Bone health In general, the major skeletal changes that occur with aging include calcium-related loss of bone mass and density, decreased circulating levels of vitamin D, and an overall decrease in bone strength (Lewis & Bottomley, 2008). Significant bone loss can lead to the pathologic condition of osteoporosis, where an imbalance occurs between breakdown of bone (osteoclast activity) and buildup of bone (osteoblast activity). This imbalance results in excessive calcium absorption from bone in order to meet the needs of various bodily systems. For women, a typical rate of bone loss per year due to aging is 1% starting at age 30 to 35, with loss starting for men at age 50 to 55 (Lewis & Bottomley, 2008). In some cases, severe osteoporosis may result in a pathologic fracture, resulting in a fall, versus the other way around. If a fall occurs, an osteoporotic bone is more likely to fracture than a healthy bone. Factors such as poor nutrition, inactivity, and smoking can accelerate the rate of bony loss, whereas age, sex, race, body type, and genetic makeup can predispose adults to development of osteoporosis. Assessing for these risk factors can help guide the clinician when developing safe and effective exercise programs aimed at strengthening lower extremity muscles and preventing falls. For example, an older adult with severe osteoporosis may not be able to tolerate single leg stance activities such as stair climbing (Lewis & Bottomley, 2008). Changes in flexibility and posture Older adults can experience several changes in flexibility that can influence fall risk. These changes can occur in the spine, in connective tissue, and in individual joints. In general, older adults can experience a loss of spinal flexibility, especially spinal extension, resulting in as much as a 50% reduction compared with young adults (Holland, Tanaka, Shigematsu, & Nakagaichi, 2002). Connective tissue loss in elastin and collagen, which increases joint and soft tissue stiffness, can lead to individual joint loss of range of motion (ROM), which happens primarily in extension ranges, and can be compounded by presence of disease, pain, surgery, or injury (Holland et al., 2002). It is also common for adults 55 to 85 years of age to experience declines in ankle joint flexibility of 50% in women and 35% in men (Holland et al., 2002). These changes in flexibility coupled with the typical age-related changes in strength can lead to a “geriatric posture” (Lewis & Bottomley, 2008). Geriatric posture results from declines in the neurologic and musculoskeletal systems, primarily in strength, flexibility, and sensory changes. The presence of a disease, such as Parkinson’s, which induces a more flexed posture, also can negatively affect posture (see Figure 1 for an example of changes in cervical posture). The typical geriatric standing posture includes the following: ● Increased forward head posture (FHP). ● Increased thoracic kyphosis and rounded shoulders. ● Increased overall hip flexion and knee flexion. ● Varying lordosis, but typically decreased. ● Overall decrease in height as spinal compression occurs. FHP and increased thoracic kyphosis are typically accompanied by internally rotated shoulders, changes in lumbar lordosis, and flexion in the hips and knees. These changes may be asymptomatic and pain free, with age-related, disease-related, and sex-related variation among older individuals. Geriatric posture can progress to a painful state, in more extreme cases, resulting in limited mobility and avoidance of functional positions, such as standing for longer periods of time or walking long distances. Postural changes can affect strength, ROM, vestibular function, visual field, balance, and ADLs (Lewis & Bottomley, 2008). Some studies more recently have linked FHP to increased fall risk and deficits in vestibular efficiency (de Groot et al., 2014; Lee, 2016; Yip, Chiu, & Poon 2008). Some researchers consider of the presence of FHP as a trigger for a fall risk assessment (Nemmers, Miller, & Hartman, 2009).
Figure 1: Forward Head Posture
Note . From Western Schools, 2019.
Frailty and falls Frailty is considered a geriatric syndrome. A geriatric syndrome is a common health condition in older adults grouped by a pattern of symptoms and signs typically with multiple underlying causes, but that may not be known or that did not fit into discrete disease categories (Tinetti, Williams, & Gill, 2000). According to a 2013 consensus meeting on frailty, physical frailty is “a medical syndrome with multiple causes and contributors that is characterized by diminished strength, endurance, and reduced physiologic function that increases an individual’s vulnerability for developing increased dependency and/or death” (Morley et al., 2013). Many researchers have attempted to measure frailty using factors such as impairment in mobility, balance, muscle strength, cognition, nutrition, weight loss, depression, incontinence, fall history, gait speed, socioeconomic status, endurance, and physical activity. Identifying reliable determinants for frailty is an important need for future researchers, but for now, the most commonly used model is the Fried model (Fried et al., 2001). The Fried research model defines frailty as three of the five following factors: 1. Unintentional weight loss of more than 10 pounds in past year. 2. Grip strength loss. 3. Gait speed decline to less than 0.60 m/s. 4. Reported exhaustion. 5. Decrease in physical activity via kcal per week; less than 1,000 with exercise activities. The incidence of frailty varies depending on which definition is used to describe it, but generally accepted statistics for adults 65 years of age and older are 3% to 7%, whereas the incidence for adults 80 years of age and older is 25% to 40%. Women experience frailty twice as often as men. It is unclear whether frailty is more prevalent in whites than in blacks or other ethnic groups (Op het Veld et al., 2015). The cumulative effects of frailty render an older adult vulnerable to situational challenges, including falls, increased mortality, disability, and loss of independence. In addition to physical factors, many frail older adults also experience dementia (51–73%) and/or depressive symptoms (22%; Vaughan, Corbin, & Goveas, 2015). When considering fall risk in older adults, it is important to screen for the presence of frailty. Regardless of the model used, older adults of more advanced age or with multiple comorbidities should be screened for presence of frailty. Lewis and Dring (2016) proposed a frailty screening with three criteria: age over 81 years, TUG score over 15 seconds, and taking more than four medications, based on an article by Abizanda, Romero, and Sanchez-Jurado (2012). Age-related changes in gait The adult gait pattern stays fairly stable overall until advanced age or pathology sets in. Gait parameters that remain stable include vertical displacement of the center of gravity, gait phasing and timing (60% stance and 40% swing), stride rate, time for recovering leg swing, and time for single- and double- limb support (Hamacher, Singh, Van Dieen, Heller, & Taylor, 2011). Several gait parameters are affected by the aging
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