Characteristics of `low risk' and `high risk' dives by young adults: risk reduction in spinal cord injury

Abstract

Study design: To establish benchmark normative data for dive entries performed by young adults of the age range most likely to sustain a diving spinal cord injury. Data acquired from analysis of the dives performed, along with survey information, were used to determine which factors make the most contribution to the level of risk in diving. Objectives: To identify in¯uential variables which could contribute to risk of spinal cord injury for each of four types of dives. The types of dives investigated were: dive entries from deck level to tread water (Treadwater); deck level to swim 25 m (Deck); starting block height to swim 25 m (Block); and a running dive entry to swim 25 m (Running). Setting: Victoria, Australia. Methods: Ninety-®ve ®rst year university students (average age 19.9 years) performed three or four dives which were video-recorded for later analysis. Maximum depth reached was used as an indicator of risk, and velocity at maximum depth, distance at maximum depth, angle of entry and¯ight distance were measured for each dive. Participants also completed a questionnaire designed to elicit information about their swimming and diving background. Unlike previous diving studies, participants were recreational rather than competitive swimmers. They were not aware that the dive was the focal point, assuming that the researchers were investigating their swimming and treadwater ability. Results: A stepwise multiple regression was applied to predict depth for each dive condition, and demonstrated that four variables were able to account for 56% of the variance for Treadwater, 68% for Deck; 73% for Running and 79% for Block. In all conditions involving swimming after the dive (ie Deck, Block and Running), beta weights showed that distance at maximum depth had the greatest in¯uence on the depth of a dive. Flight distance and angle of entry were the next most in¯uential variables. For the Treadwater condition, beta weights showed angle of entry was the most in¯uential variable, followed by velocity at maximum depth, distance at maximum depth and swim rank. Conclusion: It is recommended that divers strive to surface in as short a distance as possible by maximising¯ight distance and aiming for a low entry angle. Implementation of steering-up techniques will assist in minimising dive depth.

Spine trauma due to diving: main features and short-term neurological outcome

“…However, many people are often unaware of other disastrous consequences surrounding these practices. 1 After death, spinal cord injuries (SCIs) are the most devastating result of water sports accidents, with regard to morbidity, permanent disability and cost. 2 In the United…”

Teaching Competitive Racing Starts: Practices and Opinions of Professional Swim Coaches

“…Blanksby, Wearne, and Elliott (1996) suggest that the "vulnerability of the head when diving must be counteracted by children keeping the thumbs clasped and the upper limbs extended overhead at all times" (p. 83). Further, Blitvich, McElroy, Blanksby, and Douglas (1999) stated that "the level of risk in any dive entry can be reduced if the diver keeps the hands together and the arms extended beyond the head" (p. 558). While studying first-year university students with varied swimming and diving backgrounds, Blitvich et al (1999) found that during one out of four dives, the swimmer "pulled both arms backward before or at maximum depth, thus leaving their head totally unprotected" (p. 558).…”

“…Further, Blitvich, McElroy, Blanksby, and Douglas (1999) stated that "the level of risk in any dive entry can be reduced if the diver keeps the hands together and the arms extended beyond the head" (p. 558). While studying first-year university students with varied swimming and diving backgrounds, Blitvich et al (1999) found that during one out of four dives, the swimmer "pulled both arms backward before or at maximum depth, thus leaving their head totally unprotected" (p. 558). While the authors concluded that this acts to increase the level of risk, the degree to which the head is protected by maintaining proper streamline technique has not been verified.…”

Minimum Water Depth Rules for Competitive Swim Starts

“…The first part of the rules above, the minimum water depth, has been the subject of reasonably extensive debate within the swimming and scientific communities (Welch & Owens, 1986;Counsilman, Nomura, Endo, & Counsilman, 1988;Blanksby, Wearne, & Elliott, 1996;Gehlsen & Wingfield, 1998;Blitvich, McElroy, Blanksby, & Douglas, 1999;Blitvich, McElroy, Blanksby, Clothier, & Pearson, 2000a;and Blitvich, McElroy, & Blanksby, 2000b;Cornett, White, Wright, Willmott, & Stager, 2010, 2011a, 2011b, 2011c, 2011d, 2012aCornett, White, Wright, & Stager, 2012b, 2014Cornett, Naganobori, & Stager, 2012c;White, Cornett, Wright, Willmott, & Stager, 2011;Stager, Cornett, & Naganobori, 2013). The second aspect of the rules, the distance from the wall for which the minimum water depth must be maintained, has not received much discussion.…”