Crash-test dummy and pendulum impact tests of ice hockey boards: greater displacement does not reduce impact.

BACKGROUND: One injury mechanism in ice hockey is impact with the boards. We investigated whether more flexible hockey boards would provide less biomechanical loading on impact than did existing (reference) boards. METHODS: We conducted impact tests with a dynamic pendulum (mass 60 kg) and with crash test dummies (ES-2 dummy, 4.76 m/s impact speed). Outcomes were biomechanical loading experienced by a player in terms of head acceleration, impact force to the shoulder, spine, abdomen and pelvis as well as compression of the thorax. RESULTS: The more flexible board designs featured substantial displacement at impact. Some so-called flexible boards were displaced four times more than the reference board. The new boards possessed less stiffness and up to 90 kg less effective mass, reducing the portion of the board mass a player experienced on impact, compared with boards with a conventional design. Flexible boards resulted in a similar or reduced loading for all body regions, apart from the shoulder. The displacement of a board system did not correlate directly with the biomechanical loading. CONCLUSIONS: Flexible board systems can reduce the loading of a player on impact. However, we found no correlation between the displacement and the biomechanical loading; accordingly, displacement alone was insufficient to characterise the overall loading of a player and thus the risk of injury associated with board impact. Ideally, the performance of boards is assessed on the basis of parameters that show a good correlation to injury risk.

Saccadic eye movements after low-dose oral alcohol exposure.

OBJECTIVES: The influence of low-dose alcohol intake on reflexive visually guided saccades was investigated. METHODS: 40 healthy human subjects were orally given alcohol resulting in low-dose alcohol concentration (less than 0.8‰) blood alcohol concentration. Before and after exposure, horizontal saccadic eye movements were recorded at several points in time. The recordings were evaluated with regard to accuracy of the eye movements, latency, the peak eye velocity and the time constant that characterizes the main sequence. The results were compared to recordings from a reference group. RESULTS: It was found that the saccadic eye movement was clearly altered by low-dose alcohol intake. However, its characteristics were not unambiguously pathological when compared to the reference group, even though the subjects reported a moderate to strong effect of alcohol and there were clear signs of inebriation. CONCLUSIONS: The findings render the evaluation of saccades unsuitable as a simple test for the detection of low-dose alcohol intake.

Comparing eye movements recorded by search coil and infrared eye tracking.

OBJECTIVE: The performance of a new video-based infrared eye tracker (IR) was compared to the magnetic search coil technique (SC). Since the IR offers interesting possibilities as a diagnostic tool in neuro-ophthalmology, it was investigated whether the new device has overcome shortcomings that were reported from former IR systems. METHODS: Horizontal saccades were recorded using the IR and the SC. The IR allowed eye movement recordings at different sampling rates ranging from 250 Hz to 1000 Hz while the SC recorded at 1000 Hz. RESULTS/CONCLUSIONS: The results show that the IR and the SC were in good agreement and produced similar results. In contrast to other studies, the influence of the sampling rate of the IR was small. The saccade main-sequences did not show significant differences. The latency times observed for both systems were mainly in the short-latency range.

Assessment of pelvis and upper leg injury risk in car-pedestrian collisions: comparison of accident statistics, impactor tests and a human body finite element model.

In this study, we first present a comparison between pelvis/upper leg injuries observed in real-world accidents as recorded in the database of the Medical University of Hanover, and the EEVC test results of corresponding cars as published by EuroNCAP. The fact that modern cars with rounded hood edges cause very few pelvis/upper leg injuries is discussed against the findings of the EEVC tests, where these cars do not perform significantly better than their older counterparts with sharper hood leading edges. This discrepancy could be due to the fact that the radius of the hood edge is not accounted for in the current version of the test protocol. In a second step, various impacts against several different simplified hood shapes were simulated using a detailed finite element model of a 50(th) percentile male pedestrian. The finite element model (THUMS) has been extensively validated against PMHS experiments in previous studies. The validated model affords detailed insight into pelvic and femoral deformations and loading patterns, and reveals, as expected, that the shape of the hood leading edge plays a critical role in the resulting biomechanical loading patterns. Based upon the results of this study, recommendations are offered for a more appropriate characterization of the hood shape with regard to pelvis/upper leg injury risk.