Skip to main content

Elevations in myofibrillar protein fractional synthesis rates following 5-weeks of dynamic resistance exercise

Publication ,  Conference
Dobson, J; Nilsson, M; Gasier, H; Fluckey, J

Anabolic responses to a single bout of high intensity exercise are elevated, but these responses appear to be diminished with chronic training. PURPOSE: To determine the effects of resistance exercise (RE) training on cumulative (36 hour) fractional synthesis rates (FSR) in gastrocnemius muscle of the Sprague-Dawley rat. METHODS: Fifteen rats were assigned to one of three groups: resistance exercise (RE; n=6), exercise control (EC; n=5), or sedentary cage control (CC; n=4). RE and EC animals were then operantly conditioned to perform the exercise regimen which consisted of a movement similar to a traditional "squat" exercise. Over a 5 week period, RE and EC performed 15 incremental resistance exercise sessions consisting of 50 repetitions for the first session with a 5% decrease in total volume per week. EC group performed sessions with an 80g vest while RE group started with only the vest and progressively increase weight to 410g by session 15. All cohorts were euthanized 16 hours following the final session and muscle tissues were collected. Cumulative FSR (%/day), as determined by a 2H2O primed-continuous method, was measured in red and white portions of the gastrocnemius. Isolation of myofibrillar, mitochondrial (subsarcolemmal or intermyofibrillar) and cytosolic protein subfractions were obtained through differential centrifugation. RESULTS: This study demonstrated that cumulative FSR in the myofibrillar subfraction maintained an exercise response with training, and was incrementally dependent on intensity (CC < EC < RE; p<0.05) in both red and white portions. No other subfractions of the muscle were responsive to high intensity exercise after 5-weeks of training (p>0.05). CONCLUSION: Results suggest that elevations of muscle protein synthesis with chronic training are selectively targeted to the myofibrillar fraction and are not a generalized response. Further, our data suggest that cumulative FSR responses may be dose-responsive in an intensity-dependent manner.

Duke Scholars

DOI

Volume

42

Issue

10

Start / End Page

86 / 86

Location

Baltimore, MD

Publisher

Wolters Kluwer

Conference Name

American College of Sports Medicine

Related Subject Headings

  • Sport Sciences
  • 1117 Public Health and Health Services
  • 1116 Medical Physiology
  • 1106 Human Movement and Sports Sciences
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Dobson, J., Nilsson, M., Gasier, H., & Fluckey, J. (n.d.). Elevations in myofibrillar protein fractional synthesis rates following 5-weeks of dynamic resistance exercise (Vol. 42, pp. 86–86). Presented at the American College of Sports Medicine, Baltimore, MD: Wolters Kluwer. https://doi.org/10.1249/01.MSS.0000389429.54631.5f
Dobson, Justin, Matts Nilsson, Heath Gasier, and James Fluckey. “Elevations in myofibrillar protein fractional synthesis rates following 5-weeks of dynamic resistance exercise,” 42:86–86. Wolters Kluwer, n.d. https://doi.org/10.1249/01.MSS.0000389429.54631.5f.
Dobson J, Nilsson M, Gasier H, Fluckey J. Elevations in myofibrillar protein fractional synthesis rates following 5-weeks of dynamic resistance exercise. In Wolters Kluwer; p. 86–86.
Dobson, Justin, et al. Elevations in myofibrillar protein fractional synthesis rates following 5-weeks of dynamic resistance exercise. Vol. 42, no. 10, Wolters Kluwer, pp. 86–86. Manual, doi:10.1249/01.MSS.0000389429.54631.5f.

DOI

Volume

42

Issue

10

Start / End Page

86 / 86

Location

Baltimore, MD

Publisher

Wolters Kluwer

Conference Name

American College of Sports Medicine

Related Subject Headings

  • Sport Sciences
  • 1117 Public Health and Health Services
  • 1116 Medical Physiology
  • 1106 Human Movement and Sports Sciences