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Women and Cycling - What makes women different to men ? |
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Some of the scientific stuff
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The fundamental difference between men and women is that women have two X chromosomes whereas the men have one X and one Y chromosome.
Although the rest of the chromosomal make up is the same, the genetic differences caused by the differences in the sex chromosomes are responsible for the differences between the sexes. | |
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The Y chromosome contains the genes for development of the testes. These produce the male sex hormone testosterone. Although this hormone is also present in women, the larger amounts in males accounts for the male primary and secondary sexual characteristics including body fat distribution and muscle bulk. Without testosterone men would be women.
It is these fundamental differences in hormones which lead to the differences observed between the sexes. These can be summarised as…
Biomechanical differences.
The sex of skeletons can be determined from the shape of the forehead and the width of the pelvis and lower vertebrae. Whilst the first does not affect athletic performance the latter certainly does. A girl's gait and ability to run fast alters dramatically following puberty due to the widening of the pelvis and the change in orientation of the hip muscles. In cycling terms this means women may require different saddles and a different angle of saddle tilt. Furthermore the obvious anatomical differences in this area need appropriate consideration in terms of position and clothing.
Women tend to have relatively longer legs in comparison with their height than men, with the thigh often accounting for a greater percentage of leg length. These factors need to be taken into account when setting up a female cyclist's position or when buying a bike. Long thigh bones mean the saddle will need to be further back and the seat angle shallow. However, women with short legs, relative to their total height, will need a steeper frame angle and the seat further forward.
Women also tend to have a shorter reach and weaker upper body than men of a similar height. This means that they need a relatively smaller frame size to allow for a reasonable stem length to be fitted (8/10cms minimum). As women are naturally more flexible, a greater seat to bar height difference can usually be accommodated. Too many women are wrongly advised when purchasing a bike and purchase too large a frame and compensate by pushing their saddle forward and use a short stem. Thus the handling of the bike and the potential power output are impaired.
Women also tend to have smaller feet than men. A women with a 28" inside leg and small feet would need the saddle considerably lower than a male with a similar leg length and size 12 feet.
Very little work has been published on the role of foot size in cycling but it certainly has an effect on rider position. Similarly, crank length may need to be adjusted with smaller women , with petite feet, possibly benefiting from 165cm, as opposed to the standard 170cm cranks.
The key muscles involved in the flexion and extension of the ankle, and thus in transmitting force along the foot lever to the pedal interface, are the calf (gastrocnemius) and shin (tibialis anterior) muscles. The shorter the distance from the ankle to the pedal interface (the ball of the foot) the greater the force required in this muscles. Thus the rider with larger feet has a greater mechanical advantage over the small footed rider.
Due to this mechanical disadvantage the fore and aft positioning of the saddle is even more critical. The saddle should be positioned so that maximum efficiency is attained in the transfer of muscle power from the knee extensor muscles (the quadricep group) to the pedal.
Positioning the saddle so that a point just behind the patella (knee-cap) is vertically above the pedal spindle has been shown to be the most effective. Similarly, a smooth pedalling action with minimum resistance applied to the up-pedal stroke is required.
Physical size.
Women tend to be physically smaller than men. Larger cyclists have a lower oxygen requirement relative to body weight than small cyclists at a given speed meaning that women are disadvantaged even in flat time trials. In the hills, percentage body fat and absolute body weight are more important, so most women are again handicapped. Like their male counterparts small, lightly built women are more suited to hilly courses than taller, heavier riders who tend to excel at events on level ground.
Body fat distribution and percentage.
