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By: Alan Wheeldon Email: alan.wheeldon@btinternet.com |
Well why didn't you win the Combine? Your birds have been fed the same
basic food as the winner. Your training up to the race couldn't have been
far different from that of the winner. You increased the maize content
nearer basketing and fed copious numbers of peanuts.
Your pigeons received the same medications as the winner. The same vitamins. Your tiled loft is the same as the winners. Your race preparation was the same, your birds were on widowhood and you showed the hens before the basketing, just like the winner, and your pigeons have been coming home on the right line. Oh well the winner must have just been lucky! Maybe.........but then again maybe not. The biggest single contributor to winning the race was probably the winning pigeon's muscles. The muscle fibres that operated the wings of the winner were probably able to generate more power during the race than those in your birds. The winner was able to maintain more wing beats per minute, for longer. So why was that? A pigeon's breast muscle, known as the major pectoral, is the most abundant muscle in the pigeon's body, and probably one of the most adaptable. It runs either side of the keel and it can make up 25% of the pigeon's total body weight. Vigorous training, can double the size of the muscles, or lack of use can shrink it by as much as 20%. A pigeon that gets flown out by a long arduous flight home can lose much more. The breast muscles can get sacrificed as fuel to get the bird safely home, as new muscle tissue can be replenished later. The major pectorals are responsible for pulling the wings downwards to keep the pigeon in the air and to propel it forwards. The minor pectorals lie deeper. They are smaller and make up about 5% of the pigeon's weight. They raise and rotate the wings so that the downward beat can be repeated again. Using these muscles the pigeon can raise and lower it's wings on average about 5 times a second. That's 330 times a minute. So if the pigeon is flying for approximately 8 hours it will raise and lower its wings about 160,000 times. To achieve such a feat, you can imagine that the muscle must be a highly specialised and efficient organ. Muscle is made up of a bundle of cells known as muscle fibres, held together by collagen, a tough elastic-like connective tissue. The inside of each one of these muscle cells is made up of thousands of smaller strands called myofibrils. These run the entire length of the muscle cell. Each myofibril is made up of even smaller fibres called sarcomeres, and these lie end to end. Two proteins, myosin and actin interact to cause the sarcomeres to contract, and thus, the myofibrils then also contract. The myofibrils are responsible for causing the entire muscle fibre to contract in response to a nerve impulse. The muscle fibres will contract in unison, subsequently causing the entire breast muscle to contract. The nerves that control these muscle fibres run from the spinal cord. Each nerve controls several hundred to 1000 muscle fibres. The type of myosin present in the muscle determines the functional characteristics of the muscle. It determines what the muscle is capable of doing. There are three different types of myosin: Type 1, Type 2a and Type 2x. Type 1 produces slow twitch fibres. Type 2a and Type 2x fast twitch fibres. Type 2x myosin, present in the fast twitch fibres, makes them ten times faster at contracting than the fibres containing Type 1 myosin and five times faster than the fibres containing Type 2a. A pigeon usually carries a mixture of Type 1, 2a and 2x fibres, but the actual proportions will vary between pigeons. The ratios of the three types of fibre, can be changed by exercise and by the type of training that the pigeon gets, and also by the race program in which it competes. The slow twitch Type 1 fibres are thought to be better for the longer distance races and the faster twitch Type 2a and Type 2x are thought best for the sprint races. Each type of muscle fibre, slow or fast, uses different ways to obtain their energy. Slow fibres utilise efficient aerobic metabolism, where fuel is 'burnt' using oxygen, whereas fast twitch fibres depend more on anaerobic metabolism, without oxygen. Endurance pigeons, that have predominantly slow twitch fibres, tend to burn their fuel aerobically. This means that they require considerable amounts of oxygen. They have to fly great distances maintaining a consistently fast wing beat for long periods of time. They also have to maintain a continuous and constant breathing pattern in which to take in enough oxygen to keep up with the demands of the muscles. To achieve this they require an extremely efficient cardiovascular system, in which a powerful heart, and massive network of capillaries, can rapidly transport oxygen from the lungs to all parts of the body, particularly the muscles. In addition, the lungs and air sacs have to be very large in proportion to the pigeon's body. Furthermore the pigeon must have an extremely good power to weight ratio and offer little resistance to headwinds. A small streamline body and silky feathering is essential in achieving this. That is why most distance pigeons are small to medium in size. A parallel exists in the human