Aquatic exercise allows the application of the physical stress theory for individuals who cannot tolerate the stresses of land-based exercises. The buoyancy of the water allows a deconditioned individual or an individual with significant joint pathology to exercise by decreasing the forces needed to move and decreasing the forces on the joint.
Measurements of aquatic exercise are similar to land-based exercise. Target heart rate can be determined using the same formulas as for land-based exercise. However, because heart rate is lower in the pool, an “aquatic heart rate reduction” should be included in the formula. The heart rate reduction model was determined by Fernado Martins Kruel and is sometimes referred to as the Kruel protocol.83 An aquatic heart rate reduction is determined by subtracting a 1-minute in-pool heart rate from a 1-minute land-based heart rate. The difference is referred to as the aquatic reduction. Subjective perceived exertion scales can also be used to determine the intensity of an aquatic exercise program. Land-based functional assessments are used to determine the benefits of an aquatic exercise program.