Recovery: a lot evoked, little explored
Periods of rest are active phases
You probably urge yourself as often as your trainer does to take a rest. You can hardly stand the breaks and tend to carry on training again – much too early. And you have a bad conscience when you are not training. But how are you supposed to judge your own period of regeneration in a reliable way? Or put it another way: which criteria should you choose in order to make the decision to take a rest both rationally and with a good conscience? Doesn't it just stay a gut instinct that can also be very deceptive when it gives the command to get on?
Regeneration is probably one of the most commonly used terms in the world of sports. And one of the most diffuse. For research, it is one of the most difficult fields to be comprehended because the exact starting point of readings is lacking. Studies focus on sections of the problem and observe athletes who are only similar to each other in a superficial way.
In doing so, athletes who appear to be as homogenous as possible when it comes to age, sex, type of sport, diet, and amount of training, intensity and length of training are chosen. The length of their sports career and level of performance also plays a role. This group is then given a training plan and a diet and is examined over a certain period of time, which is mostly too short. During this time, relatively random parameters are measured, depending on the issue and usually, then brought into a linear relation and statistically evaluated.
But the body is not a thing that functions in a linear-causal relation.
The mechanics of action=reaction can hardly be transferred to our organism.
On the contrary, it comprises many interacting positively (activating) and negatively (suppressing) coupled regulatory circuits, which maintain the dynamic balance necessary to survive.
Even today we still know too little about which parameters must concord in order to collect data that is comparable and can thus be transferred to each individual one. The question about what kind follows this.
Healing processes demand periods of recovery
It is common knowledge that endurance strains always go hand in hand with micro injuries in muscles, sinews, connective tissue and smallest blood vessels. These tiny injuries are required in order for the muscle to adapt to a higher performance level. The injuries can affect only muscle membranes, certain fibers or the whole fiber bundle. This makes the difference in the levels of muscle pain that you percept after training. Fiber ruptures also develop in the sinews and the connective tissue. Smallest vessels can tear.
The reasons for these micro injuries are not only due to mechanical forces but are also due to rising- and falling temperature in the tissue, disturbed blood flow, shifting of the ph-level, flooding with free oxygen radicals and/or missing energy supply can influence the extent of the inevitable muscle injury.
The results of all these influences are injuries that can be so tiny that the athlete does not even notice them or so bad that long lasting muscle pains arise. An extreme increasing in creatinkinasis and myoglobine are typical in such cases.
Every injury triggers an inflammatory process in the organism regardless of where it is located. Inflammations are the general strategy to deal with disturbing influences and initiate healing. For healing, now the immune system steps into the scene as a system that triggers the inflammation, catalyses it and brings forth healing. Immune cells wonder into the muscle. Solvable cytokines are released by muscle cells and immune cells and control the inflammatory process. This means that start –and stop-signals are generated by the immune system and control the process in the direction of healing. An intact immune system can heal micro injuries within 3 to 5 days.
When micro injuries do not heal well due to a weakened immune system or because of insufficient time for recuperation, muscle ruptures and injuries to the sinews can be the result. Any form of inflammation pays its toll by consuming energy and consequently leading to a performance drop.
But because all muscle fibers are never activated at once- studies speak of a maximum of 50% with competitive athletes- the muscle can tolerate an over strain for quite a long time. Different fibers are activated by a kind of rotary principle. The active fiber pattern even changes during one and the same training cycle. Parts of the muscle can find time to recuperate even if the muscle is not given the proper time.
Efficient build up processes require
periods of recovery
Training and competitions are renowned as being phases in which decomposition transactions stand in front: Carbohydrate and fat depots are used and if necessary protein is transformed into glucose. The metabolism becomes catabolic, the cortisone level and catecholamines in the blood are increased and the anti-inflammatory components in the immune system are activated.
The phase of regeneration is dominated by build up processes. The metabolism becomes anabolic. Now we have enough energy for protein synthesis and with it enough for muscle build up. This is the actual goal of the exercise. Sex hormones, insulin and growth hormones are strong build up hormones (anabolica). Things change in the cells as well. The inflammatory stimulus is joined by a metabolic stimulus.
Growth factors (IGF-1) and cytokines become active in the cells and their surroundings which enhance the protein synthesis. The mechanical stimulus is transformed into a biochemical stimulus. Sinews, connective tissue, muscles and cells must harmonize perfectly to make this amazing translatory performance possible.
By the movement, biochemical signal chains are triggered and the adaptation processes are initiated. The muscle cells and their milieu can now receive the correct signal chains for build up, transformation and multiplication. Skeletal muscles, sinews and the connective tissue surrounding the muscles and the sinews, form a living entity, which underlies a constant protein build up and proteolysis. They posses the extreme ability, to adapt their form and structure to raising demands.
Muscle fibers multiply and grow thicker, connective tissue fibers increase, mesh more effectively and become stronger. The number of mitochondria in the muscle cells increases. Buffering systems for protection against free radicals raise their capacity. The vessels also grow. A fine but tight net of blood vessels crosses the healthy muscle. It guaranties an optimal oxygen-and energy supply because of its enormous ability to adapt the blood flow in the muscle.
All that can be the deserved result of training with an optimal exchange between exercise and regeneration: increasing muscle strength, enhancement of speed and endurance of the muscles as well as an increasing of the energy utilization.
*Personal comment: The quality of the studies is not at debate. That would be a topic of its own. I only wanted to comment on the problems of accomplishing such studies in general.