By Flavia Yazigi, PhD and Mushi Harushi, MS
This article is an updated and expanded version of the article, Osteoporosis & Aquatic Exercise, originally printed in the April May 2016 issue of AKWA magazine 29(6): 6.
The innumerable benefits of aquatic exercise can be explained by the hydrostatic and hydrodynamic properties of the environment. On the other hand, the buoyant force of water seems to be responsible for the misconception that "exercise in water has no impact, so it is not good for osteoporosis." This article intends to clarify and correct preconceived ideas, and provide fitness professionals with guidelines to effectively use aquatic exercise for the prevention and management of osteoporosis.
According to the World Health Organization (WHO 2018), osteoporosis and osteopenia are listed in the International Classification of Diseases as Musculoskeletal Conditions. Osteopenia is an early stage of osteoporosis described as a low bone mass index. Osteoporosis (porous bone) is a multifactorial disorder characterized by progressive loss of bone mass and enhanced skeletal fragility associated with an increased risk of fractures. Common sites of fracture include the spine, hip, forearm and proximal humerus. Fractures at the hip incur the greatest morbidity and mortality, and give rise to the highest direct costs for health services. It is expected that osteoporosis incidence will increase exponentially with the global aging population.
Risk Factors
Among non-modifiable risk factors, age is the most important. Age-related bone loss is asymptomatic, and the morbidity of osteoporosis is secondary to the fractures that occur. Peak bone mass occurs between the ages of 18 and 25. Greater bone density at this time decreases the risk of osteoporosis later in life. Bone loss increases after menopause due to decreases in estrogen. Women can lose up to 20% of their bone density in the five to seven years after menopause. A woman’s risk of breaking a hip due to osteoporosis is equal to her risk of breast, ovarian and uterine cancer combined. A man age 50 or older is more likely to break a bone due to osteoporosis than he is to get prostate cancer.
Modifiable risk factors includes poor nutrition (mainly calcium deficiency), inactivity or insufficient exercise, smoking, excessive intake of alcohol, low body mass index BMI <20 kg/m2, vitamin D deficiency, and estrogen deficiency. Additionally, sarcopenia, an age-associated decline of skeletal muscle mass and function, can lead to frailty and osteoporosis (Yoo et al., 2018).
General Exercise Recommendations
Beyond education and a balanced nutrition, exercise is an economical, effective, and safe method for osteoporosis prevention and also for its management. Exercise acts on bone remodeling; effects on bone cells as well as on bone mass, bone strength, and geometry improve the osteogenic, or bone formation, process.
Some body regions have better responsiveness to the ground reaction forces (impact) and other regions are more responsive to strength training due to the tension that muscles exert, through the tendons, on the bones. To benefit from the ground reaction forces, it is necessary to select exercise patterns that provides an impact level with a mechanical loading at least of 1.22 times body weight. This is sufficient for increases leg muscle mass and preservation of bone mineral density (BMD) in postmenopausal women (Borer, et al. 2007).
Individuals with osteoporosis may feel more comfortable performing exercises in the water due to the decreased risk of falling. It is important for those with advanced osteoporosis, characterized by multiple fractures and severely reduced bone mineral density, to avoid further fractures, prevent falls and facilitate daily activities.
Aquatic Exercise Facts
Aquatic exercise was determined to be effective to create an anabolic (growth) effect on the bone of the postmenopausal, sedentary subjects (Ay, et al. 2003).
Although weight-bearing physical activity is known to be superior to non-weight-bearing activity to increase the bone mass, evidence shows that aquatic and weight-bearing exercises both increased calcaneal BMI in 62 postmenopausal sedentary women with a mean age of 54.1 +/- 7 years (Ay, et al. 2005).
Muscular resistance training may be more applicable to the basic rules of bone adaptation and site-specific effects of exercise, have more positive effects in maintaining or improving bone mass and architecture, and be safe and feasible for older people (Suominen 2006).
Aquatic exercise is predominantly based on resistance training due to the multidirectional resistance of the water.
Based upon the laws of action/reaction and acceleration, the vertical Impact provided from ground reaction forces will be influenced by the water depth/depth of immersion, body density, and choice of aquatic exercise movements. Ground reaction forces dissipate vertically, horizontally or through a combination of both. Knee lifts, front kicks and other movements that focus on vertical rebounding provide greater impact than exercise patterns that are more horizontally-oriented, such as a cross-country ski or jumping jack. Below is a comparison of mechanical loading in three popular aquatic exercise patterns (Alves 2008):
KNEE LIFT performed at a depth of 1 meter produced 1.66 times body weight* and 1.15 times body weight at 1.3 meters. *Adequate to increase bone mineral density.
CROSS-COUNTRY SKI performed at a depth of 1 meter produced 0.94 times body weight and 0.60 times body weight at 1.3 meters.
JUMPING JACK performed at a depth of 1 meter produced 0.89 times body weight and 0.53 times body weight at 1.3 meters.
