Alexandre Fouré1,2,3, Augustin C Ogier4, Maxime Guye5,6, Julien Gondin7,8, David Bendahan5. 1. Aix Marseille Univ, CNRS, Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339, Faculté de Médecine de la Timone, 27 boulevard Jean Moulin, 13385, Marseille, France. alexandre.foure@hotmail.fr. 2. APHM, Hôpital Universitaire Timone, Centre d'Exploration Métabolique par Résonance Magnétique (CEMEREM), 13005, Marseille, France. alexandre.foure@hotmail.fr. 3. Université de Lyon, Université Claude Bernard Lyon 1 (UCBL1), Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM), EA 7424, 27-29 Boulevard du 11 Novembre 1918, Villeurbanne, 69622, France. alexandre.foure@hotmail.fr. 4. Aix Marseille Univ, Université de Toulon, CNRS, Laboratoire d'Informatique & Systèmes (LIS), UMR 7020, 13385, Marseille, France. 5. Aix Marseille Univ, CNRS, Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339, Faculté de Médecine de la Timone, 27 boulevard Jean Moulin, 13385, Marseille, France. 6. APHM, Hôpital Universitaire Timone, Centre d'Exploration Métabolique par Résonance Magnétique (CEMEREM), 13005, Marseille, France. 7. Aix Marseille Univ, CNRS, Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339, Faculté de Médecine de la Timone, 27 boulevard Jean Moulin, 13385, Marseille, France. julien.gondin@univ-lyon1.fr. 8. Institut NeuroMyoGène (INMG), Univ Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U1217, Faculté de Médecine et de Pharmacie, 8 avenue Rockefeller, Lyon, 69008, France. julien.gondin@univ-lyon1.fr.
Abstract
PURPOSE: This study aimed at determining through MRI investigations, force and soreness assessments whether the modulation of muscle length is a relevant strategy for minimising neuromuscular electrical stimulation (NMES)-induced muscle damage in young healthy participants. METHODS: Comparison of 2 NMES sessions (40 isometric electrically-evoked contractions of the knee extensors) was randomly performed on 1 knee flexed at 50° (short muscle length) and the contralateral at 100° (long muscle length) in a single group of healthy participants. Indirect markers of muscle damage including changes in maximal voluntary isometric contraction (MVC) force, muscle volume and transverse relaxation time (T2) were measured before, 2 days (D2), 4 days (D4) and 7 days (D7) after the NMES sessions in each limb of the ten participants. RESULTS: Although stimulation intensity was similar during the NMES session on both limbs, significantly lower force production was recorded at long muscle length (peak at 30 ± 5% MVC force) as compared to short muscle length (peak at 61 ± 12% MVC force). In the following days, MVC force at long muscle length was decreased from D2 to D7, whereas no significant change occurred at short muscle length. Increases in muscle volume and T2 were found at each time point in stimulated muscles at long muscle length, whereas no change was found at short muscle length. CONCLUSION: For the same stimulation intensity, NMES-induced isometric contractions generate higher knee extension force output and result in lower muscle tissues alterations that could be related to a lower intramuscular shear strain when exercise is performed at short muscle length.
PURPOSE: This study aimed at determining through MRI investigations, force and soreness assessments whether the modulation of muscle length is a relevant strategy for minimising neuromuscular electrical stimulation (NMES)-induced muscle damage in young healthy participants. METHODS: Comparison of 2 NMES sessions (40 isometric electrically-evoked contractions of the knee extensors) was randomly performed on 1 knee flexed at 50° (short muscle length) and the contralateral at 100° (long muscle length) in a single group of healthy participants. Indirect markers of muscle damage including changes in maximal voluntary isometric contraction (MVC) force, muscle volume and transverse relaxation time (T2) were measured before, 2 days (D2), 4 days (D4) and 7 days (D7) after the NMES sessions in each limb of the ten participants. RESULTS: Although stimulation intensity was similar during the NMES session on both limbs, significantly lower force production was recorded at long muscle length (peak at 30 ± 5% MVC force) as compared to short muscle length (peak at 61 ± 12% MVC force). In the following days, MVC force at long muscle length was decreased from D2 to D7, whereas no significant change occurred at short muscle length. Increases in muscle volume and T2 were found at each time point in stimulated muscles at long muscle length, whereas no change was found at short muscle length. CONCLUSION: For the same stimulation intensity, NMES-induced isometric contractions generate higher knee extension force output and result in lower muscle tissues alterations that could be related to a lower intramuscular shear strain when exercise is performed at short muscle length.
Authors: Jonathan Galvão Tenório Cavalcante; Álvaro de Almeida Ventura; Leandro Gomes de Jesus Ferreira; Alessandra Martins Melo de Sousa; Ivo Vieira de Sousa Neto; Rita de Cássia Marqueti; Nicolas Babault; João Luiz Quagliotti Durigan Journal: Appl Bionics Biomech Date: 2022-07-22 Impact factor: 1.664