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Frequently Asked Questions (FAQS);faqs.173 --------------------------------------------------------------------------- Descending II (Jobst Brandt jobst_brandt@hplabs.hp.com) The Art of Descending (an assessment) Descending on a bicycle requires a combination of skills that are more commonly used in motorcycling. Only when descending does the bicycle have the power and speed that the motorcycle encounters regularly, not to say that criterium racing doesn't also challenge these skills. It requires a combination of lean angle and braking while selecting an appropriate line through curves. Unlike motorcycle tires, bicycle tires have little margin and even a small slip on pavement is usually unrecoverable. Understanding the forces involved and how to control them is more natural to some than others. For some these skills may have atrophied from disuse at an early age and need to be regenerated. How to Corner Cornering is the skill of anticipating the appropriate lean angle with respect to the ground before you get to the apex of the turn. The angle is what counts and it is limited by traction. This means you must have an eye for traction. For most pavement this is about 45 degrees in the absence of oil, water or other smooth and slick spots. So if the curve is banked 10 degrees, you could lean to 55 degrees from the vertical. In contrast, a crowned road with no banking, where the surface falls off about 10 degrees, would allow only 35 degrees (at the limit). Estimating the required lean angle for a curve is derived from the apparent traction and what your speed will be in the apex of the turn at the current rate of braking. Anticipating the lean angle is something humans, animals and birds do regularly in self propulsion. When running you anticipate how fast and sharply you can turn on the sidewalk, dirt track or lawn on which you run. You estimate the lean for the conditions and you control your speed to not exceed that angle. Although the consequences are more severe, the same is true for the bicycle. These are reflexes that are normal to most people in youth but some have not exercised them in such a long time that they don't trust their skills. A single fall strongly reinforces this doubt. For this reason, it is best to improve and regenerate these abilities gradually through practice. Braking Once the nuts and bolts of getting around a corner are in place the big difference between being fast and being faster is another problem entirely. First it must be understood that braking is a primary skill that is greatly misunderstood. When traction is good, the front brake should be used almost exclusively because, with it, the bike can slow down so rapidly that the back wheel lifts off the road. When slowing down at this rate the rear brake is obviously useless. Once you enter the curve, more and more traction is used by the lean angle but braking is still used to trim speed. This is done with both brakes because neither wheel has much additional traction to give. It is good to practice hard front braking at a low and safe speed to develop a feel for rear wheel lift-off. You may ask why you should be braking in the turn. If you do all your braking before the turn you will be going too slowly too early. Because it is practically impossible to anticipate the exact maximum speed for the apex of the turn, you should anticipate braking in the turn. Fear of braking usually comes from an incident caused by injudicious braking. How you use the front and rear brake must be adapted to various conditions. When riding straight ahead with good traction, you can safely allow substantial transfer of weight from the rear to the front wheel allowing strong use of the front brake. When traction is poor, deceleration and weight transfer is small, so light braking with both wheels is appropriate. If traction is miserable, you should use only the rear brake because, although a rear skid is permissible, one in the front is not. Take for example a rider cornering on good traction, banked over at 45 degrees. With 1 G centrifugal acceleration, he can still apply the brakes at 0.1 G. The increases in side force on the wheels is given by the square root(1^2+0.1^2)=1.005. In other words, you can do appreciable braking while at maximum cornering. The centrifugal acceleration is also reduced by the square of the speed by which the lean angle rapidly reduces. Being aware of this relationship should leave no doubt about why racers are often seen pulling their brake levers in max speed turns. Suspension Beyond lean and braking, suspension helps immeasurably in descending. For bicycles without built-in suspension, this is furnished by your legs. If the road has fine ripples you needn't stand up but merely take the weight off your pelvic bones. For rougher roads, you should rise high enough so the saddle does not carry any weight. The reason for this is twofold. Your vision will become blurred if you don't rise off the saddle, and traction will be compromised by momentary overloads while skipping over bumps. The ideal is to keep the tire on the ground at uniform load. Some riders believe that sticking out their knee or leaning their body away from the bike, improves cornering. Sticking out a knee is the same thing that riders without cleats do when they stick out a foot, it is a useless but reassuring gesture that, on uneven roads, actually works against you. Any body weight that is not centered on the bicycle (leaning the bike