{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T11:25:42Z","timestamp":1784805942752,"version":"3.55.0"},"reference-count":55,"publisher":"American Physiological Society","issue":"3","funder":[{"name":"University of Michigan's Rehabilitation Robotics Interdisciplinary Faculty Initiative Funds"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Applied Physiology"],"published-print":{"date-parts":[[2015,8,1]]},"abstract":"<jats:p> Quadriceps strength and activation deficits after anterior cruciate ligament (ACL) injury or surgery are typically evaluated at joint positions that are biomechanically advantageous to the quadriceps muscle. However, the effect of knee joint position and the associated changes in muscle length on strength and activation is currently unknown in this population. Here, we examined the effect of knee angle on quadriceps strength, activation, and electrically evoked torque in individuals with ACL reconstruction. Furthermore, we evaluated whether knee angle mediated the relationship between quadriceps weakness and functional performance after ACL reconstruction. Knee strength and activation were tested bilaterally at 90\u00b0 and 45\u00b0 of knee flexion in 11 subjects with ACL reconstruction using an interpolated triplet technique. The magnitude of electrically evoked torque at rest was used to quantify peripheral muscle contractile property changes, and the single-leg hop for distance test was used to evaluate functional performance. The results indicated that although quadriceps strength deficits were similar between knee angles, voluntary activation deficits were significantly higher in the reconstructed leg at 45\u00b0 of knee flexion. On the contrary, the side-to-side evoked torque at rest ratio [i.e., (reconstructed\/nonreconstructed) \u00d7 100] was significantly lower at 90\u00b0 than at 45\u00b0 of knee flexion. The association between quadriceps strength and functional performance was stronger at 45\u00b0 of knee flexion. The results provide novel evidence that quadriceps activation is selectively affected at 45\u00b0 of knee flexion and emphasize the importance of assessing quadriceps strength and activation at this position when feasible because it better captures activation deficits. <\/jats:p>","DOI":"10.1152\/japplphysiol.01044.2014","type":"journal-article","created":{"date-parts":[[2015,5,22]],"date-time":"2015-05-22T02:36:38Z","timestamp":1432262198000},"page":"223-231","source":"Crossref","is-referenced-by-count":38,"title":["Effect of knee angle on quadriceps strength and activation after anterior cruciate ligament reconstruction"],"prefix":"10.1152","volume":"119","author":[{"given":"Chandramouli","family":"Krishnan","sequence":"first","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, Michigan;"},{"name":"School of Kinesiology, University of Michigan, Ann Arbor, Michigan; and"},{"name":"Deparment of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul","family":"Theuerkauf","sequence":"additional","affiliation":[{"name":"Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, Michigan;"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1993.74.2.532"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1007\/BF01565472"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-4598(199803)21:3<318::AID-MUS5>3.0.CO;2-D"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.2519\/jospt.1997.26.5.238"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1002\/mus.20610"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.01254.2006"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1002\/mus.1053"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1996.81.5.2267"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.1007\/BF00182976"},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.2106\/00004623-200209000-00001"},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.1136\/bjsm.2008.052522"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1016\/S0966-6362(01)00201-6"},{"key":"B13","doi-asserted-by":"publisher","DOI":"10.1177\/0363546509349492"},{"key":"B14","doi-asserted-by":"publisher","DOI":"10.1007\/s00221-003-1463-z"},{"key":"B15","doi-asserted-by":"publisher","DOI":"10.1519\/JSC.0b013e3182986d5f"},{"key":"B16","doi-asserted-by":"publisher","DOI":"10.2519\/jospt.1993.17.3.133"},{"key":"B17","doi-asserted-by":"publisher","DOI":"10.4085\/1062-6050-45.1.87"},{"key":"B18","doi-asserted-by":"publisher","DOI":"10.1007\/s00421-011-1958-4"},{"key":"B19","doi-asserted-by":"publisher","DOI":"10.1152\/jn.1981.46.1.143"},{"key":"B20","doi-asserted-by":"publisher","DOI":"10.1097\/00003086-200003000-00007"},{"key":"B21","doi-asserted-by":"publisher","DOI":"10.1016\/S0736-0266(02)00160-2"},{"key":"B22","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-4598(199607)19:7<861::AID-MUS8>3.0.CO;2-7"},{"key":"B23","doi-asserted-by":"publisher","DOI":"10.1093\/ptj\/63.6.938"},{"key":"B24","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-0838.2011.01332.x"},{"key":"B25","doi-asserted-by":"publisher","DOI":"10.1097\/JES.0b013e3181c84195"},{"key":"B26","doi-asserted-by":"publisher","DOI":"10.1002\/mus.21981"},{"key":"B27","doi-asserted-by":"publisher","DOI":"10.1002\/mus.21279"},{"key":"B28","doi-asserted-by":"publisher","DOI":"10.1007\/s00421-009-1057-y"},{"key":"B29","doi-asserted-by":"publisher","DOI":"10.1002\/jor.21316"},{"key":"B30","doi-asserted-by":"publisher","DOI":"10.1002\/mus.21613"},{"key":"B31","doi-asserted-by":"publisher","DOI":"10.1007\/s00421-003-1025-x"},{"key":"B32","doi-asserted-by":"publisher","DOI":"10.1016\/j.knee.2014.02.008"},{"key":"B33","doi-asserted-by":"publisher","DOI":"10.1016\/j.clinph.2011.01.011"},{"key":"B34","doi-asserted-by":"publisher","DOI":"10.1177\/1941738113479925"},{"key":"B35","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1954.sp005070"},{"key":"B36","doi-asserted-by":"publisher","DOI":"10.1519\/JSC.0b013e3181d83335"},{"key":"B37","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0000000000000269"},{"key":"B38","doi-asserted-by":"publisher","DOI":"10.1016\/j.ptsp.2014.02.003"},{"key":"B39","doi-asserted-by":"publisher","DOI":"10.1097\/JES.0b013e3181aa6669"},{"key":"B40","doi-asserted-by":"publisher","DOI":"10.1016\/j.csm.2008.02.001"},{"key":"B41","doi-asserted-by":"publisher","DOI":"10.1123\/jsr.22.1.1"},{"key":"B42","doi-asserted-by":"publisher","DOI":"10.1016\/j.jbiomech.2004.02.005"},{"key":"B43","doi-asserted-by":"publisher","DOI":"10.2519\/jospt.2009.2864"},{"key":"B44","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2005.101600"},{"key":"B45","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0b013e3181677530"},{"key":"B46","doi-asserted-by":"crossref","first-page":"56","DOI":"10.2106\/JBJS.K.01412","volume":"94","author":"Roos PE","year":"2012","journal-title":"J Bone Joint Surg Br"},{"key":"B47","doi-asserted-by":"publisher","DOI":"10.2165\/00007256-200434040-00005"},{"key":"B48","doi-asserted-by":"publisher","DOI":"10.2106\/00004623-199404000-00010"},{"key":"B49","doi-asserted-by":"publisher","DOI":"10.1249\/MSS.0b013e318167812a"},{"key":"B50","doi-asserted-by":"publisher","DOI":"10.1080\/17453670610046451"},{"key":"B51","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.91220.2008"},{"key":"B52","doi-asserted-by":"publisher","DOI":"10.1177\/0363546513510672"},{"key":"B53","doi-asserted-by":"publisher","DOI":"10.1302\/0301-620X.83B8.11618"},{"key":"B54","doi-asserted-by":"publisher","DOI":"10.1177\/0363546504266483"},{"key":"B55","doi-asserted-by":"publisher","DOI":"10.1177\/0363546504268042"}],"container-title":["Journal of Applied Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.physiology.org\/doi\/pdf\/10.1152\/japplphysiol.01044.2014","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,9,8]],"date-time":"2019-09-08T23:44:09Z","timestamp":1567986249000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.physiology.org\/doi\/10.1152\/japplphysiol.01044.2014"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,8,1]]},"references-count":55,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2015,8,1]]}},"alternative-id":["10.1152\/japplphysiol.01044.2014"],"URL":"https:\/\/doi.org\/10.1152\/japplphysiol.01044.2014","relation":{},"ISSN":["8750-7587","1522-1601"],"issn-type":[{"value":"8750-7587","type":"print"},{"value":"1522-1601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,8,1]]}}}