{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,31]],"date-time":"2025-08-31T23:23:07Z","timestamp":1756682587414,"version":"3.44.0"},"reference-count":23,"publisher":"BMJ","issue":"1","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open Sport Exerc Med"],"accepted":{"date-parts":[[2016,2,24]]},"published-print":{"date-parts":[[2016,4]]},"abstract":"<jats:sec>\n                  <jats:title>Introduction<\/jats:title>\n                  <jats:p>Neck pain is a widespread health problem in the skydiver athlete population, epidemiologically linked to repeated exposure to parachute opening shock (POS). During POS, a parachutist is subjected to considerable deceleration forces. This study aims to evaluate the use of preventive free fall acrobatics to reduce the biomechanical load on the neck of parachutists during parachute opening.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods and analysis<\/jats:title>\n                  <jats:p>Interventional study with a cross-over, within-subject, repeated measures design. Two consecutive skydives are made on the same day with random ordering of either an \u2018intervention jump\u2019 or a \u2018control jump\u2019. The intervention jump contains two acrobatic elements prior to main parachute extraction: Reducing parachute deployment airspeed and positioning the human body head high. The primary outcome measure is the magnitude of initial Gx deceleration. All other directions of accelerations will be measured as well, as will magnitudes of multidirectional jerks (rates of changes of accelerations) and lower neck torque. Repeated within group measures analysis of variance will be used to quantify effects, and regression used to test for relationships between the elements of the intervention.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Ethics and dissemination<\/jats:title>\n                  <jats:p>Regional Medical Research Ethics Committee of Stockholm approval 2015\/1189-31. The intervention protocol has been systematically prevalidated with an emphasis on participant safety. The study will be conducted in compliance with the Declaration of Helsinki, and its results published in peer-reviewed journals, preferably Open Access, to maximise access for the target athlete population.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Trial registration number<\/jats:title>\n                  <jats:p>NCT02625896. Pre-results.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1136\/bmjsem-2015-000108","type":"journal-article","created":{"date-parts":[[2016,4,27]],"date-time":"2016-04-27T00:05:13Z","timestamp":1461715513000},"page":"e000108","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":1,"title":["Free Fall Acrobatics to Reduce Neck Loads During Parachute Opening Shock: Evaluation of an Intervention (ACROPOSE)"],"prefix":"10.1136","volume":"2","clinical-trial-number":[{"clinical-trial-number":"nct02625896","registry":"10.18810\/clinical-trials-gov"},{"clinical-trial-number":"nct02625896","registry":"10.18810\/clinical-trials-gov"},{"clinical-trial-number":"nct02625896","registry":"10.18810\/clinical-trials-gov"}],"author":[{"given":"Anton","family":"Westman","sequence":"first","affiliation":[{"name":"Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden"},{"name":"Department of Anesthesia and Intensive Care Medicine, Karolinska University Hospital, Huddinge, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bj\u00f6rn O","family":"\u00c4ng","sequence":"additional","affiliation":[{"name":"Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden"},{"name":"Department of Physical Therapy, Karolinska University Hospital, Stockholm, Sweden"},{"name":"Centre for Clinical Research Dalarna, Falun, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2016,4,26]]},"reference":[{"key":"2025083109375525000_2.1.e000108.1","unstructured":"McNulty L . International Parachuting Commission Technical and Safety Committee 2010 Safety Report. 2012."},{"key":"2025083109375525000_2.1.e000108.2","unstructured":"Westman A . Dangers in sport parachuting [Elektronisk Resurs]. Ume\u00e5: Univ, 2009. http:\/\/urn.kb.se\/resolve?urn=urn:nbn:se:umu:diva-19690"},{"key":"2025083109375525000_2.1.e000108.3","doi-asserted-by":"publisher","DOI":"10.1136\/bjsm.2006.031682"},{"key":"2025083109375525000_2.1.e000108.4","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM200307173490325"},{"key":"2025083109375525000_2.1.e000108.5","first-page":"40","article-title":"Hard openings","volume":"54","author":"Crouch","year":"2013","journal-title":"Parachut"},{"key":"2025083109375525000_2.1.e000108.6","doi-asserted-by":"crossref","first-page":"1034","DOI":"10.3357\/ASEM.3570.2013","article-title":"Musculoskeletal pain and related risks in skydivers: a population-based survey","volume":"84","author":"Nilsson","year":"2013","journal-title":"Aviat Space Environ Med"},{"key":"2025083109375525000_2.1.e000108.7","doi-asserted-by":"publisher","DOI":"10.1007\/s00586-004-0864-4"},{"key":"2025083109375525000_2.1.e000108.8","unstructured":"Parks College Parachute Research Group. Parachute opening shock basics. Outl Present 2001 Parachut Ind Assoc Symp Present by Jean Potvin Gary Peek; 2001. http:\/\/www.pcprg.com\/sym01out.htm"},{"key":"2025083109375525000_2.1.e000108.9","first-page":"68","article-title":"High-risk head and neck movements at high G and interventions to reduce associated neck injury","volume":"75","author":"Coakwell","year":"2004","journal-title":"Aviat Space Environ Med"},{"key":"2025083109375525000_2.1.e000108.10","first-page":"1085","article-title":"Acute soft tissue neck injury from unexpected acceleration","volume":"74","author":"Green","year":"2003","journal-title":"Aviat Space Environ Med"},{"key":"2025083109375525000_2.1.e000108.11","unstructured":"Fryer DI . Glossary of aerospace medical terms. Neuilly-sur-Seine: NATO, 1971. http:\/\/www.theeuropeanlibrary.org\/tel4\/record\/2000026994025 (accessed 6 Dec 2014)."},{"key":"2025083109375525000_2.1.e000108.12","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1111\/sms.12428","article-title":"Neck muscle activity in skydivers during parachute opening shock","volume":"26","author":"Lo Martire","year":"2016","journal-title":"Scand J Med Sci Sports"},{"key":"2025083109375525000_2.1.e000108.13","doi-asserted-by":"publisher","DOI":"10.1097\/ACM.0b013e3181ccd618"},{"key":"2025083109375525000_2.1.e000108.14","first-page":"411","article-title":"Advances in the epidemiology of injuries as a basis for public policy","volume":"95","author":"Haddon","year":"1980","journal-title":"Public Heal Rep"},{"key":"2025083109375525000_2.1.e000108.15","doi-asserted-by":"publisher","DOI":"10.1007\/s40279-013-0136-8"},{"key":"2025083109375525000_2.1.e000108.16","unstructured":"Miller S . Body Language: Helping Your Canopy Open Better. Dropzone.com. 2006. http:\/\/www.dropzone.com\/safety\/Canopy_Control\/Body_Language_Helping_Your_Canopy_Open_Better_636.html (accessed 17 Nov 2014)."},{"key":"2025083109375525000_2.1.e000108.17","unstructured":"Consort\u2014The CONSORT Flow Diagram. http:\/\/www.consort-statement.org\/consort-statement\/flow-diagram (accessed 15 Dec 2015)."},{"key":"2025083109375525000_2.1.e000108.18","first-page":"610","article-title":"Development and validation of a web-based questionnaire for surveying skydivers","volume":"82","author":"Nilsson","year":"2011","journal-title":"Aviat Space Environ Med"},{"key":"2025083109375525000_2.1.e000108.19","doi-asserted-by":"crossref","first-page":"1205","DOI":"10.3357\/ASEM.3637.2013","article-title":"Decelerations and muscle responses during parachute opening shock","volume":"84","author":"Gladh","year":"2013","journal-title":"Aviat Space Environ Med"},{"key":"2025083109375525000_2.1.e000108.20","doi-asserted-by":"crossref","unstructured":"Free Fall Acrobatics to Reduce Neck Loads During Parachute Opening Shock: Evaluation of an Intervention ACROPOSE ClinicalTrials.gov. https:\/\/clinicaltrials.gov\/ct2\/show\/NCT02625896?term=acropose&rank=1 (accessed 30 Dec 2015).","DOI":"10.1136\/bmjsem-2015-000108"},{"key":"2025083109375525000_2.1.e000108.21","doi-asserted-by":"crossref","unstructured":"Westman A , \u00c4ng BO . Validation of a free fall acrobatics intervention protocol to reduce neck loads during parachute opening shock. BMJ Open Sport Exerc Med 2015;1:000045.doi:10.1136\/bmjsem-2015-000045. doi:10.1136\/bmjsem-2015-000045","DOI":"10.1136\/bmjsem-2015-000045"},{"key":"2025083109375525000_2.1.e000108.22","first-page":"373","article-title":"World Medical Association Declaration of Helsinki. Ethical principles for medical research involving human subjects","volume":"79","author":"World Medical Association","year":"2001","journal-title":"Bull World Health Organ"},{"key":"2025083109375525000_2.1.e000108.23","doi-asserted-by":"crossref","unstructured":"Nosek BA , Alter G , Banks GC , et al . SCIENTIFIC STANDARDS. Promoting an open research culture. Science. 2015;348:1422\u20135.","DOI":"10.1126\/science.aab2374"}],"container-title":["BMJ Open Sport &amp; Exercise Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bmjsem-2015-000108","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,8,31]],"date-time":"2025-08-31T16:38:05Z","timestamp":1756658285000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmjopensem.bmj.com\/lookup\/doi\/10.1136\/bmjsem-2015-000108"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2016,4]]},"references-count":23,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2016,4,26]]},"published-print":{"date-parts":[[2016,4]]}},"alternative-id":["10.1136\/bmjsem-2015-000108"],"URL":"https:\/\/doi.org\/10.1136\/bmjsem-2015-000108","relation":{},"ISSN":["2055-7647"],"issn-type":[{"type":"electronic","value":"2055-7647"}],"subject":[],"published":{"date-parts":[[2016,4]]}}}