Posted on August 28, 2015 by Jenny Cromack
Exercise Adaptations for Injuries
Despite Summer slowly slipping away from us it is nice to see people still braving the unpredictable weather and hitting the tarmac, along with other activities. This, however, often results in a lot of people picking up injuries, such as muscles strains.
The standard initial management applies to the injury where by you actively rest from any aggravating activities, apply ice for pain relief, compress the injured site, and elevate the limb. A big part of this process however is also to progressively overload the muscles. This is very important for the healing process which we will come on to.
Range of Movement and Stretching Exercises
With any injury, as part of the healing process, collagen is laid down and forms scar tissue. These fibres are laid down to ‘bridge’ the damaged areas and fibres of the injured muscle, but they are laid down in a very random and unorganised fashion. If left untreated these ‘messy patches’ of collagen will restrict the movement of the muscle.
To overcome any restriction of scar tissue we need to start to gently break it down and stretch it so it is re-aligned in a more functional pattern. To do this range of movement exercises and stretching exercises are advised in the early stages of rehabilitating a muscular injury. By moving the injured limb through its pain free range of movement in a controlled way will provide some dynamic stretching through the muscle and start to realign these collagen fibres. This can be accompanied by some pain free static stretches holding the muscle in a stretched position to create optimal length in the muscle fibres and stretch the scar tissue. The benefits of these is that the muscle will be achieve optimal length and therefore the range of movement of the individual will return to normal without any restrictions, and this will help prevent any re-injury.
By moving the joint through its range of motion will also cause the muscle to gently contract and act as a ‘muscle pump’ which will help increase circulation to the injured tissue which will deliver the nutrients and remove the dead cells and fluid from the injured site. This will help reduce swelling but also accelerate the healing process.
Resistance Exercises
One of the major aims of rehabilitation is to return the injured muscle back to its normal strength so the individual is able to safely return to their activity without risking re-injury. The general adaptations of resistance training are very important for rehabilitation, in that it increases circulation, aids the realignment of scar tissue, corrects muscle imbalances, and by overloading the muscle with resistance it causes the muscle to increase the size of its fibres and thus its strength. These adaptations will allow the muscle to function with optimal strength but also to support the joints during activity so the individual lowers their risk of injury. The resistance exercises can be tailored to suit the weakness of the individual for example eccentric (muscle contraction as it lengthens) movements in the hamstring can be used to strengthen the controlled straightening of the leg during running.
Improving muscular strength and function is vital to ensure that the individual is strong enough to meet the demands of their activity safely and effectively.
Proprioception Exercises
Proprioceptive exercises involve balance and co-ordination and the exercises encourage the smaller muscle groups, which aid the function of limbs and joints, to become more active. They also facilitate the connection between the brain and the muscles (neuromuscular function) so that the body can make ongoing minor adjustments to posture, joint position, and muscle activity to ensure that movements are controlled, efficient, and safe. This prevents any compensatory patterns to form or any excessive responsibility placed upon specific muscles such as the hamstring having to work harder because other muscles are weaker or less active.
Mechano-Transduction and Exercise
This is basically the process that occurs in all injured tissues as a result of progressive overload. The tissues, such as the injured muscle, can be loaded through simple weight bearing exercise progressions i.e., walking to jogging to jumping. Resistance exercises will also become part of the loading of the muscles. The earlier this loading can occur in an injured muscle the quicker and more optimal the healing process will be.
Mechano-transduction works via the stimulation of biochemical signalling which causes genes to be upregulated, increases the synthesis of protein for tissue building, and alters the structure of the injured tissue. This stimulation comes from the loading, which causes tension and sensations in the muscle, which then stimulate genes to be coded and proteins to be synthesised optimising the tissue healing.
The process appears to be split into 3 stages as described by Kahn & Scott (2009) who suggest that the 3 stages are mechano-coupling, cell-cell communication, and effector response.
- Mechano-Coupling
This is basically loads placed upon the tissues. The compression or tensioning forces that occurs during loading cause the chemical signals to stimulate the above mentioned responses. For example, in the hamstring, when the muscle is loaded via walking etc. The muscle absorbs forces, and contracts which pulls on its tendons causing the cells to become deformed which results in the chemical and biological triggers and responses. The type of responses depend upon the type, intensity, and duration of the loading.
- Cell-Cell Responses
Although the injury and the loading may occur in one region of the muscle or body the signals are soon spread throughout the limb signalling responses and adaptations throughout. The spread of the signals is achieved through signalling proteins and ions such as calcium.
- Effector Response
The cell membrane communicates with the nucleus of the cell after being triggered by the loading and cell deformation. This response causes the nucleus to start to create gene codes which are synthesised into proteins which get released by the cell and starts to help rebuild and remodel the injured tissue. This process is the reason muscle and other tissues rebuild stronger in adaptation to the loads they are put under. This is why it is important to start progressively overloading the injured muscle as early as possible in rehab via safe and progressive exercises. It allows optimal and efficient healing, if immobilisation is used for too long the whole process is hindered and prolonged.
The whole process is ongoing and it is what keeps our tissues such as muscles and bones healthy and is why our tissues are always in a state of repair and rebuilding.
Application
The stimulus of the load needs to be done progressively and safely to ensure that we don’t relapse the injury to its starting point. To do this we need to structure exercise and loading types. However, we do need to make sure that the loads do slightly exceed the comfortable limits of the tissues as this is how we create a stronger adaptation and improvement in the tissues. An absence of the mechano-transduction signalling results in weaker tissues which is not what we want after injury. Therefore complete rest and immobilisation should be used sparingly or coupled with some form of loading for the tissue.
The loads and exercise should be used in a therapeutic manner so the individual needs to be aware that, although an element of pushing themselves is required, it is not to the same intensity as their usual training. The exercises are used to stimulate chemical and biological processes of healing.
Reading
Khan, K. and Scott, A. (2009). Mechanotherapy: how physical therapists’ prescription of exercise promotes tissue repair. British Journal of Sports Medicine, 43, 247-251.