or sticking out a knee) puts a side load on the bicycle, and side loads cause steering motions if the road is not smooth. To verify this, ride down a straight but rough road standing on one pedal with the bike slanted, and note how the bike follows an erratic course. In contrast, if you ride centered on the bike you can ride no-hands perfectly straight over rough road. When you lean off the bike you cannot ride a smooth line over road irregularities, especially in curves. For best control, stay centered over your bike. Vision Where you look is critical to effective descending. Your central vision involves mostly the cones in the retina of your eye. These are color receptive and images generally are more time consuming to interpret than information received by the rods in the peripheral vision. For this reason you should focus on the pavement where your tire will track while looking for obstacles and possible oncoming traffic in your peripheral vision that is fast and good at detecting motion. If you look at the place where an oncoming vehicle or obstacle might appear, its appearance will bring data processing to a halt for a substantial time. You needn't identify the color or model of car so leave it to the peripheral vision in high speed black and white because processing speed is essential. The Line Picking the broadest curve through a corner should be obvious by the time the preceding skills are mastered but the line is both a matter of safety and road surface. Sometimes it is better to hit a bump or a "Bott's dot" than to alter the line, especially at high speed. In that respect, your tire should be large enough to absorb the entire height of a "Bott's dot" without pinching the tube. Mental Speed Mental speed is demanded by all of these and, it is my experience, those who are slow to grasp an idea, do not have good hand-eye coordination, or are "accident prone", should be extra cautious in this. In contrast, being quick does not guarantee success either. Above all, it is important to not be daring but rather to ride with a margin that leaves a comfortable feeling rather than one of high risk. At the same time, do not be blinded by the age old presumption that everyone who rides faster than I is crazy. It is one of the most common descriptions used by a slower observer. "He descended like a madman!" means merely that the speaker was slower, nothing more. Ride bike! --------------------------------------------------------------------------- Trackstands (Rick Smith ricks@sdd.hp.com) How to trackstand on a road bike. With acknowledgments to my trackstanding mentor, Neil Bankston. Practice, Practice, Practice, Practice, .... 1. Wear tennis shoes. 2. Find an open area, like a parking lot that has a slight grade to it. 3. Put bike in a gear around a 42-18. 4. Ride around out of the saddle in a counter-clockwise circle, about 10 feet in diameter. Label Notation for imaginary points on the circle: 'A' is the lowest elevation point on the circle. 'B' is the 90 degrees counterclockwise from 'A' . 'C' is the highest elevation point on the circle. 'D' is the 90 degrees counterclockwise from 'C' . C / \ D B Aerial View \ / A 5. Start slowing down, feeling the different sensation as the bike transitions between going uphill (B) and downhill (D). 6. Start trying to go real slowly through the A - B region of the circle. This is the region you will use for trackstanding. Ride the rest of the circle as you were in step 5. The trackstanding position (aerial view again): ---| / ------| |----/ |--- / The pedal are in a 3 o'clock - 9 o'clock arrangement (in other words, parallel to the ground). Your left foot is forward, your wheel is pointed left. You are standing and shifting you weight to keep balance. The key to it all is this: If you start to fall left, push on the left peddle to move the bike forward a little and bring you back into balance. If you start to fall right, let up on the peddle and let the bike roll back a little and bring you back into balance. 7. Each time you roll through the A - B region, try to stop when the left peddle is horizontal and forward. If you start to lose your balance, just continue around the circle and try it again. 8. Play with it. Try doing it in various regions in the circle, with various foot position, and various amounts of turn in your steering. Try it on different amounts of slope in the pavement. Try different gears. What you are shooting for is the feel that's involved, and it comes with practice. The why's of trackstanding: Why is road bike specified in the title? A true trackstand on a track bike is done differently. A track bike can be peddled backwards, and doesn't need a hill to accomplish the rollback affect. Track racing trackstands are done opposite of what is described. They take place on the C - D region of the circle, with gravity used for the roll forward, and back pedaling used for the rollback. This is so that a racer gets the assist from gravity to get going again when the competition makes a move. Why a gear around 42-18? This is a reasonable middle between too small, where you would reach the bottom of the stroke on the roll forward, and too big, where you couldn't generate the roll forward force needed. Why is the circle counter-clockwise? Because I assume you are living in an area where travel is done on the right side of the road. When doing trackstands on the road, most likely it will be at traffic lights. Roads are crowned - higher in the middle, lower on the shoulders - and you use this crown