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This paper aims to profile on how the aerobic fitness of a marathon runner can be improved via training and how the runner can have muscular fatigue during and after training and competitions. In addition, to suggest some recovery strategies after the runner completed the marathon race.
The marathon is a long distance running event with an official distance of 42.195 kilometers (26 miles and 385 yards).
The event was to commemorate a Greek messenger named Pheidippides who ran 40 km (25 miles) from the battlefield near Marathon to Athens to announce the Greek victory over Persia in the Battle of Marathon (490 BC) with the word "ÎÎµÎ½Î¹ÎºÎ®ÎºÎ±Î¼ÎµÎ½" (Nenikékamen, "We have won"). Once he reached Athens, he collapsed and died on the spot from exhaustion.
The marathon was one of the original modern Olympic events in 1896, though the distance did not become standardized until 1921. More than 500 marathons are contested throughout the world each year, with the vast majority of competitors being recreational athletes. Larger marathons can have tens of thousands of participants. (Wikipedia, 2010)
To date, the world's best 10 marathon races according to "Runner World" rating are:
New York City Marathon,
These races are rated according to the experience of an ordinary runner with the following:
Number of elites field,
No of competitors,
Money to the race,
In Singapore, marathon participation continues to rise exponentially (Jeanette Wang, 2009). In May, the Adidas Sundown Marathon saw 10,000 runners, including more than 600 for the 84km ultra marathon, a doubled figure of last year's inaugural event. In 2009, over 13,000 people finished the Standard Chartered Singapore Marathon 42km, up from about 2,000 in 2008.
However, Dr Teh Kong Chuan, Alexandra Hospital's sports medicine department senior consultant, stressed that the human body is not meant to run marathons. He said that while a small number of people will have no problems running distances longer than a marathon, most people are unable to do long-distance running without breaking down, death is possible if one do not have the appropriate fitness and training (Jeanette Wang, 2009). The recent Kuala Lumpur (Malaysia) marathon race was marred by the death of a 25 year old runner doing the 10km run, he collapsed and died of cardiac arrest before crossing the finishing line.
Aerobic fitness improvement /Endurance training
Endurance in sports is refers to an athlete's ability to sustain a prolonged exercise for hours or days. Generally, endurance is refers to aerobic endurance, which is often associated with cardiovascular fitness. Endurance sports like the above marathon race, requires both the respiratory and circulatory systems to supply energy to the working muscles in the body.
The primary function of the respiratory system is to supply the blood with oxygen to all parts of the body. When one breathe, one inhales oxygen and exhales carbon dioxide, the exchange of these gases through the following mouth, nose, trachea, lungs, and diaphragm is the way of getting oxygen to the blood (The Franklin Institute , 1996-2010). One of the important principal for calculating the amount of air moved in or out of the lungs per minutes (V) is known as Minute ventilation. It can be calculated by taking the tidal volume (Vt - amount of air moved per breath) and multiplying it by the respiratory rate (f - the number of breaths per minute a person is taking).
On average, the body has about 5 liters of blood traveling through it by way of the circulatory system. The circulatory system consists of the heart, the lungs, and the blood vessels working together to form the circle. The pumping of the heart forces the blood on its journey to the different parts of the body (The Franklin Institute , 1996-2010). One of the important principal for calculating the volume of blood being pumped by the heart, in particular by a ventricle in a minute is known as Cardiac output.. It can be calculated by taking the heart rate (HR) (number of heart beats per minute) and multiplying it by the stroke volume (SV) (the amount of blood ejected in each heartbeat).
Many athletes push their capacity to exercise harder and longer and increase their endurance. The factors that limit sustained high intensity efforts include fatigue and exhaustion, therefore aerobic fitness or endurance training is to modify and postpone the point at which this fatigue occurs. Likewise, VO2 max, the maximum amount of oxygen that one can utilize during maximal or exhaustive exercise is one factor that can determine an athlete's capacity to perform sustained exercise, hence aerobic fitness or endurance training aims to increase this VO2 number.
In short, the objective of aerobic fitness improvement or endurance training is to develop the energy production systems to meet the demands of the activity such as marathon.
