Read below for summaries on the effects of exteme conditions, circadian rhythms, the female athlete triad and overtraining upon rowing. Click the titles listed previously to jump to the section.
Due to competitions and training camps situated all over the world elite rowers are exposed to many extremes of environment. During travel jet lag can cause some issues, it adjusts the bodies circadian rhythm and affects the timing of the biological processes of the body including strength and flexibility being more efficient at later times of the day. Heart rate, core body temperature and VO2 are found to be reduced for 5 days post travel on a long haul flight. An intervention for athletes to use to improve the recovery period post flight are to adjust sleep patterns the days before travelling, or to consume caffeine and conduct physical activity which speeds up the biological processes so are in time with the new time zone.
Post travelling the climate maybe hot, or the major competitions during the summer months could cause some heat stress during rowing. When in hot conditions the body's natural response is to sweat more, this transfer’s heat away from the body, this causes some dehydration. There is also competition for the blood as the skin needs it to maintain homoeostasis and muscles need for exercise, reducing the performance. During heat stress the delivery of substrate and lactate is not affected, there is however more lactate produced and more glycogen depleted, leading to earlier fatigue. In rowers acclimatization to dehydration has a major impact on performance, in a first trial rowers are 22 seconds slower over 2km, but no change in performance on a second trial. Possible prevention methods of heat stress would be to wear suitable clothing to prevent radiative heat from sun, however caps are inefficient at wicking so increase body temperature.
Pollution comes in the form of carbon monoxide which develops carboxyhaemoglobin preventing oxygen transport and therefore reducing VO2max. The other form which is found to affect performance is ozone, this creates free radicals in the lungs which cause damage and reduce lung capacities. This can be prevented or improved by supplementation of antioxidants.
Effects of altitude training shows small increases in performance, current trends suggests living high, training low is best, this stimulates erythropoietin release to create more erythrocytes to increase VO2. However some studies find an increase in aerobic power by 5.2% but not VO2max. Due to increased risk of illness at altitude intermittent hypoxic exposure has become more popular, with 2 hours being enough to stimulate erythropoietin release. Athletes should be screened before training as only some individuals release more erythropoietin after hypoxic exposure and therefore no performance benefits.
Precautions should be taken at extremes and individuals respond in very different ways. Interventions should be applied to prevent impairment of performance and maximise from the benefits.
Circadian rhythms are the daily natural bodily functions occurring within the body, these can have an effect on rowing performance. Individuals either have morningness chronotypes reaching minimum body temperature at 3.50am or eveningness at 5.02am. This however shows no effect on rowing performance in a 2k ergometer test where an afternoon trial is 2.4 seconds slower than the morning.
Power, particularly in quadriceps are important in rowing, this has been found greater at 2pm or 6pm than at 9am. Flexibility is used in rowing to achieve a longer stroke to propel the boat further each stroke in reduced when muscles are colder in the morning, with no improvement after 30 minutes warm-up or morningness/eveningness. Shift work takes between 10 and 60 days to adjust to when temperature is lowest during daytime sleep but would then be disadvantageous to day time competitions. Use of light simulation alarm clocks could advance these changes.
Sleep quality does not differ when training is tapered before competition, but during an intense training camp with double the workload, sleep quality is reduced. Sleep deprivation has an effect on subsequent exercise, VO2max decreases by 4.7ml-kg-min-1 and as a plateau was reached it was not due to lack of motivation. Similar to rowing intensities, running at 80% VO2max causes exhaustion 11% quicker after sleep deprivation. Similar to most rowing training, early awakening causes the workload at lactate threshold to be lower, but no change at maximum effort.
Lightweight rowers are most at risk from an anovulatory menstrual cycle, during competition it can be 47.9 days long, but only 28.0 off season.Progesterone excretion is inhibited during heavy training causing a longer follicular phase and shorter luteal phase. A 1km rowing ergometer test shows that lower amounts of menstrual hormones during the follicular phase leads to greater performance. However maintaining intensities at 70% VO2peak till exhaustion is unaffected by stage of menstrual cycle. Estradil, found in oestrogen can inhibit collagen synthesis, increasing ligament stiffness, reducing flexibility required for rowing. A shorter luteal phase and reduced progesterone levels that would aid formation of bone minerals, leading to high incidences of rib stress fractures.
The arms needed for 23% of the rowing stroke, fatigue no quicker at any certain time of day. Increased temperature at later times of day causes faster synaptic transmission and greater alertness required for focusing on technique when rowing. Stimulants can prevent this loss of alertness in the morning.
The effects of circadian rhythms appear to have some significant effect to performance during sub-maximal exercise. However has little or no effect during competition. The effects apparent for loss of alertness can be prevented with prior planning with consumption of caffeine taken before an early morning race.
