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Pre-Training Muscle Characteristics of Subjects Who Are Obese Determine How Well Exercise Training Will Improve Their Insulin Responsiveness.
J Strength Cond Res. 2017 Mar; 31(3):798-808.JS

Abstract

Stuart, CA, Lee, ML, South, MA, Howell, MEA, Cartwright, BM, Ramsey, MW, and Stone, MH. Pre-training muscle characteristics of subjects who are obese determine how well exercise training will improve their insulin responsiveness. J Strength Cond Res 31(3): 798-808, 2017-Only half of prediabetic subjects who are obese who underwent exercise training without weight loss increased their insulin responsiveness. We hypothesized that those who improved their insulin responsiveness might have pretraining characteristics favoring a positive response to exercise training. Thirty nondiabetic subjects who were obese volunteered for 8 weeks of either strength training or endurance training. During training, subjects increased their caloric intake to prevent weight loss. Insulin responsiveness by euglycemic clamps and muscle fiber composition, and expression of muscle key biochemical pathways were quantified. Positive responders initially had 52% higher intermediate muscle fibers (fiber type IIa) with 27% lower slow-twitch fibers (type I) and 23% lower expression of muscle insulin receptors. Whether after weight training or stationary bike training, positive responders' fiber type shifted away from type I and type IIa fibers to an increased proportion of type IIx fibers (fast twitch). Muscle insulin receptor expression and glucose transporter type 4 (GLUT4) expression increased in all trained subjects, but these moderate changes did not consistently translate to improvement in whole-body insulin responsiveness. Exercise training of previously sedentary subjects who are obese can result in muscle remodeling and increased expression of key elements of the insulin pathway, but in the absence of weight loss, insulin sensitivity improvement was modest and limited to about half of the participants. Our data suggest rather than responders being more fit, they may have been less fit, only catching up to the other half of subjects who are obese whose insulin responsiveness did not increase beyond their pretraining baseline.

Authors+Show Affiliations

1Department of Internal Medicine, Quillen College of Medicine; 2Department of Allied Health, College of Clinical and Rehabilitative Health; and 3Department of Exercise and Sports Science, Clemmer College of Education, East Tennessee State University, Johnson City, Tennessee.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Journal Article

Language

eng

PubMed ID

27379957

Citation

Stuart, Charles A., et al. "Pre-Training Muscle Characteristics of Subjects Who Are Obese Determine How Well Exercise Training Will Improve Their Insulin Responsiveness." Journal of Strength and Conditioning Research, vol. 31, no. 3, 2017, pp. 798-808.
Stuart CA, Lee ML, South MA, et al. Pre-Training Muscle Characteristics of Subjects Who Are Obese Determine How Well Exercise Training Will Improve Their Insulin Responsiveness. J Strength Cond Res. 2017;31(3):798-808.
Stuart, C. A., Lee, M. L., South, M. A., Howell, M. E., Cartwright, B. M., Ramsey, M. W., & Stone, M. H. (2017). Pre-Training Muscle Characteristics of Subjects Who Are Obese Determine How Well Exercise Training Will Improve Their Insulin Responsiveness. Journal of Strength and Conditioning Research, 31(3), 798-808. https://doi.org/10.1519/JSC.0000000000001530
Stuart CA, et al. Pre-Training Muscle Characteristics of Subjects Who Are Obese Determine How Well Exercise Training Will Improve Their Insulin Responsiveness. J Strength Cond Res. 2017;31(3):798-808. PubMed PMID: 27379957.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Pre-Training Muscle Characteristics of Subjects Who Are Obese Determine How Well Exercise Training Will Improve Their Insulin Responsiveness. AU - Stuart,Charles A, AU - Lee,Michelle L, AU - South,Mark A, AU - Howell,Mary E A, AU - Cartwright,Brian M, AU - Ramsey,Michael W, AU - Stone,Michael H, PY - 2016/7/6/pubmed PY - 2017/4/25/medline PY - 2016/7/6/entrez SP - 798 EP - 808 JF - Journal of strength and conditioning research JO - J Strength Cond Res VL - 31 IS - 3 N2 - Stuart, CA, Lee, ML, South, MA, Howell, MEA, Cartwright, BM, Ramsey, MW, and Stone, MH. Pre-training muscle characteristics of subjects who are obese determine how well exercise training will improve their insulin responsiveness. J Strength Cond Res 31(3): 798-808, 2017-Only half of prediabetic subjects who are obese who underwent exercise training without weight loss increased their insulin responsiveness. We hypothesized that those who improved their insulin responsiveness might have pretraining characteristics favoring a positive response to exercise training. Thirty nondiabetic subjects who were obese volunteered for 8 weeks of either strength training or endurance training. During training, subjects increased their caloric intake to prevent weight loss. Insulin responsiveness by euglycemic clamps and muscle fiber composition, and expression of muscle key biochemical pathways were quantified. Positive responders initially had 52% higher intermediate muscle fibers (fiber type IIa) with 27% lower slow-twitch fibers (type I) and 23% lower expression of muscle insulin receptors. Whether after weight training or stationary bike training, positive responders' fiber type shifted away from type I and type IIa fibers to an increased proportion of type IIx fibers (fast twitch). Muscle insulin receptor expression and glucose transporter type 4 (GLUT4) expression increased in all trained subjects, but these moderate changes did not consistently translate to improvement in whole-body insulin responsiveness. Exercise training of previously sedentary subjects who are obese can result in muscle remodeling and increased expression of key elements of the insulin pathway, but in the absence of weight loss, insulin sensitivity improvement was modest and limited to about half of the participants. Our data suggest rather than responders being more fit, they may have been less fit, only catching up to the other half of subjects who are obese whose insulin responsiveness did not increase beyond their pretraining baseline. SN - 1533-4287 UR - https://www.unboundmedicine.com/medline/citation/27379957/Pre_Training_Muscle_Characteristics_of_Subjects_Who_Are_Obese_Determine_How_Well_Exercise_Training_Will_Improve_Their_Insulin_Responsiveness_ L2 - https://doi.org/10.1519/JSC.0000000000001530 DB - PRIME DP - Unbound Medicine ER -