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. 2023 Mar 1;134(3):491-507.
doi: 10.1152/japplphysiol.00605.2022. Epub 2023 Jan 12.

Molecular predictors of resistance training outcomes in young untrained female adults

Morgan A Smith  1 , Casey L Sexton  1 , Kristen A Smith  2 , Shelby C Osburn  1 , Joshua S Godwin  1 , Jonathan P Beausejour  1 , Bradley A Ruple  1 , Michael D Goodlett  3   4 , Joseph L Edison  3   4 , Andrew D Fruge  2   5 , Austin T Robinson  1 , L Bruce Gladden  1 , Kaelin C Young  1   4 , Michael D Roberts  1   4
Affiliations

Molecular predictors of resistance training outcomes in young untrained female adults

Morgan A Smith et al. J Appl Physiol (1985). .

Abstract

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/m2) 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.

Keywords: myofibrillar protein synthesis; physiology; resistance training; ribosomes; satellite cells.

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Conflict of interest statement

No conflicts of interest, financial or otherwise, are declared by the authors.

Figures

None
Graphical abstract
Figure 1.
Figure 1.
Study design. A: outline of the study design. More in-depth descriptions of procedures can be found in the text. B: outline of the protocol for D2O dosing and collection of salivette samples in relation to the points of data collection. DXA, dual energy X-ray absorptiometry; pQCT, peripheral quantitative computed tomography; 3RM, 3-repetition maximum; RT, resistance training; VL, vastus lateralis; PRE-1, first visit pretesting; PRE-2, second visit pretesting; T2, second skeletal muscle biopsy visit; USG, urine specific gravity.
Figure 2.
Figure 2.
Adaptations in variables used for classifying response groups. A: pre- to postintervention change scores for outcome variables used to generate response groups in all 34 female participants. B: pre- to postintervention change score differences between the higher (n = 8) and lower (n = 8) responders. For DXA LSTM, VL mCSA, and midthigh mCSA, dashed lines in B represent minimal difference scores based on test-retest statistics discussed in methods. All bar graphs are expressed as means ± SD values and contain individual respondent values as well. DXA, dual energy X-ray absorptiometry; HR, higher responder; LR, lower responder; LSTM, lean/soft tissue mass; mCSA, muscle cross-sectional area; VL, vastus lateralis; 1RM, 1-repetition maximum; DL est., deadlift estimated.
Figure 3.
Figure 3.
Mean fCSA changes in all participants and higher vs. lower responders. A: pre- and postintervention mean fCSA values in the 31 of 34 female participants that yielded enough tissue for analyses (*P < 0.05 comparing pre to post). B: pre- and postintervention mean fCSA values between the higher (n = 8) and lower (n = 8) responders. All bar graphs are expressed as means ± SD values and contain individual respondent values as well. fCSA, fiber cross-sectional area; GxT, group × time interaction; HR, higher responder; LR, lower responder.
Figure 4.
Figure 4.
Integrated MyoPS response to the first bout of training in all participants and higher vs. lower responders. A: 24-h integrated MyoPS response to the first bout of training in the 32 of 34 female participants that yielded enough tissue for analyses. B: same values as in A between the higher (n = 7) and lower (n = 8) responders. All bar graphs are expressed as means ± SD values and contain individual respondent values as well. C: scatterplot showing the association between the MyoPS responses presented in A and the pre- to postchange in VL mCSA in all participants. D: scatterplot showing the association between the MyoPS responses presented in panel a and the pre- to postchange in mean fCSA in all participants. mCSA, muscle cross-sectional area; fCSA, fiber cross-sectional area; HR, higher responder; LR, lower responder; MyoPS, myofibrillar protein synthetic; VL, vastus lateralis.
Figure 5.
Figure 5.
The satellite cell response to training in all participants and higher vs. lower responders. A: PAX7+/DAPI+ (or satellite cell) response to 10 wk of training in the 31 of 34 female participants that yielded enough tissue for analyses. B: same values as in A between the higher (n = 8) and lower (n = 8) responders. *Increase in HR from pre to post. All bar graphs are expressed as means ± SD values and contain individual respondent values as well. C: scatterplot showing the association between the pre- to postchange in satellite cells and the pre- to postchange in VL mCSA in all participants. D: scatterplot showing the association between pre- to postchange in satellite cells and the pre- to postintervention change in mean fCSA in all participants. E: ×20 representative image of PRE (scale bar = 100 µm). F: representative image of POST of the same participant (white circles identify satellite cells; colors: green, laminin; blue, DAPI; red, Pax-7; purple, satellite cell). mCSA, muscle cross-sectional area; fCSA, fiber cross-sectional area; GxT, group × time interaction; HR, higher responder; LR, lower responder; VL, vastus lateralis.
Figure 6.
Figure 6.
The myonuclear response to training in all participants and higher vs. lower responders. A: myonuclear number response to 10 wk of training in the 31 of 34 female participants that yielded enough tissue for analyses. B: same values as in A between the higher (n = 8) and lower (n = 8) responders. All bar graphs are expressed as means ± SD values and contain individual respondent values as well. C: scatterplot showing the association between the pre- to postchange in myonuclear number and the pre- to postchange in VL mCSA in all participants. D: scatterplot showing the association between pre- to postchange in myonuclear number and the pre- to postchange in mean fCSA in all participants. E and F: ×10 representative image of PRE (E) and representative image of POST (F) of the same participant (colors: red, dystrophin; blue, DAPI; white scale bar = 200 µm). mCSA, muscle cross-sectional area; fCSA, fiber cross-sectional area; GxT, group × time interaction; HR, higher responder; LR, lower responder.
Figure 7.
Figure 7.
The muscle ribosome content response to training in all participants and higher vs. lower responders. A: muscle total RNA concentration (per wet tissue mass, or ribosome density) response to 10 wk of training in the 33 of 34 female participants that yielded enough tissue for analyses. B: same values as in A between the higher (n = 8) and lower (n = 8) responders. All bar graphs are expressed as means ± SD values and contain individual respondent values as well. C: scatterplot showing the association between the pre- to postchange in ribosome density and the pre- to postchange in VL mCSA in all participants. Notably, the removal of one subject (subject 54) changes the P value from 0.060 to 0.937. D: scatterplot showing the association between the pre- to postchange in ribosome density and the pre- to postchange score in mean fCSA in all participants. mCSA, muscle cross-sectional area; fCSA, fiber cross-sectional area; GxT, group × time interaction; HR, higher responder; LR, lower responder; VL, vastus lateralis.
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References

    1. Sheel AW. Sex differences in the physiology of exercise: an integrative perspective. Exp Physiol 101: 211–212, 2016. doi:10.1113/EP085371. - DOI - PubMed
    1. Miller VM. Sex-based physiology prior to political correctness. Am J Physiol Endocrinol Metab 289: E359–E360, 2005. doi:10.1152/classicessays.00035.2005. - DOI - PubMed
    1. Costello JT, Bieuzen F, Bleakley CM. Where are all the female participants in Sports and Exercise Medicine research? Eur J Sport Sci 14: 847–851, 2014. doi:10.1080/17461391.2014.911354. - DOI - PubMed
    1. Kraemer WJ, Ratamess NA, French DN. Resistance training for health and performance. Curr Sports Med Rep 1: 165–171, 2002. doi:10.1249/00149619-200206000-00007. - DOI - PubMed
    1. Stone M, Potteiger J, Pierce K, Proulx C, O'Bryant H, Johnson R, Stone M. Comparison of the effects of three different weight-training programs on the one repetition maximum squat. J Strength Cond Res 14: 332–337, 2000.

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