Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle

Milesi, S. ; Capelli, C. ; Denoth, J. ; Hutchinson, T. ; Stüssi, E.
Springer
Published 2000
ISSN:
1439-6327
Keywords:
Key words Bedrest ; Electromyography ; Maximal voluntary isometric contraction ; Maximal isometric torque ; Muscle atrophy ; Plantar and dorsal flexors of the ankle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Maximal voluntary isometric torque values of the ankle plantar (T im,PF) and dorsal flexors (T im,DF) were assessed in eight healthy adult males at 5° and 15° of dorsal flexion (DF) and at 5°, 15° and 25° of plantar flexion (PF) with the knee at right angles, before (two times), during (three times) and after (three times) 17 days of 6° head-down tilt bedrest (BR). Integrated electromyograms (iEMG) were also recorded from the gastrocnemius medialis and tibialis anterior. T im,PF and the iEMG of the gastrocnemius medialis were significantly larger (by 14% and by 27%, respectively) at the end of recovery than before BR. This was probably the consequence of training and/or habituation leading to: (1) increased activation of the plantar flexors; and (2) decreased co-activation of the antagonist muscles. Neither T im,DF nor the tibialis anterior iEMG changed significantly. The effects of BR on muscle performance were evaluated as follows. The net torque generated by a given muscle group was assumed to be the algebraic sum of the torque generated by the agonists and by the antagonists. Thus, for the plantar flexors Tim,PF=αiEMGGm − βiEMGTa, where: (1) iEMGGm and iEMGTa are the iEMGs of gastrocnemius medialis and of tibialis anterior during maximal PF; and (2) the constants α and β represent the electromechanical coupling of the plantar (α) and dorsal (β) flexors. Similarly for the dorsal flexors: Tim,DF=βiEMGTa − αiEMGGm, where iEMGTa and iEMGGm are the iEMGs of tibialis anterior and gastrocnemius medialis during maximal DF. Torque and iEMG values were assessed for all subjects under all experimental conditions. Thus, since the biomechanical leverage of the system was constant, α and β could be calculated. During BR, α decreased by 25% and it dropped by a further 30% during recovery. In contrast, β remained almost unchanged. This suggests that, in spite of training and/or habituation, BR significantly impaired the maximal isometric performance of the plantar flexors, an effect that continued during the initial 10 days of recovery.
Type of Medium:
Electronic Resource
URL:
_version_ 1798297420619055104
autor Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
autorsonst Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
book_url http://dx.doi.org/10.1007/s004210050672
datenlieferant nat_lic_papers
hauptsatz hsatz_simple
identnr NLM204530458
issn 1439-6327
journal_name European journal of applied physiology
materialart 1
notes Abstract Maximal voluntary isometric torque values of the ankle plantar (T im,PF) and dorsal flexors (T im,DF) were assessed in eight healthy adult males at 5° and 15° of dorsal flexion (DF) and at 5°, 15° and 25° of plantar flexion (PF) with the knee at right angles, before (two times), during (three times) and after (three times) 17 days of 6° head-down tilt bedrest (BR). Integrated electromyograms (iEMG) were also recorded from the gastrocnemius medialis and tibialis anterior. T im,PF and the iEMG of the gastrocnemius medialis were significantly larger (by 14% and by 27%, respectively) at the end of recovery than before BR. This was probably the consequence of training and/or habituation leading to: (1) increased activation of the plantar flexors; and (2) decreased co-activation of the antagonist muscles. Neither T im,DF nor the tibialis anterior iEMG changed significantly. The effects of BR on muscle performance were evaluated as follows. The net torque generated by a given muscle group was assumed to be the algebraic sum of the torque generated by the agonists and by the antagonists. Thus, for the plantar flexors Tim,PF=αiEMGGm − βiEMGTa, where: (1) iEMGGm and iEMGTa are the iEMGs of gastrocnemius medialis and of tibialis anterior during maximal PF; and (2) the constants α and β represent the electromechanical coupling of the plantar (α) and dorsal (β) flexors. Similarly for the dorsal flexors: Tim,DF=βiEMGTa − αiEMGGm, where iEMGTa and iEMGGm are the iEMGs of tibialis anterior and gastrocnemius medialis during maximal DF. Torque and iEMG values were assessed for all subjects under all experimental conditions. Thus, since the biomechanical leverage of the system was constant, α and β could be calculated. During BR, α decreased by 25% and it dropped by a further 30% during recovery. In contrast, β remained almost unchanged. This suggests that, in spite of training and/or habituation, BR significantly impaired the maximal isometric performance of the plantar flexors, an effect that continued during the initial 10 days of recovery.
