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Feb 02

Overtraining in Sport: Achieving the Delicate Balance – Part 1

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I wanted to write about this subject for some time as I keep noticing people on Facebook praising the ‘more is better’ approach regarding the programming of athletes. However, this training method is more harmful than helpful, and leads to overreaching and overtraining, fatigue, body breakdown, and eventually injuries!
I was a 50m/100m/200m Breaststroke specialist and did not train ‘yardage garbage’ or the ‘more is better’ method, rather I trained for the specific events in competition! As a hurdler in athletics, it was technique – technique – technique (!), the Start, the first hurdle approach, lead leg action, Hurdle clearance, stepping pattern, and the rhythm to the second Hurdle. After that, it was walking alongside Hurdles to train and refine lead leg and trail leg action. Once a week, I trained for the entire event at 95% training speed with the necessary Recovery/Rest periods (2-4 repetitions). For Jumping events, the training consisted of the approach run for both the Long and High jump, and then again it was technique – technique – technique! So, what exactly is the rationale for all this common ‘yardage/garbage/mileage’ in running or swimming? Let’s examine what researchers have to tell us!

Overtraining in Sport – Achieving the Delicate Balance in Training

When developing basic sport skills in children and youth, we are dealing with various physical and technical capabilities, mental, and psychological competencies. Training to enhance all these at a higher and then at the elite level becomes even more demanding and complex; it is an ‘art and a science’ as everything has to be planned carefully to achieve the lofty goals of athletes, but many things can also go wrong! Fatigue, overreaching and overtraining, and proper recovery are areas with many unknowns despite scientists’ attempts to identify specific indicators of overreaching and overtraining since the 1920s. The process of training athletes becomes especially intricate as some with identified indicators perform at very high level while others with the same indicators perform poorly. Coaches and athletes always have to walk a fine line between the training load that creates positive adaptation and one that leads to potential breakdown. According to research, athletes need a balanced training program composed of both high-intensity and low-intensity days for the proper recovery.

Misunderstanding of Overtraining

There seems to be a lot of misunderstanding about overtraining, leading to subsequent bad applications. Overtraining was recognized as being detrimental to endurance performance in the early 1920s. However, much of that published information was limited to anecdotal accounts making quantification of prevalence difficult as multiple signs and symptoms were associated with the application of overtraining. Scientists have now organized these according to physical/ physiological performance as well as psychological information processing information, immunological and biochemical manifestations. The negative physiological and psychological effects of training ‘too frequently and too intensely’ have been a significant focus of research in exercise science over the last 20 years. In addition, researchers have conducted studies on ways to monitor and prevent overreaching and overtraining (Fry, Morton & Keast, 1991).

First of all, ‘more is not necessarily better’, according to research; furthermore, the same formula for success and hard training can also become the downfall. The apparent limitation to endurance exercise performance is the ability of the athlete to endure strenuous training in order to elicit positive adaptations without breakdown or maladaptation in any physiological system. Regrettably, no model exists that can be used so that the overload training stimulus results in optimal improved performance while minimizing the potential of developing overreaching or overtraining syndromes. The universal finding in overreached or overtrained athletes is a decrease in performance ability. Associated signs or symptoms may be varied in nature, resulting in generalized fatigue with or without a variety of physiological symptoms. On the other hand, a specific physiological symptom may break down certain aspects of the musculoskeletal system, which can result in an overuse syndrome such as a stress fracture (O’Toole, in Kreider, Fry, O’Toole, 1991, p. 3).

The borderline between hard training and overtraining is not clear as individual variability in response to training is such that an appropriate training load for one athlete may cause the overtraining syndrome in another. Furthermore, it was found that not all aspects of performance in endurance athletes are affected simultaneously, and may potentially not be the same at the onset of initial symptoms and their full development. Some even seem to be contradictory as they increased and decreased heart rates whereas other athletes lack specific symptoms, yet experienced performance decrease and the inability to train at the usual levels.

Terms, Definitions, and Prevalence

Various terms have been used throughout scientific literature since 1920s for ‘overtraining’, such as overwork, overreaching, staleness, burnout, overstress, and over-fatigue among others. Nevertheless, this use of different terminology has created confusion in the review of research literature. For our purpose, we are using overreaching and overtraining based upon the review of selected research used for this article.

