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Changes in Posture Following a Single Session of Long-Duration Water Immersion

Stephen M. Glass, Christopher K. Rhea, Matthew W. Wittstein, Scott E. Ross, John P. Florian, and F.J. Haran

hypermetropia (ie, images become severely blurred and unfocused) and the eye loses about two-thirds of its refractive power. 13 , 14 Diving masks restore the air-to-cornea interface allowing for high underwater acuity; however, they produce a refraction at their outer surface, which results in a narrowing of

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Self-Talk in a SCUBA Diving Context

Judy L. Van Raalte, Lorraine Wilson, Allen Cornelius, and Britton W. Brewer

( Theodorakis et al., 2008 ). However, research that explores the effects of self-talk on effort, confidence, focus, and performance in adventure-sport contexts with high risk, such as self-contained underwater breathing apparatus (SCUBA) diving, is lacking. High-risk contexts such as those experienced in the

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Parameter Determination for a Computer Simulation Model of a Diver and a Springboard

Maurice R. Yeadon, Pui W. Kong, and Mark A. King

This study used kinematic data on springboard diving performances to estimate viscoelastic parameters of a planar model of a springboard and diver with wobbling masses in the trunk, thigh, and calf segments and spring dampers acting at the heel, ball, and toe of the foot segment. A subject-specific angle-driven eight-segment model was used with an optimization algorithm to determine viscoelastic parameter values by matching simulations to four diving performances. Using the parameters determined from the matching of a single dive in a simulation of another dive resulted in up to 31% difference between simulation and performance, indicating the danger of using too small a set of kinematic data. However, using four dives in a combined matching process to obtain a common set of parameters resulted in a mean difference of 8.6%. Because these four dives included very different rotational requirements, it is anticipated that the combined parameter set can be used with other dives from these two groups.

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Circulating Venous Bubbles in Children after Diving

Frédéric Lemaître, Daniel Carturan, Claire Tourny-Chollet, and Bernard Gardette

Doppler ultrasonic detection of circulating venous bubbles after a scuba dive is a useful index of decompression safety in adults, since a relationship between bubbles and the risk of decompression sickness has been documented. No study, however, has investigated circulating venous bubbles in young recreational divers after their usual dives. The aim of this study was to determine whether these bubbles would be detected in children who performed a single dive without any modification in their diving habits. Ten young recreational divers (13.1 ± 2.3 years) performed their usual air dive. They were Doppler-monitored 20 min before the dive (12 ± 3 m for 26 ± 7 min) and for 60 min after surfacing, at 20-min intervals. No circulating venous bubbles were detected after the children surfaced. The results showed that during a usual shallow diving session, venous bubbles were not detected in children.

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Association of Jumping Ability and Maximum Strength With Dive Distance in Swimmers

Jessica A. Calderbank, Paul Comfort, and John J. McMahon

takeoff from the blocks to the 15-m mark down the pool. The first 15 m of the race comprises a sequence of different stages which include the following: block time, dive distance (DD), dive time, angle of entry, depth achieved, distance/average velocity of the underwater phase, and total time to 15 m. 5

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Biomechanical Comparison of the Track Start and the Modified One-Handed Track Start in Competitive Swimming: An Intervention Study

H. Galbraith, J. Scurr, C. Hencken, L. Wood, and P. Graham-Smith

This study compared the conventional track and a new one-handed track start in elite age group swimmers to determine if the new technique had biomechanical implications on dive performance. Five male and seven female GB national qualifiers participated (mean ± SD: age 16.7 ± 1.9 years, stretched stature 1.76 ± 0.8 m, body mass 67.4 ± 7.9 kg) and were assigned to a control group (n = 6) or an intervention group (n = 6) that learned the new one-handed dive technique. All swimmers underwent a 4-week intervention comprising 12 ± 3 thirty-minute training sessions. Video cameras synchronized with an audible signal and timing suite captured temporal and kinematic data. A portable force plate and load cell handrail mounted to a swim starting block collected force data over 3 trials of each technique. A MANCOVA identified Block Time (BT), Flight Time (FT), Peak Horizontal Force of the lower limbs (PHF) and Horizontal Velocity at Take-off (Vx) as covariates. During the 10-m swim trial, significant differences were found in Time to 10 m (TT10m), Total Time (TT), Peak Vertical Force (PVF), Flight Distance (FD), and Horizontal Velocity at Take-off (Vx) (p < .05). Results indicated that the conventional track start method was faster over 10 m, and therefore may be seen as a superior start after a short intervention. During training, swimmers and coaches should focus on the most statistically significant dive performance variables: peak horizontal force and velocity at take-off, block and flight time.

