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Menstrual Cycle
A female athlete's performance may depend on the phase of the
menstrual cycle she is in. The menstrual cycle ranges from 24 to 35 days and
comprises of three phases: menstrual phase (menses), preovulatory phase and the
postovulatory phase. The menstrual phase is the periodic discharge of 25 to
65ml of blood, tissue fluid etc. and lasts for approximately 3 to 7 days.
Example of the phases of 28 day menstrual cycle:
| Days 1 to 5 |
Days 6 to
13 |
Day 14 |
Days 15 to
28 |
| Menstruation
phase |
Preovulatory
phase |
Ovulation |
Postovulatory
phase |
The effect of sport
Physically active women increase their chances of changes to their
menstrual cycle. These include irregular cycles (oligomenorrhea) or complete
cessation of the cycle (amenorrhea). In the general population, amenorrhea
occurs in 2 to 5% of women of reproductive age, whereas for women participating
in sport it can be as high as 40%.
Other factors
All women need to be aware that exercise is not the only factor
that can result in oligomenorrhea or amenorrhea. The other factors are a high stress level, body weight and body composition (% body fat level below 20%).
Athletes are prime candidates for oligomenorrhea or amenorrhea as
they are likely to experience:
- heavy training loads
- high stress levels from trying to manage the training program
with work and family life and the pressures of competition
- as a result of the training, body weight may reduce and the fat
level may fall below 20% for some months
Consequences
Amenorrhea reduces the body's capacity to absorb calcium,
decreases bone density and increases the risk of musculoskeletal injury in
vigorous exercise.
Impact on training
The hardest time to race efficiently, for athletes experiencing a
menstrual cycle, is during the week before menstruation and a week after
ovulation (Tracy Williams Ph. D 1993). At these times increased levels of
progesterone simulate the brain's respiratory centre increasing ventilation
rates (progesterone is also linked to the mood swings). Athletes use breathing
rate as an indicator of exercise intensity so exercise can tend to feel harder
at these times.
The time of maximum efficiency for athletes experiencing a 28 day
menstrual cycle might be pre-ovulation (days 9 to 12) or post-ovulation (days
17 to 20).
Reference Papers
- "Menstrual Cycle Phase and Running Economy", Medicine and
Science in Sports and Exercise, vol 25(5), p.S74, 1993
- "Blood lactate concentrations and lactate threshold during
menstrual cycle phases of distance runners", Medicine and Science in Sports and
Exercise, vol 25(5), p.S144, 1993
- "The menstrual cycle and exercise: performance, muscle,
glycogen, and substrate responses," International Journal of Sports Medicine,
vol. 10(4), pp. 264-269, 1989
- "Respiratory Drives and exercise in menstrual cycles of
athletic and non-athletic women," Journal of Applied Physiology, vol. 50, pp.
1300-1305, 1981
- Barrow and Saha, "Menstrual irregularity and stress fractures
in collegiate female distance runners", American Journal of Sports Medicine,
1998, vol. 18, pp 209-216
- Myburgh and co-workers, "Low bone mineral density at axial and
appendicular sites in amenorrhoeic athletes", Medicine and Science in sports
and exercise, vol.25, no. 11, pp 1197-1202)
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Human Anatomy & Physiology
This heavily illustrated self-teaching course
gives you everything you need to know.
Find out how human muscles, nerves, bones,organs, glands, connective tissue and more, function and communicate with each other. Discover the molecular-level workings of your glandular, genitourinary, digestive, cardiovascular, and other systems. But that is just part of the story.
Select this link for more information on "Human Anatomy & Physiology". |
Associated Pages
The following Sports Coach pages should be read in conjunction with this page:
Associated Books
The following books provide more information related to this topic:
- Principles of Anatomy and Physiology, G.J. Tortora et al., ISBN 0 06 046704 5
- Strength Training Anatomy, F. Delavier, ISBN 0 7360 4185 0
- Atlas of Skeletal Muscles, R.J. Stone et al., ISBN 0 697 13790 2
- The Muscle Book, P. Blakey, ISBN 1 873017 00 6
- Advanced Studies in Physical Education and Sport, P Beashel et al., ISBN 0 17 4482345
- Physical Education and the Study of Sport, B. Davis et al., ISBN 0 7234 31752
- Essentials of Exercise Physiology, W.D. McArdle et al., ISBN 0 683 30507 7
- Physical Education and Sport Studies, D. Roscoe et al., ISBN 1 901424 20 0
- The World of Sport Examined, P. Beashel et al., ISBN 0 17 438719 9
- Advanced PE for Edexcel, F. Galligan et al., ISBN 0 435 50643 9
- Examining Physical Education, K. Bizley, ISBN 0 435 50660 9
- Sport and PE, K Wesson et al., ISBN 0 340 683821
- PE for you, J. Honeybourne, ISBN 0 7487 3277 2
Keywords: menstrual, cycle, phase, sport, training, amenorrhea, oligomenorrhea, physiology, exercise, anatomy, level, muscle, preovulatory, postovulatory, range, athlete, comprises, women, medicine, ovulation, physical, education
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