Hes 383 Physical Dimensions Of Aging: Neuromuscular Changes With Aging PDF

HES 383 – PHYSICAL DIMENSIONS OF AGING NEUROMUSCULAR CHANGES WITH AGING Prof Gina Whitaker, BSc Kin, PhD Oct 10th, 2023 The UBC Okanagan Campus and the City of Kelowna are located on the traditional, ancestral, and unceded territory of the Syilx Okanagan Nation. WHICH OF THE FOLLOWING IS AN ACCURA...

HES 383 – PHYSICAL DIMENSIONS OF AGING NEUROMUSCULAR CHANGES WITH AGING Prof Gina Whitaker, BSc Kin, PhD Oct 10th, 2023 The UBC Okanagan Campus and the City of Kelowna are located on the traditional, ancestral, and unceded territory of the Syilx Okanagan Nation. WHICH OF THE FOLLOWING IS AN ACCURATE NEUROMUSCULAR CHANGE ASSOCIATED WITH AGING? a) Fewer and smaller motor units b) More type 1 muscle fibers lost vs type II c) Fewer and larger motor units d) Different fiber types are spread more randomly through the muscle WHICH OF THE FOLLOWING IS AN ACCURATE FUNCTIONAL CONSEQUENCE OF NEUROMUSCULAR AGING a) Force steadiness declines for females but not males b) Force steadiness declines for males but not females c) Force steadiness declines for both males and females across all force levels d) Force steadiness is independent of strength FORCE STEADINESS Raw force outputs from a young (age 21) and an old (age 60) adult during isometric knee extension contractions at 10%, 20% and 40% MVC. The output of the old adult is characterized by a greater magnitude of variability, as measured by the CV Pethick, J., Taylor, M. J. D., & Harridge, S. D. R. (2022). Aging and skeletal muscle force control: Current perspectives and future directions. Scandinavian journal of medicine & science in sports, 32(10), 1430–1443. https://doi.org/10.1111/sms.14207 SUMMARY SO FAR IN NM AGING Aging leads to: Mechanical changes in the muscle-tendon unit Changes to the muscle ultrastructure Loss and remodeling of motor units Decreased integrity of the neuromuscular junction Muscle fiber atrophy and death Intrinsic changes to the muscle fibers Together leading to the following declines in motor performance: • Decreased Strength • Decreased Power • Decreased Force Control (force steadiness) • Increased Fatiguability (Isotonic contractions, sex- and limb-dependent) AGE-RELATED SKELETAL MUSCLE WEAKNESS LEADS TO • Impaired mobility, decreased walking speed • Poor balance • Impaired functional performance (ADLs, IADLs) • Loss of independence • Pathological consequences: Sarcopenia, Dynapenia, Physical Frailty ADLs = activities of daily living: basic self-care tasks (e.g. bathing, dressing, toileting, transferring, feeding) IADLs = instrumental activities of daily living – the things you do daily to take care of yourself and your home (e.g. shopping, transport, food prep, housekeeping, laundry) THE DEVELOPMENT AND PROPAGATION OF SARCOPENIA • Sarcopenia defined: The progressive decline of muscle mass and function to a critical low • Function: muscle weakness and/or impaired physical performance • A strong predictor of falls, frailty, other morbidities and premature death • Regular physical activity and nutritional interventions positively impact outcomes Recall Sarcopenic Obesity & Osteosarcopenic Obesity: Sarcopenia, combined with Obesity and/or low bone mass as co-morbidities  Even further poor outcomes ESTIMATED PREVALENCE (USA) Is Sarcopenia more prevalent in males or females? a) Males b) Females Laurent, M. R., Dedeyne, L., Dupont, J., Mellaerts, B., Dejaeger, M., & Gielen, E. (2019). Age-related bone loss and sarcopenia in men. Maturitas, 122, 51–56. https://doi.org/10.1016/j.maturitas.2019.01.006 UPDATED STAGING OF SARCOPENIA Assessments:  Low muscle mass: e.g. DXA  Low muscle strength  Low physical performance Dhillon, R. J., & Hasni, S. (2017). Pathogenesis and Management of Sarcopenia. Clinics in geriatric medicine, 33(1), 