| Autor: |
Smith MA; School of Kinesiology, Auburn University, Auburn, Alabama., Sexton CL; School of Kinesiology, Auburn University, Auburn, Alabama., Smith KA; Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama., Osburn SC; School of Kinesiology, Auburn University, Auburn, Alabama., Godwin JS; School of Kinesiology, Auburn University, Auburn, Alabama., Beausejour JP; School of Kinesiology, Auburn University, Auburn, Alabama., Ruple BA; School of Kinesiology, Auburn University, Auburn, Alabama., Goodlett MD; Athletics Department, Auburn University, Auburn, Alabama.; Edward Via College of Osteopathic Medicine, Auburn, Alabama., Edison JL; Athletics Department, Auburn University, Auburn, Alabama.; Edward Via College of Osteopathic Medicine, Auburn, Alabama., Fruge AD; Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama.; College of Nursing, Auburn University, Auburn, Alabama., Robinson AT; School of Kinesiology, Auburn University, Auburn, Alabama., Gladden LB; School of Kinesiology, Auburn University, Auburn, Alabama., Young KC; School of Kinesiology, Auburn University, Auburn, Alabama.; Edward Via College of Osteopathic Medicine, Auburn, Alabama., Roberts MD; School of Kinesiology, Auburn University, Auburn, Alabama.; Edward Via College of Osteopathic Medicine, Auburn, Alabama. |
| Abstrakt: |
We sought to determine if the myofibrillar protein synthetic (MyoPS) response to a naïve resistance exercise (RE) bout, or chronic changes in satellite cell number and muscle ribosome content, were associated with hypertrophic outcomes in females or differed in those who classified as higher (HR) or lower (LR) responders to resistance training (RT). Thirty-four untrained college-aged females (23.4 ± 3.4 kg/m 2 ) completed a 10-wk RT protocol (twice weekly). Body composition and leg imaging assessments, a right leg vastus lateralis biopsy, and strength testing occurred before and following the intervention. A composite score, which included changes in whole body lean/soft tissue mass (LSTM), vastus lateralis (VL) muscle cross-sectional area (mCSA), midthigh mCSA, and deadlift strength, was used to delineate upper and lower HR ( n = 8) and LR ( n = 8) quartiles. In all participants, training significantly ( P < 0.05) increased LSTM, VL mCSA, midthigh mCSA, deadlift strength, mean muscle fiber cross-sectional area, satellite cell abundance, and myonuclear number. Increases in LSTM ( P < 0.001), VL mCSA ( P < 0.001), midthigh mCSA ( P < 0.001), and deadlift strength ( P = 0.001) were greater in HR vs. LR. The first-bout 24-hour MyoPS response was similar between HR and LR ( P = 0.367). While no significant responder × time interaction existed for muscle total RNA concentrations (i.e., ribosome content) ( P = 0.888), satellite cell abundance increased in HR ( P = 0.026) but not LR ( P = 0.628). Pretraining LSTM ( P = 0.010), VL mCSA ( P = 0.028), and midthigh mCSA ( P < 0.001) were also greater in HR vs. LR. Female participants with an enhanced satellite cell response to RT, and more muscle mass before RT, exhibited favorable resistance training adaptations. NEW & NOTEWORTHY This study continues to delineate muscle biology differences between lower and higher responders to resistance training and is unique in that a female population was interrogated. As has been reported in prior studies, increases in satellite cell numbers are related to positive responses to resistance training. Satellite cell responsivity, rather than changes in muscle ribosome content per milligrams of tissue, may be a more important factor in delineating resistance-training responses in women. |
