[Human dynamic response to landing impact in selected body orientations].

Objective. To study changes of human dynamic response to landing impact in selected body orientations. Method. Five healthy young men were exposed to 10 G, 50 ms half-sine acceleration pulses. The angle included between human head-ilium axis and impact force direction was 30 degrees-70 degrees. The acceleration responses at head, shoulder, chest and ilium of the subjects were recorded along head-ilium and chest-back directions. Result. Within limits of the experiments, the minimum peak response at the head along head-ilium direction was 10.36 +/- 2.44 G at 50 degrees, and the maximum was 18.07 +/- 3.29 G at 70 degrees. The minimum peak response at the chest along head-ilium direction was 10.39 +/- 3.97 G at 70 degrees, and the maximum was 15.42 +/- 3.61 G at 60 degrees. The minimum peak response at the head along chest-back direction was 7.58 +/- 1.18 G at 30 degrees, and the maximum was 18.89 +/- 1.85 G at 70 degrees. The minimum peak response at the chest along chest-back direction was 7.21 +/- 1.99 G at 30 degrees, and the maximum was 17.67 +/- 2.16 G at 70 degrees. Conclusion. It was inferred that the best body orientation angle for landing impact might be 50 degrees.