Muscle Damage and Fatigue:
One of the consequences of high intensity training and competition is muscle damage and fatigue. This is a result of working to a point where the muscle contractile properties are damaged as well as a depletion of the muscles energy source and oxygenated blood causing waste chemicals to be left in the muscle. Muscle damage and fatigue manifest in a number of different ways such as muscle soreness, muscle swelling, temporary loss of maximal force production capabilities and loss of proprioception.
- Muscle Soreness and Swelling
Delayed onset muscle soreness (DOMS) is one of the main markers of muscle damage following high intensity exercise. The soreness is caused by damage to the muscles contractile properties following repeated contractions, maximal contractions but mostly eccentric contractions such as decelerations. The muscles contractile properties are damaged under stress and this damage causes the release of chemicals into the muscle (Creatine Kinase/Hydrogen/Lactic Acid).
Muscle soreness can also occur when the chemicals that work as the body’s energy source are depleted and there is not enough oxygenated blood being delivered to the working muscles. This means that chemicals that were previously being removed begin to build up in the muscle causing pain. The damage to the muscles contractile properties and the chemical build up in the muscle can take a number of days to fully recover and in most cases cause more pain in the 48 hours following exercises than immediately post exercise.
- Loss of Force production and proprioception
When the muscles contractile properties are damaged there is less available muscle to recruit when attempting to produce maximum force. This is why although submaximal contractions are still possible, as the brain recruits undamaged muscle to perform the contraction, maximum force will be lower until full recovery is reached. The loss of force caused by muscle damage also effects proprioception which leads to an increased chance of injury as a person will have less awareness of joint position and will also have less joint stability.
Methods of Recovery:
Although there are negative effects of muscle soreness and fatigue, none are long term or irreversible and time spent recovering will allow them to dissipate. However, muscle damage and soreness does effect performance and everyday life so speeding up the recovery process can be highly beneficial with a faster recovery reducing injury risk of competing while fatigued while also allowing a higher volume of training and competition.
To repair damaged muscle, protein synthesis must take place to repair the muscle and waste chemicals must be removed. There are a number of methods that aim to speed up the recovery process mostly aimed at either increasing the blood flow to the working muscles or increasing the delivery of muscle proteins in the system.
Compression garments are a common recovery tool. They attempt to work as a pump with high pressure at the ankle and lower pressure at the thigh, forcing blood back towards the area of low pressure and therefore towards the heart where waste products can be removed and the blood can be oxygenated. The external pressure also pushes fluids such as muscle proteins into the central cavities of the muscle reducing pain and inflammation. Although there is research suggesting that these garments do reduce perceived soreness, there is little to no evidence of commercially available garments reducing recovery time or improving subsequent performance as the compression achieved is not high enough.
- Cold Water Immersion (CWI)
Cold water immersion also uses the increased compressive force of the water at the ankle to force blood from the damaged muscles. This has been found to reduce the perception of soreness but there is little evidence to support its effect on actual recovery time as similarly to compression garments the compressive pressure is not high enough. A further use of cold water immersion is in conjunction with warm or room temperature to alternate between vasodilation and vasoconstriction of the arteries, again working as a pump to speed up the delivery of oxygenated blood to the damaged muscle.
There are no negative side effects of using compression garments and as the benefits are mostly perceptual it can be used at any point within a training cycle and before or after training. The same cannot be said for CWI as although there are some benefits to muscle function and perceived soreness peaking at 24 hours following exercise, when used following each session throughout a 12 week hypertrophy training period research found both the size and strength of the lower limb muscles remained significantly lower than a training group performing 5 minutes of cycling as active recovery.
It is suggested that CWI should only be used during a periods where performance gains are not being made such as during periods of intense competition or towards the end of the season. The suggested protocol is two periods of 9 minutes of immersion at a temperature of 9.2°C with 1 minute of sitting at room temperature in between immersions
- Active Recovery
A popular recovery strategy is active recovery where a low intensity session is performed with the intention of the increased heart rate and movement increasing blood flow and therefore removing waste products from the blood and avoiding muscle stiffness. Although this has been found to be effective or at least not detrimental in some cases, there is a fine line between a low intensity recovery session and a session that causes further muscle damage and fatigue that prolongs the recovery process.
- Diet and Sleep
The previous methods of recovery have all focussed on using external methods or additional training to improve recovery time. Although these methods can be effective, sleep and diet are the two easiest and cost effective methods of recovery available but also the two that are most often forgotten.
Sleep deprivation has been found to impair recovery following high intensity exercise and also to inhibit performance. The body recovers most effectively when you are asleep as all energy can be used to focus on repairing damaged muscle and removing waste chemicals. The recommended amount of sleep for a healthy adult is 7 to 9 hours with that time increasing when recovering from exercise. A sleep duration of more than 9 hours is suggested for recovery from illness or exercise as well as for young adults and children. To get the best sleep possible it is suggested to avoid phone and television screens in the hours before sleep as well avoiding disruptions such as phones and natural light.
Alongside sleep, a healthy diet is the most important method of recovery following exercise. To recover fully the body must replace energy used during the exercise and provide the nutrients needed to repair the damaged muscle which includes a balance of protein, carbohydrate, sugars and fats. Although it is possible to use supplements to provide the body with these nutrients, the most effective method is to have a healthy and balanced diet.
When choosing a recovery protocol it is important to ensure that you are doing the basics, such as diet and sleep, right first before you add in additional recovery methods such as compression garments and ice baths. There is no harm in using these additional methods but they are also no replacement for the basics.