package_name Springer
publikationsjahr_anzeige 2000
publikationsjahr_facette 2000
publikationsjahr_intervall 7999:2000-2004
publikationsjahr_sort 2000
publisher Springer
reference 82 (2000), S. 197-205
schlagwort Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
search_space articles
shingle_author_1 Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
shingle_author_2 Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
shingle_author_3 Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
shingle_author_4 Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
shingle_catch_all_1 Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
Abstract Maximal voluntary isometric torque values of the ankle plantar (T im,PF) and dorsal flexors (T im,DF) were assessed in eight healthy adult males at 5° and 15° of dorsal flexion (DF) and at 5°, 15° and 25° of plantar flexion (PF) with the knee at right angles, before (two times), during (three times) and after (three times) 17 days of 6° head-down tilt bedrest (BR). Integrated electromyograms (iEMG) were also recorded from the gastrocnemius medialis and tibialis anterior. T im,PF and the iEMG of the gastrocnemius medialis were significantly larger (by 14% and by 27%, respectively) at the end of recovery than before BR. This was probably the consequence of training and/or habituation leading to: (1) increased activation of the plantar flexors; and (2) decreased co-activation of the antagonist muscles. Neither T im,DF nor the tibialis anterior iEMG changed significantly. The effects of BR on muscle performance were evaluated as follows. The net torque generated by a given muscle group was assumed to be the algebraic sum of the torque generated by the agonists and by the antagonists. Thus, for the plantar flexors Tim,PF=αiEMGGm − βiEMGTa, where: (1) iEMGGm and iEMGTa are the iEMGs of gastrocnemius medialis and of tibialis anterior during maximal PF; and (2) the constants α and β represent the electromechanical coupling of the plantar (α) and dorsal (β) flexors. Similarly for the dorsal flexors: Tim,DF=βiEMGTa − αiEMGGm, where iEMGTa and iEMGGm are the iEMGs of tibialis anterior and gastrocnemius medialis during maximal DF. Torque and iEMG values were assessed for all subjects under all experimental conditions. Thus, since the biomechanical leverage of the system was constant, α and β could be calculated. During BR, α decreased by 25% and it dropped by a further 30% during recovery. In contrast, β remained almost unchanged. This suggests that, in spite of training and/or habituation, BR significantly impaired the maximal isometric performance of the plantar flexors, an effect that continued during the initial 10 days of recovery.
1439-6327
14396327
Springer
shingle_catch_all_2 Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
Abstract Maximal voluntary isometric torque values of the ankle plantar (T im,PF) and dorsal flexors (T im,DF) were assessed in eight healthy adult males at 5° and 15° of dorsal flexion (DF) and at 5°, 15° and 25° of plantar flexion (PF) with the knee at right angles, before (two times), during (three times) and after (three times) 17 days of 6° head-down tilt bedrest (BR). Integrated electromyograms (iEMG) were also recorded from the gastrocnemius medialis and tibialis anterior. T im,PF and the iEMG of the gastrocnemius medialis were significantly larger (by 14% and by 27%, respectively) at the end of recovery than before BR. This was probably the consequence of training and/or habituation leading to: (1) increased activation of the plantar flexors; and (2) decreased co-activation of the antagonist muscles. Neither T im,DF nor the tibialis anterior iEMG changed significantly. The effects of BR on muscle performance were evaluated as follows. The net torque generated by a given muscle group was assumed to be the algebraic sum of the torque generated by the agonists and by the antagonists. Thus, for the plantar flexors Tim,PF=αiEMGGm − βiEMGTa, where: (1) iEMGGm and iEMGTa are the iEMGs of gastrocnemius medialis and of tibialis anterior during maximal PF; and (2) the constants α and β represent the electromechanical coupling of the plantar (α) and dorsal (β) flexors. Similarly for the dorsal flexors: Tim,DF=βiEMGTa − αiEMGGm, where iEMGTa and iEMGGm are the iEMGs of tibialis anterior and gastrocnemius medialis during maximal DF. Torque and iEMG values were assessed for all subjects under all experimental conditions. Thus, since the biomechanical leverage of the system was constant, α and β could be calculated. During BR, α decreased by 25% and it dropped by a further 30% during recovery. In contrast, β remained almost unchanged. This suggests that, in spite of training and/or habituation, BR significantly impaired the maximal isometric performance of the plantar flexors, an effect that continued during the initial 10 days of recovery.
