Body Adaptations. The human body is resilient. It can be molded, remolded, and demolished repeatedly in one lifetime. Cycling is one of several methods you can use to transform your lump of quivering flesh into a lean, strong, fuel-efficient powerhouse. Let's take a closer look at what goes on inside the body of a trained cyclist.
More and Larger Energy Factories. Studies show that trained skeletal muscles contain more and larger mitochondria (aerobic ATP factories) than untrained skeletal muscles. These larger mitochondria also have a greater capacity to generate ATP anaerobically than their untrained counterparts. The number of aerobic and fat-metabolizing enzymes in trained muscles also doubles. Because of these physiological changes, trained muscles prefer to metabolize fats rather than carbohydrates. However, trained muscles also exhibit an increased capacity to oxidize carbohydrates compared to untrained muscles. These aerobic adaptations occur in fast- and slow-twitch muscle fibers, and contribute to an overall decrease in total body fat and relative increase in total lean mass. Training also improves body heat transfer. A trained cyclist dissipates heat faster and cools off more effectively than an untrained person, which minimizes the physiological burdens imposed by overheating. The end result: a leaner, cooler, perhaps happier you.
A Bigger Heart, More Blood, More Oxygen. The heart of a trained cyclist shows an increase in the size of its left ventricle (the chamber that pumps oxygenated blood to the rest of the body) as well as a slight thickening of its walls. Within four to five training sessions, plasma volume (the liquid portion of blood) significantly increases. With aerobic training, resting and submaximal-exercise heart rates decrease. As a result of intense demand, the heart's stroke volume (how much blood the left ventricle pumps out each beat) increases at rest and during exercise. Training produces significant increases in the amount of oxygen extracted from circulating blood cells during exercise. Aerobic training causes large increases in muscle blood flow during maximal exercise because of improvements in maximal cardiac output and redistribution of blood from nonactive areas (such as your stomach). Training decreases systolic and diastolic blood pressures during rest and submaximal exercise. It also improves your breathing volume, a result of increases in tidal volume and breathing frequency, and your max VO2 (as much as 15 to 30 % in the first 3 months of training and 50% over a 2-year period).
Detraining and The Reversibility Principle. About one-half the benefits of aerobic training are lost within 2 to 3 weeks if training stops. A 1% decrease occurs in aerobic capacity each day muscles are not used. The number of capillaries within trained muscle decreases by as much as 14 to 25% within 3 weeks if training ceases. The saying " use it or lose it" can be aptly applied to cycling.
Time To Adapt. For novices, expect your body to get with the program in 6 weeks. Extra time is needed if more intense cycling demands are imposed. The rule of thumb is to increase the intensity, duration, or frequency of workouts by 10% each week until your goal is met, interspersed with rest cycling. Flexibility in applying this rule is relative to your aerobic base. A stronger, deeper aerobic base allows you to increase the intensity of your workouts significantly and minimize the risk of physiological damage. Remember too that your body has its own genetic agenda. Eighty-five percent of your physiological respond is controlled by the raw materials you were provided with at birth. The remaining 15% are up for grabs. Scientific studies clearly show that some bodies-regardless of training regime and nutritional status-are just more trainable than others. Consistent cycling with periodic increases in physiological load is important to extort performance improvements. In the big picture of wellness, however, it is more important to enjoy cycling-and keep cycling throughout your lifetime-rather than become a slave to a heart rate monitor, a rigid training program, an overly enthusiastic buddy, or an unrealistic or one-shot goal.
Is Your Body Adapting? Here are two easy ways to determine if your body is responding to training. The first method is one I borrowed from triathlete Mark Allen (used to evaluate his running performances) and modified to evaluate my cycling performance. First, select a comfortable, exercising heart rate. It is important to select a heart rate that you can replicate consistently each month, such as 80% of your maximum working heart rate or what you perceive as a moderate effort for heart and legs. Next, select a flat terrain of a predetermined mileage; for example, 5 miles. To minimize environmental variables, perform this test on a trainer. Warm up adequately. Adjust your gears and ramp your heart rate to the target to begin the effort. Record the time. Keeping your heart rate as close to the target as possible, cycle the course, and record the time as you finish. Perform this routine once a month. If your body is adapting, your times will improve. The second method is suggested by Chris Carmichael (Lance Armstong's coach) and appeared in the March 2000 issue of Bicycling magazine. Warm up adequately. Then, cycle 3 miles at time trial speed (greater than 93% of your maximum heart rate). The Carmichael standards are: You are ready to rumble if your time is less than 8 minutes for men and 11 minutes for women.
