Greg Louganis’ Springboard Takeoff: II. Linear and Angular Momentum Considerations

Abstract

A linear and angular momentum analysis was conducted on Greg Louganis' forward and reverse 3-m springboard takeoffs performed during National Sports Festival V in Colorado Springs, and differences among dives were examined. At initial contact with the board, his horizontal velocity approximated 0.5 m/s across all dives analyzed. In the forward 3.5 somersaults pike, the horizontal velocity subsequently increased in magnitude until the latter half of recoil. By contrast, in the forward and reverse dives and reverse 2.5 somersaults, horizontal velocity displayed an initial reduction followed by an increase to the final value of 0.8 to 1.2 m/s. His vertical velocities at touchdown (−4.3 to −4.5 m/s) increased to 5.0 to 6.0 m/s during the takeoff, with the final upward velocity being related to the type of dive performed. At initial contact, Louganis’ total body angular momentum with respect to his center of gravity was negligible. By the end of the takeoff, it had increased to 18 kg-m-m/s for the forward dive straight and was three and four times that magnitude for his reverse 2.5 and forward 3.5 somersaults pike, respectively. Between 80 and 90% of the total angular momentum at the end of the takeoff was due to the segment remote contributions. The importance of the upper extremities in developing somersaulting angular momentum was shown by the fact that they were responsible for between 30 and 43% of the final angular momentum in all but the forward dive straight.

Maximising forward somersault rotation in springboard diving

“…The takeoff technique in optimisation 4 was similar to that of the matching simulation during the board depression phase with most changes occurring during the recoil phase (Figures 2b, 2d). This is consistent with the findings of experimental studies that angular momentum is built up (Figure 4) mainly during the recoil phase of the takeoff (Miller and Munro, 1985). The optimised takeoff technique was characterised by greater hip flexion and smaller shoulder flexion at takeoff in comparison with the matched simulation.…”

“…Angular momentum is built up mainly during the recoil phase of takeoff (Miller, 1981;Miller and Munro, 1985). Hamill et al (1985) found that platform divers increased forward angular momentum by decreasing the trunk angle to the horizontal and increasing the angular velocity of the trunk at takeoff.…”

Functional variability in the flight phase of one metre springboard forward dives

“…Many competitive sports incorporate an aerial phase within which acrobatic movements are performed as in gymnastics, trampolining and springboard diving. For competitive springboard diving the main mechanical objectives are: generating sufficient angular momentum, obtaining maximum dive height and therefore flight time, travelling safely away from the board, and having the correct orientation angle on entry into the water (Miller & Munro, 1985). The latter is often considered one of the primary performance outcomes of the dive, since it is the last part of the movement the judges see, with incorrect orientation at entry accompanied by greater splash of the water.…”

Angular Momentum Requirements of the Twisting and Nontwisting Forward 1 1/2 Somersault Dive

“…The largest absolute value of 4.6 kg m2 s-' was measured using the quasi-rigid approach in the hurdle phase of the pike dive of S2 and was counter to the desired direction of rotation. Similarly, Miller and Munro (1985b) reported a very small total body angular momentum at the beginning of the takeoff phase for a range of forward and reverse dives of Greg Louganis (1 to 2 kg m2 S-I).…”