Numerical Study on the Characteristics of Air Flows through Helmet Bicycle Racing Using the Effect of Variation of Trailing Edge

Research on aerodynamics on racing bicycles always develops from time to time. The various geometry of a time-trial helmet produces different characteristics of fluid flow, this is due to the relative movements of air that are in the area throughout the body shape of the helmet. Basically the fluid flow that passes on a racing bicycle helmet will produce a drag force, where this must be minimized in order to hinder the pace of drivers to achieve maximum speed, so drivers should pay attention to how to design the geometry of helmet that should be used. Computational fluid dynamics (CFD) method is used to simulate the case studies in this research. In this study, four kinds of models trailing edge geometry was varied to determine where the most optimal in accepting the drag force. The validation was also conducted to determine the suitability of this study with prior research, where in this validation the results of this study are compared with the research owned (Sims and Jenkins, 2011). The results of this validation show that the resulting drag coefficient has a very small difference of 0.001. The four models are simulated with Reynold number values of 7.14 × 104, 1.00 × 105, and 1.16 × 105. The results of this study indicate that with differences in the geometry of the trailing edge affect the drag force that occurs. From the research result when Reynold 7.0 x 10 ^ 4, the drag force produced by model 3 is bigger than model 1 and 2 which is equal to 0.182 N. Whereas on Reynold which is bigger 1.16 x 10 ^ 5 model 3 receives drag smaller than model 1 and 2 which is equal to 0.283 N. In the world of bicycle racing, the difference in the small drag force affects the speed of the bicycle and affects the resulting victory.

PERBEDAAN DENYUT JANTUNG DAN TEKANAN DARAH PADA ATLET PREDOMINAN AEROBIK DAN ANAEROBIK KONI JAWA BARAT TAHUN 2016

Exercise when done regularly will give big impact to the body. One of the alteration in an athlete that can be made is the cardiovascular system change. This study aimed to discover the difference of heart rate and blood pressure between aerobic predominant athlete and anaerobic predominant athlete. The study design was case-control, data collected from 80 athletes divided into 40 aerobic predominant athletes (canoe, sail, gantole, shooting, and bicycle racing) and 40 anaerobic predominant athletes (weight lifting, taekwondo, softball, tarung derajat, and rock climbing) in KONI West Java, Bandung. Sample was collected by random sampling and analyzed by T test independent. The result showed there was significant difference of heart rate between aerobic predominant athlete and anaerobic predominant athlete (p=0,0001), and lower in aerobic. There was also no significant difference of systolic blood pressure between predominant aerobic athlete and predominant anaerobic athlete (p=0,404), and was higher in anaerobic. Another result showed no significant difference of diastolic blood pressure between predominant aerobic athlete and predominant anaerobic athlete (p=0,553) and was higher in anaerobic. In conclusion, there was significant difference of the heart rate, but no difference of systolic and diastolic blood pressure between aerobic predominant and anaerobic predominant athlete.

FACTORS INFLUENCING THE DEGREE OF ERECTILE DYSFUNCTION IN BICYCLE RACE ATHLETES

Objective: This research aims to identify factors influencing the degree of erectile dysfunction in bicycle racing athletes. Material & Methods: This study used quantitative analysis and cross-sectional research design. Samples included in this research were 54 respondents in accordance to the inclusion and exclusion criteria of this study, and were willing to participate in this research. The data were collected using the IIEF-5 (International Index of Erectile Function-5) questionnaire. The data were then edited, coded and analyzed using Chi-square (bivariate analysis). Results: The results showed correlations between the degree of erectile dysfunction in bicycle race athletes and age (PR= 1.182; 95%CI= 0.403-3.465; p= 0.976), cycling history (PR= 0.462; 95% CI= 0.490-4363; p= 0.687), cycling frequency (PR=1.400; 95% CI= 0.299-6.560; p= 0.72), cycling duration (PR= 0.333; 95% CI= 0.074-1.507; p= 0.165), furthest cycling distance (PR= 0.883; 95% CI= 0.267-2.919; p= 1.00), and type of saddle (PR= 0.271; 95% CI= 0.481-1.547; p= 0.221) respectively. Conclusion: There were no significant correlation (p= >0.05) in all variables analyzed in this study.

Women’s High-Wheel Bicycle Racing in Nineteenth-Century America: More than Salacious Entertainment

During the nineteenth century in North America, a small group of working-class women turned to sport to earn a living. Among them were circus performers, race walkers, wrestlers, boxers, shooters, swimmers, baseball players, and bicycle racers. Through their athleticism, these women contested and challenged the prevailing gender norms, and at the same time expanded notions about Victorian women’s capabilities and appropriate work. This article focuses on one of these professional sports, namely high-wheel bicycle racing. Bicycle historians have mostly dismissed women’s racing during the brief high-wheel era of the 1880s as little more than sensational entertainment, and have not fully understood its importance. I hope to change these perceptions by providing evidence that female high-wheel racers in the United States, who often began as pedestriennes (race walkers), were superb athletes competing in an exciting, well-attended, and profitable sport.