Adaptation of training
With endurance training, the body becomes better able to produce ATP through aerobic metabolism. The cardio-respiratory system and aerobic energy systems become more efficient at delivering oxygen to the working muscles and converting carbohydrate and fat to energy.
Respiratory adaptation to training
The following shows a detailed list of changes of the parameters when there is a respiratory adaptation to training:
Increase during maximal effort.
Increases at maximal work rates
More oxygen being extracted by the lungs
More oxygen being extracted by tissues
Cardiovascular adaptation to training
The next table shows a list of changes in the components and their performance, when there is a cardiovascular adaptation to endurance training.
internal dimension increase
Wall thickness increase
Increase transport of oxygen
Increase transport of oxygen
Decrease during resting or sub maximal exercise
Increases dramatically at maximal exertion
Increase transport of oxygen
Increase transport of oxygen
Increase transport of oxygen
Metabolic adaptation to training
The following shows a list of effects and changes in performance when there is a metabolic adaptation to training.
Delay in fatigue
Respiratory exchange ratio
An RER of 0.70 indicates that fat is the predominant fuel source, RER of 0.85 suggests a mix of fat and carbohydrates, and a value of 1.00 or above is indicative of carbohydrate being the predominant fuel source
Increased at maximal exertion
No change at rest
Decrease at sub maximal training
Type of endurance training for marathon runners
There are many types of aerobic endurance training - each with specific outcome. Different duration, frequency, intensity of sessions varies with each form of training leads to different physiological adaptations within the body. Long, slow distance run is refers to low intensity but long period runs. Pace/Tempo run refers to a series of shorter bouts with brief recovery periods, example start the run with 5 to 10 minutes of easy running to warm up, then continue with 15 to 20 minutes of running about 10 seconds slower than the10K pace. Finish with 5 to 10 minutes of cooling down. Interval run refers to short bouts of 3-5 minutes with an intensity that is close to VO2max. Repetition run is performed at a pace greater than VO2max, it helps to improve running speed, running economy and builds a greater tolerance to lactic acid. A typical Fartlek training session consists of:
Warm up: easy running for 5 to 10 minutes.
Steady, hard speed for 1.5-2.5 km; like a long repetition.
Recovery: rapid walking for about 5 minutes.
Start of speed work: easy running interspersed with sprints of about 50-60 m, repeated until a little tired.
Easy running with three or four "quick steps" now and then (simulating suddenly speeding up to avoid being overtaken by another runner).
Full speed uphill for 175-200 m.
Fast pace for 1 minute.
The whole routine is then repeated until the total time prescribed on the training schedule has elapsed.
The table below summarizes the main types of aerobic endurance training and suggested parameters for marathon runners:
(Essentials of strength training & conditioning, 2000)
In addition, the following gives an overview of a weekly plan of the different types of training for a marathon runner.
Skeletal muscle system in exercise
The human body contains more than 650 individual muscles which are attached to the skeleton. The muscular system has 3 different types of muscle tissues: skeletal, cardiac, smooth. Each of these different tissues has the ability to contract, which then allows body movements and functions. The muscle in which one can control are called the voluntary muscles and the ones cannot control are the involuntary muscles like cardiac muscle (Oracle Think Quest Education Foundation, 1997).
The skeletal muscle makes up about 40 % of an adults body weight. The skeletal muscles are composed of long muscle fibers. Each of these muscles fiber is a cell which contains several nuclei. The nervous system controls the contraction of the muscle. Many of the skeletal muscle contractions are automatic, but one can still control the action of the skeletal muscle (Oracle Think Quest Education Foundation, 1997).
Regular and routine exercise is a vital component of sustainable health. Although exercise also provides benefits to the cardiovascular and skeletal systems, but the primary benefit is for the muscular system. The following will illustrate the different types of muscular adaptation to training.
Neuromuscular adaptation to training
The first type of adaptation to training is known as Neuromuscular adaptation.
The following shows the list of neuromuscular adaptation when someone is engaged in a prolong endurance training.
There will be an increased in motor unit recruitment. When there are more motor units recruited to perform a task in the muscles, the more there will be the contraction of the muscles.
Coordination of motor unit recruitment (synchronous). Synchronization is referred as the tendency of two motor units to fire at fixed time intervals with respect to each other. This synchronization will improve the rate of force development and the ability to exert a steady force.