1439-6327
14396327
Springer
shingle_catch_all_3 Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
Abstract Maximal voluntary isometric torque values of the ankle plantar (T im,PF) and dorsal flexors (T im,DF) were assessed in eight healthy adult males at 5° and 15° of dorsal flexion (DF) and at 5°, 15° and 25° of plantar flexion (PF) with the knee at right angles, before (two times), during (three times) and after (three times) 17 days of 6° head-down tilt bedrest (BR). Integrated electromyograms (iEMG) were also recorded from the gastrocnemius medialis and tibialis anterior. T im,PF and the iEMG of the gastrocnemius medialis were significantly larger (by 14% and by 27%, respectively) at the end of recovery than before BR. This was probably the consequence of training and/or habituation leading to: (1) increased activation of the plantar flexors; and (2) decreased co-activation of the antagonist muscles. Neither T im,DF nor the tibialis anterior iEMG changed significantly. The effects of BR on muscle performance were evaluated as follows. The net torque generated by a given muscle group was assumed to be the algebraic sum of the torque generated by the agonists and by the antagonists. Thus, for the plantar flexors Tim,PF=αiEMGGm − βiEMGTa, where: (1) iEMGGm and iEMGTa are the iEMGs of gastrocnemius medialis and of tibialis anterior during maximal PF; and (2) the constants α and β represent the electromechanical coupling of the plantar (α) and dorsal (β) flexors. Similarly for the dorsal flexors: Tim,DF=βiEMGTa − αiEMGGm, where iEMGTa and iEMGGm are the iEMGs of tibialis anterior and gastrocnemius medialis during maximal DF. Torque and iEMG values were assessed for all subjects under all experimental conditions. Thus, since the biomechanical leverage of the system was constant, α and β could be calculated. During BR, α decreased by 25% and it dropped by a further 30% during recovery. In contrast, β remained almost unchanged. This suggests that, in spite of training and/or habituation, BR significantly impaired the maximal isometric performance of the plantar flexors, an effect that continued during the initial 10 days of recovery.
1439-6327
14396327
Springer
shingle_catch_all_4 Milesi, S.
Capelli, C.
Denoth, J.
Hutchinson, T.
Stüssi, E.
Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
Key words Bedrest
Electromyography
Maximal voluntary isometric contraction
Maximal isometric torque
Muscle atrophy
Plantar and dorsal flexors of the ankle
Abstract Maximal voluntary isometric torque values of the ankle plantar (T im,PF) and dorsal flexors (T im,DF) were assessed in eight healthy adult males at 5° and 15° of dorsal flexion (DF) and at 5°, 15° and 25° of plantar flexion (PF) with the knee at right angles, before (two times), during (three times) and after (three times) 17 days of 6° head-down tilt bedrest (BR). Integrated electromyograms (iEMG) were also recorded from the gastrocnemius medialis and tibialis anterior. T im,PF and the iEMG of the gastrocnemius medialis were significantly larger (by 14% and by 27%, respectively) at the end of recovery than before BR. This was probably the consequence of training and/or habituation leading to: (1) increased activation of the plantar flexors; and (2) decreased co-activation of the antagonist muscles. Neither T im,DF nor the tibialis anterior iEMG changed significantly. The effects of BR on muscle performance were evaluated as follows. The net torque generated by a given muscle group was assumed to be the algebraic sum of the torque generated by the agonists and by the antagonists. Thus, for the plantar flexors Tim,PF=αiEMGGm − βiEMGTa, where: (1) iEMGGm and iEMGTa are the iEMGs of gastrocnemius medialis and of tibialis anterior during maximal PF; and (2) the constants α and β represent the electromechanical coupling of the plantar (α) and dorsal (β) flexors. Similarly for the dorsal flexors: Tim,DF=βiEMGTa − αiEMGGm, where iEMGTa and iEMGGm are the iEMGs of tibialis anterior and gastrocnemius medialis during maximal DF. Torque and iEMG values were assessed for all subjects under all experimental conditions. Thus, since the biomechanical leverage of the system was constant, α and β could be calculated. During BR, α decreased by 25% and it dropped by a further 30% during recovery. In contrast, β remained almost unchanged. This suggests that, in spite of training and/or habituation, BR significantly impaired the maximal isometric performance of the plantar flexors, an effect that continued during the initial 10 days of recovery.
1439-6327
14396327
Springer
shingle_title_1 Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
shingle_title_2 Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
shingle_title_3 Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
shingle_title_4 Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
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source_archive Springer Online Journal Archives 1860-2000
timestamp 2024-05-06T10:07:43.038Z
titel Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
titel_suche Effects of 17 days bedrest on the maximal voluntary isometric torque and neuromuscular activation of the plantar and dorsal flexors of the ankle
topic WW-YZ
uid nat_lic_papers_NLM204530458