Wearing a lifejacket when immersed in water should support the wearer, maintaining their airway clear of the water. It is proposed that a retention system would improve airway protection by improving retention of the lifejacket around the torso. Study one (n ¼ 10) quantified the performance of lifejackets immediately following a step into water from height when a lifejacket was worn with a crotch strap (two different tightness) and without a crotch strap. Airway freeboard was improved when wearing a crotch strap (P , 0.05) compared with no crotch strap. Study two used a manikin to examine the performance of lifejackets with and without a crotch strap during 3-h exposures to waves. During exposure to waves, the time taken to aspirate the lethal dose of seawater for drowning was doubled when wearing a crotch strap compared with the no-crotch-strap conditions (P , 0.001). Therefore, wearing a crotch strap (functioning retention system) on a correctly fitted lifejacket improves airway protection following accidental immersion and prolonged wave exposure.Practitioner Summary: Following a step from height into water, wearing a crotch strap on a correctly fitted lifejacket improved lifejacket performance. Wearing a lifejacket with the crotch strap fitted minimised the reduction in lifejacketperformance, compared with the no-crotch-strap condition, when exposed to waves for 3 h.
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