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DC Field | Value | Language |
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dc.contributor.advisor | Phillips, Stuart M | - |
dc.contributor.author | Murphy, Caoileann H | - |
dc.date.accessioned | 2016-04-07T15:57:06Z | - |
dc.date.available | 2016-04-07T15:57:06Z | - |
dc.date.issued | 2016 | - |
dc.identifier.uri | http://hdl.handle.net/11375/19058 | - |
dc.description.abstract | There is a saturable, dose-response relationship between the amount of protein ingested at a meal, the ensuing hyperaminoacidemia, and the subsequent skeletal muscle protein synthesis (MPS) response. Imposition of an external load, usually practiced as resistance exercise, on skeletal muscle is also a potent stimulus for increasing MPS and adds synergistically to the hyperaminoacidemia-induced rise in MPS. The current thesis examined the potential for meal-focused protein/leucine intake strategies, alone and in combination with resistance exercise, to augment MPS in older men. MPS was measured acutely (hours) using the continuous infusion of L-[ring-13C6]phenylalanine (Study 1) or over longer-term, integrated periods via ingestion of deuterated water (Study 2: 2-wk and Study 3: 3-d) while participants were free-living. In Studies 1 and 2 we examined whether a balanced versus a skewed pattern of protein intake across daily meals would enhance MPS during energy restriction (ER) in overweight/obese older men. Study 1 showed that a balanced consumption of protein during ER stimulated acute (%/h) myofibrillar protein synthesis (MyoPS) more effectively than a traditional, skewed distribution. Combining resistance training (RT) with a balanced protein intake pattern restored the lower acute rates of MyoPS during ER to the higher levels observed in energy balance. Study 2 showed no effect of daily protein intake pattern during ER on longer-term integrated MyoPS (%/d). However, the inclusion of RT during ER enhanced integrated MyoPS and the synthesis of numerous individual contractile, sarcoplasmic and mitochondrial skeletal muscle proteins with both protein intake patterns. Study 3 showed that leucine co-ingestion with daily meals enhanced integrated (%/d) MyoPS in healthy older men who were in energy balance and was equally effective among those consuming higher (1.2 g/kg/d) and lower (0.8 g/kg/d) protein intakes. Furthermore, the stimulatory effect of leucine co-ingestion on integrated MyoPS was further potentiated with the performance of resistance exercise. Collectively, these studies support the potential for per-meal recommendations, optimizing the protein dose consumed on a per-meal basis and leucine co-ingestion with meals, to augment MyoPS in older men, especially when combined with RT. These data have implications for recommendations to optimize MyoPS and possibly muscle mass in aging persons. | en_US |
dc.language.iso | en | en_US |
dc.subject | Muscle | en_US |
dc.subject | Protein | en_US |
dc.subject | Aging | en_US |
dc.subject | Leucine | en_US |
dc.title | STRATEGIES TO MAXIMIZE SKELETAL MUSCLE PROTEIN SYNTHESIS IN OLDER ADULTS | en_US |
dc.type | Thesis | en_US |
dc.contributor.department | Kinesiology | en_US |
dc.description.degreetype | Thesis | en_US |
dc.description.degree | Doctor of Philosophy (PhD) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Murphy CH Thesis Mar 24th 2016.pdf | 10.01 MB | Adobe PDF | View/Open |
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