What are the resistances to water exercises?

When the summer heat melts away your workout motivation, water exercise --- sometimes called aqua aerobics or aqua-toning --- provides an appealing alternative to land-based fitness activities. In fact, professional athletes, including marathon runners, football players and boxers, use the pool's reduced-gravity environment for performing high-intensity but low-impact workouts. Specialized ankle and wrist cuffs add resistance to an aquatic workout.
Water Training Principles
Understanding the basic physics of water exercise helps you maximize the benefits of arm and ankle cuffs. Archimedes' law explains the principles of buoyancy. Submerging your body in water creates an upward, buoyant force, which depends on your level of body fat. Fat floats toward the surface, whereas lean muscle tissue sinks toward the bottom of the pool. Water up to your neck increases buoyancy by 90 percent, but a lean person may still find it difficult to stay near the surface, explains the "Aquatic Fitness Professional Manual."
Cuffs for Buoyancy
Deeper water submerges your body and creates resistance in all planes of movement while minimizing the impact on your joints. The jumping jack illustrates this important quality of water. When you perform jumping jacks at the shallow end of the pool, your feet touch the pool's floor. Moving to the deeper end improves the workout in two ways: It takes the stress off of your joints and it increases the available water resistance. In addition to adding resistance to your workout, upper-arm and ankle cuffs increase buoyancy, thereby facilitating exercise in the deeper and more challenging end of the pool.
Ankle Cuffs
Your legs are not the only body parts that benefit from aquatic ankle cuffs, explains the Aquatic Exercise Association. Using the cuffs requires you to engage your deeper core muscles to maintain an upright and vertical postural alignment. The ankle cuffs also make it harder to transition from supine or prone exercises into an upright position. The association suggests that new aquatic students use a buoyancy belt in addition to ankle cuffs. Eliminate the belt as your core muscles gain strength.
Wrist Cuffs
Attaching the cuffs to your upper arms increases buoyancy, but attaching them to your wrists creates more resistance, particularly when you are submerged in deeper water. The cuffs provide the most resistance when your arms are completely underwater. Taking your hands out of the water minimizes the challenge. Aquatic exercise, like all types of workouts, requires progressive training. The water, by itself, may provide sufficient resistance for anyone unaccustomed to working out. An inability to maintain postural alignment while performing the exercises may indicate that you are adding much resistance too soon.