The purpose of this study was to develop a springboard model that could be used to predict, in future diving simulation studies, the vertical interaction forces between a diver’s feet and the board during the time of board depression and recoil. To achieve this, the characteristic parameters (effective mass, stiffness, and damping) for a Duraflex springboard were first examined using a finite element approach. The finite element results indicated that a linear model, consisting of a lumped mass and spring, could be used to simulate the actual dynamic behavior of a springboard system. The effects of damping on the board’s motion were found to be negligible and could safely be ignored. The values for the model’s parameters (board stiffness and effective board mass) were determined empirically and are reported in this paper.
Eric J. Sprigings, Denise S. Stilling and L. Glen Watson
Agnès Bonnet, Vincent Bréjard and Jean-Louis Pedinielli
Objectives for this study were, first, to describe individual differences in risk taking among scuba divers. Differences were examined on personality dimensions and psycho-affective variables, including positive and negative affect, as well as alexithymia. In addition, the study examined contributors to two types of behavior associated with scuba diving—deliberate risk taking and controlled participation in a high-risk sport (non-risk-taking). A cross-sectional design was used, and 131 participants were assessed on extraversion-neuroticism, affectivity, and alexithymia. The broad dimensions of personality and affectivity explained risk taking among divers. Alexithymia differentially predicted two types of risktaking behavior (direct or short-term and indirect or long-term) and was associated significantly with short-term risk-taking behavior.
Carlo Minganti, Laura Capranica, Romain Meeusen and Maria Francesca Piacentini
The aim of the present study was to assess the effectiveness of perceived exertion (session-RPE) in quantifying internal training load in divers.
Six elite divers, three males (age, 25.7 ± 6.1 y; stature, 1.71 ± 0.06 m; body mass, 66.7 ± 1.2 kg) and three females (age, 25.3 ± 0.6 y; stature, 1.63 ± 0.05 m; body mass, 58.3 ± 4.0 kg) were monitored during six training sessions within a week, which included 1 m and 3 m springboard dives. The Edwards summated heart rate zone method was used as a reference measure; the session-RPE rating was obtained using the CR-10 Borg scale modified by Foster and the 100 mm visual analog scale (VAS).
Significant correlations were found between CR-10 and VAS session-RPE and the Edwards summated heart rate zone method for training sessions (r range: 0.71–0.96; R 2 range: 0.50–0.92; P < 0.01) and for divers (r range: 0.67–0.96; R 2 range: 0.44–0.92; P < 0.01).
These findings suggest that session-RPE can be useful for monitoring internal training load in divers.
Eric J. Sprigings and Doris I. Miller
Optimized computer simulation, using a mathematical model of a diver, was employed to gain insight into the primary mechanical factors responsible for producing height and rotation in dives from the reverse group. The performance variable optimized was the total angular displacement of the diver as measured from last contact to the point where the diver's mass center passed the level of the springboard or platform. The times of onset, and lengths of activation for the joint torque actuators, were used as the control variables for the optimization process. The results of the platform simulation indicated that the magnitude of the hip torque was approximately twice that generated by the knee joint during the early extension phase of the takeoff. Most of the knee extension for the simulation model coincided with the period of reduced hip torque during the later phase of takeoff, suggesting that the knee torque served mainly to stabilize the lower limbs so that the force from the powerful hip extension could be delivered through to the platform. Maintaining a forward tilt of the lower legs (~50° from the horizontal) during hip and knee extension appeared to be paramount for successful reverse somersaults. Although the movement pattern exhibited by the springboard model was limited by the torque activation strategy employed, the results provided insight into the timing of knee extension. Peak knee extension torque was generated just prior to maximum springboard depression, allowing the diver's muscular efforts to be exerted against a stiffer board. It was also apparent that the diver must maintain an anatomically strong knee position (~140°) at maximum depression to resist the large upward force being exerted by the springboard against the diver's feet. The optimization process suggested that, as the number of reverse somersaults increases, both the angle of the lower legs with respect to the springboard and the angle of knee extension at completion of takeoff should decrease.
Jacalyn J. Robert
Recreational sport diving is becoming an increasingly popular sport for women. Women now comprise approximately 25% of the diving community according to Divers Alert Network statistics. In the diving literature it has been stated that women are at a greater risk for decompression sickness than men. Most of these statements were derived from high-altitude (hypobaric environment) studies rather than from a scuba diving (hyperbaric) environment. Data from the naval diving and salvage training center were analyzed, and it was found that women are not more susceptible to decompression sickness than men during dives between 4 and 10 atmospheres. More specific studies on sport diving should be completed on factors contributing to underwater decompression sickness in both men and women.
