{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,4]],"date-time":"2026-11-04T04:01:05Z","timestamp":1793764865574,"version":"4.6.1"},"reference-count":61,"publisher":"SAGE Publications","issue":"4","license":[{"start":{"date-parts":[[2023,4,1]],"date-time":"2023-04-01T00:00:00Z","timestamp":1680307200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Orthopaedic Journal of Sports Medicine"],"published-print":{"date-parts":[[2023,4,1]]},"abstract":"<jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>Research has demonstrated that performing a secondary task during a drop vertical jump (DVJ) may affect landing kinetics and kinematics.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose:<\/jats:title>\n                    <jats:p>To examine the differences in the trunk and lower extremity biomechanics associated with anterior cruciate ligament (ACL) injury risk factors between a standard DVJ and a DVJ while heading a soccer ball (header DVJ).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Study Design:<\/jats:title>\n                    <jats:p>Descriptive laboratory study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>Participants comprised 24 college-level soccer players (18 female and 6 male; mean \u00b1 SD age, 20.04 \u00b1 1.12 years; height, 165.75 \u00b1 7.25 cm; weight, 60.95 \u00b1 8.47 kg). Each participant completed a standard DVJ and a header DVJ, and biomechanics were recorded using an electromagnetic tracking system and force plate. The difference (\u0394) in 3-dimensional trunk, hip, knee, and ankle biomechanics between the tasks was analyzed. In addition, for each biomechanical variable, the correlation between the data from the 2 tasks was calculated.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>Compared to the standard DVJ, performing the header DVJ led to significantly reduced peak knee flexion angle (\u0394 = 5.35\u00b0; P = .002), knee flexion displacement (\u0394 = 3.89\u00b0; P = .015), hip flexion angle at initial contact (\u0394 = \u22122.84\u00b0; P = .001), peak trunk flexion angle (\u0394 = 13.11\u00b0; P = .006), and center of mass vertical displacement (\u0394 = \u22120.02m; P = .010), and increased peak anterior tibial shear force (\u0394 = \u22120.72 N\/kg; P = .020), trunk lateral flexion angle at initial contact (\u0394 = 1.55\u00b0; P &lt; .0001), peak trunk lateral flexion angle (\u0394 = 1.34\u00b0; P = .003), knee joint stiffness (\u0394 = 0.002 N*m\/kg\/deg; P = .017), and leg stiffness (\u0394 = 8.46 N\/kg\/m; P = .046) compared to those in standard DVJs. In addition, individuals' data for these variables were highly and positively correlated between conditions ( r = 0.632-0.908; P &lt; .001).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>The header DVJ task showed kinetic and kinematic parameters that suggested increased risk of ACL injury as compared with the standard DVJ task.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Clinical Relevance:<\/jats:title>\n                    <jats:p>Athletes may benefit from acquiring the ability to safely perform header DVJs to prevent ACL injury. To simulate real-time competition situations, coaches and athletic trainers should incorporate such dual tasks in ACL injury prevention programs.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/23259671231164706","type":"journal-article","created":{"date-parts":[[2023,4,17]],"date-time":"2023-04-17T13:07:10Z","timestamp":1681736830000},"update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":14,"title":["Effect of Heading a Soccer Ball as an External Focus During a Drop Vertical Jump Task"],"prefix":"10.1177","volume":"11","author":[{"given":"Hadi","family":"Akbari","sequence":"first","affiliation":[{"name":"Department of Sport Sciences, Faculty of Literature and Humanities, University of Zabol, Zabol, Iran."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Satoshi","family":"Kuwano","sequence":"additional","affiliation":[{"name":"Faculty of Business Information Science, Jobu University, Gunma, 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