Safety floors (also known as compliant floors) may reduce the risk of fall-related injuries by attenuating impact force during falls, but are only practical if they do not negatively affect balance and mobility. In this study, we evaluated seven safety surfaces based on their ability to attenuate peak femoral neck force during simulated hip impacts, and their influence on center of pressure (COP) sway during quiet and tandem stance. Overall, we found that some safety floors can attenuate up to 33.7% of the peak femoral impact force without influencing balance. More specifically, during simulated hip impacts, force attenuation for the safety floors ranged from 18.4 (SD 4.3)% to 47.2 (3.1)%, with each floor significantly reducing peak force compared with a rigid surface. For quiet stance, only COP root mean square was affected by flooring (and increased for only two safety floors). During tandem stance, COP root mean square and mean velocity increased in the medial-lateral direction for three of the seven floors. Based on the substantial force attenuation with no concomitant effects on balance for some floors, these results support the development of clinical trials to assess the effectiveness of safety floors at reducing fall-related injuries in high-risk settings.
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Michal N. Glinka, Kim P. Cheema, Stephen N. Robinovitch, and Andrew C. Laing
Andrew G Jameson, Stephen J Kinzey, and Jeffrey S Hallam
Context:
Cryotherapy is commonly used in the care of acute and chronic injuries. It decreases pain, reduces swelling, and causes vasoconstriction of blood vessels. Its detrimental effects on motor activity might predispose physically active individuals to further injury.
Objective:
To examine the effects of cryotherapy on vertical-ground-reaction-force (VGRF) during a 2-legged landing from a 2-legged targeted vertical jump.
Design:
2 × 4 MANOVA with repeated measures.
Setting:
Biomechanics laboratory.
Participants:
10 men, means: 22.40 ± 1.26 years, 76.01 ± 26.95 kg, 182.88 ± 6.88 cm.
Intervention:
VGRF during landing from a targeted vertical jump (90% of maximum) was measured before and after four 20-minute cryotherapy treatments.
Results:
There were no significant differences in VGRF as a result of cryotherapy.
Conclusion:
Under the constraints of this study there is no evidence that returning to activity immediately after cryotherapy predisposes an athlete to injury because of a change in VGRF.
Shivam Bhan, Iris Levine, and Andrew C. Laing
The biomechanical effectiveness of safety floors has never been assessed during sideways falls with human volunteers. Furthermore, the influence of body mass index (BMI) and gender on the protective capacity of safety floors is unknown. The purpose of this study was to test whether safety floors provide greater impact attenuation compared with traditional flooring, and whether BMI and gender modify their impact attenuation properties. Thirty participants (7 men and 7 women of low BMI; 7 men and 9 women of high BMI) underwent lateral pelvis release trials on 2 common floors and 4 safety floors. As a group, the safety floors reduced peak force (by up to 11.7%), and increased the time to peak force (by up to 25.5%) compared with a traditional institutional grade floor. Force attenuation was significantly higher for the low BMI group, and for males. Force attenuation was greatest for the low BMI males, averaging 26.5% (SD = 3.0) across the safety floors. These findings demonstrate an overall protective effect of safety floors during lateral falls on the pelvis, but also suggest augmented benefits for frail older adults (often with low body mass) who are at an increased risk of hip fracture.
Benoit R. Lafleur, Alyssa M. Tondat, Steven P. Pretty, Marina Mourtzakis, and Andrew C. Laing
, 7 – 9 , 23 – 26 the net force applied to the proximal femur ( F femur , in Newtons) was predicted by subtracting the force attenuation provided by trochanteric soft tissues 20 from peak total impact force (in Newtons) as follows: F femur = Peak total force − ( 71 × TSTT ) , where TSTT is
Mark A. Sutherlin, L. Colby Mangum, Shawn Russell, Susan Saliba, Jay Hertel, and Joe M. Hart
increased muscle activity of the trunk 5 and delayed muscle onsets of the trunk and thigh 6 , 7 along with smaller knee flexion 6 and hip abduction 7 at initial contact. These alterations may influence force attenuation on lower-extremity and spinal structures during landing tasks among these
John R. Harry, Leland A. Barker, Jeffrey D. Eggleston, and Janet S. Dufek
peak vGRF and/or decreased loading time) mechanical stress. When evaluating the loading rate and similar loading parameters during landing, the ankle joint should be closely considered, as it is the first joint to contribute to mechanical energy absorption and force attenuation. 15 , 16 By increasing
Chad Van Ramshorst and Woochol Joseph Choi
distribution pattern had a greater surface area for force attenuation and an indirect path bypassing the tibial tuberosity, resulting in decreased contact forces at the knee and increased contact forces at the hip. As a result from the data, technique 2 yields a safer load dissipation pattern and decreased
Lucy S. Kember, Rhodri S. Lloyd, Gregory D. Myer, and Isabel S. Moore
H-T . Changes in biomechanical properties during drop jumps of incremental height . J Strength Cond Res . 2011 ; 25 ( 9 ): 2510 – 2518 . PubMed ID: 21869631 doi:10.1519/JSC.0b013e318201bcb3 21869631 19. Harrison AD , Ford KR , Myer GD , Hewett TE . Sex differences in force attenuation
Josu Gomez-Ezeiza, Jordan Santos-Concejero, Jon Torres-Unda, Brian Hanley, and Nicholas Tam
better running economy. 17 , 18 This implicates the lower limb musculature in ground reaction force attenuation during braking at initial ground contact; this is achieved through optimizing joint stiffness for a more efficient transfer of energy. 19 Whether this neural preparation is also important in
Christopher A. DiCesare, Adam W. Kiefer, Scott Bonnette, and Gregory D. Myer
inversion of the foot—allows for a similar force-attenuating mechanism through eccentric contraction and energy absorption by the plantar flexors and passive absorption by the structures of the foot via rearfoot pronation, respectively. A reduction in the frontal plane ankle excursion on landing, as
