Folland_japplphysiol.00224.2019.pdf (918.51 kB)

What makes long-term resistance-trained individuals so strong? A comparison of skeletal muscle morphology, architecture, and joint mechanics

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journal contribution
posted on 23.06.2020 by Tom Maden-Wilkinson, Tom Balshaw, Garry Massey, Jonathan Folland
The greater muscular strength of long-term resistance-trained (LTT) individuals is often attributed to hypertrophy, but the role of other factors, notably maximum voluntary specific tension (ST), muscle architecture, and any differences in joint mechanics (moment arm), have not been documented. The aim of the present study was to examine the musculoskeletal factors that might explain the greater quadriceps strength and size of LTT vs. untrained (UT) individuals. LTT (n = 16, age 21.6 ± 2.0 yr) had 4.0 ± 0.8 yr of systematic knee extensor heavy-resistance training experience, whereas UT (n = 52; age 25.1 ± 2.3 yr) had no lower-body resistance training experience for >18 mo. Knee extension dynamometry, T1-weighted magnetic resonance images of the thigh and knee, and ultrasonography of the quadriceps muscle group at 10 locations were used to determine quadriceps: isometric maximal voluntary torque (MVT), muscle volume (QVOL), patella tendon moment arm (PTMA), pennation angle (QΘP) and fascicle length (QFL), physiological cross-sectional area (QPCSA), and ST. LTT had substantially greater MVT (+60% vs. UT, P < 0.001) and QVOL (+56%, P < 0.001) and QPCSA (+41%, P < 0.001) but smaller differences in ST (+9%, P < 0.05) and moment arm (+4%, P < 0.05), and thus muscle size was the primary explanation for the greater strength of LTT. The greater muscle size (volume) of LTT was primarily attributable to the greater QPCSA (+41%; indicating more sarcomeres in parallel) rather than the more modest difference in FL (+11%; indicating more sarcomeres in series). There was no evidence in the present study for regional hypertrophy after LTT.NEW & NOTEWORTHY Here we demonstrate that the larger muscle strength (+60%) of a long-term (4+ yr) resistance-trained group compared with untrained controls was due to their similarly larger muscle volume (+56%), primarily due to a larger physiological cross-sectional area and modest differences in fascicle length, as well as modest differences in maximum voluntary specific tension and patella tendon moment arm. In addition, the present study refutes the possibility of regional hypertrophy, despite large differences in muscle volume.

History

School

  • Sport, Exercise and Health Sciences

Published in

Journal of Applied Physiology

Volume

128

Issue

4

Pages

1000 - 1011

Publisher

American Physiological Society

Version

VoR (Version of Record)

Rights holder

© American Physiological Society

Publisher statement

This is an Open Access Article. It is published by American Physiological Society under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date

23/12/2019

Publication date

2020-04-13

Copyright date

2020

ISSN

8750-7587

eISSN

1522-1601

Language

en

Depositor

Prof Jonathan Folland . Deposit date: 23 June 2020

Licence

Exports