Average men & women over age 30 begin losing muscle at a rate of 15% per yearSedentary adults risk losing up to 30%of muscle by age 75
Muscle of Muscle AfterAverage Healthy SarcopeniaAdult Occurs
DECREASE OF LEAN MASS IS ASSOCIATED WITH AN INCREASEIN THE TOTAL AMOUNT OF LIPID STORES Body composition in man as a function of age. black bar, Muscle; light grey, other tissues; dark grey, fat. (Adapted from Cohn et al. 1980.)
reduced Aerobic cApAcity decreAsed muscle strength frAilty gAit problems WeAk bones (osteoporosis) fAlls & frActures loss of physicAl function & independencedecreAsed bAsAl metAbolic rAte(middle-Age Weight gAin)
Fast twitch(FT) neurons tend to die off first.Adjacent motor neuron(slow twitch (ST) motor neuron),may reinnervate the muscle fibers:MOTOR UNIT REMODELLING . Less Efficient Motor Units.: MOTOR UNIT RESTRUCTURINGLess precise Less force Less Loss ofcontrol of production coordinated balance andmovements and quick speed movements
Loss of satellite cell functionLOSS OF ABILITY TO DECREASE INMUSCLE CELLS TO MUSCLE PROTEINREGENRATE SYNTHESIS Loss of muscle mass
Decreased concentrations of :GROWTH HARMONE TESTESTERONE INSULIN LIKE GROWTH FACTOR
Reduced levels of growth hormone associated with aging contributeto age-related decreases in muscle mass, strength, and lipolysis.
grAph shoWing decline in testesterone With Aging in men
Strengt #1 way to prevent or reverse muscleh lossTrainingAerobic Walking, cycling, golfing, swimmingActivityProperDiet Protein, Carbohydrates, Fiber
In 3 - 4 months, adultscan increase strength by2-3 times their currentstrength ability.
enefits of Weight trAining for older Adults Weight training is especially important to slow the process of sarcopenia Regular weight training has shown to: •reduce blood pressure •improve blood cholesterol levels •improve insulin sensitivity •increase bone mineral density •improve cardiovascular function •relieve depression •reduce body fat •improve functional abilities
In a New England Journal of Medicinestudy, 100 nursing home residents intheir 80s and 90s were put on a weight-training program for 10 weeks.At the end of the 10 weeks, some of theresults were so positive that a number ofresidents were able toswitch from a walker to a cane! The results appear next…
% Increase 28% Strength12% Walking Speed 113% Stair-Climbing Power
SARCOPENIA IN ELDERLY MEN AND WOMEN: THE RANCHO BERNARDO STUDY.Castillo EM, Goodman-Gruen D, Kritz-Silverstein D, Morton DJ, Wingard DL, Barrett-Connor E.American Journal of Preventive Medicine, 2003 Oct;25(3):226-31.METHODS: Height, weight, muscle strength, fat-free mass (FFM), fat mass by bioelectricimpedance analysis and grip strength(men) were measured for community-dwelling men (694) andwomen (1006) aged 55-98 years (mean=73)were selected; alcohol and medication use, smoking,and physical activity were ascertained.RESULTS:•Mean FFM was 43.5 kg for women and 61.7 kg for men. Sarcopenia, defined as FFM of > or =2.0standard deviations below the gender-specific mean of a young reference population, was presentin 6.0% overall. Prevalence increased dramatically from 4% of men and 3% of women aged 70-75to 16% of men and 13% of women aged 85 and older.•Both men and women with sarcopenia had a significantly lower fat mass and body mass indexthan those without sarcopenia.•Grip strength, but not quadriceps strength, was lower in men and women with sarcopenia.• Physically active women were about half as likely to have sarcopenia, but no association wasfound in men.• Few men and women were current smokers, but they were more likely to have sarcopenia.• Co morbidities (heart disease, diabetes, pulmonary disease, arthritis, cancer) and medications(thyroid hormones, corticosteroids, and hormone replacement therapy) were not associated withsarcopenia. CONCLUSIONS:This study also identified lack of physical activity and current smoking asreversible risk factors for sarcopenia.
