noun - Ins and outs are high-intensity interval training sets performed by open water swimmers
and lifeguards. Typically, the athletes will stand on shore, then run into the water (ocean or lake), dolphin through the shallow water or under the waves, and then swim out to a point not far from shore. They can either rest or turn back immediately to reverse their course: swim, body surf and/or dolphin, and then run up to shore. The ins and outs are repeated and done at maximum intensity.
The advantages of the intense aerobic exercise include working on starts, Dolphining, Body surfing, transitions and finishes.
Ins-and-outs are a form of the Tabata method in an open body of water and are one element of the concept of interleaving in the training of open water swimmers and triathletes.