Rate Coding, The firing frequency of the motor units were observed to be increased by training and decreased by periods of disuse. Weight training involves increased firing rates since most motor units are activated. Motor units are fired faster during eccentric contraction and slower during concentric and isometric contractions.
Autogenic inhibition is a protective mechanism that prevents muscles from exerting more force than the bones and tendons can tolerate. Muscle tension is monitored by the Golgi tendon organs. A decreased in autogenic inhibition in the muscles, will also means a decreased in the sensitivity of the Golgi tendon organs to tension, this will results in the injury of the athletes.
Metabolic Adaptation to training
Athletes will experience different training effect with different type of training performed. Specifically, an aerobic endurance training will increase the following components in the skeletal muscle system for greater performance:
Muscle capillary density (increase blood flow)
Myoglobin (increase O2 diffusion)
Mitochondrial density (increase mitochondria)
Mitochondrial enzymes (increase ATP synthesis)
Muscle glycogen & fat stores (increase fuel stores for energy production) (Dr. Fred W. Kolkhorst, 2007)
And an anaerobic endurance training will increase the following:
Muscular adaptation to training
Studies have shown that there are more muscular adaptations to anaerobic training as compared to aerobic training. The following shows the different type of adaptations.
Muscle Development Process
As mentioned, the primary benefit of regular endurance training is felt by the muscular system. Training in the body causes micro trauma in the muscles, small "injuries" that must be repaired. A certain intensity of the exercise will convince the body that additional muscle is necessary for survival, the body super compensates and repairs old muscle tissue and creating new tissue (TS Jordan, 2009).
Muscle Recruitment (Motor unit recruitment)
Muscle recruitment increase with an increase in training. Any neglect ion of the muscle use will results in atrophy to the muscle and the underlying nerve that activates that muscle. One will usually have noticed that the longer he train with weights, the more he can "feel" the muscle working (TS Jordan, 2009).
In general, people want to train because they want to increase their maximal strength levels. The more someone uses a muscle, the more efficient will be the muscle, and the more potential for muscle force generation. Muscle size is not linearly coordinated with muscle strength; small people at the gym sometimes can lift larger amounts of weight. The reason because these small people are more efficient at generating maximal strength with the muscle tissue they have (TS Jordan, 2009).
Another effect of exercise on the muscular system is an increase in muscular size. So long as someone continues to progress in the gym by lifting more weights, his body will continue to adapt--adding additional size (and strength) to meet the imposed demands.
The endurance of the muscles will also increase if there is a consistency in the training. This is because the muscle becomes more capable of disposing of accumulated waste such as lactic acid. Example, during the first week of training one might be able to perform only five reps before "the burn" becomes too intense to continue. He might be able to perform 10 or more reps the following week. This is not necessarily because the muscle became "stronger." It could be because the muscle became more efficient at disposing of waste products through the bloodstream.
Muscle fatigue in exercise
Muscle fatigue is used to describe the inability to continue with an exercise. The causes the fatigue can due to these factors including
the availability of fuel for the muscles
the mechanism of hydronium ions
the calcium in muscle cell action.
The main energy source that the body's muscles require is ATP (adenosine triphosphate) . During an intense activity, one of the energy systems for the body is anaerobic but it has a limited value (ATP/CP pathway approximately 10 seconds and the Anaerobic Lactic pathway approximately 2 minutes). The aerobic system also can help to produce ATP (with the breakdown of glucose and glycogen) and requires oxygen, carried by the blood, to support the process, but the cardiovascular system is limited in its ability to deliver blood and oxygen to the working muscles.
The breakdown of glucose or glycogen produces lactate and hydronium ions. If insufficient oxygen is available to the working muscles then hydrogen ion concentrations increase and the blood and muscle become acidic. This acidic environment start to block the nerve signals from the brain to muscle fibers so the legs begin to feel heavy and one has to slow down in order to allow more oxygen to get to the working muscles.
One of the functions of calcium is to help control muscle contractions. Researchers at the Columbia University Medical Centre conducted a study which found that muscle fatigue after long intense exercise may be caused by tiny leaks of calcium inside muscle cells. The researchers found that after extended high intensity exercise, 3 hours of cycling by experienced cyclists, small channels in the athlete's muscle cells were leaking calcium. This calcium leak weakens muscle contraction and stimulates an enzyme that attacks muscle fibers resulting in muscle fatigue. These calcium leaks stopped after a few days rest (Bellinger AM, Reiken S, Dura M, Murphy PW, Deng SX, Landry DW, Nieman D, Lehnart SE, Samaru M, Lacampagne A, Marks AR, 2008).
Sport recovery strategies
Recovery is one of the basic principles of training methodology (Rushall & Pyke, 1990) and it has two primary roles: The first is to monitor the athlete's adaptation to training and stress so that appropriate recovery strategies can be used. The second is the selection of specific recovery techniques and strategies to minimize any residual fatigue from training and competing. The 2 types of recovery strategies mainly used are Nutritional and Therapy strategies.
The most important nutritional strategy for recovery is fluid and fuel replacement strategies (Burke, 2000). A bodyweight loss of two percent or more during exercise will result in a reduction in aerobic output. If an athlete becomes excessively dehydrated, his body will becomes overheated and his aerobic capacity can be reduced by up to six-percent. Hence, it is very important to keep fluid loss to a minimum.
Createine Supplementation is refers to the use of dietary creatine so that there will be an increased of muscular stores of creatine and phosphocreatine, this will resulted in an increased of PCr in the body. A study published in 1992, demonstrated approximately a 20% increase in total creatine stores in subjects fed 20 g of creatine per day for several days (Harris R, 1992)
Bicarbonate soda is refers the use taking a spoonful of bicarbonate soda or baking powder to keep athletes to go faster or longer. According to Dr Jonathan Folland (1992) from Loughborough University, that alkali substance will increases the pH of the blood which will helps to reduce and offset the acidity produced in the muscles during intense, anaerobic exercise that produces lactic acid most quickly, such as fast running or swimming.
Carbo loading and free fatty acids is refers to take a diet of foods high in starch that increases carbohydrate reserves in muscles or maximize glycogen levels in the liver, and it is used by endurance athletes just before competing.
Antioxidants and amino acids supplementation are refer to the use of vitamin C and E for sport recovery. The following studies have shown some positive results:
Reduced muscle soreness after shuttle running when taking vitamin C (Int J Sport Nutr Exerc Metab, 2001);
Reduced exercise-induced DNA damage in immune cells in women when taking vitamins C and E (Free Radic Biol Med, 2004);
Enhanced muscle damage repair in older runners running downhill when taking vitamin E (Am J Physiol, 1990).
Branched chain amino acid (BCAA) is comprise three essential amino acids--leucine, isoleucine and valine. The muscles use BCAA for fuel or for building more muscles. Besides boosting energy levels by providing a direct fuel source, BCAAs also enhance energy through another mechanism--one that involves the brain. French researchers discovered by taking BCAAs before workouts lowers the amount of tryptophan that gets into the brain, thus reduces fatigue, which will allow one to train harder and longer, encouraging greater muscle growth.
Physical therapy strategies
There are a variety of therapies can be used to assist athletes for recovery, some of the most commonly used recovery techniques are as follows (Angela Calder, 2003).
Passive rest, this is refers to a good sleep of 7 to 9 hours, which will provides invaluable adaptation time for adult individuals to adjust to the physical, neurological, immunological and emotional stressors that they experience during the day.
Active rest, this is refers to performing light exercises like swimming or cycling, that stimulate the recovery process without imposing undue stress on the injured body part.
Hydrotherapies particularly alternating hot and cold water immersion is refers to a limb or body is immersed in ice water followed by the immediate immersed in warm water. Generally, it helps remove metabolic waste, reduce post exercise oedeme, helps lactate clearance.
Sports Massage is a special form of massage and is typically used before, during, and after athletic events. The purpose of the massage is to prepare the athlete for peak performance, to drain away fatigue, to relieve swelling, to reduce muscle tension, to promote flexibility and to prevent injuries (MamasHealth, Inc , 2010).
In conclusion, a marathon runner in order to have a better performance and a successful injury free career in his marathon career, he needs to use the correct training strategies that will increase his aerobic capacity and also good and fast recovery strategies to aid his recovery for the upcoming races.