First defined in 1992, the three corners of the female athlete triad include osteoporosis, amenorrhoea and disordered eating. Osteoporosis requires the athletes bone mineral density (BMD) to be below 2.5SD of normal, but osteopenia only 1SD. As Osteoporosis often has no incidence but osteopenia has 40% prevalence maybe a change in the triad is required. The lack of calcium, and progesterone caused by disordered eating and amenorrhoea are the cause of poor BMD formation.
Disordered eating diagnosis requires some form of unhealthy weight control method, and occurs in rowing due to contour revealing clothing, weight categories and a need for high power to weight ratio. The 'energy-drain' or 'exercise-drain' hypothesis can be used to explain amenorrhoea. This intense exercise reduces gonadotropin releasing hormone excretion, limiting follicle stimulating hormone and luteinizing hormone therefore reducing ovarian stimulation.
In a study of 1275 participants, lean athletes like rowers were more at risk from the female athlete triad than ball sports or non athletes, 70.1%, 52.6% and 69.2% respectively. Conflicting research from American collegiate leagues suggest that rowers have significantly less abnormal menstruation and greater BMD than other endurance sports and even soccer.
Lean sport athletes have higher body dissatisfaction scores, leading to eating disorders than non-lean athletes, this is because lightweight rowers require longer limbs, yet only weight 57kg. Amenorrhoea and the lack of sex hormones in rowers could improve 1km performance, suggested elsewhere more hormones as seen mid-luteal phase could allow a higher exercise intensity to be reached at the lactate threshold on a rowing ergometer.
Where prevention is too late, long term measures to increase body mass by 1-2kg and decrease training by 10% is essential to treat the female athlete triad, but change may not be seen for up to 6 months. The contraceptive pill can be used short term to resolve hormone imbalance, restarting the menstrual cycle and promoting BMD formation. Calcium and vitamin D supplementation should be taken to increase BMD, with 1200mg to 1500mg a day of calcium. If a rib stress fracture occurs in rowing due to low BMD training must be ceased for 6 weeks to allow time to heal, following this additional coaching of safe rowing technique is required. BMD can reform by 6.3% in the first year, 3% after that until a plateau far below normal. There is no standard procedure for screening for the female athlete triad, a combination of questionnaires based on diet, fractures, menstruation and body image should be applied across all sports to increase awareness and prevent amongst sports.
Overtraining is a loss of performance and prevalence of other physiological or psychological symptoms over multiple weeks or months, overreaching lasts just days and the end product is increased performance. Most common of symptoms are sleep disturbances in 90% of cases within endurance athletes. Within rowing there is up to a 20% incidence, with 50% of all cases occurring within a competition period.
During rowing training camps a 100% increase in training causes overtraining symptoms and decreases 2 km rowing ergometer performance by 11.7secs. Following tapering for two weeks there is 3.3 seconds decrease in 2km time comparing prior to the overtraining symptoms. Alternatively cross training could improve symptoms whilst the athlete still trains, due to different muscles being used.
Biochemical markers of cortisol, testosterone and creatine kinase increase as quantity of rowing training increases. However there is no significant relationship between reduced rowing performance and free testosterone cortisol ratio, but is in reduced recovery time, a major part of overtraining.
Although not clinically immune deficient, over-trained athletes, have 5-10% less NK cells that well trained counterparts. Another lymphocyte, T cells are in the same volume for over-trained athletes as well trained. Other markers such as plasma glutamine which are essential for lymphocyte multiplication show no link with upper respiratory tract infection within endurance athletes. Vitamin C supplementation reduces the risk of upper respiratory tract infection by 50% following an ultra marathon. Dietary manipulation also increases lymphocyte volume. A low carbohydrate diet produces more lymphocytes, counteracting the high levels of cortisol this low carbohydrate diet is not ideal for rowing and therefore this method of dietary manipulation would not aid performance.
5-HT is a neurotransmitter; excessive quantities within the brain impair the central nervous system function, reducing endurance performance. When over-trained, athletes become more sensitive to 5-HT, leading to a performance decrement and increase in central fatigue. Prolactin is released within the body when there is more 5-HT, this chemical is measured during testing as 5-HT is only present within the central nervous system. Repeated endurance cycles, using the same muscle groups as rowing shows a 11% decrease in performance and 168% less prolactin than well trained athletes. Caffeine could be an effective supplement to minimize central fatigue, reducing pain and force sensation and increasing maximal voluntary contractions and spine excitability.
The RESTQ-sport questionnaire can accurately predict fatigue leading to overtraining within rowing, and an inverse iceberg profile in POMs points towards overtraining. A set of guidelines needs to be placed so athletes can be correctly identified and all research follows the same reliable guide.
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