Overtraining

The Canadian National Coaching Certification Program (NCCP) defines ‘overtraining’ as ‘staleness or burnout’, which occurs when athletes train intensely but do not recover from ‘acute or chronic fatigue’ (NCCP Module ‘Recovery and Regeneration’). Performance deteriorates instead of improving, even after an extended period of rest. Recovery may take weeks and may make it impossible for the athlete to peak as planned.

Kreider, Fry, and O’Toole (1998) provide the following:

Major Signs and Symptoms of Overtraining
Physical/Physiological Emotional/Behavioural/

Psychological

Immunological Bio-chemical
Deterioration/decrease of performance Feelings of depression Increased susceptibility to & severity of illness, colds, allergies Negative nitrogen balance
Inability to meet previously attained performance standards or criteria Mood changes One-day colds, flu-like illness, mono Hypothalamic dysfunction
Inability to maintain training load Irritability/excitability Decreased functional activity of neutrophils Depressed muscle glycogen concentration
Reduced toleration of loading Emotional instability Reduced response to mitogens Decreased bone mineral content
Decrease in power output over time Excessive emotional displays Bacterial infection Delayed menarche
Recovery prolonged Anger/aggressiveness Reactivation of herpes viral infections Decreased hemoglobin
Decreased muscular strength Lethargy Swelling of the lymph glands Decreased serum iron
Decreased muscular capacity General apathy/boredom Unconfirmed glandular fever Mineral depletion
Decreased maximum work capacity Decreased self-esteem or worsening feelings of self Minor scratches heal slower Increased urea concentrations
Changes in heart rate at rest, exercise, & recovery Difficulty or inability to concentrate at work or training Decreased lymphocyte counts Elevated cortisone levels
Increased differences between lying & standing heart rate Decreased ability to narrow concentration Low free testosterone
Elevated resting heart rate Increased internal & external distractibility Increased uric acid production
Slower heart rate recovery Sensitivity to environmental & emotional stress
Heart discomfort on slight exertion Anxiety
Increased oxygen consumption at submaximal workload Inability to relax
Increased ventilation and heart rate at submaximal workload Fear of competition
Elevated blood pressure/changes in blood pressure Low motivation
Elevated metabolic rate Giving up when going gets tough
Increased frequency of respiration, perfuse respiration Decreased capacity dealing with large amounts of information
Decreased body fat Sleep disturbance
Decreased evening post-workout weight Loss of appetite
Elevated resting lactic-acid levels
Low hemoglobin levels

Overreaching

Is the accumulation of training and non-training stressors resulting in a short-term decrease in performance capacity with or without physiological or psychological signs, and symptoms of overtraining. Rebuilding of performance or performance capacity may take several weeks or even months.

Overtraining

Is the accumulation of training and non-training stressors resulting in a long-term decrease in performance capacity with or without physiological or psychological signs, and symptoms of overtraining. Rebuilding of performance or performance capacity may take several weeks or even months.

Exercise training is an adaptive process as the body adjusts to the stress of exercise with increased fitness – if the stress is above minimum threshold intensity. Factors involved in the adaptation of muscle to stress and deconditioning have to be considered in order to achieve maximum effectiveness. In the general athlete population, adaptation to training seems to be dependent on factors such as training volume, intensity, frequency, and the initial level of fitness. In highly trained athletes, however, training intensity and initial performance level appear to be most important factors influencing the response to training, and competition performance, provided that the necessary training volume and frequency are assured. Athletes also have to be optimally trained to optimize and maximize performance. There are, however, two major issues, namely a) those who undertrain may not perform to their maximum potential; and b) those who overtrain (too often or too intensely) and may experience negative training adaptations and decreased performance capacity (Kreider, Fry, & O’Toole, 1998).

According to Kreider, Fry, and O’Toole (1998), “the critical factor is decreased performance capacity versus simply manifestations of overt signs or symptoms” (p. viii preface) because some athletes experience a decline in performance with no signs or symptoms while others show the very same but demonstrate no decrease in performance. In addition, different types of training seem to elicit different signs and symptoms of overreaching and overtraining. Moreover, there is a consensus among researchers that it is important to differentiate between training resulting in short-term (overreaching) versus more prolonged (overtraining) decline in performance. Therefore, it may be actually somewhat difficult to differentiate between overreaching and overtraining as a continuum from undertraining, to optimal training, to overreaching, to overtraining. Additionally, not all signs and symptoms occur in any one overtrained athlete at any one time since great variations exist. However, the most important signs of overtraining are identified as the change in mood and a drop in performance.

