{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,29]],"date-time":"2026-10-29T20:50:18Z","timestamp":1793307018337,"version":"4.5.0"},"reference-count":37,"publisher":"National Athletic Trainers' Association","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2012,7,1]]},"abstract":"<jats:sec>\n                  <jats:title>Context:<\/jats:title>\n                  <jats:p>Hamstrings strains are common and debilitating injuries in many sports. Most hamstrings exercises are performed at an inadequately low hip-flexion angle because this angle surpasses 70\u00b0 at the end of the sprinting leg's swing phase, when most injuries occur.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Objective:<\/jats:title>\n                  <jats:p>To evaluate the influence of various hip-flexion angles on peak torques of knee flexors in isometric, concentric, and eccentric contractions and on the hamstrings-to-quadriceps ratio.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Design:<\/jats:title>\n                  <jats:p>Descriptive laboratory study.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Setting:<\/jats:title>\n                  <jats:p>Research laboratory.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Patients and Other Participants<\/jats:title>\n                  <jats:p>Ten national-level sprinters (5 men, 5 women; age = 21.2 \u00b1 3.6 years, height = 175 \u00b1 6 cm, mass = 63.8 \u00b1 9.9 kg).<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Intervention(s):<\/jats:title>\n                  <jats:p>For each hip position (0\u00b0, 30\u00b0, 60\u00b0, and 90\u00b0 of flexion), participants used the right leg to perform (1) 5 seconds of maximal isometric hamstrings contraction at 45\u00b0 of knee flexion, (2) 5 maximal concentric knee flexion-extensions at 60\u00b0 per second, (3) 5 maximal eccentric knee flexion-extensions at 60\u00b0 per second, and (4) 5 maximal eccentric knee flexion-extensions at 150\u00b0 per second.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Main Outcome Measure(s):<\/jats:title>\n                  <jats:p>Hamstrings and quadriceps peak torque, hamstrings-to-quadriceps ratio, lateral and medial hamstrings root mean square.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results:<\/jats:title>\n                  <jats:p>We found no difference in quadriceps peak torque for any condition across all hip-flexion angles, whereas hamstrings peak torque was lower at 0\u00b0 of hip flexion than at any other angle (P &amp;lt; .001) and greater at 90\u00b0 of hip flexion than at 30\u00b0 and 60\u00b0 (P &amp;lt; .05), especially in eccentric conditions. As hip flexion increased, the hamstrings-to-quadriceps ratio increased. No difference in lateral or medial hamstrings root mean square was found for any condition across all hip-flexion angles (P &amp;gt; .05).<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions:<\/jats:title>\n                  <jats:p>Hip-flexion angle influenced hamstrings peak torque in all muscular contraction types; as hip flexion increased, hamstrings peak torque increased. Researchers should investigate further whether an eccentric resistance training program at sprint-specific hip-flexion angles (70\u00b0 to 80\u00b0) could help prevent hamstrings injuries in sprinters. Moreover, hamstrings-to-quadriceps ratio assessment should be standardized at 80\u00b0 of hip flexion.<\/jats:p>\n               <\/jats:sec>","DOI":"10.4085\/1062-6050-47.4.04","type":"journal-article","created":{"date-parts":[[2017,3,2]],"date-time":"2017-03-02T14:53:42Z","timestamp":1488466422000},"page":"390-395","source":"Crossref","is-referenced-by-count":56,"title":["Influence of Hip-Flexion Angle on Hamstrings Isokinetic Activity in Sprinters"],"prefix":"10.4085","volume":"47","author":[{"given":"Kenny","family":"Guex","sequence":"first","affiliation":[{"name":"Department of Physiotherapy, School of Health Sciences, University of Applied Sciences Western Switzerland, Lausanne;"},{"name":"Institute of Sport Sciences, Department of Physiology, University of Lausanne, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Boris","family":"Gojanovic","sequence":"first","affiliation":[{"name":"Sports Medicine Unit, University Hospital Center and University of 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