as the uphill portion of the circle (region A-B). If you are in a country where travel is done on the left side of the road, please interpret the above aerial views as subterranial. Why is this done out of the saddle? It's easier!! It can be done in while seated, but you lose the freedom to do weight adjustments with your hips. Why is the left crank forward? If your right crank was forward, you might bump the front wheel with your toe. Remember the steering is turned so that the back of the front wheel is on the right side of the bike. Some bikes have overlap of the region where the wheel can go and your foot is. Even if your current bike doesn't have overlap, it's better to learn the technique as described in case you are demonstrating your new skill on a bike that does have overlap. Why the A - B region? It's the easiest. If you wait till the bike is around 'B', then you have to keep more force on the peddle to hold it still. If you are around the 'A' point, there may not be enough slope to allow the bike to roll back. Questions: What do I do if I want to stop on a downhill? While there are techniques that can be employed to keep you in the pedals, for safety sake I would suggest getting out of the pedals and putting your foot down. Other exercises that help: Getting good balance. Work through this progression: 1. Stand on your right foot. Hold this until it feels stable. 2. Close your eyes. Hold this until it feels stable. 3. Go up on your toes. Hold this until it feels stable. 4. If you get to here, never mind, your balance is already wonderful, else repeat with other foot. =========================================================================== Nutrition and Food Nutrition (Bruce Hildenbrand bhilden@unix386.Convergent.COM) Oh well, I have been promising to do this for a while and given the present discussions on nutrition, it is about the right time. This article was written in 1980 for Bicycling Magazine. It has been reprinted in over 30 publications, been the basis for a chapter in a book and cited numerous other times. I guess somebody besides me thinks its OK. If you disagree with any points, that's fine, I just don't want to see people take exception based on their own personal experiences because everyone is different and psychological factors play a big role(much bigger than you would think) on how one perceives his/her own nutritional requirements. Remember that good nutrition is a LONG TERM process that is not really affected by short term events(drinking poison would be an exception). If it works for you then do it!!! Don't preach!!!! BASIC NUTRITION PRIMER Nutrition in athletics is a very controversial topic. However, for an athlete to have confidence that his/her diet is beneficial he/she must understand the role each food component plays in the body's overall makeup. Conversely, it is important to identify and understand the nutritional demands on the physiological processes of the body that occur as a result of racing and training so that these needs can be satisfied in the athlete's diet. For the above reasons, a basic nutrition primer should help the athlete determine the right ingredients of his/her diet which fit training and racing schedules and existing eating habits. The body requires three basic components from foods: 1) water; 2) energy; and 3)nutrients. WATER Water is essential for life and without a doubt the most important component in our diet. Proper hydrations not only allows the body to maintain structural and biochemical integrity, but it also prevents overheating, through sensible heat loss(perspiration). Many cyclists have experienced the affects of acute fluid deficiency on a hot day, better known as heat exhaustion. Dehydration can be a long term problem, especially at altitude, but this does not seem to be a widespread problem among cyclists and is only mentioned here as a reminder(but an important one). ENERGY Energy is required for metabolic processes, growth and to support physical activity. The Food and Nutrition Board of the National Academy of Sciences has procrastinated in establishing a Recommended Daily Allowance(RDA) for energy the reasoning being that such a daily requirement could lead to overeating. A moderately active 70kg(155lb) man burns about 2700 kcal/day and a moderately active 58kg(128lb) woman burns about 2500 kcal/day. It is estimated that cyclists burn 8-10 kcal/min or about 500-600 kcal/hr while riding(this is obviously dependent on the level of exertion). Thus a three hour training ride can add up to 1800 kcals(the public knows these as calories) to the daily energy demand of the cyclist. Nutritional studies indicate that there is no significant increase in the vitamin requirement of the athlete as a result of this energy expenditure. In order to meet this extra demand, the cyclist must increase his/her intake of food. This may come before, during or after a ride but most likely it will be a combination of all of the above. If for some reason extra nutrients are required because of this extra energy demand, they will most likely be replenished through the increased food intake. Carbohydrates and fats are the body's energy sources and will be discussed shortly. NUTRIENTS This is a broad term and refers to vitamins, minerals, proteins, carbohydrates, fats, fiber and a host of other substances. The body is a very complex product of evolution. It can manufacture many of the resources it needs to survive. However, vitamins, minerals and essential amino acids(the building