Groen et al. BMC Research Notes 2010, 3:111 http://www.biomedcentral.com/1756-0500/3/111 Open Access RESEARCH ARTICLE BioMed Central © 2010 Groen et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Research article Could martial arts fall training be safe for persons with osteoporosis?: a feasibility study Brenda E Groen* 1,2 , Ellen Smulders 1,2 , Jacques Duysens 1,2,3 , Wim van Lankveld 4 and Vivian Weerdesteyn 1,2,5 Abstract Background: Osteoporosis is a well-established risk factor for fall-related hip fractures. Training fall arrest strategies, such as martial arts (MA) fall techniques, might be useful to prevent hip fractures in persons with osteoporosis, provided that the training itself is safe. This study was conducted to determine whether MA fall training would be safe for persons with osteoporosis extrapolated from the data of young adults and using stringent safety criteria. Methods: Young adults performed sideways and forward MA falls from a kneeling position on both a judo mat and a mattress as well as from a standing position on a mattress. Hip impact forces and kinematic data were collected. For each condition, the highest hip impact force was compared with two safety criteria based on the femoral fracture load and the use of a hip protector. Results: The highest hip impact force during the various fall conditions ranged between 1426 N and 3132 N. Sideways falls from a kneeling and standing position met the safety criteria if performed on the mattress (max 1426 N and 2012 N, respectively) but not if the falls from a kneeling position were performed on the judo mat (max 2219 N). Forward falls only met the safety criteria if performed from a kneeling position on the mattress (max 2006 N). Hence, forward falls from kneeling position on a judo mat (max 2474 N) and forward falls from standing position on the mattress (max 3132 N) did not meet both safety criteria. Conclusions: Based on the data of young adults and safety criteria, the MA fall training was expected to be safe for persons with osteoporosis if appropriate safety measures are taken: during the training persons with osteoporosis should wear hip protectors that could attenuate the maximum hip impact force by at least 65%, perform the fall exercises on a thick mattress, and avoid forward fall exercises from a standing position. Hence, a modified MA fall training might be useful to reduce hip fracture risk in persons with osteoporosis. Background Hip fractures among the elderly are a health problem associated with high mortality and morbidity rates. In particular persons with osteoporosis or low bone mineral density (BMD) are at risk for hip fractures due to their reduced bone strength [1,2]. Therefore, in clinical prac- tice hip fracture prevention focuses mainly on treating osteoporosis. About 90% of hip fractures are caused by falls [3]. Apart from a low BMD, fall characteristics have been identified as independent risk factors for hip fractures [1,2]. Hence, fall prevention and reduction of fall severity may also pre- vent hip fractures. Falls with the highest risk for hip frac- tures are sideways falls and falls with direct impact on the greater trochanter of the proximal femur [2]. To reduce the hip fracture risk in these types of falls, hip protectors may be useful. In vitro experiments have shown that the best hip protectors can attenuate femoral impact forces by as much as 85% [4,5]. However, to prevent hip frac- tures in everyday life, user compliance is a problem [6]. Alternatively, people may be taught safe fall arrest strat- egies. Recent studies have indicated that fall strategies based on martial arts (MA) fall techniques reduce the impact forces during a volitional fall. When using an MA fall technique, the fall is changed into a rolling move- ment. During the roll the forces are distributed over a larger impact site. Furthermore, the amount of energy to be absorbed during impact is reduced because kinetic energy is preserved during the rolling movement. Experi- mental studies have shown that MA techniques during a * Correspondence: b.groen@maartenskliniek.nl 1 Sint Maartenskliniek Research, Development and Education, Hengstdal 3, 6522 JV Nijmegen, the Netherlands Full list of author information is available at the end of the article