Adding more power to a cross-country ski or jumping jack, such as a power tuck performed in level I or adding propulsion up and out of the water can increase the magnitude of vertical impact (Aboarrage Junior et al., 2018).
Aquatic Program Considerations
Water offers an opportunity to perform a multiplanar exercise and with different impact levels. This is beneficial for people that may be limited when performing land-based impact exercises. When designing an aquatic exercise program, keep in mind that at least eight months of exercise, twice per week, is necessary to provide significant changes in the bone mineral density (Moreira 2014). General exercise goals should focus on increasing muscle strength and mass, but aerobic exercise should not be excluded from the routine. The emphasis of exercise should gradually transition from muscle strengthening (for better functionality and mechanical and body weight support) to vertical impact loading of the lower body skeleton.
A well-balanced aquatic exercise program for individuals with osteoporosis might include the following general concepts to provide functional improvement:
Exercise intensity can be managed with rating of perceived exertion, such as the Borg, Omni and Aquatic Exercise Intensity (AEA 2018) scales.
Include specific exercises to target posture, balance (static and dynamic), gait, coordination, hip and trunk stabilization, range of motion and flexibility.
Emphasize ankle-related muscles to reduce risk of falls. For example, tap the toes up and down on the pool bottom (targeting tibialis anterior) and then the heels (targeting gastrocnemius and soleus) to help correct foot position during walking.
For pain management, low to moderate aerobic exercise is recommended (5-8 out of 0-10 Borg Scale). Aquatic walking patterns (from simple movements to power walking, backward, forward, with and without arms assistance, etc.) are a great way to train the cardiorespiratory system without vertical impact
Proper form and alignment is important; cue and correct as necessary. Allow adequate time to rest and recover – between exercises to ensure proper form and alignment, as well as between sessions.
Exercises should be chosen according to the anatomic region.
Lower limb (hip) and the lumbar region of the spine have better responsiveness to the ground reaction forces, thus impact exercises are important to include. Aquatic exercise for hip osteoporosis should include:
Impact (rebounding) exercises in shallow water (except during pain crises).
Impact (rebounding) exercises to stimulate different angles of the bone by moving in various planes and adding travelling.
Wrist and upper limb are more responsive to strength training due to the tension that muscles exert, through the tendons, on the bones. Aquatic exercise for wrist osteoporosis should include:
Isometric – grip strength using a hand bar or noodle.
Isotonic – flexion/extension of the wrist with an open hand, applying power against the water’s resistance; optional drag equipment to increase intensity.
Deep-water exercise, although non-impact in the vertical axis, does offer benefits to individuals with osteoporosis when the workout is based on aerobic and resistance exercises. Firstly, the relatively constant water temperature and hydrostatic pressure may facilitate blood circulation, ease soft-tissue contracture, and relieve muscle spasms and fatigue. Secondly, when water resistance acts in the opposite direction of body motion, greater muscle activity is required, which may enhance muscular strengthening (Yázigi at al., 2019). Additionally, the hydrostatic and hydrodynamic properties encountered during aerobic and resistance exercises release endorphin and serotonin, which help with pain and the control of other symptoms.
Exercise Precautions
Most exercise limitations are specific to land-based exercise, due to excessive force being placed on the weakened bone structure.
Since gravity is reduced in the aquatic environment, the precautions are less restrictive. However, in the end of an aquatic class, the transition from water to land should be done carefully, particularly in cases of severe osteoporosis.
Avoid spinal flexion on land to prevent vertebral fractures. In the water, some spinal flexion can be performed, including flexion in a modified supine position. Focus should be placed bracing the core by contracting the transverse abdominis.
Avoid twisting movements, such as a golf swing, on land. In the water, slow, range of motion and rotational motion is acceptable as an active stretch.
Avoid abrupt or explosive loading or high impact loading on land.
Additionally, it is important to focus on positive reinforcement – activities can, and should, be safely enjoyed, rather than always placing emphasis on what should be avoided. The goal is to create a safe, but also enjoyable, exercise experience to improve daily activities and promote healthy lifestyles.
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URL Sources
http://orthoinfo.aaos.org/topic.cfm?topic=a00232
www.iofbonehealth.org/exercise-recommendations
ABOUT THE AUTHORS
Flavia Yazigi, PhD, is a professor at the University of Lisbon, an international AEA Training Specialist, a member of the AEA Research Committee and the recipient of AEA’s 2011 Global Award for Contribution to the Aquatic Fitness Industry. She has a PhD in physical activity and health. Flavia believes that the secret for aquatic success is the fusion between scientific research and result-oriented strategies
Mushi Harush, MS, has a master’s degree in education and physical education and is the founder and owner of the Israeli Aquatic Exercise Center, where she organizes conventions and clinics. She has been an international AEA Training Specialist since 1994 and presents internationally at health and fitness conventions. Mushi was the recipient of the 2005 AEA Global Award for Contribution to the Aquatic Industry.
This article is an updated and expanded version of the article, Osteoporosis & Aquatic Exercise, originally printed in the April May 2016 issue of AKWA magazine 29(6): 6.