Overtraining

Listed below are some of the common effects and cited signs of overtraining.[6][7][8][9]

Overtraining may be accompanied by one or more concomitant symptoms:[6][7]

• Persistent muscle soreness[10]
• Persistent fatigue,[11] different from just being tired from a hard training session, occurs when fatigue continues even after adequate rest.[5]
• Elevated resting heart rate, a persistently high heart rate after adequate rest such as in the morning after sleep, can be an indicator of overtraining.[5]
• Reduced heart rate variability
• Increased susceptibility to infections
• Increased incidence of injuries
• Irritability
• Depression
• Mental breakdown
• Burnout[12][13]

It is important to note the difference between overtraining and over-reaching; over-reaching is when an athlete is undergoing hard training but with adequate recovery, overtraining however, is when an athlete is undergoing hard training without the adequate recovery. With over-reaching, the consequential drop in performance can be resolved in a few days or weeks.[14]

Like pharmacological drugs, physical exercise may be chemically addictive. Addiction can be defined as the frequent engaging in the behavior to a greater extent or for a longer time period than intended.[16][17] It is theorized that this addiction is due to natural endorphins and dopamine generated and regulated by the exercise.[18] Whether strictly due to this chemical by-product or not, some people can be said to become addicted to or fixated on psychological/physical effects of physical exercise and fitness.[19] This may lead to overexercise, resulting in the "overtraining" syndrome.[20]

A number of possible mechanisms for overtraining have been proposed:

• Microtrauma to the muscles are created faster than the body can heal them.[21]
• Amino acids are used up faster than they are supplied in the diet. This is sometimes called "protein deficiency".[22]
• Systemic inflammation which results in the release of cytokines activating an immune response[23]

Allowing more time for the body to recover:

• Taking a break from training to allow time for recovery.[24]
• Reducing the volume and/or the intensity of the training.
• Suitable periodization of training.[25]
• Splitting the training program so that different sets of muscles are worked on different days.[24]
• Increase sleep time.
• Deep-tissue or sports massage of the affected muscles.[26]
• Self-massage or rub down of the affected muscles.[27]
• Short sprints with long resting time once the athlete is able to continue with light training[5]

Exertional rhabdomyolysis is an extreme form of overtraining that leads to a break down of skeletal muscle which makes its way into the blood. Many molecules such as potassium, creatine kinase, phosphate, and myoglobin are released into circulation. Myoglobin is the protein that causes the lethal reaction in the body. Early detection of the syndrome is essential in full recovery. A serious late complication of rhabdomyolysis which occurs in 15% of the population is acute kidney injury, and in some cases it can lead to death [29]

As CrossFit has become more and more prevalent and popular among many athletes and individuals, speculation has occurred leading many to believe that spikes in rhabdomyolysis cases leaves CrossFit to blame. According to a study performed in the Journal of Strength and Conditioning Research, unless performed incorrectly and in harmful environments, CrossFit presents no serious physical threat to the human body, and research is inconclusive to prove that rhabdomyolysis cases and crossfit are correlated [31].

Passive recovery, instead of active recovery, is a form of rest that is recommended to be performed by athletes in between rigorous, intermittent exercise. With active recovery, time to exhaustion is much shorter because the muscles are deoxygenated at a much quicker rate than with passive recovery. Thus, if avoiding overtraining means preventing exhaustion, passive recovery or "static rest" is safest.. If active recovery is performed during intense exercise, an athlete may find themselves in a state of being over trained[32]. The gradual variation of intensity and volume of training is also an effective way to prevent overtraining.