Evaluation of ankle joint protection effect of parachute ankle brace on paratrooper landing / 中华劳动卫生职业病杂志

Objective: To study the protective effect of parachute ankle brace on ankle joint during simulated parachuting landing. Methods: In August 2021, 30 male paratroopers were selected as the test subjects by simple random sampling method. They jumped from the 1.5 m and 2.0 m height platforms respectively with and without parachute ankle brace, and landed on the sandy ground in a semi-squat parachute landing position. The experiment was divided into 1.5 m experimental group and control group and 2.0 m experimental group and control group. Angle sensor and surface electromyograph were used to measure and analyze the coronal tilt range of the ankle joint and the percentage of maximal voluntary contraction (MVE%) of the muscles around the ankle joint, respectively, to evaluate the protective effect of the parachute ankle brace. Results: At the same height, the tilt range of coronal plane of ankle in experimental group was significantly reduced compared with control group, and the difference was statistically significant (P<0.05). Under the same protection state, the tilt range of the coronal plane of the ankle in the 1.5 m group was significantly reduced compared with that in the 2.0 m group, and the difference was statistically significant (P<0.05). The coronal plane inclination range of the ankle in 2 m experimental group was significantly lower than that in 1.5 m control group, and the difference was statistically significant (P<0.05). Compared with 1.5 m control group, MVE% of right tibialis anterior muscle and bilateral lateral gastrocnemius decreased in 1.5 m experimental group, while MVE% of bilateral peroneus longus increased, with statistical significance (P<0.05). Compared with 2.0 m control group, the MVE% of bilateral tibialis anterior muscle and right lateral gastrocnemius decreased in 2.0 m experimental group, while the MVE% of bilateral peroneus longus increased, with statistical significance (P<0.05). The MVE% of bilateral tibialis anterior muscle, bilateral lateral gastrocnemius muscle and right peroneus longus muscle in 1.5 m experimental group decreased compared with 2.0 m experimental group, and the differences were statistically significant (P<0.05). Compared with 2.0 m control group, the MVE% of bilateral tibialis anterior muscle, right lateral gastrocnemius muscle and right peroneus longus muscle in 1.5 m control group decreased, and the differences were statistically significant (P<0.05) . Conclusion: Wearing parachute ankle brace can effectively limit the coronal plane inclination range of ankle joint, improve the stability of ankle joint and reduce the load on the muscles around ankle joint by landing. Reducing the height of the jumping platform can reduce the coronal plane incline range of the ankle and the muscle load around the ankle during landing.

Present status of oxygen supply devices for high altitude parachuting at home and abroad / 医疗卫生装备

The necessity of paratroopers equipped with high altitude parachuting oxygen supply devices was elaborated firstly,the selection of oxygen source,working principle and the physiological requirements of high altitude parachuting oxygen supply device were also expounded in detail.The technical indexes of high altitude parachuting oxygen supply devices produced by COBHAM and Airborne systems were mainly introduced.The present status of high altitude parachuting oxygen supply devices in China was summarized.The advantages of high altitude parachuting oxygen supply devices at abroad were analyzed,the gaps between domestic and foreign high altitude parachuting oxygen supply devices and the future development direction of them in China were proposed.In order to provide life support for paratroopers to perform special tasks such as parachuting,the following points need to be specified:more scientific researches need to be strengthened in China and the superior performance of high altitude parachuting oxygen supply devices than foreign ones should be developed as soon as possible.