EXTRA WEIGHT ON HANDS INCREASE STANDING LONG JUMP PERFORMANCE Chenfu Huang, Hung-ying Chen and Hsiente Peng National Taiwan Normal University, Taipei, Taiwan Standing long jump is one of the events in ancient Olympiad Game. Extra weights were handed by athletes during the jump. It has been argued whether the extra weights can make the challenge more difficult or enhance the jumping performances. The purpose of this study was to investigate the effect of extra weights on standing long jump. A Redlake high-speed camera was synchronized with a Kistler force platform to collect the data of eight male jumping performances. The results indicate that the total horizontal propelling time, time to maximal horizontal force, horizontal impulse and horizontal velocity of body CG at takeoff all increased with loaded jumps. In addition, the vertical velocity of body CG and angles at takeoff decrease with loaded weights. It was suggested optimal extra weights for extending standing jump distance is 8% of body mass. KEY WORDS: biomechanics, standing long jump, extra weight INTRODUCTION: Standing long jump is one of events in ancient Olympic game and in the eighteenth ancient Olympiad in 708 BC; extra weights (halteres) were used either to make the challenge more difficult or to enhance the jumping performance. Halteres were swung back and forth by the jumper before take-off, thrust forwards during the first part of the flight, and finally swung backwards just before landing. Minetti and Ardigo (2002) use computer simulation to determine the optimal extra weights that would be needed to maximally increase a jumping distance. They suggested that the extra mass 2-9 kg would increase a 3-meter jump by at least 17 cm. However, they only asked subjects to perform the vertical jump with halteres instead of standing long jump. The purpose of this study was to investigate the effect of extra weights on standing long jump performance. METHODS: Eight male sprint runners (age 23.62.5yr, height 179.03.9cm, body mass 70.63.9kg) served as subjects for this study. All subjects were informed of the experimental procedures and gave their consent before participating. Before performing any jumps, the subjects were instructed to warm up for a few minutes by doing some light running, jumping, deep-knee bends, and stretching. For each trial, the subjects were instructed to initially stand on a force platform and jump as far as possible once given a verbal signal. Each subject performed maximal standing long jump and swung his upper limbs forward and upwards while loaded with one pair of dumbbell randomly donated out of 7 (0,2,4,6,8,10,12) that ranged from zero (unloaded) to 12 kg of total extra mass. Each subject performed six jumps: two jumps with unloaded and two jumps with two different loaded weights. Three best jumps (one unloaded and two loaded trials) for each subject were selected for analysis. The subjects were asked to drop the handbell backward in the mid-air. A Redlake high-speed camera (125Hz) was synchronized with a Kistler force platform (9287B, 1250Hz) to collect the kinematical and kinetic data of jumping performance. Nine body landmarks (ear, shoulder, elbow, wrist, hip, knee, ankle, toe and heel) were digitized by Peak Motus system. Dempster's study (1955) was used to calculate body segment parameters. A Butterworth digital recursive filter with 6Hz cutoff frequency was used to filter the random noise during the digitizing process. The ground reaction forces and impulses of standing long jump were analyzed by Kistler Bioware software. The jumping distance was defined as the horizontal displacement of toe at takeoff and heel at landing. Total time (T total) was defined as total time of horizontal propelling force (positive horizontal force). RESULTS AND DISCUSSION: The standing long jump distance for eight unload trials ranged from 2.50m to 2.85m, and for the loaded 16 trials ranged from 2.55m to 3.29m. The mean values for the unloaded and loaded trials are 2.67 ± 0.13m and 2.79 ± 0.19m respectively. Compared with unload trials, fifteen out of sixteen loaded trials improved the