Cyclists

The human engine cannot match this power output, yet the mechanical efficiency of the bicycle helps tremendously because a vei y small amount of horsepower can generate great speed. For example, 0.4 horsepower (298 watts) of output can result in 25 niph (40 kph) speeds or better. One set of calculations shows that if a cyclist rode on level ground, with no rolling resistance, and aided by a 25 mph tailwind, it would require only around 0.2 horsepower (150 watts) to sustain a 25 mph pace. 

CdcaCcd shoes and toeclips arc also advocated on efficiency grounds. Eveiy world-class cyclist uses toe-clips today because studies have shown significant aerobic and anaerobic benefits. Toe clips often give elite riders a false sense of power production during... 

These elliptical chainwheels have never been widely popular. Sophisticated cyclists tend to shun them because cyclist develop a riding rhythm and a comfort pattern from years of experience. Novices do not even know they exist. Most bike designers fear that elliptical chainwheels would tend to make novice cyclists less inclined to develop a smooth pedaling style. 

A bicyclist has to expend energy to cycle up a steep hill. The energy the cyclist expends is determined by the product of the power the cyclist develops and the time the cyclist is pumping (energy = power x time). The cyclist may choose to develop a relatively large amount of power and pump for a short period of time. Or he may prefer to take it easy developing a... 

Each cyclist must convert the energy stored in his or her muscles into torque to move the pedals. To go uphill, the necessary rate ol work (power) increases as does the required torque. (Corbis Corporation)... 

The first commercially successful pneumatic tire was developed in 1888 in Belfast by the Scottish veterinarian John Boyd Dunlop primarily to improve the riding comfort of bicycles. Dunlop also showed, albeit qualitatively, that his air-inflated pneumatic took less effort to rotate than did the solid rubber tires in use at that time. His qualitative tests were the first known rolling resistance experiments on pneumatic tires. Due to this significant reduction in rolling loss, many professional cyclists in Britain and Ireland adopted air-inflated tires for their bicycles by the early 1890s. Pneumatics for the nascent automobile industry soon followed. 

The most familiar examples of one-way clutches are the bicycle freewheel, which enables the cyclist to stop pedaling without stopping the bicycle, and the non-reversing ratchet used on vertical turbine pumps. 

C06-0007. Bicyclists in the Tour de France are on the road an average of 4.0 hr/day, and their average speed is at least 20 km/hr. How much ground beef must a 55-kg bicyclist consume daily to maintain his weight If the cyclist ate fruit rather than ground beef, how much fruit would he require (Consult the tables in the. )... 

Perhaps the most influential and most cited work on the topic of caffeine and endurance is the original study by Costill et al.61 in which nine competitive cyclists (including two women) exercised to exhaustion on a bicycle ergometer. In the experiemental protocol, subjects received 330 mg... 

In yet another interesting protocol, Passman and colleagues74 focused on dose-response effects. Nine well-trained cyclists received either 0, 5, 9, or 13 mg/kg caffeine 1 h prior to cycling to exhaustion. All subjects were habituated to caffeine (minimum use 100 mg/d). Significant increases in both endurance and FFA production were associated with caffeine but no significant dose-response effects were noted. 

Flinn, S., Gregory, J., McNaughton, L. R. Tristan, S., and Davies, R., Caffeine ingestion prior to incremental cycling to exhaustion in recreational cyclists, International Journal of Sports Medicine, 11, 188, 1990. 

The concept of tandem generally recalls to mind tandem bicycles in which at least two cyclists ride the same bicycle. If the cyclists want to avoid falling, they must synchronize their movements and the trajectory of the tandem Similarly, tandem MS[28] involves two or more partners, in the specific case the analyzers, which are synchronized. This is particularly important for obtaining structural information and for quantitative analysis. 

It wasn t until 1874 that the first truly modem bicycle appeared on the scene. Invented by another Englishman, H. J. Lawson, the safety bicycle would look familiar to today s cyclists. The safety bicycle had equal-sized wheels, which made it much less prone to toppling over. Lawson also attached a chain to the pedals to drive the rear wheel. By 1893, the safety bicycle had been further improved with air-filled rubber tires, a diamond-shaped frame, and easy braking. With the improvements provided by Lawson, bicycles became extremely popular and useful for transportation. Today, they are built, used, and enjoyed all over the world. 

One way to think about Hess s law is to compare the energy changes that occur in a chemical reaction with the changes in the potential energy of a cyclist on hilly terrain. This comparison is shown in Figure 5.14. 

Macmillan added iron rims to the tires of his today s cyclists. b. Two hundred years ago, bicycles didn t... 

The writer cannot be certain that the safety bicycle would look familiar to today s cyclists it is his or her opinion that this is so. The other choices are presented as facts. 386. c. 

The great advantage of the technique is that the measurements do not affect normal daily activities in any way, so it can be used to measure energy expenditure in a number of different activities or conditions (e.g. by cyclists in the Tour de France race, climbers on Mount Everest, members of a trans-Antarctic expedition, women during pregnancy or lactation, obese animals including humans carrying out their normal daily activities) (Prentice 1988). 

There was a considerable increase in interest in adult-onset mitochondrial disorders when the American cyclist,... 

Figure 13.4 Electron micrographs of the different fibres in different athletes. The fibre composition (type I and type II) of two selected top athletes, (a) A swimmer, whose speciality is the 50 metre crawl sprint, (b) A professional world-class cyclist of the roller type, (c) and (d) Cryostat sections of the swimmer s and cyclist s vastus lateralis stained for myosin ATPase, after preincubation at pH 4.3. Type I fibres stain dark, type II fibres remain unstained, (c) Almost all of the swimmer s fibres are type II. (d) Almost all of the cyclist s fibres are type I. Photographs kindly provided by Professor Hans Hoppeler, Department of Anatomy, University of Bern, Switzerland. Published in Strength and Power in Sport, ed. P.V. Komi, Blackwell Science (1992), pp.39-63.

The main use of fluorescent dyes is in the coloration of synthetic fibres, especially polyester, polyamide and acrylics in conjunction with elastane fibres, for fashion, leisure and especially sportswear uses. The fluorescent textiles offer not only high design options but also a large degree of safety in use, for instance increasing the visibility of cyclists and runners in busy urban areas. 

In one particular case, a motorcyclist hit a car and was severely injured. At the hospital, approximately one hour after the accident, the cyclist s blood alcohol content (BAG) was 0.021%. Back extrapolation (see Chapter 7) to the time of the accident could increase that value to 0.036%. His urine tests revealed use of cocaine and marijuana. Marijuana metabolites were confirmed by gas chromatography/mass spectrometry (GC/MS). All these results were used to try and prove that the cyclist was impaired. However, the presence of drug in urine is not a good indicator of drug concentration in blood or of impairment at the time of the accident, and the BAG was probably too low to cause impairment. At best, one could say that the cyclist does use drugs and uses several of them at the same time, but use of the drugs may not have played a role in causing the accident. The case was settled. 

When both injurers and victims care and activity levels affect damages but the victims do not purchase products from the injurers, as in cases of damages to cyclists from automobiles, no liability rule is optimal (ShaveU 1987, 29). In contrast, if cyclists suffer damages as a result of defective bike manufacturing, strict UabUity induces bike prices to reflect aggregate damages. 

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