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Disordered Eating and Eating Disorders in Aquatic Sports

Anna Melin, Monica Klungland Torstveit, Louise Burke, Saul Marks, and Jorunn Sundgot-Borgen

Disordered eating behavior (DE) and eating disorders (EDs) are of great concern because of their associations with physical and mental health risks and, in the case of athletes, impaired performance. The syndrome originally known as the Female Athlete Triad, which focused on the interaction of energy availability, reproductive function, and bone health in female athletes, has recently been expanded to recognize that Relative Energy Deficiency in Sport (RED-S) has a broader range of negative effects on body systems with functional impairments in both male and female athletes. Athletes in leanness-demanding sports have an increased risk for RED-S and for developing EDs/DE. Special risk factors in aquatic sports related to weight and body composition management include the wearing of skimpy and tight-fitting bathing suits, and in the case of diving and synchronized swimming, the involvement of subjective judgments of performance. The reported prevalence of DE and EDs in athletic populations, including athletes from aquatic sports, ranges from 18 to 45% in female athletes and from 0 to 28% in male athletes. To prevent EDs, aquatic athletes should practice healthy eating behavior at all periods of development pathway, and coaches and members of the athletes’ health care team should be able to recognize early symptoms indicating risk for energy deficiency, DE, and EDs. Coaches and leaders must accept that DE/EDs can be a problem in aquatic disciplines and that openness regarding this challenge is important.

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Dr. Richard C. Nelson: Behind the Scenes

Doris I. Miller

interest in competitive diving, having coached the sport for the previous 2 years, I decided to develop a 3-dimensional simulation model with an accompanying computer graphics display for my doctoral dissertation. In that pre-Direct Linear Transformation era, data collection to provide validation

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Risk of Neurological Insult in Competitive Deep Breath-Hold Diving

Kay Tetzlaff, Holger Schöppenthau, and Jochen D. Schipke


It has been widely believed that tissue nitrogen uptake from the lungs during breath-hold diving would be insufficient to cause decompression stress in humans. With competitive free diving, however, diving depths have been ever increasing over the past decades.


A case is presented of a competitive free-diving athlete who suffered stroke-like symptoms after surfacing from his last dive of a series of 3 deep breath-hold dives. A literature and Web search was performed to screen for similar cases of subjects with serious neurological symptoms after deep breath-hold dives.

Case Details:

A previously healthy 31-y-old athlete experienced right-sided motor weakness and difficulty speaking immediately after surfacing from a breathhold dive to a depth of 100 m. He had performed 2 preceding breath-hold dives to that depth with surface intervals of only 15 min. The presentation of symptoms and neuroimaging findings supported a clinical diagnosis of stroke. Three more cases of neurological insults were retrieved by literature and Web search; in all cases the athletes presented with stroke-like symptoms after single breath-hold dives of depths exceeding 100 m. Two of these cases only had a short delay to recompression treatment and completely recovered from the insult.


This report highlights the possibility of neurological insult, eg, stroke, due to cerebral arterial gas embolism as a consequence of decompression stress after deep breath-hold dives. Thus, stroke as a clinical presentation of cerebral arterial gas embolism should be considered another risk of extreme breath-hold diving.

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Scuba-Dive-Related Changes in Heart Rate in Children

Bernd E. Winkler, Kay Tetzlaff, Claus-Martin Muth, Klaus Paulat, and Helge Hebestreit

The purpose of this study was to monitor heart rate (HR) and rhythm during open water SCUBA dives. Nine children performed 25-min open water SCUBA dives to 8 m depth. Before, during and after these dives, ECG was recorded. Compared with predive heart rate, heart rate declined by -24 ± 8% (range -36%; -15%) during the dive. In some children a further decline in HR was observed within the last minutes of the dive. Older and taller subjects and those with a high initial HR showed a more pronounced decline in HR. Furthermore singular supraventricular and ventricular extrasystoles were observed in some children. Immersion as well as facial and skin cooling presumably account for the initial decline in heart rate. A further drop in HR within the last minutes of the dive might be related to mild hypothermia. Single supraventricular and ventricular extrasystoles might occur in healthy children during dives.