Journal of Applied Physiology 107: 1172-1180, 2009.Effects of aging on human skeletal muscle after immobilization and retrainingC. Suetta, L. G. Hvid, L. Justesen, U. Christensen, K. Neergaard, L. Simonsen, N. Ortenblad, S. P. Magnusson, M. Kjaer, and P. Aagaard .AIM: To investigate the effects of unilateral lower limb immobilization and subsequent retraining on muscle mass, muscle architecture, neuromuscular activation, and resting twitch characteristics in young and aged human individuals.SUBJECTS: Twenty healthy men, 9 old (OM: 67.3 yr, range 61–74 yr) and 11 young (YM: 24.4 yr, range 21–27 yr), volunteered to participate in the study.METHOD: All subjects were subjected to unilateral (randomly selected limb) lower limb casting from the hip to the ankle for 2 wk. All measurements were conducted at baseline previous to the immobilization procedure (Pre), after 2 wk of immobilization, and again after 4 wk of heavy resistance training (6 wk).RESULTS:After retraining, both young and old regained their initial muscle strength, but old had smaller gains in quadriceps volume compared with young.CONCLUSIONThe present data shows that aging is accompanied by an attenuated rate of muscle atrophy in response to immobilization compared with that of young individuals, and importantly that old subjects demonstrate a diminished capacity to restore muscle size and muscle architecture during subsequent retraining
PREVALENCE OF SARCOPENIA AND PREDICTORS OF SKELETAL MUSCLE MASS INHEALTHY, OLDER MEN AND WOMENThe Journals of Gerontology: Series A, Volume57, Issue12Pp. M772-M777.Michele Iannuzzi-Sucich a ,. Karen M. Prestwood a and Anne M. Kenny a.OBJECTIVE The objective of this study was to determine the prevalence of sarcopenia in apopulation of older, community-dwelling research volunteers.METHODAppendicular skeletal muscle mass was measured by dual x-ray absorptiometry in 195 womenaged 64 to 93 years and 142 men aged 64 to 92 years. Body mass index (BMI) was calculated andphysical activity and performance were measured with the Physical Activity Scale for the Elderly,the Short Physical Performance Battery, and the Physical Performance Test. They measuredhealth-related quality of life by using the SF-36 general health survey. Serum estrone, estradiol, sexhormone-binding globulin, parathyroid hormone, and 25-hydroxy vitamin D were measured in allparticipants and bioavailable testosterone was measured only in men. Leg press strength and legpress power were determined in men.RESULTSThe prevalence of sarcopenia in our cohort was 22.6% in women and 26.8% in men. A subgroupanalysis of women and men 80 years or older revealed prevalence rates of 31.0% and 52.9%,respectively. In women, skeletal muscle mass correlated significantly with BMI and levels of serumestrone, estradiol, and 25-hydroxy vitamin D; in men, it correlated significantly with BMI, single legstance time, leg press strength, leg press power, SF-36 general health score, Physical PerformanceTest total score, and bioavailable testosterone levels.
LEUCINE: A KEY AMINO ACID IN AGEING-ASSOCIATED SARCOPENIA.Nutrition Research Reviews(2003), 16: 61-70Dominique Dardevet, Isabelle Rieu, Pierre Fafournoux, Claire Sornet, Lydie Combaret,Alain Bruhat, Sylvie Mordier, Laurent Mosoni and Jean GrizardAIM: To find out whether chronic oral leucine supplementation would be beneficial formaintaining muscle protein mass in elderly men and women.SUBJECTS: The effect of meal Leucine supplementation on in vivo protein synthesis inadult and ageing rats. FININDINGS :Leucine has been shown to stimulate insulin secretion, and therestoration of muscle protein synthesis in ageing rats
grAph shoWing effect of orAl leucine onmuscle protein synthesis
Journal of Applied Physiology 104: 1452-1461, 2008SKELETAL MUSCLE PROTEIN ANABOLIC RESPONSE TO RESISTANCEEXERCISE AND ESSENTIAL AMINO ACIDS IS DELAYED WITH AGINGMicah J. Drummond, Hans C. Dreyer, Bart Pennings, Christopher S. Fry, ShaheenDhanani,Edgar L. Dillon, Melinda Sheffield-Moore, Elena Volpi, Blake B.RasmussenMETHODSeven young and six old male subjects (age range: 24–77 yr) wereselected. dual-energy X-ray absorptiometry scan (Hologic QDR 4500W,Bedford, MA) was performed to measure body composition and leanmass. Each subject ingested 20 g of EAA 1 h following leg resistanceexerciseOBSERVATIONMuscle protein synthesis MPS increased early in young (1–3 hpostexercise) and later in old (3–6 h postexercise). The acute muscleprotein synthesis (MPS) response( usually delayed with aging) afterresistance exercise and EAA ingestion is similar between young and oldmen.
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BOOKS• Aspinall R.J , “Skeletal muscle aging” , Biology of aging and its modulation :aging of organs & system, Kluwer academic publishers,2003, 73-76.• Holiday R., “Theories of aging”, Understanding ageing ,2nd edition, Cambridge university press 1995,41-48.• Bales C. W., Ritchie C.S., “Sarcopenia”, Handbook of clinical nutrition and aging,2nd edition , Humana press,2009,183-184.• Asea A.A. , Pedersen B. K. , “Biochemical changes in response to intensive resistance training in the elderly", Heat shock proteins and whole body physiology, vol.5 ,Springer, 2010,365-367.• Chandler T.J., Brown L. E., “geriatrics: foundation of strength training for special population”, Conditioning for strength and human performance, Wolters Kluwer health,2008, 351-352.