blocks of proteins) and fatty acids cannot be manufactured, hence they must be supplied in our food to support proper health. Vitamins and Minerals No explanation needed here except that there are established RDA's for most vitamins and minerals and that a well balanced diet, especially when supplemented by a daily multivitamin and mineral tablet should meet all the requirements of the cyclist. Proper electrolyte replacement(sodium and potassium salts) should be emphasized, especially during and after long, hot rides. Commercially available preparations such as Exceed, Body Fuel and Isostar help replenish electrolytes lost while riding. Proteins Food proteins are necessary for the synthesis of the body's skeletal(muscle, skin, etc.) and biochemical(enzymes, hormones, etc.)proteins. Contrary to popular belief, proteins are not a good source of energy in fact they produce many toxic substances when they are converted to the simple sugars needed for the body's energy demand. Americans traditionally eat enough proteins to satisfy their body's requirement. All indications are that increased levels of exercise do not cause a significant increase in the body's daily protein requirement which has been estimated to be 0.8gm protein/kg body weight. Carbohydrates Carbohydrates are divided into two groups, simple and complex, and serve as one of the body's two main sources of energy. Simple carbohydrates are better known as sugars, examples being fructose, glucose(also called dextrose), sucrose(table sugar) and lactose(milk sugar). The complex carbohydrates include starches and pectins which are multi-linked chains of glucose. Breads and pastas are rich sources of complex carbohydrates. The brain requires glucose for proper functioning which necessitates a carbohydrate source. The simple sugars are quite easily broken down to help satisfy energy and brain demands and for this reason they are an ideal food during racing and training. The complex sugars require a substantially longer time for breakdown into their glucose sub units and are more suited before and after riding to help meet the body's energy requirements. Fats Fats represent the body's other major energy source. Fats are twice as dense in calories as carbohydrates(9 kcal/gm vs 4 kcal/gm) but they are more slowly retrieved from their storage units(triglycerides) than carbohydrates(glycogen). Recent studies indicate that caffeine may help speed up the retrieval of fats which would be of benefit on long rides. Fats are either saturated or unsaturated and most nutritional experts agree that unsaturated, plant-based varieties are healthier. Animal fats are saturated(and may contain cholesterol), while plant based fats such as corn and soybean oils are unsaturated. Unsaturated fats are necessary to supply essential fatty acids and should be included in the diet to represent about 25% of the total caloric intake. Most of this amount we don't really realize we ingest, so it is not necessary to heap on the margarine as a balanced diet provides adequate amounts. WHAT THE BODY NEEDS Now that we have somewhat of an understanding of the role each food component plays in the body's processes let's relate the nutritional demands that occur during cycling in an attempt to develop an adequate diet. Basically our bodies need to function in three separate areas which require somewhat different nutritional considerations. These areas are: 1) building; 2) recovery; and 3) performance. Building Building refers to increasing the body's ability to perform physiological processes, one example being the gearing up of enzyme systems necessary for protein synthesis, which results in an increase in muscle mass, oxygen transport, etc. These systems require amino acids, the building blocks of proteins. Hence, it is important to eat a diet that contains quality proteins (expressed as a balance of the essential amino acid sub units present)fish, red meat, milk and eggs being excellent sources. As always, the RDA's for vitamins and minerals must also be met but, as with the protein requirement, they are satisfied in a well balanced diet. Recovery This phase may overlap the building process and the nutritional requirements are complimentary. Training and racing depletes the body of its energy reserves as well as loss of electrolytes through sweat. Replacing the energy reserves is accomplished through an increased intake of complex carbohydrates(60-70% of total calories) and to a lesser extent fat(25%). Replenishing lost electrolytes is easily accomplished through the use of the commercial preparations already mentioned. Performance Because the performance phase(which includes both training rides and racing)spans at most 5-7 hours whereas the building and recovery phases are ongoing processes, its requirements are totally different from the other two. Good nutrition is a long term proposition meaning the effects of a vitamin or mineral deficiency take weeks to manifest themselves. This is evidenced by the fact that it took many months for scurvy to show in sailors on a vitamin C deficient diet. What this means is that during the performance phase, the primary concern is energy replacement (fighting off the dreaded "bonk") while the vitamin and mineral demands can be overlooked. Simple sugars such a sucrose, glucose and fructose are the quickest sources of energy and in moderate quantities of about 100gm/hr(too much can delay fluid absorption in the stomach) are helpful in providing fuel for the body and the brain. Proteins and