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Cited by 95Muscle Physiology and DisordersSports Performance and TrainingMuscle metabolism and nutrition

Effects of training, detraining, and retraining on strength, hypertrophy, and myonuclear number in human skeletal muscle

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Psilander, Niklas, Eftestøl, Einar, Cumming, Kristoffer Toldnes, Juvkam, Inga, Ekblom, Maria M., Sunding, Kerstin, Wernbom, Mathias, Holmberg, Hans-Christer +4 more·2019·Journal of Applied Physiology
DOI 10.1152/japplphysiol.00917.2018
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Abstract

Previously trained mouse muscles acquire strength and volume faster than naïve muscles; it has been suggested that this is related to increased myonuclear density. The present study aimed to determine whether a previously strength-trained leg (mem-leg) would respond better to a period of strength training than a previously untrained leg (con-leg). Nine men and 10 women performed unilateral strength training (T1) for 10 wk, followed by 20 wk of detraining (DT) and a 5-wk bilateral retraining period (T2). Muscle biopsies were taken before and after each training period and analyzed for myonuclear number, fiber volume, and cross-sectional area (CSA). Ultrasound and one repetition of maximum leg extension were performed to determine muscle thickness (MT) and strength. CSA (~17%), MT (~10%), and strength (~20%) increased during T1 in the mem-leg. However, the myonuclear number and fiber volume did not change. MT and CSA returned to baseline values during DT, but strength remained elevated (~60%), supporting previous findings of a long-lasting motor learning effect. MT and strength increased similarly in the mem-leg and con-leg during T2, whereas CSA, fiber volume, and myonuclear number remained unaffected. In conclusion, training response during T2 did not differ between the mem-leg and con-leg. However, this does not discount the existence of human muscle memory, since no increase in the number of myonuclei was detected during T1 and no clear detraining effect was observed for cell size during DT; thus, the present data did not allow for a rigorous test of the muscle memory hypothesis. NEW & NOTEWORTHY If a long-lasting intramuscular memory exists in humans, this will affect strength-training advice for both athletes and the public. Based on animal experiments, we hypothesized that such a memory exists and that it is related to the myonuclear number. However, a period of unilateral strength training, followed by detraining, did not increase the myonuclear number. The training response, during a subsequent bilateral retraining period, was not enhanced in the previously trained leg.

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  • When a highly trained individual abruptly ceases resistance exercise, macroscopic atrophy occurs rapidly within weeks, driven largely by the shedding of sarcoplasmic fluid and a rapid downregulation of translational efficiency.

    “When a highly trained individual abruptly ceases resistance exercise, macroscopic atrophy occurs rapidly within weeks, driven largely by the shedding of sarcoplasmic fluid and a rapid downregulation of translational efficiency [63,113].”

    From Ribosome Biogenesis as a Putative Bottleneck to Skeletal Muscle Hypertrophy: Mechanisms, Human Evidence, and Practical Modulators (2026) · cites this paper as [113]

    The Results (Muscle strength; page unavailable) report that the gain in muscle thickness was lost after 20 weeks without training. But the participants were initially untrained, and the paper does not establish atrophy within weeks or attribute the thickness loss to sarcoplasmic-fluid shedding or reduced translational efficiency. It also reports that muscle-fiber cross-sectional area remained unchanged during detraining. (LLM, conf=0.88)

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Authors
Psilander, N., Eftestøl, E., Cumming, K. T., Juvkam, I., Ekblom, M. M., Sunding, K., Wernbom, M., Holmberg, H.-C., Ekblom, B., Bruusgaard, J. C., Raastad, T., & Gundersen, K.
Affiliations
  • Swedish School of Sport and Health Sciences (SE)
  • University of Oslo (NO)
  • Norwegian School of Sport Sciences (NO)
  • Karolinska Institutet (SE)
  • University of Gothenburg (SE)
  • Mid Sweden University (SE)
  • Department of Sport Performance and Training, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
Corresponding author
Psilander, Niklas
ORCID
Venue
Journal of Applied Physiology
Publisher
American Physiological Society
Published
2019-06-01
Volume
126
Issue
6
Pages
1636-1645
ISSN
  • 0161-7567 (ISSN-L)
  • 8750-7587
  • 1522-1601
DOI
10.1152/japplphysiol.00917.2018
OpenAlex
W2939895576
Cited by
95
References
49
Citations by year
2026: 6 · 2025: 11 · 2024: 12 · 2023: 13 · 2022: 9 · 2021: 30 · 2020: 11 · 2019: 3
FWCI
4.39
Type
journal article
Language
en
Open access
Locations
  • Journal of Applied Physiology (publishedVersion)
  • PubMed (publishedVersion)
  • KTH Publication Database DiVA (KTH Royal Institute of Technology) (submittedVersion, other-oa)
  • NORA - Norwegian Open Research Archives (submittedVersion, other-oa)
Funders
  • The Swedisch National Centre for Reaserch in Sports (P2016-0134)
  • Mittuniversitetet (MM10)
  • Reaserch Council of Norway (240374)
  • The Swedish Military Forces Reaserch Authority (AF9220915)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Muscle Physiology and Disorders
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
Keywords
muscle memory, myonuclear number, resistance training, detraining, retraining, skeletal muscle hypertrophy, muscle strength, cross-sectional area, muscle thickness, motor learning, unilateral training, bilateral training, leg extension
MeSH terms
Adaptation, Physiological, Adult, Female, Humans, Hypertrophy, Male, Muscle Fibers, Skeletal, Muscle Strength, Resistance Training

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