Keeping Senior Muscle Strong

Transcription

1 Keeping Senior Muscle Strong

2 Some Terms Hypertrophy Growth of muscle cell Gain in mass Gain in muscle strength Atrophy Reduced contractile properties Increased adipose cell infiltration Sarcopenia Age related loss of muscle mass About 3% loss of muscle mass per year after the age of 50. Sedentary lifestyle can increase this to greater than 5% in a year. Dynapenia Age related loss of muscle strength Due more to neural impairment than loss of muscle mass

3 Some Terms Muscle Strength Maximal force in which a muscle or muscle group can generate Expressed as 1- RM (repetition max) Maximal load that can be moved through a full range of motion Muscle Endurance Ability of a muscle to make repeated contractions against a submaximal load Low-resistance training results in gains in muscle endurance (20 plus reps per set) High-resistance training results in gains of muscle strength (8-12 reps per set)

4 Mechanisms for Exercise Induced Muscle Strength Nervous System Initial improvement in muscle activity is due to improved central coordination of motor unit activity Interesting: training of one arm will also begin training of opposite arm Sometimes better to train non-dominant before dominate Muscle Tissue Growth Hypertrophy Increase size of existing fibers (particularly Type II) Cell expresses gene for additional contractile proteins Cell incorporates satellite cells Hyperplasia Increase in number of muscle cells More evidence of this in animal studies

5 Shared Contribution to Strength Gains

6 How Hypertrophy Works Muscle Stretch (eccentric work) will initiate a signal pathway that encourages skeletal protein synthesis.

7 Satellite cells Located along the surface of the muscle cells

8 How it Works Incorporation of satellite cells will increase the number of nuclei available to maintain larger muscle cells

9 How it Works In order for optimum protein synthesis and hypertrophy to occur adequate amounts of protein need to be ingested within an hour before or after exercise.

10 Protein Intake and Protein Synthesis Timing Amount Type It appears that muscle uptake of essential amino acids is best when ingested before the exercise bout. Fast protein: uptake into the muscle is rapid. The increased blood flow to the muscle during exercise may facilitate uptake (Tipton, et al Some of the essential amino acids can stimulate protein translation. Some of the resultant proteins can increase rate of muscle protein uptake or synthesis. Protein synthesis will continue up to about 3 hours after exercise About g of protein should be ingested before or after exercise to provide enough protein for muscle uptake of AA. Whey, the liquid, is a fast protein and muscle uptake is fairly rapid Slow Protein: Casein = the curds of milk. Digestion of this is slowed in the stomach and uptake is slower than fast proteins. Casein reduces muscle atrophy

11 Protein Recommendations Do athletes need extra protein? AA may be oxidized during exercise Damage tissue requires AA for repair AA are needed to maximize training adaptations Best Answer There is an initial need for increased AA but as the athlete trains his or her body adapts the need for extra AA is not really needed. This is known as: Protein Sparing

12 Do seniors need more protein? Maybe: Current recommendations are about.8 grams per kilogram body weight. Some advocate grams per kilogram of body weight. Particularly at times of stress.

13 Amino Acid Supplements

14 Health Risk due to too much protein Ingestion Risk AA vs Protein Cost Kidney damage: excess excretion of nitrogen Can result in Dehydration: AA s can be consumed in greater quantity when not part of a food. Supplements are expensive Whole foods tend to come with other important nutrients Increased lipoprotein levels: May be due to excess calories that are not needed Impairment of intracellular signaling pathways that promote muscle synthesis Whole food might be cheaper and almost as effective. Increased food intake will often provide plenty of protein, but also bring in other important nutrients,

15 Some Suggestion Milk Cottage cheese Eggs/egg whites Fish Turkey, Chicken Lean beef, lamb, pork Bone broths Tree nut and seed butters (have good minerals too!) Hummus Stay away from deli meats! Avoid large smoothies drink in small doses.

16 Protein synthesis favors a Mixed diet Hormonal milieu that promotes AA uptake and protein synthesis is optimized with a mixed post-exercise diet. It appears the carbohydrate will stimulate insulin, which then sets the stage in the cell toward synthesis (uptake pack stuff away).

17 Lunch SOUP, SANDWICH, AND A GLASS OF MILK

18 Training is More Important than Protein Ingestion! You need to eat enough for repair but over ingestion is not stored as muscle protein. It can, however, be stored as glycogen or fat.

19 Seniors and Muscle Loss Aging process, inactivity, bed rest, inadequate diet, life stressors.

20 Contributions to Sarcopenia/Dynapenia Seene & Kaasik (2012)

21 Brief Clinical Bed Rest Can be devastating for senior muscle mass and strength Accelerates muscle tissue loss over and above the aging process Seniors loose muscle at a faster rate (about 6 times faster) than young adults during bed rest Most of this loss is from lower body and leg muscles. balance gait Power Social interactions (English & Paddon Jones, 2010)

22 Detraining the good news Decreases in muscle is lowest in slow twitch fibers. Gains seen after retraining are encouraging! Maintenance of gains due to strength training is fairly easy!

23 Seene & Kaasik (2012)

24 Recommendation grams of protein 3 times a day during or after illness. Resistance Exercise to increase muscle protein synthesis and hypertrophy Endurance exercise to increase mitochondrial number, oxygen carrying potential and overall tissue repair Improves mood Improves energy Eat soon within the hour before or after exercise to maximize nutrient uptake by muscles Eat a mixed diet Supplement wit AA when needed Move frequently during the day (English & Paddon Jones, 2010)

25 References English, Kirk, L. & Paddon-Jones (2010). Protecting muscle mass and function in older adults during bed rest. Curr Opin Nutr Metab Care. 13 (1): Jeukendrup, Asker & Gleeson, Michael (2010). Sport Nutrition: an introduction to energy production and performance. Human Kinetics, Champaign, IL. Seene, Teet & Kaasik, Pritt (2012). Muscle weakness in the elderly role of sarcopenia, dynapenia, and possible rehabilitation. Eur Rev Aging Phys Act. 9: