Science on Sunday: Monitoring Overtraining in Athletes
Overtraining is a common issue with Endurance Athletes. In an attempt to get better, athletes train harder and/or longer, but not necessarily more beneficial. This is a summary of an article by Sue Hooper and Laurel Mackinnon in the journal Sports Medicine.
Hooper, SL; Mackinnon, LT; (1995) Monitoring Overtraining in Athletes Sports Med, 20 (5): 321-327
Whilst attempting to improve fitness athletes may find themselves overtrained. Often they will display symptoms including chronic, high-levels of fatigue and deterioration of performance. As a result of overtraining they have an increased risk of injury or illness. Rest or greatly reducing training load for several weeks may be required to enable complete recovery.
Overtraining may be defined as high volume and/or high intensity training, with inadequate recovery, resulting in nonadaptation to training, requiring several weeks of rest or greatly reduced training for complete recovery. Overreaching should be used to describe training which causes few of the signs and symptoms of overtraining syndrome but does produce short term fatigue and performance decrements from which the athlete recovers after a few days rest.
When there are high levels in the blood of Creatine Kinase (CK) this indicates alterations to the cell membrane of the muscle cells, often resulting from intense exercise. This was previously considered a good indicator of overtraining. This has been discredited by being shown to be also high in athletes that aren’t overtrained, as well as sometimes in the normal range for athletes who are overtrained.
Similar to Creatine Kinase (CK) low erythrocyte (Red Blood Cells) counts, haemoglobin (oxygen binding site of a Red Blood Cell) levels or serum ferritin (iron in your blood plasma) levels are also no longer considered good indicators of your level of overtraining. Levels once considered to be reflective of overtraining but have been found in athletes who are not overtrained and in some instances don’t change much for athletes who become overtrained.
Physiologically it is simple to measure your resting Heart Rate (rHR), it has been shown to increase 5-10/bpm when overtrained but also similar occurrences occur when an athlete becomes ill with an infection; emotionally upset; or had insufficient or poor sleep.
Other physiological traits such as blood pressure; resting or post-exercise oxygen consumption have also been investigated, amongst other parametres. A number of studies reported changes with athletes who are overtrained but not in all studies.
A possible explanation for this can be explained by splitting what is defined as overtraining into two categories: sympathetic and parasympathetic overtraining syndrome.
In Sympathetic Overtraining Syndrome symptoms include increased resting Heart Rate (rHR) and blood pressure, decreased appetite, loss of body mass, disturbed sleep and irritability.
In Parasympathetic Overtraining Syndrome symptoms include low resting Heart Rate (rHR) and blood pressure, long periods of sleep and depression.
Both types show deterioration in performance and persistent fatigue. It is possible that the overtraining response progressively moves from from sympathetic to parasympathetic symptoms. That is for example the resting Heart Rate (rHR) initially increases but as the condition gets more chronic, your resting Heart Rate (rHR) decreases and is significantly suppressed compared to previous (non-overtrained) values.
Psychological tools such as the Profile of Mood States (POMS) can successfully identify athletes who are overtrained by picking up on changes in mood states such as tension, anfer, depression, vigour, fatigue and confusion. However, they are not precise enough to detect differences between athletes who are overtrained and athletes who have been training intensely but not overtrained.
There is research that shows that athletes who are overtrained have POMS Total Mood Disturbance (TMD) scores to be higher than non-overtrained athletes. The classic example reported is three overtrained swimmers compared to eleven other swimmers completing the same training sessions but are not overtrained.
Although there is no proof that using self-analysis tools accurately and reliably predict overtraining, self-analysis helps provide valuable insight into how the individual athlete responds to training, and therefore can be used to monitor overtraining.
The Daily Analysis of Life Demands for Athletes is a questionnaire developed to help avoid overtraining. Athletes are required to assess sources of stress within the life and rate the respective symptoms. Using it in a log book format it has been successful with Australian Olympic Teams and a similar concept has been used by British athletes. Using these sorts of tool a group of 14 swimmers managed to successfully predict overtraining six weeks before deterioration in performance and other signs or symptoms of overtraining appeared.
A monitoring programme for overtraining should be part of any effective professional management strategy for athletes training. The most appropriate tools are a combination of physiological and psychological. Conscientious self-analysis by the athlete is the most effective method of monitoring overtraining, because long-term, daily records of simple metrics can be kept with relative ease compared with the more invasive and time consuming methods such as POMS or Daily Analysis of Life Demands for Athletes.
At Qwik Kiwi Coaching, I monitor athletes on my Elite and Team coaching programmes by getting them to log metrics into Training Peaks and tracking this in the long term to detect any trends and mitigate issues early.