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Overtraining (OT)CONTENTS
The feeling of fatigue that follows a good ride or workout tells us that we are pushing our physical limits, and is a necessary part of improving our personal performance. However, in certain circumstances, fatigue may also be our only warning that we are pushing too hard and indicating a need to back off or risk a deterioration in our abilities. This is a common dilemma in a personal training program: Hard work makes us faster, but how much is too much?
BACKGROUND/PHYSIOLOGYFiercer competition between athletes and a wider knowledge of optimal training regimens have dramatically influenced current training methods. A single training bout per day was previously considered sufficient, whereas today’s athletes regularly train twice a day or more. Consequently, the number of athletes who are overtraining and have insufficient rest is increasing. The positive result of training in any sport is adaptation and improved performance: the supercompensation principle - which includes the breakdown process (training) followed by the recovery process (rest). Overtraining results from an imbalance between training and recovery, exercise and exercise capacity, stress and stress tolerance. Elite sports require large numbers of training hours per week. It is assumed that the relationship between training and improved performance is an inverted U-shape. Overreaching (or short term overtraining) is most likely associated with insufficient recovery in the muscle with a decline in ATP levels. Overtraining (OT) or staleness is a more generalized physiologic problem, perhaps related to failure of the hypothalamus to cope with the total amount of stress. Short term OT (overreaching, peripheral or muscle related overtraining) lasts a few days to 2 weeks and is associated with fatigue, reduction of maximum performance capacity, and a brief interval of decreased personal performance. Recovery is achieved within 72 hours. Long term OT (overtraining syndrome, staleness, systemic overtraining) is the result of many weeks of exceeding the athlete’s physiologic limits and can result in weeks or months of diminished performance - symptoms normally resolve in 6-12 weeks but may continue much longer or recur if athletes return to hard training too soon. It involves mood disturbances, muscle soreness/stiffness, and changes in blood chemistry values, hormone levels, and nocturnal urinary catecholamine excretion. Stress factors such as the monotony of a training program, and an acute increase in training program intensity lasting more than 3 weeks increase the risk of development of an overtraining syndrome. On the other hand, heavy training loads appear to be tolerated for extensive periods of time if athletes take a rest day every week and use alternating hard and easy days of training. For those of you interested in the basic physiology of the OT syndrome, the underlying pathology is felt to be an autonomic or neuroendocrine imbalance. Several findings support this thesis. During heavy endurance training or overreaching periods, the majority of studies indicate a reduced adrenal responsiveness to ACTH which is compensated by an increased pituitary ACTH release. In early OT syndrome, despite increased pituitary ACTH release, the decreased adrenal responsiveness is no longer compensated and serum cortisol levels fall. In advanced stages of overtraining syndrome, pituitary ACTH release also decreases. In this stage, there is additional evidence of decreased intrinsic sympathetic activity and sensitivity of target organs to catecholamines - indicated by decreased catecholamine excretion during night rest, decreased beta-adrenoreceptor density, decreased beta-adrenoreceptor-mediated responses, and increased resting and exercise induced plasma norepinephrine levels. There is also a psychological toll from overtraining. For the most part, the competitive athlete is a well-adjusted individual who demonstrates considerable vigor and well-being, as well as less depression, anxiety, and fatigue than nonathletic counterparts. The well-trained athlete, however, may also have a personality that is somewhat rigid, strongly goal oriented, and perfectionist. It is not unrealistic to expect that when confronted with diminished performance or success, such an athlete may be compelled to drive himself or herself harder to succeed. Such behavior can express itself in the form of chronic fatigue and depression. Listed below are some of the physiologic and performance changes that have been documented with OT. A common thread is the inability to attain maximum energy output in whatever sport you are attempting (aerobically and anaerobically) and the psychological consequences that go along with failing to do your best.
And several studies have suggested that OT may be associated with other health issues above and beyond a deterioration in physical performance. One study of Harvard alumni found a lower death rate (mortality) among men expending as few as 200 Calories per week in exercise versus those leading sedentary lifestyles, but when they routinely spent over 4000 Calories on exercise per week the death rate began to rise again. And two different studies have suggested a decrease in immune system competence with intense training (cycling 300 miles per week for 6 months or 2 intensive sessions of running per day for 6 days). But before you give up exercising completely, there is plenty of evidence that a moderate cycling program will actually stimulate and improve your immune system. The key is planning your own personal training program to occasionally overreach but not overtraining. Back to topTo review, there are four levels of fatigue are experienced by the regular cyclist.
Back to topWho is at risk from Overtraining? Cyclists are one of the few groups of athletes capable of reaching the over trained level associated with prolonged fatigue. It has been speculated that this is due to the way cycling stresses the body with muscle activity concentrated in a single muscle group - the quadriceps. And it isn't necessary to undertake an extensive training program to be at risk. In fact those working out sporadically and with light training schedules are at risk. While a professional cyclist might consider a 50 mile ride as part of a light recovery week, your 20 mile ride could produce all the symptoms of OT. Back to topHow do YOU know when you are in danger of OT? The following are clues which might suggest that an extra day or two of rest is in order.
But when it comes right down to it, you are how you feel, so to speak. Your sense of well being, sense of fatigue throughout the day, and sense of perceived effort as you take that weekly ride over your regular route all appear to be more sensitive than the most sophisticated laboratory study in identifying early overtraining. Back to topIn a nutshell, overtraining is the result of "doing too much, too quickly". The body likes regular, moderate changes, not upheaval, in a training program. So don't increase your mileage or training time by more than 10% per week. The most important aspect of preventing OT is realizing you are almost there. And a good training diary is the single most important tool you have at your immediate disposal to alert you to the risk. In addition to the usual training facts such as mileage and times, it should include a daily notation on:
For professional coaches, there are some intriguing additional tools available. J C Puffer and J M Shane in Clin Sports Med 1992 Apr.11(2):327-38 reviewed the issue of chronic fatigue as it related to OT versus other medical diagnoses, and presented a diagnostic framework to assist in the assessment of the athlete who presents with such complaints. G Kenatta and P Hassmen in Sports Med 1998 Jul 26(1):1-16 describe a methodology they call refer to as the total quality recovery (TQR) process. By using a TQR scale, structured around the scale developed for ratings of perceived exertion (RPE), they suggest that the recovery process can be monitored and matched against the breakdown (training) process (TQR versus RPE). The TQR scale emphasizes both the athlete's perception of recovery and the importance of active measures to improve the recovery process. Directing attention to psychophysiological cues serves the same purpose as in RPE, i.e. increasing self-awareness. They suggest that using this tool (i) differentiates between the types of stress affecting an athlete's performance, (ii) identifies factors influencing an athlete's ability to adapt to physical training, and (iii) structures the recovery process. From the laboratory or biochemical perspective, A C Snyder et al in Int J Sports Med 1993 Jan 14(1):29-32 proposed monitoring the ratio of blood lactate concentration to ratings of perceived exertion. They performed an incremental exercise test to maximal effort monitoring blood lactate concentration (HLa) and ratings of perceived exertion (RPE) for each workload. They found that at maximal workload all seven subjects had HLa:RPE ratios of less than 100 when over-reached and concluded that the ease and speed at which the HLa:RPE ratio can be determined may make it useful for coaches and athletes in monitoring intensive exercise training and recovery. P Pelayo et al in Eur J Appl Physiol 1996;74(1-2):107-13 reviewed measurements of blood lactate concentration both during and after a maximal anaerobic lactic test (MANLT). The percentage of mean blood lactate decrease (% [La-]recovery) between min. 3 and min. 12 of the passive recovery post-MANLT increased from week 2 to 10 with aerobic training and decreased from week 10 to 21. The lowest % [La-]recovery coincided with signs of OT, such as bad temper and increased sleeping heart rate. They concluded that the % [La-]recovery could be an efficient marker for avoiding OT in elite athletes. In addition, you can structure your training program to decrease the risk of OT. It should include at least one (and sometimes two) rest days per week as well as a day or two of easy spinning. This reflects the practical experience of coaches who have had to deal with the results of pushing too hard for too long. Increasing variation (decreasing monotony) both in your training routine from week to week (long rides, intervals) as well within individual rides has been proven to minimize training stress and decrease the risk of OT. Back to topOvertraining refers to prolonged fatigue and reduced performance despite increased training. Its roots include muscle damage, cytokine actions, the acute phase response, improper nutrition, mood disturbances, and diverse consequences of stress hormone responses. The clinical features are varied, non-specific, anecdotal and legion. No single test is diagnostic. The best treatment is prevention, which means (1) balancing training and rest, (2) monitoring mood, fatigue, symptoms and performance, (3) reducing distress and (4) ensuring optimal nutrition, especially total energy and carbohydrate intake. Over reaching is a normal part of the training/recovery cycle, but if your performance is not improving after a few days of recovery, it's time to switch to other aerobic activities which will keep you at 70% of your maximum heart rate (to maintain your level of fitness) or risk entering the zone of OT which may take a month or two to recover. How long do you need to rest? If you have made a significant increase in your training schedule, and have been at it for 3 weeks or more, the chances are that you are entering that gray zone of overreaching. If so, recovery (and again this means keeping your general level of aerobic activity at 70% max. heart rate, not complete inactivity) takes at least 3 days and often up to several weeks as opposed to the normal recovery cycle of less than 3 days. The implication in that situation is that you may need more than 1 or 2 days of rest before a big event to perform at your personal best. As in all aspects of personal training programs there is individual variability, so it is up to you to decide where to draw your own line. But remember that rest is a key part of any training program and may be the toughest training choice you'll have to make. And finally, don't forget to pay particular attention to post exercise carbohydrate replacement. Part of the fatigue of overtraining may be related to chronically inadequate muscle glycogen stores from poor post training ride dietary habits. Back to top
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