:Thor S. Nilsen (NOR):Ted Daigneault (CAN), Matt Smith (USA) - PDF document

:Thor S. Nilsen (NOR):Ted Daigneault (CAN), Matt Smith (USA) AUTHORÕS NOTEPhysiology Sigmund B. Stršmme, Norwegian College ofPhysical Education and Sport, for his suggestions as to thesketches, and to Sturla Kaasa, the illustrator. 28 1.0 INTRODUCTIONRowing is a sport which requires a well conditioned body tooperate at a high performance level during periods of trainingbody acts as the engine to propel the rowing boat across thewater. As an engine, the body requires energy to enable it tooperate. The source of the energy for muscle contraction is thebreakdown of chemical bonds in the muscle cells. However,these chemical bonds must be replaced by the fuels of the body.we eat. They are stored in the body in the form of glycogen andfat and, when needed, are used to restore the chemical bondsIn order to improve the efÞciency of the human body to utilizethe fuels and produce energy, many adaptations take placeexercise will be presented in a way that will allow an under-2.0 THE ROWING MOTIONIt is necessary, in the beginning, to study the rowing motion toforward and backward on a sliding seat while pulling on an oarplaced in the water. This will result in the boat being pried for-ward across the surface of the water. When the athlete is pullingon the oar, he creates a positive directional force on the boatative directional forces. This will optimize the prying motion of 29 BASICROWINGPHYSIOLOGY 30 achieved during a 2000 metre rowing race. During each stroke,to the oarhandle in each of the 220 to 250 strokes that occur3.0 THE ROWING RACENext, we will examine a rowing race. The 2000 metre rowingrace consists of three parts or phases: the start phase, the middleDuring the start phase, the rowing boats generally start the raceat a stroke rate that is higher than the stroke rate of the middleaverage velocity achieved by the boat during the race. Thethe breakdown of stored fuels. However, during this phase of therace, the muscle cells are operating without sufÞcient oxygen inthe breakdown of these fuels. This process is termed anaerobicthat is obtained by converting the stored fuels into energy usingoxygen. The presence of sufÞcient oxygen in the system results inthe more complete breakdown of these fuels and is termed debilitating waste product, lactic acid. However, anaerobicmetabolism provides energy more quickly and can support highAs with the start phase, the crews will increase the stroke rate during the Þnish or sprint phase in an attempt to increase the veloc-This increase in stroke rate, and resultant increase in boat veloc-ity, will increase the energy requirements of the body to a levelto provide sufÞcient energy. Therefore, the anaerobic metaboliclactic acid, is produced in increasing amounts. Figure 1 - The Phases of the Raceover the water, it is necessary to increase the athleteÕs capacityto produce energy and to improve the athleteÕs ability to endurethe physical demands placed upon the body. This is called theathleteÕs endurance capacity. But what exactly is endurance BASICROWINGPHYSIOLOGY 32 4.0 ENDURANCE CAPACITYEndurance capacity is deÞned broadly as the ability to persist inthe performance of physical activity. However, a more precisedeÞnition would be the ability of the athlete to perform at a givenFor the athlete to perform at a greater load (and, thereby, movethe boat over the race course in a shorter period of time), it isnecessary to increase the endurance capacity of the athlete byAs a coach of rowing, you have a responsibility to understandthe effects of training on your athletes. This knowledge will assisteffectively produce the desired physiological adaptations. Yourgoal will be to give the athlete an opportunity to obtain anincreased performance level and, thereby, realize his or her5.0 AEROBIC METABOLISMsystem contributes 75 to 80 percent of the energy used in a rowing race. Thus, the importance of oxygen transportation and utilization is very clear. However, this raises two important of the FISA CDP.5.1 The Oxygen Transportation SystemThere are three systems involved in the journey of oxygen from theair to the muscle cells. The Þrst system, the respiratory system, takes After the lungs receive air, the oxygen diffuses from the air throughThe second system, the circulatory system, carries the blood,now saturated with oxygen, from the lungs to the heart where itis pumped out through the arteries to the areas most in need oftravels through the circulatory system, the arteries become smaller and branch off into thousands of small arteries calledFigure 2 - The Oxygen Transportation SystemIn the third system, the muscular system, an important transfer ordiffusion of oxygen occurs as oxygen is passed through the wallsof the capillary to the muscle cells. In the muscle cells, the oxy-We have now seen that the oxygen utilizes three different syst-ems while reaching the muscle cells where it is used to produceenergy in the aerobic metabolic process: the respiratory system,the circulatory system and the muscular system. The air that is inhaled into the lungs is the primary carrier of oxy- 33 BASICROWINGPHYSIOLOGY 34 oxygenated blood is carried to the heart, pumped out throughthe arteries and then to the capillaries.When the capillaries carrying the blood reach the muscle Þbres,the oxygen is used in the process of producing energy. We shallsystems and the possibility of increasing their effectivenessFigure 3 - The Transportation System SimpliÞed5.2 The Major Components of Oxygen Transportation180 litres of air per minute during exercise in normal people.Top rowing athletes have been observed with an intake of over200 litres of air per minute. percent of oxygen, this means that up to 42 litres of oxygen per The second component is the ability of the blood to carry thenumber of red blood cells in the blood. The red blood cells carryblood. Trained athletes generally have more total blood volumeIt has been observed that endurance training can produce up toa 16 percent increase in resting blood volume. This change iscaused by an increase in plasma volume and red blood cell Figure 4 - Diffusion of O2 to the BloodThe third component is the heart. The cardiac output is the meas-ure of the quantity of blood pumped by the heart through the circulatory system to the body in one minute. It is equal to