A reduction in lower limb cross-sectional area (CSA) occurs after bed rest (BR). This should lead to an equivalent reduction in maximal instantaneous muscular power (Wp) if the body segments' lengths remain unchanged. Wp was determined during maximal jumps off both feet on a force platform before and on days 2, 6, 10, 32, and 48 after a 42-day duration BR. CSA of thigh muscles was measured by magnetic resonance imaging before and on day 5 after BR. Before BR, Wp was 3.63 ± 0.43 kW or 48.6 ± 3.3 W/kg. On days 2 and 6 after BR, Wp was reduced by 23.7 ± 6.9 and 22.7 ± 5.4% (P < 0.01), respectively. Thigh extensors CSA (CSAEXT) was 16.7 ± 4.7% (P < 0.01) lower than before. When normalized per CSAEXT, Wp was reduced by only 4.8 ± 4.5% (P < 0.05). By day 48 of recovery, Wp had returned to baseline values. Therefore, if Wp is appropriately normalized for CSA of the extensor muscles, the reduction in CSAEXT explains most of the decrease in Wp decrease after BR. Other factors such as a deficit in neural activation or a decrease in fiber-specific tension may account for only 5% of the Wp loss after BR.

Maximal instantaneous muscular power after prolonged bed rest in humans / H. Berg, A.E. Minetti, C. Moia, S. Rampichini, M.V. Narici. - In: JOURNAL OF APPLIED PHYSIOLOGY. - ISSN 8750-7587. - 90:2(2001), pp. 431-435.

Maximal instantaneous muscular power after prolonged bed rest in humans

A.E. Minetti;S. Rampichini;
2001

Abstract

A reduction in lower limb cross-sectional area (CSA) occurs after bed rest (BR). This should lead to an equivalent reduction in maximal instantaneous muscular power (Wp) if the body segments' lengths remain unchanged. Wp was determined during maximal jumps off both feet on a force platform before and on days 2, 6, 10, 32, and 48 after a 42-day duration BR. CSA of thigh muscles was measured by magnetic resonance imaging before and on day 5 after BR. Before BR, Wp was 3.63 ± 0.43 kW or 48.6 ± 3.3 W/kg. On days 2 and 6 after BR, Wp was reduced by 23.7 ± 6.9 and 22.7 ± 5.4% (P < 0.01), respectively. Thigh extensors CSA (CSAEXT) was 16.7 ± 4.7% (P < 0.01) lower than before. When normalized per CSAEXT, Wp was reduced by only 4.8 ± 4.5% (P < 0.05). By day 48 of recovery, Wp had returned to baseline values. Therefore, if Wp is appropriately normalized for CSA of the extensor muscles, the reduction in CSAEXT explains most of the decrease in Wp decrease after BR. Other factors such as a deficit in neural activation or a decrease in fiber-specific tension may account for only 5% of the Wp loss after BR.
Settore BIO/09 - Fisiologia
2001
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/14718
Citazioni
  • ???jsp.display-item.citation.pmc??? 4
  • Scopus 45
  • ???jsp.display-item.citation.isi??? ND
social impact