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[HUMAN-POWERED FLIGHT BY AN AMATEUR FEMAL PILOT] 4. Physical Fitness Training 4.1 Female Pilots for Human-Powered Flight Usually, females have more fat, less muscle and less physical fitness than males. Furthermore, because of the influence of hormones, muscle strength training is reported to be less effective in females than in males.(4) All these suggest that males are more suitable as HPA pilots than females, if their physiques are the same. However, the most important limiting factor in HPF is the total weight. For HPF, the only advantage of females over males lies in the fact that the physique of females is usually smaller than that of males. The female pilot, who was the subject of this study, was 154cm tall and weighed 44kg. Her height and weight are smaller than the average for Japanese females at age 24(157.5cm, 50.4kg). The Rohrer's index (the ratio of weight to height) was 120.5 for this woman, which was smaller than the national average (129) for 24-year-old females. Thus, she had a slim physique, which is ideal for a pilot of HPA. In general, females have a higher percent of fat body than males. It was therefore essential for her to increase her physical strength while preserving her slim physique. 4.2 Methods of Power Generation and Postures During HPF, the power is usually produced by pedaling. Pedaling is advantageous in that it can produce stable levels of power. The power is maximal when both the upper and lower limbs are used. In the case of human-powered flight, the upper limbs are used to control the flight. For this reason, only the lower limbs can be used to pedal. 4.2.1 Posture The pilot of HPA can usually take either one of two positions (the conventional upright cycling position or the reclining position). The power produced from the flexors and extensors of the knee joint does not seem to differ between these two positions. However, the hip joint flexors may be too short and the hip joint extensors may be too long when the pilot assumes a reclining position. On the other hand, the reclining position allows the trunk of the pilot to be immobilized easily, and the counter-force from pedaling can be absorbed by the back of the reclining seat. Considering these factors, we concluded that the reclining position is more suitable for female pilots of HPA who generate a relatively smaller amount of power. 4.2.2 Pedal Rotation Numerous physiologists reported that the most efficient pedal rotation rate for aerobic exercise increases as the power output becomes greater (5) and it ranges from 50 to 60 rpm.(6) in fact, however, most experienced cyclists
4.2.3 Training Conditions The effects of muscle training are related to the specific principle.(8)(9) The effects of muscle training are maximized when the effects are assessed using the same posture and load as those which were used for the training. The effects are smaller when assessed in other postures or at other load levels. Therefore, what is the most important in pedaling exercises is to use apparatus, posture, rotation rates, power output and other conditions which are as close as possible to those used during actual flight. In the present case, the trainee first spent 3 months exercising, using a conventional bicycle ergometer and subsequently performed her exercise using another type of ergometer which had been modified so that the trainee could assume a reclining position (the position used during human-powered flight). After that, training using both ergometers was carried out. 4.3 Physical Fitness Training Program Full-scale training was started for 6 months before the planned attempt for a record. Because the pilot was employed by a company, she spent one hour or less on physical fitness training and 1 or 2 hours on study of aviation engineering on weekday evenings. On Saturdays and Sundays, she worked on the HPA and practiced aircraft handling techniques. We took special care to satisfy the following 6 requirements, (1) to keep the trainee's workout at a level slightly beyond her capacity, (2) to achieve a well-balanced training of the whole body, (3) to gradually increase the training load as the trainee's physical fitness increased, (4) to match the contents of the training to the trainee's physical fitness level, (5) to guide the trainee in practice training for 3 days or more a week, (6) to make the trainee fully understand the goal and function of each of the aspects of the training.
4.4 Training Schedules and Efficacy Assessment 4.4.1 Pedal Training We prepared three training schedules, placing an emphasis on the pursuit of high power training. The first schedule involved three sets of 10 seconds of full-power pedaling at intervals of 15 minutes. The ergometer was adjusted so that the torque would be equal to 220 watts of power when the pedal was rotated at a rate of 90 rpm. This schedule was intended to build the power needed for the take-off of the aircraft, primarily through elevating alactic anaerbic power. The second schedule was an interval type of training. The trainee practiced 5 or 6 sets of exercise at intervals of 90 seconds. The duration of one round was 60, 120 or 180 seconds. For each of those three exercises with different durations, the torque was set to 90% of the level which caused the trainee to become exhausted at a given duration after one round of exercise. This schedule was intended to build the ability to maintain a necessary power level after the aircraft has begun level flight, by elevating both the lactic anaerobic power and the aerobic power. The third schedule was full-power training. The trainee continued pedaling at a power of 220 watts and a rotation rate of 90 rpm until she became exhausted. The purpose of this schedule was the same as that of the second schedule. This schedule was used only once a week because it caused great mental stress and physical fatigue. After the trainee began to practice these three training schedules, her endurance time at a 220 watts power was measured once monthly at the university laboratory. The endurance time was 84 seconds one month after the start of training and reached the target of 120 seconds two months after the start. 4.4.2 Muscular Strength Training Because power is the product of force and speed, it increases as muscular strength becomes greater. In fact, individuals with greater muscular strength can produce higher levels of power. For this reason, strength training was performed three times a week in parallel with the pedaling exercise. It was conducted using daily neccessities without any special facilities. The muscles primarily employed in pedaling are the flexors and extensors of hip and knee joints. To train these muscles, a half squat exercise was incorporated. The reason why we selected a half squat exercise instead of a full squat exercise is that the knee joint is bent only about 90 degrees during pedaling. Since it is known that the effective load levels for muscle training are over 70% of the maximal strength, we set the load at level a high enough that the trainee could only repeat the exercise 5-10 times. Under these conditions, a half squat exercise was performed until the trainee became exhausted. With adequte intervals, 5 or 6 sets of this exercise were carried out. Other exercises used for muscle training included pull-ups (for training the upper limb flexors), push-ups for the upper limb extensors, sit-ups for the abdominal muscles and back hyperextensions for the dorsal muscles. 
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