Mònica Solana-Tramunt, Jose Morales, Bernat Buscà, Marina Carbonell and Lara Rodríguez-Zamora
50% of the routine time, 3 oxygen is mobilized from finite stores in the lungs, blood, and other tissues and the cardiovascular diving response restricts blood flow to selected regions and reduces heart rate (HR) and cardiac output. 3 Elite SS athletes perform 2 training sessions (TS) per day, and
Doris I. Miller, Ian C. Jones, Marc A. Pizzimenti, Ewald Hennig and Richard C. Nelson
Takeoffs for 10-m platform dives from the reverse group at the 1986 World Championships and 1989 FINA Cup were analyzed to provide insights into their kinetic and kinematic characteristics. As with back takeoffs, the major changes in both linear and angular momentum occurred during final weighting (i.e., upward acceleration). Vertical velocities at last contact were higher for reverse dives than reverse multiple somersaults, and different moment-of-force patterns were associated with increased rotational requirements. Last-contact vertical velocities were less for reverse rotating dives than corresponding dives from the back group. Although last-contact horizontal velocities for the two groups were not statistically different, the horizontal acceleration patterns of the three composite body segments were near mirror images of one another. Finally, implications of a resultant head velocity of 10 m/s when passing the leading edge of the platform in reverse multiple somersaulting dives were considered.
Doris I. Miller, Ewald Hennig, Marc A. Pizzimenti, Ian C. Jones and Richard C. Nelson
Reaction forces elicited from the 10-m platform by the 29 male and 26 female competitors in the Fifth World Diving Championships during the takeoffs for dives from the back group were analyzed and related to their patterns of motion. Major changes in linear and angular momentum occurred during the final period of upward acceleration. During this “final weighting” phase, maximum vertical reactions of 3.0 to 4.0 times body weight (BW) and maximum horizontal reactions in the “propulsive” direction of 0.5 BW were recorded. Further, the moment of vertical platform reaction with respect to the center of gravity, which was dominant and promoted backward rotation, was opposed by the moment of the horizontal component. At final contact with the platform, higher vertical velocities were more evident for back dives than multiple back somersaults, and for dives performed in tuck than in pike, and in pike than in straight positions.
Deborah L. Feltz, Daniel M. Landers and Ursula Raeder
This study investigated the effectiveness of participant, live, and videotape modeling on the learning of a high-avoidance springboard-diving task (back dive). The effectiveness of each form of modeling upon the strength of self-efficacy also was investigated. In accord with Bandura's (1977) self-efficacy theory, it was hypothesized that the participant-modeling group would perform more correct back dives and would show stronger efficacy expectations compared to the live-modeling group which in turn would perform better on these measures than the videotape group. Results indicated that the participant-modeling treatment produced more successful dives and stronger expectations of personal efficacy than either the live-modeling or videotaped-modeling treatments. The hypothesis that students in the live-modeling condition would perform better behaviorally and show stronger efficacy expectations than students in the videotape condition was not supported.
Deborah L. Feltz and Denise A. Mugno
The present investigation was designed to replicate and extend the Feltz (1982) study of the causal elements in Bandura's (1977) theory of self-efficacy. Path analysis techniques were employed to investigate the predictions based on Bandura's model of self-efficacy, along with the additional influence of autonomic perception on the approach/avoidance behavior of female college students (N = 80) attempting a modified-back dive. The Bandura model predicted a reciprocal relationship between self-efficacy and back-diving performance, and between self-efficacy and physiological arousal (heart rate). It was also predicted that autonomic perception was a better predictor of self-efficacy than was physiological arousal, but not better than previous back-diving performance. Additionally, self-efficacy was hypothesized to be the mediator of past performance accomplishments, physiological arousal, and autonomic perception on back-diving performance. Bandura's model was tested against a “full” model that included performance, autonomic perception, and actual physiological arousal, along with self-efficacy as direct causal influences of back-diving performance. Results provided greater support for the full model. Although one's self-efficacy was the major predictor of performance on Trial 1, subjects' heart rates also significantly predicted performance on Trial 1. After Trial 1, back-diving performance on a previous trial was the major predictor of performance on the next trial. Furthermore, one's perception of autonomic arousal was a significant influence on self-efficacy but not on performance. Previous back-diving performance, however, was a better predictor of self-efficacy than autonomic perception. No reciprocal relationship was found between self-efficacy and physiological arousal. Moreover, the full model explained more performance variance than did the Bandura model.