swimming are those distances that are longer than are typically swum in pool competitions. When a given swim calls more on endurance than outright speed, the more likely it is to be considered a long distance swim...

. The sidestroke allows the swimmer increased endurance because, instead of working both arm

Arm

In human anatomy, the arm is the part of the upper limb between the shoulder and the elbow joints. In other animals, the term arm can also be used for analogous structures, such as one of the paired forelimbs of a four-legged animal or the arms of cephalopods...

s and legs

Human leg

The human leg is the entire lower extremity or limb of the human body, including the foot, thigh and even the hip or gluteal region; however, the precise definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle.Legs are used for standing,...

 simultaneously in the same way, the side stroke uses them simultaneously but differently. A swimmer tired of exercising one side can just turn over and use the other, the change of action helping the limbs to recover.

The hands act directly upon the water like oar

Oar

An oar is an implement used for water-borne propulsion. Oars have a flat blade at one end. Oarsmen grasp the oar at the other end. The difference between oars and paddles are that paddles are held by the paddler, and are not connected with the vessel. Oars generally are connected to the vessel by...

s, and do not waste any power by oblique action. In ordinary swimming on the right side the left arm moves gently in the water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

, almost at rest. Then, after some time, the swimmer turns on the other side, and the left arm has its chance to work while the right idles.

A modification of swimming on the side is the Trudgen

Trudgen

The trudgen is a swimming stroke sometimes known as the racing stroke, or the East Indian stroke. It is named after the English swimmer John Trudgen ....

stroke.