The challenge then for coaches and athletes is to determine and design the appropriate type of training, volume, and intensity that optimize performance, but do not produce negative training adaptations. It is, however, difficult to determine this optimal amount of training because the volume of training may optimize performance in some athletes, but may undertrain or overtrain others. Furthermore, internal and external psychological pressures may also add to the stress of training, and thereby promote negative adaptations. Whether due to physical or psychological stress, once maladaptation to training is provoked, performance may deteriorate for several weeks or even months despite rest or reduction in training volume. In addition to potential adverse medical consequences of overtraining, a prolonged deterioration in performance can interrupt the season or athletic career. Consequently, overtraining is an increasingly major problem among competitive and especially elite and high-performance athletes.

Susceptibility of Endurance Athletes to Overtraining Signs and Syndromes

The imbalance between training and recovery that may lead to overreaching and ultimately to overtraining syndromes in endurance athletes may be the result of increased training or decreased recovery. Highly motivated athletes who are experiencing either a plateau or slight decrease in performance are likely to increase their training, and therefore are particularly susceptible to overreaching or overtraining. Increased training can be in the form of either increased volume or intensity. Fry, Morton, Garcia-Webb, Crawford, and Keast (1992) suggest that failure to allow adequate recovery is the leading training-related factor in the progression to overreaching and overtraining syndromes.

Other Contributing Factors

Factors other than those of heavy training may lead to a training/recovery imbalance. This may lead to overreaching in response to a previously well-tolerated training program. Poor nutrition, in particular, inadequate carbohydrate and fluid intake, as well as infections such as the common cold make it difficult to tolerate usual training loads. One of the syndromes that come to mind is mononucleosis whereby the body’s immune system is affected, and signs of extreme fatigue appear. In addition, researchers also cite academic, economic, and social factors as a potential influence. In the 1990s, the high incidence of overreaching and overtraining was well documented but equally noticeable at the same time was/is the lack of well-researched and effective treatment programs designed to rehabilitate overtrained athletes. The primary prescription offered appeared to be rest, perhaps for several weeks or even months, and often a prolonged break from training and competition. However, the difficulties in persuading affected athletes that they need to rest have been highlighted by various researchers, even though this would seem to be recognized as the primary basis for treatment. While the success of rehabilitation programs remains at such low level, it will also remain the consensus among researchers and coaches alike, that it is more critical to prevent overtraining than to treat it (Rowbottom, Keast, & Morton, in Kreider, Fry, & O’Toole, 1998, p. 47).

Progressive Overload Training

Progressive overload is the basis of all successful training. According to research, stress causes a temporary decrease in function, followed by an adaptation that improves that function. In the training response, overload is the stress causing fatigue (temporary decrease in exercise ability) and improved performance is the adaptation following recovery from fatigue. In essence, all fatigue is ultimately the result to generate energy at a rate sufficient to meet the needs/demands of the performance (O’Toole, in Kreider, Fry & O’Toole, 1991, p. 10).

On the other hand, in terms of prevention, undertraining would seem to be the surest way of avoiding prolonged fatigue, although this inevitably will lead to underperformance. If an athlete is to reach the full potential at the international level, performance and consequent training stress have to be optimized. Optimal performance can only be achieved through the precise balance of training stress and adequate recovery on an individual basis. It makes it difficult because the exact boundary between optimal training and overtraining is still not clearly defined.

Use of Performance Indicators

Performance decrements along with chronic fatigue are the most obvious indicators of both overreaching and overtraining. Researchers have used various methods such as oxygen uptake, running speed, and maximal effort trials among others to assess performance decrease. This demonstrates that various performance measures used by researchers is, in itself, a reflection of the lack of consensus. It is essential that the performance indicator used is a true replication of competition performance in the athlete’s particular event. Another complication is the important issue of ‘how much’ a given performance actually has to deteriorate before overreaching or overtraining can be diagnosed; some researchers report it as much as 29%. It is likely that the early signs of overreaching and overtraining are far more subtle while other researchers suggest that a stagnant performance may be sufficient evidence of overtraining (Hooper, & Mackinnon, 1995).

Optimizing and Maximizing Performance

Progressive overload is the basis of all successful training. According to research, stress causes a temporary decrease in function, followed by an adaptation that improves that function. In the training response, overload is the stress causing fatigue (temporary decrease in exercise ability), whereas improved performance is the adaptation following recovery from fatigue. In essence, all fatigue is ultimately the result to generate energy at a rate sufficient to meet the needs or demands of a given performance (O’Toole, in Kreider, Fry & O’Toole, 1991, p. 10).

Training Volume

It is after all about optimizing and maximizing training and performance capacity. The volume of training that is optimal to performance improvement is difficult to define. As weekly training volumes are reported, daily training volumes or even a single session’s training volume are important in order to optimize performance. The ideal adaptation results from being able to manipulate the combination of volume and intensity in the correct ratio of work and rest. Indeed, this presents the ‘art and science’ of coaching (Schloder)! Moreover, athletes may also differ as the same training volume may be excessive overload for one athlete but less than that may cause adequate adaptation in another (O’Toole, in Kreider, Fry & O’Toole, 1991, p. 11).

Many athletes and coaches have tended to equate large volumes with success, and there are numerous narratives cited in research. Although cause and effect cannot be established definitely for many musculoskeletal injuries, overuse syndromes have been associated with high training volumes. More recently, scientific evidence is showing that training volume may be reduced by as much as one half in some sports with no negative effects on performance. For example, changes in swim performance of a 100yard swim were compared over a four-year period in two groups of swimmers with similar ability. One group trained more than 10,000meters per day; the other no more than 5,000 meters. The average improvement of 0.8% per year was identical! The conclusion is that the amount that training volume contributing to performance improvement is likely related to competition distances!

The role excessive volume plays in the development of overtraining syndromes is not very clear. In a study by Foster and Lehman (1997), the researchers purposefully overloaded distance runners by either doubling their weekly training volume in three weeks or doubling the amount of interval and speed workouts. Increased training volume caused endurance performance to plateau and decreased maximal performance, while increase intensity resulted in performance improvements. Other studies suggest that overtraining is unlikely to occur in programs in which peak volumes are limited to 3000-5000 yards, but overtraining is a potential problem in programs of 10,000-15,000 yards.

Training Intensity

Manipulation of intensity functions to overload specific metabolic pathways. The timing and length of recovery intervals, either during sets of a single exercise/drill session or session to session, should be determined by the specifics of the systems that have been stressed. For instance, short, all-out bursts of activity overload the high-energy phosphate systems. For optimal adaptation, complete recovery should occur before a second stimulus is given.

Example in Swimming:

chart

*  Total work time per set refers to Work Time per Repetition multiplied by the number of Repetitions in a Set. This Work Time does not include swimmers’ Rest Intervals (active or inactive).

** The distance in sample Sets should be such that they can be swam in the recommended Work Time.

On the other hand, to build up a tolerance to high lactate levels, initiating a second stimulus before complete recovery may be desirable, according to research. Between workouts, however, optimal response is thought to occur during the transition following recovery from the previous stimulus. If the time to the next training session is too long, the overcompensation will regress to the original functional state, and progressive improvement will not occur. Conversely, if the training stimulus is given too frequently, such that it interrupts the recovery/overcompensation phase, adaptation will not occur. If the overload has been properly designed, a progressive improvement in performance will result (O’Toole, in Kreider, Fry & O’Toole, 1991, p. 12).

Periodization of Training

Increased training can be in the form of either increased volume or increase intensity. Periodization attempts to carefully plan a progression that would not lead to overtraining and the implementation of planned rest in each training cycle. Although the recovery of athletes in detail has been studied on a limited basis, the concept of periodization is well accepted. Cyclic training may be essential to elicit optimal performance and to avoid the overtraining syndromes. In its simplest form, athletes have been following hard/easy training patterns for years.

In a more sophisticated format, the training year is divided into so-called macro-cycles (given number of months) in which a particular type of training is emphasized in relation to minor and major competitions. The cycles are further sub-divided into mezzo-cycles (given number of weeks) and micro-cycles (given number of days). Micro-cycles with very low training loads allow proper recovery and regeneration to occur periodically throughout to allow adequate recovery from a hard training cycle before competition is universally accepted. During the taper period, some combination of training frequency, volume and intensity is altered to reduce the training stimulus. Most evidence suggests that a rather drastic reduction in volume (in some cases up to 85-90%) in combination with short intense workouts provide the best results. This type of training has shown to result in performance improvement of approximately 3% in swimmers and distance runners. The tapering pattern provides indirect evidence for the reduction of training volume, and increase in recovery time to avoid detrimental effects of excessive training, including mood disturbances. Following a taper, mood-state, including increased vigor, energy, and decreased anxiety has been shown to improve. Some researchers demonstrate that even markedly increased training loads could be tolerated as long as intensive exercise days were separated by days of moderate intensity.

I have to add here, that ‘tapering’ is for the training of elite and high-performance athletes whereas training of younger athletes should focus on technique development and refinement.

The Body – Training Stress and Dietary Deficiencies

According to Berning, Troup, VanHandel, P. Daniels, & N. Daniels (1991), the body maintains or at least strives to maintain a constant environment (homeostasis) even in periods of heavy training or overreaching. A key aspect during this time is satisfying the body’s required energy intake as well as other nutrients (in Kreider, Fry, & O’Toole, 1998, p. 275) as muscle damage, dietary intake, and overtraining tend to interrelate. Some athletes, who are overtrained, appear to have decreased hunger and appetite, which can lead to reduced energy intake and less than optimal intake of carbohydrates and other nutrients. These dietary deficiencies can result in reduced muscle glycogen levels, and therefore affect performance, mood, and normal body functions.

For example, dietary food records from adolescent male and female swimmers participating in a national developmental training camp were analyzed for nutrient density. The mean caloric intake was 5,221.6 kcal for males and 3,572.6 kcal for females. The distribution of calories between carbohydrates, protein, and fat was not ideal for athletes trying to optimize performance. The young swimmers consumed too much fat and not enough carbohydrate. They consumed more than the RDA (Recommended Dietary Allowance) of vitamins A and C, and thiamine, riboflavin, and niacin; however, some concern was also expressed for females who did not meet the RDA for calcium and iron. The study shows that although a group of adolescent swimmers may be consuming enough nutrients, individual swimmers may have very poor dietary habits, and thus may not be providing adequate fuel or nutrients for optimal training or performance (Berning, Troup, VanHandel, J. Daniels, & N. Daniels (1991), in Kreider, Fry, & O’Toole, 1998, p. 275).

Present Issues

It appears that one or multiple training systems in combination may occur when an athlete experiences performance decrease. Many studies have focused on immunology in short but intense training, which seems to indicate overreaching rather than over-training. Only a few studies are available in which athletes were monitored for a prolonged period of time such as a full season. However, these studies do provide the most information about the true over-training problems, including its prevalence as well as major symptoms (O’Toole, in Kreider, Fry & O’Toole, 1998, p. 4).

One aspect that stills needs to be addressed is the cumulative nature of stress. The question is whether training volume and intensity during periods of high stress from outside factors (educational, personal, social) need to be modified or scaled down. While coaches are still unable to confidently prescribe training for optimal performance, there is a clear need for scientific testing programs to be regularly incorporated into an athlete’s training regime, which should consist of parameters suitable for early detection of overtraining. However, due to the complexity of the interrelationships among variables associated with overreaching and overtraining, it is probable that there will never be a single definite parameter that is diagnostic of an overtrained state.

Summary

Prevention and overtraining has to start with structuring the need of the individual athlete’s training program in a way to adequately balance training stress and recovery. Too often the recovery phase is overlooked as an essential aspect of the training regime. However, researchers are still ways away from having a thorough insight into the quantitative relationships between training and performance. It remains a major problem for both the coach and athlete to confidently prescribe training regimes to optimize performance, while avoiding overtraining. There is great need for further carefully controlled research into the systematic monitoring of training stress and performance. In addition, it is that individual athletes can tolerate different levels of training and competition stress, and therefore require different lengths of recovery periods. Varied training is also essential to avoid problems of monotonous overtraining, which has been identified particularly among swimmers (Budgett, 1994, in D.G. Rowbottom, D. Keast & A.R. Morton, in Kreider, Fry, & O’Toole, 1998, p. 47).

Overtraining appears to be caused by too much high volume and intensity training, and/or too little regeneration (recovery) time, often combined with other training and non-training stressors. There are a multitude of symptoms of overtraining, which vary depending upon each athlete’s physical and physiological makeup, type of exercise, and other factors. The set of causes of overtraining may therefore be different in athletes, suggesting that coached need an awareness of a wide variety of parameters as markers of overtraining.

At present, there is no one single diagnostic test that can define overtraining. The recognition of overtraining requires the identification of potential stress indicators following a period of regeneration such as an imbalance of the neuroendocrine system, suppression of the immune system, indicators of muscle damage, depressed muscle glycogen reserves, deteriorating aerobic, respiratory or cardiac efficiency, a depressed psychological profile, and poor performance in sport specific tests, e.g. time trials. Screening for changes in parameters indicative of overtraining needs to be a routine component of the training program and has to be incorporated into the training program in such a way that short-term fatigue associated with overload training is not confused with chronic fatigue characteristic of overtraining. An in-depth knowledge of periodization of training theory is necessary to promote optimal performance improvements, to prevent overtraining, and to develop a system for incorporating a screening system of the training program.

Note: screening for overtraining and performance improvements has to occur at the end of the regeneration periods.

References

Berning, J. R., Troup, J.P., VanHandel, P.J., Daniels, J., & Daniels N. (1991). The nutritional habits of young adolescent swimmers. Human Kinetics Journals 1, 240-248. September.

Bompa, T.O. (1983). Theory and method of training. Dubuque, IA: Kendall/Hunt.

Budgett, R. (1990). Overtraining syndrome. British Journal of Medicine 24, 231-236.

Budgett, R. (1994). Overtraining syndrome. British Journal of Medicine 309, 465-468.

Councilman, J.E. (1955). Fatigue and staleness. Athletic Journal 15, 16-20.

Foster, C., & Lehman, M. (1997). Overtraining syndrome. In G.N. Guten (Ed.), Running Injuries (pp.173-178). Philadelphia: Sanders.

Fry, R.W., Morton, A.R., & Keast, D. (1991). Overtraining in athletes: an update. Sport Medicine 12, 32-65.

Fry, R.W., Morton, A.R., Keast, D. (1992). Periodization and the prevention of overtraining. Canadian Journal of Sport Science 17, 241-248.

Fry, R.W., Morton, A.R., Garcia-Webb, P., Crawford, G.P.M., & Keast, D. (1992). Biological responses to overload training in endurance sports. European Journal of Applied Physiology 64, 335-344.

Hooper, S.L., Mackinnon, L.T., Gordon., R.D., & Bachman, A.W. (1993). Hormonal responses of elite swimmers to overtraining. Medicine and Science in Sports and Exercise 25, 741-747.

Hooper, S.L., & Mackinnon, L.T. (1995). Monitoring overtraining in athletes. Sports Medicine, 20, 321-327.

Hooper, S.L., Mackinnon, L.T., Howard, A., Gordon, R.D., & Bachman, A.W. (1995). Markers for monitoring overtraining and recovery. Medicine and Science in Sports  and Exercise 27, 106-112.

Kreider, R.B., Fry, A.C., & O’Toole, M.L. (Eds). (1998). Overtraining in sport. Champaign, IL: Human Kinetics.

MacKinnon, L.T. (2000). Overtraining effects on immunity and performance in athletes. Immunology and Cell Biology 78, 502-509.

Lehman, M., Foster C., & Keul, J. (1993). Overtraining in endurance athletes: a brief review. Medicine and Science in Sports Medicine 25, 854-862.  

Rowbottom, D.G., Keast, D., & Morton, A.R. (1996).  The emerging role of glutamine as an indicator of exercise stress, and overtraining. Sports Medicine 21, 80-97.

Stone, M.H., Keith, R.E., Kearney, J.T., Fleck, S.J., Wilson, J.D., & Tripett, N.T. (1991). Overtraining: a review of the signs, symptoms, and possible causes. Journal of Applied Sport Science Research 5, 35-50.

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