Recovery-Aerobic Is Faster Than Anaerobic. Your body will recover from an aerobic effort (less than 85% of your maximum heart rate) within 24 to 48 hours. Recovery from an anaerobic session may take as long as 72 hours. Older cyclists need extra time to recover between intense workouts. To speed recovery, try some of the following ideas. After each workout, spin easily for 10 minutes using very low resistance. After an intense effort (greater than 85% of your maximum heart rate), rehydrate completely, drinking more water than you really want in addition to your usual electrolyte replacement drinks. A high-intensity 1-hour workout can decrease liver glycogen by about 55%. A 2-hour strenuous workout can almost deplete the glycogen content of your liver and specifically exercised muscles. Glycogen is not rapidly replenished when it becomes severely depleted. At least 24 hours are needed to restore muscle glycogen after prolonged, exhaustive exercise. To replenish carbohydrate stores, start consuming carbohydrate-rich foods as soon as possible after your workout. A general rule is to eat 50 to 75 grams of carbohydrate every 2 hours until 500 grams are consumed. To meet this 500-gram goal, you have to eat plenty. An apple or banana contains 20 grams of carbohydrate; a slice of bread, 12 grams; 8 ounces of fruit juice, 40 grams; one serving of breakfast cereal, 27 grams; and 2 ounces of cooked pasta, 42 grams. Drinking several large glasses of fruit juice and munching on energy bars throughout the evening may be more physiologically and psychologically feasible than eating a loaf of bread smothered in jam. Be aware that the carbohydrates contained in legumes (beans), dairy products, some fruits and honey (which contain fructose) are absorbed slower than those carbohydrates found in breads, pastas, potatoes, and energy bars and require extra time to perform their magic. Eat a high-quality protein food (meat, milk, and/or eggs) later that day. Several key hormonal fluctuations also influence recovery. When you are cycling, changes in adrenal hormones cause your body to retain sodium and dump potassium. When you stop, your body strives to regain electrolyte balance by retaining potassium and dumping sodium. Replenish both. Excellent sources of potassium are bananas, dried fruits (raisins, dates, and apricots), citrus fruits (oranges, tomatoes, and grapefruit), fruits that contain a large percentage of water (watermelons and cantaloupes), and muscle meats (beef and chicken). An 8-ounce glass of orange or tomato juice replaces almost all potassium excreted in 2 to 3 liters of sweat. Calcium and magnesium are two other important minerals that need to be replaced following an intense cycling workout. The bottomline: nibble throughout the day, eating a wide variety of foods each day. Key point: it's always better to get your vitamins, minerals, and nutrients from foods rather than from supplements.
Leg Cramps, Tiredness, and Soreness. Muscle cramps-not soreness-may indicate electrolyte replenishment: salt (sodium chloride), potassium, and magnesium and calcium (dairy products, vegetables, cashews, almonds, and other nuts). Tired legs need active rest as well as carbohydrates and protein. Minor aches, pains, and tingles may be caused by muscle knots or bunching, the result of overuse, incorrect use (improper cycling techniques), or-the most likely culprit-improper or inadequate post-exercise stretching. Leg massages and gentle stretching exercises, with therapeutic heat treatments, may help relieve these pains. Prolonged soreness is a different matter. Four feasible theories have been postulated concerning the origins of prolonged post-exercise soreness-designated delayed onset muscle soreness (DOMS). The four probable causes of DOMS include (1) minute muscle spasms, (2) minute muscle fiber tears, (3) excess metabolites surrounding muscle fibers, or (4) connective tissue damage. A recent study at Tufts University demonstrated that vitamin E supplementation (800 IU) taken every day for 7 days before severe anaerobic training may minimize muscle damage and reduce muscle inflammation and soreness.
Overtraining-It's Not In Your Head. In strength-training studies, research has proven that three exhaustive sessions for each muscle group each week is the minimum to elicit maximum gains in strength. This rule is, in general, applied to most aerobic exercise as well because activities aimed at cardiopulmonary improvements are in essence strength training for your heart and lungs. Some studies indicate that more frequent efforts of strength training can actually decrease-not improve-muscle strength. As a general guideline, maximum gains are best achieved by cycling near maximal intensities (either for your heart and lungs or leg muscles or both) 2 to 3 days each week and actively resting the remaining 4 days. Active rest is defined as engaging in leisurely (F-U-N) efforts involving your leg muscles such as walking, stretching, and easy hiking. Rest cycling is defined as lower resistance (high leg speeds, 100 to 110 RPMs) and/or lower heart rate (approximately 65 to 82% of your maximum) efforts. Overtraining is defined as excessive volume and/or intensity of training resulting in chronic fatigue. The first sign is a sudden decline in performance that can't be remedied by a few days of rest and nutritious food. Physical and psychological symptoms, changes, and signs that may indicate that you are doing too much are unwanted weight loss; loss of appetite; sleep disturbances; elevated resting heart rate and/or blood pressure; muscle tenderness; stomach and/or intestinal disturbances; nausea; increased susceptibility to upper respiratory infections and/or bone, joint, and muscle injury; decreased motivation, concentration, and/or confidence; and increased tension, depression, anger, fatigue, anxiety, and/or irritability.
A Final Ponder: Practice safe downhill cycling techniques often; they can save your life.
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