fats are not recommended because of their slow and energy intensive digestion mechanism. Short, one day rides or races of up to one hour in length usually require no special nutritional considerations provided the body's short term energy stores (glycogen) are not depleted which may be the case during multi-day events. Because psychological as well as physiological factors determine performance most cyclists tend to eat and drink whatever makes them feel "good" during a ride. This is all right as long as energy considerations are being met and the stomach is not overloaded trying to digest any fatty or protein containing foods. If the vitamin and mineral requirements are being satisfied during the building and recovery phases no additional intake during the performance phase is necessary. IMPLICATIONS Basically, what all this means is that good nutrition for the cyclist is not hard to come by once we understand our body's nutrient and energy requirements. If a balanced diet meets the RDA's for protein, vitamins and minerals as well as carbohydrate and fat intake for energy then everything should be OK nutritionally. It should be remembered that the problems associated with nutrient deficiencies take a long time to occur. Because of this it is not necessary to eat "right" at every meal which explains why weekend racing junkets can be quite successful on a diet of tortilla chips and soft drinks. However, bear in mind that over time, the body's nutritional demands must be satisfied. To play it safe many cyclists take a daily multivitamin and mineral supplement tablet which has no adverse affects and something I personally recommend. Mega vitamin doses(levels five times or more of the RDA) have not been proven to be beneficial and may cause some toxicity problems. GREY NUTRITION "Good" nutrition is not black and white. As we have seen, the body's requirements are different depending on the phase it is in. While the building and recovery phases occur somewhat simultaneously the performance phase stands by itself. For this reason, some foods are beneficial during one phase but not during another. A good example is the much maligned twinkie. In the performance phase it is a very quick source of energy and quite helpful. However, during the building phase it is not necessary and could be converted to unwanted fat stores. To complicate matters, the twinkie may help replenish energy stores during the recovery phase however, complex carbohydrates are probably more beneficial. So, "one man's meat may be another man's poison." NUTRIENT DENSITY This term refers to the quantity of nutrients in a food for its accompanying caloric(energy) value. A twinkie contains much energy but few vitamins and minerals so has a low nutrient density. Liver, on the other hand, has a moderate amount of calories but is rich in vitamins and minerals and is considered a high nutrient density food. Basically, one must meet his/her nutrient requirements within the constraints of his/her energy demands. Persons with a low daily activity level have a low energy demand and in order to maintain their body weight must eat high nutrient density foods. As already mentioned, a cyclist has an increased energy demand but no significant increase in nutrient requirements. Because of this he/she can eat foods with a lower nutrient density than the average person. This means that a cyclist can be less choosy about the foods that are eaten provided he/she realizes his/her specific nutrient and energy requirements that must be met. BALANCED DIET Now, the definition of that nebulous phrase, "a balanced diet". Taking into consideration all of the above, a diet emphasizing fruits and vegetables (fresh if possible), whole grain breads, pasta, cereals, milk, eggs, fish and red meat(if so desired) will satisfy long term nutritional demands. These foods need to be combined in such a way that during the building and recovery phase, about 60-70% of the total calories are coming from carbohydrate sources, 25% from fats and the remainder(about 15%) from proteins. It is not necessary to get 100% of the RDA for all vitamins and minerals at every meal. It may be helpful to determine which nutritional requirements you wish to satisfy at each meal. Personally, I use breakfast to satisfy part of my energy requirement by eating toast and cereal. During lunch I meet some of the energy, protein and to a lesser extent vitamin and mineral requirements with such foods as yogurt, fruit, and peanut butter and jelly sandwiches. Dinner is a big meal satisfying energy, protein, vitamin and mineral requirements with salads, vegetables, pasta, meat and milk. Between meal snacking is useful to help meet the body's energy requirement. CONCLUSION All this jiberish may not seem to be telling you anything you couldn't figure out for yourself. The point is that "good" nutrition is not hard to achieve once one understands the reasons behind his/her dietary habits. Such habits can easily be modified to accommodate the nutritional demands of cycling without placing any strict demands on one's lifestyle. --------------------------------------------------------------------------- Nuclear Free Energy Bar Recipe (Phil Etheridge phil@massey.ac.nz) Nuclear Free Energy Bars ~~~~~~~~~~~~~~~~~~~~~~~~ Comments and suggestions welcome. They seem to work well for me. I eat bananas as well, in about equal quanities to the Nuclear Free Energy Bars. I usually have two drink bottles, one with water to wash down the food, the other with a carbo drink.