17–26. https://doi.org/10.1016/j.cger.2016.08.002 TIMED UP AND GO TEST SARCOPENIA VS DYNAPENIA Dynapenia: Low Muscle Function (or strength), independent of muscle mass Kobayashi, K., Imagama, S., Ando, K., Nakashima, H., Machino, M., Morozumi, M., Kanbara, S., Ito, S., Inoue, T., Yamaguchi, H., Ishiguro, N., & Hasegawa, Y. (2020). Dynapenia and physical performance in community-dwelling elderly people in Japan. Nagoya journal of medical science, 82(3), 415–424. https://doi.org/10.18999/nagjms.82.3.415 What could cause low muscle function but normal muscle mass? FORCE DEFICIT CHANGES FROM YOUNG TO OLD  Participants performed single finger MVCs vs 4 finger MVCs  Force deficit reflects the drop in the force of the sum of individual finger contribution during the 4 finger task compared with the single-finger task  Suggests that neural drive is a key contributor to max force production (not just a reflection of muscle fiber properties)  More significant force deficit in older adults for same task (women more so than men) Clark B. C. (2019). Neuromuscular Changes with Aging and Sarcopenia. The Journal of frailty & aging, 8(1), 7–9. https://doi.org/10.14283/jfa.2018.35 PHYSICAL FRAILTY • ‘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’ (https://doi.org/10.1016/j.jamda.2013.03.022) • Discrete from disease and disability and often can be reversible Angulo, J., El Assar, M., Álvarez-Bustos, A., & Rodríguez-Mañas, L. (2020). Physical activity and exercise: Strategies to manage frailty. Redox biology, 35, 101513. https://doi.org/10.1016/j.redox.2020.101513 IMPAIRMENT IN PHYSICAL FUNCTION IS A CORE FEATURE OF BOTH SARCOPENIA AND PHYSICAL FRAILTY Landi F, et.al. Sarcopenia as the biological substrate of physical frailty (2015) Clin Geriatr Med 31:367-374 5 CRITERIA FOR FRAILTY (Fried et al) • Weakness (assessed by grip strength, in 20th percentile for age, sex, BMI) • Slowness (assessed by walking speed, in 20th percentile for age, sex, height) • Low levels of Physical Activity (self-reported) • Low levels of Energy (self-reported) • Unintentional weight loss (≥ 10lbs or 5% of total body weight in 1 year) 2 criteria: Prefrailty 3+ criteria: Frailty Fried LP, et.al. (2001) Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 56(3):M146-56 THE CSHA FRAILTY SCALE – A QUALITATIVE CLINICAL MEASURE • Used in the clinic • No baseline data needed • Distinguishes between pre-frail (apparently vulnerable), mildly frail, moderately frail, severely frail • Can help refine treatment route Rockwood K, et al. (2005) A Global clinical measure of fitness and frailty in elderly people. CMAJ 173(5): 489-495 EXERCISE PRESCRIPTION TO REVERSE FRAILTY What is one difference between prefrail and frail exercise prescription? a) Less aerobic exercise for frail b) More time on resistance training for frail c) Less time on balance for frail d) Longer total time per exercise session for frail Fig 1, taken from: Bray N.W., Smart, R.R., Jakobi, J.M., & Jones, G.R. (2016) Appl Physiol Nutr Metab. 41(10):1112-1116 (non-frail older adults should follow CSEP 24 hour movement guidelines for older adults as exercise recommendation) EXERCISE EFFECTS ON FRAILTY TRANSITION Bray, N. W., Jones, G. J., Rush, K. L., Jones, C. A., & Jakobi, J. M. (2020). Multi-Component Exercise with High-Intensity, Free-Weight, Functional Resistance Training in Pre-Frail Females: A Quasi-Experimental, Pilot Study. The Journal of frailty & aging, 9(2), 111–117. https://doi.org/10.14283/jfa.2020.13  Focus on Functional / Fun / Free  Assess Fall Risk  Assess Fears Associated with PA TREATMENT VS. PREVENTION It’s never too late to incorporate muscle strengthening exercise into an individual’s routine. Nedergaard, A. et.al. Musculoskeletal ageing and primary prevention (2013) Best Practice & Research Clinical Obstetrics and Gynaecology 27:673688