{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T04:18:20Z","timestamp":1791173900741,"version":"4.1.0"},"reference-count":54,"publisher":"American Physiological Society","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Applied Physiology"],"published-print":{"date-parts":[[2006,7]]},"abstract":"<jats:p>\n                    Strength loss following disuse may result from alterations in muscle and\/or neurological properties. In this paper, we report our findings on human plantar flexor neurological properties following 4 wk of limb suspension [unilateral lower limb suspension (ULLS)], along with the effect of motor imagery (MI) training on these properties. In the companion paper (Part I), we report our findings on the changes in skeletal muscle properties. Additionally, in the present paper, we analyze our findings to determine the relative contribution of neural and muscular factors in strength loss. Measurements of central activation, the H-reflex, and nerve conduction were made before and after 4 wk of ULLS ( n = 18; 19\u201328 yr). A subset of the subjects ( n = 6) performed PF MI training 4 days\/wk. Following ULLS, we observed a significant increase in the soleus H-reflex (45.4 \u00b1 4.0 to 51.9 \u00b1 3.7% expressed relative to the maximal muscle action potential). Additionally, there were longer intervals between the delivery of an electrical stimulus to the tibial nerve and the corresponding muscle action potential (M-wave latency; mean prolongation 0.49 ms) and H-reflex wave (H-wave latency; mean prolongation 0.46 ms). The efficacy of MI on strength was ambiguous, with no significant effect detected (although a modest effect size was observed; \u03b7\n                    <jats:sup>2<\/jats:sup>\n                    = 0.18). These findings suggest that unweighting induces plastic changes in neural function that appear to be spatially distributed throughout the nervous system. In terms of the relative contribution of neural and muscular factors regulating strength loss, we observed that neural factors (primarily deficits in central activation) explained 48% of the variability in strength loss, whereas muscular factors (primarily sarcolemma function) explained 39% of the variability.\n                  <\/jats:p>","DOI":"10.1152\/japplphysiol.01404.2005","type":"journal-article","created":{"date-parts":[[2006,3,2]],"date-time":"2006-03-02T20:48:58Z","timestamp":1141332538000},"page":"264-272","source":"Crossref","is-referenced-by-count":119,"title":["Adaptations in human neuromuscular function following prolonged unweighting: II. Neurological properties and motor imagery efficacy"],"prefix":"10.1152","volume":"101","author":[{"given":"Brian C.","family":"Clark","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Todd M.","family":"Manini","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stanley J.","family":"Bolanowski","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lori L.","family":"Ploutz-Snyder","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","reference":[{"key":"R1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.01185.2001"},{"key":"R2","doi-asserted-by":"crossref","unstructured":"Anderson J\n                      , Almeida-Silveira MI, and Perot C.\n                      Reflex and muscular adaptations in rat soleus muscle after hindlimb suspension.\n                      J Exp Biol\n                      202\n                      : 2701\u20132707, 1999.","DOI":"10.1242\/jeb.202.19.2701"},{"key":"R3","doi-asserted-by":"publisher","DOI":"10.1097\/00005768-199610000-00007"},{"key":"R4","doi-asserted-by":"publisher","DOI":"10.1002\/mus.10008"},{"key":"R5","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1997.82.1.182"},{"key":"R6","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-201X.1996.476217000.x"},{"key":"R7","doi-asserted-by":"publisher","DOI":"10.1016\/S0926-6410(96)00072-9"},{"key":"R8","unstructured":"Clark BC\n                      , Cook SB, and Ploutz-Snyder LL.\n                      Reliability of techniques to assess human neuromuscular function in vivo.\n                      J Electromyogr Kinesiol\n                      . In press."},{"key":"R8A","unstructured":"Clark BC\n                      , Fernhall B, and Ploutz-Snyder LL.\n                      Adaptations in human neuromuscular function following prolonged unweighting: I. Skeletal muscle contractile properties and applied ischemia efficacy.\n                      J Appl Physiol\n                      101: 256\u2013263, 2006."},{"key":"R9","unstructured":"Cowley PM\n                      , Clark BC, and Ploutz-Snyder LL.\n                      Kinesthetic motor imagery acutely increases spinal excitability (Abstract).\n                      Med Sci Sports Exerc.\n                      In press."},{"key":"R10","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.00386.2001"},{"key":"R11","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuroscience.2005.10.042"},{"key":"R12","doi-asserted-by":"crossref","unstructured":"Duchateau J\n                      .\n                      Bed rest induces neural and contractile adaptations in triceps surae.\n                      Med Sci Sports Exerc\n                      27\n                      : 1581\u20131589, 1995.","DOI":"10.1249\/00005768-199512000-00001"},{"key":"R13","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1990.sp017972"},{"key":"R14","unstructured":"Dudley GA\n                      , Duvoisin MR, Adams GR, Meyer RA, Belew AH, and Buchanan P.