theblood volume pumped in each beat (stroke volume) multiplied bythe heart rate. The volume of blood pumped can be increasedCardiac output varies from 5 litres per minute at rest to over 40litres per minute during strenuous exercise. Reductions in exerciseheart rate and resting heart rate, that typically occur with training,Illustration: Considering that a normal male can pump approxi-mately 110 millilitres of blood per heart beat during exercise 35 BASICROWINGPHYSIOLOGY 36 and assuming a heart rate of 200 beats per minute, the result isweight men) can produce 32 and up to 40 litres per minute ofblood pumped at maximum exercise. Therefore, blood, havinga haemoglobin level of 15 g per 100 ml blood and carrying200 ml of oxygen per litre, can deliver up to 8 liters per minuteThe fourth component is capillary density. Each muscle Þbre issurrounded by capillaries which are the extensions of the arter-ies. An increase in the number of capillaries surrounding a part-icular muscle Þbre will deliver more blood to the area and, there-by, allows more oxygen to be available to the muscles. Figure 6 - Capillary AdaptationAnother component of oxygen transportation is the ßow of bloodworking muscles does increase because arteries carrying bloodto inactive areas tend to constrict while arteries carrying blooddilate. Research indicates that training will increase the bloodbeen shown to increase the effectiveness of the machinery with-in the muscle cells to produce energy. discussed in Levels II and III of the FISA CDP.5.3 LimitationsThe major components involved in the transportation of oxygenhave been discussed. They are, however, not equally importantin a discussion of the limitations in the transportation process.The respiratory system delivers more oxygen to the circulatory 37 BASICROWINGPHYSIOLOGY 38 system than can be transported in the blood. Thus, the lungs arenot considered a limitation to a rowing athleteÕs performance. However, the circulatory system can be improved with trainingof the athlete. To produce a training effect in the circulatory system, any type of exercise that loads the heart can produceimprovement in oxygen transportation and, therefore, oxygenversion of fuels to energy. These two processes have also beentribute to improved physiological capacity. Manyexercise phys-tial for improving aerobic metabolism. To produce a trainingeffect which will inßuence the utilization of oxygen by the mus-cle cells, training should remain speciÞc to the sport by loadingthe sport at a medium training load for a long duration. Later, weAs stated, aerobic metabolism is not capable of supplying all theWe will now look at the other system that provides energy to the6.0 ANAEROBIC METABOLISMWe have now completed our discussion of the aerobic meta-bolism process. However, there is another source of energy thatcontributes 20 to 25 percent of the energy used in a rowingrace. We call this anaerobic metabolism. Anaerobic metabolism is utilized primarily in the start and Þnish the remaining energy requirement of the start phase. The intens-ity experienced during the start and Þnish phases of the racenecessitate the use of the anaerobic metabolic system to supportthe high velocity muscle contraction and provide sufÞcient energy to meet the high energy demands on the body.of the fuels produces the waste product known as lactic acid. Training improves the athleteÕs ability to tolerate the accumulationof lactic acid and improves the mechanism for its removal.However, because the aerobic metabolic system is more efÞcientand contributes a greater proportion of the energy requirementsbolism. Further information will be provided on both of thesemetabolic systems in Levels II and III of the FISA CDP. 39 BASICROWINGPHYSIOLOGY 40 7.0 MEASUREMENTHow does one measure the ability of athletes to work efÞcientlywith their bodies? By using laboratory instruments, exercise phys-VO2 Max. VO2 Max represents the bodyÕs maximal total aero-bic metabolic rate. This is an important measurement because ofthe relative importance of the aerobic metabolism to rowing. Thedifference between the oxygen content of the inhaled air and thedifference is multiplied by the amount of air exhaled (ventilation)Figure 8 - Maximal Oxygen UptakeThe following average VO2 Max values have been observedfor international athletes in rowing:Heavyweight Men:6.2 litres per minuteLightweight and Junior Men:5.3 litres per minuteHeavyweight Women:4.4 litres per minuteLightweight and Junior Women: 3.9 litres per minute umption of the athlete by dividing VO2 Max by the athleteÕswe have observed average consumptions of 68 ml/kg-min forAlthough the measurement of oxygen uptake requires the use ofexpensive equipment and the assistance of an experienced exer-cise physiologist, this information is not necessary to produceFurther measurement systems for aerobic and anaerobic metabo-lism will be discussed in Level II and III of the FISA CDP. It is nowimportant to look at the training methods that will improve the8.0 TRAINING METHODSTo relate the information presented to practical training methods,we will focus on training methods which will affect the principalented by the lungs, the heart, and the muscles. 41 BASICROWINGPHYSIOLOGY Figure 10 - Training the Body Systems8.1 The LungsThe respiratory system cannot be signiÞcantly improved toincrease the efÞciency of the entire system. Although the lungsoccurs with training, the respiratory system is not considered to8.2 The HeartThe circulatory system can be improved with training. The mosteffective type of training places a demand on the heart thating to produce this effect is interval training. Interval training is asystematic prodecure that utilizes short periods of work at a hightraining load alternating with periods of recovery. This type oftherefore, an increased capacity for oxygen transport. 42 8.3 The Musclesmost effective type of training places a demand on the musclewhich may or may not alternate with periods of rest. This type ofThis is a very brief description of the types of training that willincrease the performance level of the athlete. Other courses inwill provide further information.9.0 SUMMARYYou should now have acquired a basic understanding of thephysiological requirements of the sport of rowing. With this infor-standing of the body systems that are important to rowing and 43 BASICROWINGPHYSIOLOGY