The key physiological differences between men and women relates to the fact that the male hormone testosterone is a much more potent anabolic agent than female oestrogen, thus men tend to have larger, stronger muscles and less subcutaneous fat than women. On average women are 7-10% fatter than men. Top female runners tend to have 12-20% body fat compared to 5-10% for their male counterparts. This contrasts with 18-25% for elite female cyclists and 10-15% for elite males. This additional body fat is a consequence of being female and a difference that needs to be accepted by women athletes in general.
| The additional body fat does not seem to offer any benefits to women in endurance events even though up to 50% of the energy requirements may be met through fat metabolism. This is because a woman's additional body fat is stored in localised deposits, or sub-cutaneously, rather than intra-muscle. |
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The differences between male and female world records in endurance running events is greater than in the speed events although there have been instances where females have out-performed males. For example, in cross channel swimming several of the records are held by women and the late Beryl Burton OBE held the 12hr cycling record outright. In both these events weight bearing is less than in running and, in swimming, the higher body fat of women improves insulation and buoyancy and reduces drag. However, in general, there is no scientific evidence to suggest body fat offers women any advantages in endurance events such as cycling. Fatty tissue provides a site for steroid hormone inter-conversion thus maintaining sufficient circulating levels of oestrogen.
In summary, whilst women cyclists should endeavour to keep their body fat down to a reasonable level, they must ensure that their diet contains enough calories and carbohydrate to support the rigours of training and competition.
Dietary requirements.
Despite the observation that women tend to perspire less than men there is no evidence that they need less fluid nor that they can tolerate heat better. Women also need as much protein and fat as men relative to their body weight. The dietary requirements for men and women are broadly similar with a few exceptions :
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fewer total calories : because less weight and less muscle mass
extra iron and calcium to prevent anaemia and maintain or promote bone density
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athletes on the contraceptive pill should take a multivitamin / mineral supplement as these drugs may affect absorbtion and metabolism of certain vitamins.
The absolute amount of carbohydrate required will depend upon the individual concerned and the duration and intensity of training/competition. Total carbohydrate requirements of 2000 calories per day are not uncommon even for women endurance cyclists. However, experience has shown that most women cyclists (as in common with many other female athletes) are over pre-occupied with their weight and underestimate their nutritional needs. Like most endurance athletes women cyclists are often guilty of eating far too little carbohydrate and would benefit from additional intake without risk of increasing weight. This is due to an increase in the training potential of the body and a resultant increase in metabolic rate (Anderson, 1997).
Training and recovery.
The differences between the performances of men and women athletes are greatest in the lower ranks. This can be explained by the differences in lean body mass and muscle fibre size.
Interestingly, the differences between the VO2 max of elite men and women athletes can almost all be accounted for by the differences in lean body mass, red blood cell number and physique. Absolute maximal oxygen consumption (L.min-1) is typically 40% greater in men than women of similar athletic standing. When body weight is taken into consideration (ml. min- kg-1) this difference is reduced to 20%. It decreases to less than 10% if expressed relative to lean body weight. Thus body fat accounts for almost all of the differences in VO2 max between men and women. The remaining differences being accounted for by physical and haematological factors.
Women use the same number of calories per hour of exercise as men - (relative to lean body weight) and have similar ratios of Type I and Type II fibres. The production and clearance of lactic acid is also the same. Women, however, tend to have smaller hearts than men and higher heart rates at the same level of exertion, even when expressed as a percentage of maximum attainable. This needs to be taken into consideration when prescribing training levels purely on heart rate (visa vi BCF guidelines - which were based on a male). Using perceived rate of intensity as an additional tool is recommended. A number of tests recommend the equation 226 minus age for predicting maximal heart rates in females although, like 220-age, this rule only applies in around 55% of instances. The variation in maximum heart rate and the relationship between VO2 and heart rate varies considerably between individuals even of the same sex, thus all athletes must learn to listen to their own bodies and training accordingly.
Psychology and behaviour.
The hormonal differences between men and women may also be responsible for the distinctions in behaviour pattern. Testosterone and related male hormones are often considered as responsible for aggression and drive. When training females it is possible that they may need to be driven harder in order to attain the levels of training overload needed for effect.
Summary
| The effects of training on the female body are the same as the male and the main differences between possible levels of attainment are body fat percentage, physical differences in stature and the anabolic effects of testosterone. |
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Women athletes must learn to be proud of being female and accept their differences (and not overly compare themselves with their male counterparts). A rationalised and specific training programme coupled with a good diet and appropriate recovery will help a female athlete attain her goals and help her compete equally against other females.
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Information with kind permission from 'e-cobr'
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