Distal radius fractures are common on playgrounds. Yet current guidelines for the selection of playground surface materials are based only on protection against fall-related head injuries. We conducted “torso release” experiments to determine how common playground surface materials affect impact force applied to the hand during upper limb fall arrests. Trials were acquired for falls onto a rigid surface, and onto five common playground surface materials: engineered wood fiber, gravel, mulch, rubber tile, and sand. Measures were acquired for arm angles of 20 and 40 degrees from the vertical. Playground surface materials influenced the peak resultant and vertical force (P < .001), but not the peak horizontal force (P = .159). When compared with the rigid condition, peak resultant force was reduced 17% by sand (from 1039 to 864 N), 16% by gravel, 7% by mulch, 5% by engineered wood fiber, and 2% by rubber tile. The best performing surface provided only a 17% reduction in peak resultant force. These results help to explain the lack of convincing evidence from clinical studies on the effectiveness of playground surface materials in preventing distal radius fractures during playground falls, and highlight the need to develop playground surface materials that provide improved protection against these injuries.
Woochol J. Choi, Harjinder Kaur and Stephen N. Robinovitch
Michal N. Glinka, Kim P. Cheema, Stephen N. Robinovitch and Andrew C. Laing
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.