4.3.10 SURVIVAL BACKSTROKE
Survival Backstroke is also referred to as Lifesaving Backstroke, though technically the two styles vary. The lifesaving style is used competitively in lifesaving competitions and requires the swimmer to keep their hands under the water at all times, though parts of the arms may recover out of the water. Another feature is the arm stroke may be lengthened to a full stretch above the head. 
When used in rescues, the stroke can be modified to a Backstroke one arm stroke (the other arm being used to tow the patient) with a Breaststroke kick. The altered arm stroke of Lifesaving Backstroke means higher energy usage than Survival Backstroke.
In survival mode, the arm stroke recovery remains underwater and is shortened to conserve energy.