Buoyancy Supported
Madox Valdivia
Aquatic therapy is one of the many tools that therapists can use to assist in the healing process of musculoskeletal issues and conditions for patients of all ages, abilities, and diagnoses. This evidence-based treatment is generally designed to improve or sustain gait, muscle strength and endurance, balance, agility, function, coordination, flexibility, function, and body mechanics and posture. Therapists can specifically tailor treatment to each individual patient using underwater treadmills and orthotic or other assistive tools designed for water.
The aquatic environment allows injured muscles to use muscle memory without impact or bearing weight, and the water makes patients buoyant so they do not have to support as much of their own body weight. At OrthoCarolina, the therapy staff has introduced therapeutic techniques to the pool that have been effective among its patient population including manual therapy, injury rehabilitation, therapeutic exercise, functional training, and more.
The principles of buoyancy can be used in aquatic therapy exercise in three different ways. Buoyancy can assist in exercise, support a movement, or be used as resistance. For example, buoyancy-assisted exercises are any movements that occur in the direction toward the surface of the water. Buoyancy-supported exercise occurs perpendicular to the water surface, and resisted exercises occur against the upward thrust of buoyancy.1
As aquatic therapy continues to grow in popularity, more is being written about the subject. One study looked at individuals diagnosed with either hip or knee osteoarthritis. The study was designed as a randomized controlled trial with 71 subjects. Each was assigned to a group that received either 6 weeks of aquatic physical therapy or no aquatic physical therapy. Pain levels, physical function, physical activity levels, quality of life, and muscle strength were used as outcome measurements. Subjects in the group who received aquatic physical therapy showed significant pain reduction, increased strength, improved physical function, and increased quality of life.2
Another study looked at the effects of aquatic physical therapy in women who had been diagnosed with fibromyalgia.3 Sixty women were divided into either a control group that received no treatment or were part of an aquatic therapy program three times a week for 16 weeks. The aquatic exercise was performed in chest-deep water. Outcome measurements that were used included tender point count, health status, sleep quality, physical function, and cognitive function. The women who participated in the aquatic therapy program experienced significant results regarding decreased tender point count, improved sleep quality, improved cognitive function, and improved physical function.3
A third study took a different approach, with a control group that performed land exercise instead of no exercise.4 This study looked at individuals who were diagnosed with chronic low back pain, and divided 65 subjects into an aquatic therapy group and a land therapy group. Both groups experienced positive results regarding the modified Oswestry Disability Index and physical function, but the results did slightly favor the individuals who performed aquatic exercise.4
All public pools should keep cleanliness and safety at a high priority, including aquatic therapy pools. At this facility, water temperature, room temperature, room humidity, and filter pressure gauges are checked daily to ensure the pool is functioning properly and the environment is safe for the patients to exercise. We also monitor chemical and pH levels and make adjustments daily. The pool is drained regularly to clean the internal surfaces and liner, and to refresh the water. We service the mechanisms of the pool annually to check the functionality of all the mechanical parts, as well as the treadmill.
The pools at OrthoCarolina are kept at a therapeutic temperature, between 88 and 90 degrees Fahrenheit. The warm water increases blood flow to the muscles, allowing for ease of movement. Underwater treadmills are also used to help normalize gait patterns, improve mobility, and increase walking tolerance. For patients who are further along in treatment, jets can provide resistance against walking or jogging on the treadmill, which aids in strengthening. In many cases, someone who may be able to walk only 5 to 10 minutes on land can easily walk for 30 minutes in the water. Pressure sensors in the treadmill allow therapists to analyze gait patterns of the patients, helping examine step length, evidence of toeing out, and adequate heel strike.
Pools are also appropriate for individuals with severe mobility impairments. Both aquatic therapy pools used at this facility are outfitted with hydraulic-powered lifts that have a 250-pound weight limit. The lifts are designed to allow a patient to sit in a chair, then be lifted up over the side of the pool, and gently lowered into the water. Patients may exit the pool by reversing the process. Patients with neurological diagnoses such as cerebral palsy or quadriplegia, or who have sustained strokes or spinal cord injury, can find relief with aquatic therapy. The goal of their aquatic therapy is not to fix the problem, but to treat their symptoms. The warmth of the water and assistance of buoyancy can help these patients decrease the tone in their muscles and begin to reestablish normal movement patterns. Even if it is an unreasonable expectation for the patient to return to regular walking on land, there are great cardiovascular benefits for the patient to exercise in the upright position. And, if a patient is accustomed to sitting in a wheelchair all day, exercising in the upright position can help prevent muscle contractures through the hip and knee flexors.
The versatility of aquatic therapy can help therapists offer therapeutic exercises and activity to an extremely wide range of patients. Accessories such as water dumbbells, noodles, flotation belts and vests, fins, and other tools help patients balance while in the pool and work against resistance, allowing them to accelerate therapy and participate in rehab activities earlier than they otherwise might on dry land.
And, just as important, in many cases the qualities of water can help patients begin and continue recovery with a lower level of pain. Whether treating an athlete in the prime of performance, or an older adult with a newly replaced hip who simply wants to walk again without pain, the healing properties of water offer therapists a valuable medium to help patients reach their goals. RM
Katie White, PT, DPT, OCS, is a physical therapist and clinical manager for OrthoCarolina in Charlotte, NC. She holds her Doctorate degree from Northeastern University, and is a Board Certified Clinical Specialist in Orthopedic Physical Therapy. She is also a Certified Strength and Conditioning Specialist, certified in Trigger Point Dry Needling, a certified Clinical Instructor, and a certified Kinesiotape practitioner. For more information, contact [email protected].
All sharks are slightly negatively buoyant, which means they sink. Unlike many bony fishes, sharks do not have a swim bladder to provide buoyancy. To help compensate for their tendency to sink, their livers contain large amounts of oil that is less dense than seawater. Pelagic (open water) sharks generally have larger livers, with more and lighter oil, than sharks which live in shallower water or near the ocean bottom.
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Feature papers represent the most advanced research with significant potential for high impact in the field. A Feature Paper should be a substantial original Article that involves several techniques or approaches, provides an outlook for future research directions and describes possible research applications.
Abstract: SOLAS (Safety of Life at Sea), which was first enacted in 1914 as a result of the Titanic disaster, presents mandatory requirements for ship safety, such as the adoption of watertight bulkheads. However, ship accidents continue to occur despite the development and application of numerous safety technologies. In the case of a marine accident, the risk of sinking or capsizing due to flooding can be reduced by subdividing the watertight area, but shipbuilding costs, the weight increase for light ships, and the intact stability of the vessel must be considered together. For this reason, in this study, a BSS (buoyancy support system) was designed in accordance with ISO 23121-1 and ISO 23121-2. The characteristics of watertight and non-watertight spaces were reviewed and the BSS was implemented for a small car ferry. By applying additional safety technologies while securing economic feasibility in terms of ship construction and operation, an alternative to reduce the loss of human lives, environmental damage, and property losses in the case of a ship accident was proposed. Keywords: buoyancy support system; flooding; accidents (incidents); evacuation; stability; damaged ships
Lee, Gyeong Joong, Jang-Pyo Hong, Kwang Keun Lee, and Hee Jin Kang. 2023. "Application of Buoyancy Support System to Secure Residual Buoyancy of Damaged Ships" Journal of Marine Science and Engineering 11, no. 3: 656.
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