caa a22 4500 467939918 CHVBK 20180406153009.0 cr unu---uuuuu 170328e20060901xx s 000 0 eng 10.1007/s00421-006-0244-3 doi (NATIONALLICENCE)springer-10.1007/s00421-006-0244-3 Deficit in human muscle strength with cast immobilization: contribution of inorganic phosphate [Elektronische Daten] [Neeti Pathare, Jennifer Stevens, Glenn Walter, Prithvi Shah, Arun Jayaraman, Susan Tillman, Mark Scarborough, C. Parker Gibbs, Krista Vandenborne] Metabolic factors have been proposed to explain strength deficits observed in skeletal muscle with immobilization that are not completely accounted for by changes in muscle cross-sectional area (CSA) and neural adaptations. The aim of this study was to quantify changes in the resting inorganic phosphate (Pi) concentration from the medial gastrocnemius muscle during immobilization, reloading and rehabilitation. Additionally, we assessed the contributions of CSA, muscle activation and Pi concentration to plantar flexor torque during rehabilitation following immobilization. Eight persons with a surgically stabilized ankle fracture participated. Subjects were immobilized for 6-8weeks and subsequently participated in 10weeks of rehabilitation. Localized 31P-Magnetic resonance spectroscopy, magnetic resonance imaging, isometric torque and activation testing were performed on the immobilized and uninvolved limbs. At 6weeks of immobilization, significant differences were noted between the immobilized and uninvolved limbs for the Pi concentration and the Pi/PCr ratio (P<0.05). From 6weeks of immobilization to 3-5days of reloading, the increase in Pi concentration (15%, P=0.26) and Pi/PCr (20%, P=0.29) was not significant. During rehabilitation, the relative contributions of CSA, muscle activation and Pi concentration to plantarflexor torque were 32, 44 and 40%, respectively. Together, CSA, muscle activation and Pi concentration accounted for 76% of the variance in torque (P<0.01). In summary, our findings suggest that immobilization, independent of reloading, leads to a significant increase in the resting Pi concentration of human skeletal muscle. Additionally, alterations in resting Pi concentration may contribute to strength deficits with immobilization not accounted for by changes in muscle CSA or neural adaptations. Springer-Verlag, 2006 Immobilization nationallicence Muscle strength nationallicence Inorganic phosphate nationallicence Muscle cross-sectional area nationallicence Muscle activation nationallicence Magnetic resonance nationallicence Pathare Neeti Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut Stevens Jennifer Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut Walter Glenn Department of Physiology and Functional Genomics, University of Florida, 32610, Gainesville, FL, USA aut Shah Prithvi Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut Jayaraman Arun Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut Tillman Susan UF & Shands Rehab at the Orthopedic and Sports Medicine Institute, Gainesville, FL, USA aut Scarborough Mark Department of Orthopedics and Rehabilitation, University of Florida, Gainesville, FL, USA aut Parker Gibbs C. Department of Orthopedics and Rehabilitation, University of Florida, Gainesville, FL, USA aut Vandenborne Krista Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut European Journal of Applied Physiology Springer-Verlag 98/1(2006-09-01), 71-78 1439-6319 98:1<71 2006 98 421 https://doi.org/10.1007/s00421-006-0244-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00421-006-0244-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pathare Neeti Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut NATIONALLICENCE 700 1- Stevens Jennifer Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut NATIONALLICENCE 700 1- Walter Glenn Department of Physiology and Functional Genomics, University of Florida, 32610, Gainesville, FL, USA aut NATIONALLICENCE 700 1- Shah Prithvi Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut NATIONALLICENCE 700 1- Jayaraman Arun Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut NATIONALLICENCE 700 1- Tillman Susan UF & Shands Rehab at the Orthopedic and Sports Medicine Institute, Gainesville, FL, USA aut NATIONALLICENCE 700 1- Scarborough Mark Department of Orthopedics and Rehabilitation, University of Florida, Gainesville, FL, USA aut NATIONALLICENCE 700 1- Parker Gibbs C. Department of Orthopedics and Rehabilitation, University of Florida, Gainesville, FL, USA aut NATIONALLICENCE 700 1- Vandenborne Krista Department of Physical Therapy, University of Florida, PO Box 100154, 32610, Gainesville, FL, USA aut NATIONALLICENCE 773 0- European Journal of Applied Physiology Springer-Verlag 98/1(2006-09-01), 71-78 1439-6319 98:1<71 2006 98 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer