Leg Burnout

author : AMSSM
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Overtraining or Lasting Fatigue in Large Muscles After Training Increase

Member Question from dramaqueenjs:

"I think I have managed to burn out my quads. I've been training pretty heavy the last week because I'm a teacher and I'm off work. But I've hit the point where yesterday I tried to run and couldn't even get through 5k and today I did a 14km bike at a gentle speed and my legs just felt exhausted. I had a rest day yesterday and all I did was yoga and walk the dogs but I'm still finding my legs are just DONE. I am worried about losing training time because my friend is excelling in her training and I seem to have hit a wall. I figured that the time off work would be helpful but my body is just having none of it. She nearly beat me in the last race we did (partly because of equipment failure -- but some of it is that I can't seem to push as hard) and at this point, I will be lucky if I can get my legs to move the way I want. I'd really like to push hard the next couple of weeks to improve before my next race but I'm at a loss. I struggle to stretch properly because I'm a dancer as well and hyper mobile which means that traditional stretches don't tend to work."

Answer by Troy M. Smurawa, M.D

Member AMSSM

The goal of many athletes is to train to improve competitive performance. Determinants of performance not only include training but also recovery, physiology, genetics, nutrition, health and injuries, lifestyle and psychology. Improved performance is the result of a proper training response. Training threshold is the point at which the athlete senses a slight increase in intensity that results in a rapid onset of fatigue. In other words, it is how fast and how long an athlete can perform. A training load is the dose-response nature of exercise and helps to establish a training threshold. Whereby, if you apply a stimulus or impulse to the body it will have a predictable response. A positive response to a training stimulus results in improved performance. A negative response leads to a decline in performance. A training load is a product of training volume and intensity. Training volume is measured in either time or distance and training intensity is measured in either power or speed. A training impulse is therefore calculated by multiplying time by intensity and factoring in level of fitness. The greater the fitness, the higher the training impulse an athlete is able to sustain. Fatigue is the physiological response to a training impulse. Thus, a performance response to training is the difference between fitness and fatigue. Both fitness and fatigue increase with increased training but at different rates. Both fitness and fatigue decay exponentially after training but fatigue has a shorter half-life and decays faster. Fitness and fatigue are additive over time and performance is effected by manipulating volume, speed, intensity and the rest interval. Therefore, the rest interval is an integral component of fitness and performance improvement. The rest interval allows for adaptation and recovery. Adaptation produces improved fitness while recovery minimizes fatigue. A proper balance of training and rest will produce the greatest training benefit. Whereas, too long of a rest interval produces minimal adaptation and subsequently too short of a rest interval results in excessive fatigue and breakdown.

Supercompensation is the adaptation that improves performance and is achieved with the appropriate application of training overload, frequency, intensity and recovery. Overtraining and underperformance occurs when there is an accumulation of training and non-training stress resulting in a decrement in performance. The overtrained athlete trains more than what they can assimilate. Overtraining leads to underperformance, muscle fatigue and injury, cardiorespiratory fitness decline and psychological fatigue. Many factors contribute to overtraining and underperformance. The most common factors include excessive muscular skeletal stress, chronic muscular inflammation, insufficient recovery, inadequate nutrition and hydration and iron and glycogen depletion. An athlete performing 2-3 training sessions a day leads to excessive musculoskeletal stress, breakdown and injury. Chronic muscular inflammation results in excessive free radicals accumulation and decreased antioxidant capacity which leads to muscular damage and injury. Sufficient recovery not only includes physical rest but mental rest and adequate sleep. Sleep is a key component of exercise and training recovery. Studies have demonstrated that chronic lack of sleep is associated with increased sports injuries in adolescent athletes and disturbed sleep increases the incidence of illness in overtrained endurance athletes. The likelihood of injury significantly decreases when an athlete achieves over 8 hours of sleep per night. Poor nutrition triggers overtraining. Carbohydrates, protein, vitamins, iron, antioxidants and water are all necessary nutrients to optimize training and recovery. Studies have found that protein ingestion before sleep improves postexercise overnight recovery. Ingestion of carbohydrates is important to maintain glycogen stores in exercising muscles. Glycogen is the primary fuel for exercising muscles during high exercise intensities and competition. Muscle glycogen depletion leads to further muscle damage and muscle injury. Low carbohydrate diets coupled with intense competitive training and competition leads to overtraining and chronic muscle soreness and damage. Also, studies of collegiate female athletes have demonstrated that iron depletion without anemia decreases performance in trained endurance athletes at the beginning of a training session. Serum Ferritin is the marker of the iron stores in the blood and if serum Ferritin is low athletes should both increase dietary iron as well as take iron supplements. Vitamin D is also important for the maintenance of good bone health and the prevention of stress fractures. A good postexercise drink should contain a carbohydrate to protein ratio of 4:1 as well as all the necessary electrolytes. 

In addition to carefully monitoring an athlete’s training program, an important key to preventing overtraining and optimizing performance is to measure and monitor important physiological parameters throughout the training and competitive season. By monitoring an athlete’s physiological parameters throughout the season it is then possible to prescribe the most precise and individualized training program to improve performance. The important blood parameters to monitor include serum hemoglobin, ferritin, blood lactate and free radicals. Physiological testing is also very useful in monitoring the training of athletes. Potential physiological tests include lactate metabolism, fat metabolism, carbohydrate metabolism, metabolic efficiency, speed, power and recovery. Only with the evaluation of these parameters is it possible to develop an individualized training program for an athlete to optimize performance and minimize the effects of overtraining. These tests are not commonly available to most athletes, but a serious and highly motivated athlete can find a nearby human performance lab with experts in physiological and performance testing.

Troy M. Smurawa, M.D.
Director of Pediatric Sports Medicine
Children’s Health Andrews Institute
Plano, TX 75024


1. Decroix L, Piacentini MF, Rietjens G, Meeusen R. Monitoring Physical and Cognitive Overload During a Training Camp in Professional Female Cyclists. Int J Sports Physiol Perform. 2016 Jan 27.
2. Hausswirth C, Louis J, Aubry A, Bonnet G, Duffield R, LE Meur Y. Evidence of disturbed sleep and increased illness in overreached endurance athletes. Med Sci Sports Exerc. 2014;46(5):1036-45.
3. Chidnok W, DiMenna FJ, Fulford J, Bailey SJ, Skiba PF, Vanhatalo A, Jones AM. Muscle metabolic responses during high-intensity intermittent exercise measured by (31)P-MRS: relationship to the critical power concept. Am J Physiol Regul Integr Comp Physiol. 2013 Nov 1;305(9):R1085-92.
4. Chidnok W, Fulford J, Bailey SJ, Dimenna FJ, Skiba PF, Vanhatalo A, Jones AM. Muscle metabolic determinants of exercise tolerance following exhaustion: relationship to the "critical power". J Appl Physiol (1985). 2013 Jul 15;115(2):243-50. doi: 10.1152/japplphysiol.00334.2013.
5. Meeusen R, Duclos M, Foster C, Fry A, Gleeson M, Nieman D, Raglin J, Rietjens G, Steinacker J, Urhausen A; European College of Sport Science; American College of Sports Medicine. Prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science and the American College of Sports Medicine. Med Sci Sports Exerc. 2013 Jan;45(1):186-205.
6. DellaValle DM, Haas JD. Impact of iron depletion without anemia on performance in trained endurance athletes at the beginning of a training season: a study of female collegiate rowers. Int J Sport Nutr Exerc Metab. 2011 Dec;21(6):501-6.
7. Meeusen R, Nederhof E, Buyse L, Roelands B, de Schutter G, Piacentini MF. Diagnosing overtraining in athletes using the two-bout exercise protocol. Br J Sports Med. 2010 Jul;44(9):642-8. doi: 10.1136/bjsm.2008.049981.
8. Nederhof E, Zwerver J, Brink M, Meeusen R, Lemmink K. Different diagnostic tools in nonfunctional overreaching. Int J Sports Med. 2008 Jul;29(7):590-7.
9. Smith LL. Tissue trauma: the underlying cause of overtraining syndrome? J Strength Cond Res. 2004 Feb;18(1):185-93. Review.
10. Mujika I, Padilla S. Scientific bases for precompetition tapering strategies. Med Sci Sports Exerc. 2003 Jul;35(7):1182-7. Review.


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date: September 29, 2016


The American Medical Society for Sports Medicine (AMSSM) was formed in 1991 to fill a void that has existed in sports medicine from its earliest beginnings. The founders most recognized and expert sports medicine specialists realized that while there are several physician organizations which support sports medicine, there has not been a forum specific for primary care non-surgical sports medicine physicians.



The American Medical Society for Sports Medicine (AMSSM) was formed in 1991 to fill a void that has existed in sports medicine from its earliest beginnings. The founders most recognized and expert sports medicine specialists realized that while there are several physician organizations which support sports medicine, there has not been a forum specific for primary care non-surgical sports medicine physicians.


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