world with athletes. Distance runners usually have small frames and less muscle bulk than the large powerful sprinters. The distance runners rely on very large and powerful hearts and good blood supply to their muscles to provide a constant supply of oxygen with which to burn their fuel. They pace themselves and rely on great stamina to get them through a race. Human sprinters on the other hand need the large explosive power of their large muscle bulk to carry them rapidly over the 100 metres. Their demand for oxygen is much less, as they rely on anaerobic metabolism to generate their energy. It is said that sprinters can run the 100 metres holding their breath for the 9 or so seconds it takes them to reach the finishing line. Similarly sprint swimmers are capable of doing the same. The analogy comparing human sprinters with sprint pigeons is not as strong a parallel with the distance example. So called sprint pigeons need not necessarily be large muscle laden birds because the sprint distances that they are asked to travel far exceeds that of the human equivalent. In human terms the sprinter only has to travel 100 metres, which is only 50 times his body length. An equivalent race for pigeons would only be about 12 meters or 40 foot in length. This is why the so called sprint pigeons do not need to have the proportionally large muscle bound bulky frames that the human sprinters have but they do rely more heavily on the fast twitch muscle fibres and anaerobic metabolism. One problem associated with anaerobic metabolism is that it relies heavily on the breakdown of glucose, but this generates a large amount of lactic acid. Lactic acid is only cleared slowly from the muscle and it is what is thought to be responsible for causing muscle cramp. It can be broken down but it will not be totally cleared if glucose is still present. That is why sprint fliers break down their pigeons early on in the week after a sprint race. The meagre diet of breakdown mix, and it's poor calorific value, causes the pigeon to use up the lactic acid first, thus clearing it from the muscle. The pigeon is then ready to take on new fuel and a high carbohydrate diet is usually given at the end of the week just prior to racing. Pigeons show great variation in the type of muscle fibre they have in their pectoral or flight muscles. A pigeon that has 95% slow fibres would be more likely to perform best at the long distance races and would not be as good a sprinter as the pigeon with high percentage of fast twitch fibres. The pigeon's muscles are very adaptable. The mechanical stresses of training and exercise, trigger the muscle fibres to make more proteins and the muscles grow bigger. Provided, that is, that there is sufficient protein in the diet to provide building materials. Conversely pigeons that have flown great distances without refueling start to eat up their musculature to provide fuel. It's a trade off but the most important outcome is to get the pigeon safely home. Pigeons that use up too much muscle get 'flown out' and can be found grounded, unable to fly due to being too weak. Physical examination shows them to have lost a large amount of flesh, particularly breast muscle. Prolonged exercise leads to the production of a predominant amount of slow twitch muscle fibres, more useful for endurance races. That is why widowhood fliers, who concentrate on the sprint races, tend not to engage in long training sessions. They train their pigeons with short bursts at the beginning of the season, and during racing, break down their pigeons and allow only short stints of exercise around the loft. They are encouraging the development of predominantly fast twitch fibres, more suitable for the fast sprint events. For the longer distance stamina events, long tosses are ideal to build up slow twitch Type 1, muscle fibres. Some fanciers send to middle distance races as preparation for the longer, distance races before allowing 2-3 weeks resting period, and then they jump straight into the big ones of 500- 700 miles. These middle distance 'training tosses' are ideal for stimulating the production of Type 1 slow twitch fibres. A rest period between races is essential to stimulate a rebound overproduction of slow twitch fibres, which usually takes several weeks. Training will influence the ratio of slow and fast twitch fibres, but some pigeons have an inbred trait of holding predominantly slow or fast twitch fibres. This is why certain strains of pigeons, or even lines within a strain, are better at some types of race than others. The Jan Aarden pigeons for example are a strain that performs particularly well at the distance races, whereas the Staf Van Reet pigeons more frequently excel at the shorter to middle distance sprint type races. There are of course examples of sprint pigeons that can do well at longer races, and distance pigeons that score at shorter races, if the conditions are right, but generally the predominance of one particular type of muscle will determine at what distance the pigeon will perform best. The predominance of one type of muscle explains why it can be difficult to breed a long distance endurance pigeon from a pair of pigeons with the faster sprint type muscle fibres, and why sprint pigeons rarely breed pigeons that will score at the extreme distance. |