\n                      Adaptations to unilateral lower limb suspension in humans.\n                      Aviat Space Environ Med\n                      63\n                      : 678\u2013683, 1992."},{"key":"R15","unstructured":"Dudley GA\n                      and Ploutz-Snyder LL.\n                      Deconditioning and bed rest: musculoskeletal response. In:\n                      ACSM\u2019s Resource Manual for Guidleines for Exercise Testing and Prescription\n                      (3rd ed.), edited by Roitman JL. Baltimore, MD: Williams & Wilkins, 2001, p. 200\u2013205."},{"key":"R16","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.16-20-06513.1996"},{"key":"R17","doi-asserted-by":"publisher","DOI":"10.1016\/S0028-3932(98)00089-X"},{"key":"R18","doi-asserted-by":"publisher","DOI":"10.1002\/ar.1092240113"},{"key":"R19","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.01070.2003"},{"key":"R20","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7793.1997.259bc.x"},{"key":"R21","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-4598(199608)19:8<989::AID-MUS6>3.0.CO;2-4"},{"key":"R22","doi-asserted-by":"publisher","DOI":"10.1016\/S0166-4328(02)00397-2"},{"key":"R23","doi-asserted-by":"publisher","DOI":"10.1007\/s002210050660"},{"key":"R24","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-201X.1998.t01-1-00358.x"},{"key":"R25","unstructured":"Hopkins WG\n                      .\n                      A New View of Statistics.\n                      http:\/\/newstatsi.org."},{"key":"R26","doi-asserted-by":"publisher","DOI":"10.1016\/S1388-2457(03)00245-1"},{"key":"R27","doi-asserted-by":"publisher","DOI":"10.1007\/s004210000330"},{"key":"R28","doi-asserted-by":"publisher","DOI":"10.1016\/j.jelekin.2004.09.002"},{"key":"R29","doi-asserted-by":"publisher","DOI":"10.1016\/0924-980X(95)00194-P"},{"key":"R30","doi-asserted-by":"publisher","DOI":"10.1002\/hbm.10103"},{"key":"R31","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.09-07-02455.1989"},{"key":"R32","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1983.sp014658"},{"key":"R33","doi-asserted-by":"publisher","DOI":"10.1136\/bjsm.18.3.149"},{"key":"R34","doi-asserted-by":"publisher","DOI":"10.1080\/00140138908966121"},{"key":"R35","unstructured":"Narici M\n                      and Cerretelli P.\n                      Changes in human muscle architecture in disuse-atrophy evaluated by ultrasound imaging.\n                      J Gravit Physiol\n                      5\n                      : P73\u2013P74, 1998."},{"key":"R36","unstructured":"Penfield W\n                      and Rasmussen T.\n                      The Cerebral Cortex of Man. A Clinical Study of Localization of Function.\n                      New York: Macmillan, 1950."},{"key":"R37","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1995.79.1.168"},{"key":"R38","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.16-23-07688.1996"},{"key":"R39","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuropsychologia.2003.11.018"},{"key":"R40","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.43.11.2311"},{"key":"R41","doi-asserted-by":"publisher","DOI":"10.1002\/mus.880140611"},{"key":"R42","doi-asserted-by":"publisher","DOI":"10.1097\/00001756-199605170-00012"},{"key":"R43","doi-asserted-by":"publisher","DOI":"10.1016\/S1388-2457(02)00329-2"},{"key":"R44","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00367.2001"},{"key":"R45","doi-asserted-by":"publisher","DOI":"10.1097\/00005768-200202000-00019"},{"key":"R46","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7793.2001.0507k.x"},{"key":"R46A","doi-asserted-by":"crossref","unstructured":"Sidaway B\n                      and Trzaska AR.\n                      Can mental practice increase ankle dorsiflexor torque?\n                      Phys Ther\n                      85\n                      : 1053\u20131060, 2005.","DOI":"10.1093\/ptj\/85.10.1053"},{"key":"R47","doi-asserted-by":"publisher","DOI":"10.1152\/jn.1995.73.1.373"},{"key":"R48","doi-asserted-by":"publisher","DOI":"10.1016\/S1388-2457(02)00373-5"},{"key":"R49","doi-asserted-by":"publisher","DOI":"10.1016\/S0304-3940(99)00284-0"},{"key":"R50","doi-asserted-by":"publisher","DOI":"10.1152\/jn.1992.67.5.1114"},{"key":"R51","doi-asserted-by":"publisher","DOI":"10.1016\/j.clinph.2003.12.033"},{"key":"R52","doi-asserted-by":"publisher","DOI":"10.1002\/mus.10406"}],"container-title":["Journal of Applied Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.physiology.org\/doi\/pdf\/10.1152\/japplphysiol.01404.2005","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,7,24]],"date-time":"2021-07-24T09:30:01Z","timestamp":1627119001000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.physiology.org\/doi\/10.1152\/japplphysiol.01404.2005"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2006,7]]},"references-count":54,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2006,7]]}},"alternative-id":["10.1152\/japplphysiol.01404.2005"],"URL":"https:\/\/doi.org\/10.1152\/japplphysiol.01404.2005","relation":{},"ISSN":["8750-7587","1522-1601"],"issn-type":[{"value":"8750-7587","type":"print"},{"value":"1522-1601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2006,7]]}}}