The economist has an advantage

Our first article dealt with the difficult and scientifically insufficiently defined term of body perception. This article is about biomechanics. When hearing the word mechanics, it mostly evokes a feeling of clarity and science. Here and now we are going to trace down this clarity and its limits.

Biomechanics – a short sketch

The best athletes are the most economic ones!

Biomechanics represents the idea that a muscle does not need to produce as much tension while contracting, if its ability to store elastic energy is higher. Also, the connecting sinews and connective tissue structures must be able to function as springs. The muscle's properties are often compared with those of other elastic materials. However, these properties vary according to the training condition and the nervous innervations and  also the type of the muscle's composition (feathered, bulging, etc.). Biomechanics classifies a muscle's work:

• Before impact of external force, (e.g. floor reaction force, inertia of equipment) activation (preinnervation) of the contractive part occurs (isometric tension).
• The main phase of movement comes next, which is a more or less distinct elongation of the muscle, combined with the storage of elastic energy.
• Ater that origin and onset of the muscle converge. This is accompanied by an energy release from the sinew/muscle system (heat development)

These phases of energy release can be influenced. The preliminary tension of the muscle (preflex), as well as the mechanical features of the muscles and sinews can be trained. Finally the outer force (different sport, different equipment) can also be modified.

Personal record economically

The more efficient a muscle moves, the longer you can exercise it. The metabolites that are responsible for muscle fatigue come in more slowly and  heat development is delayed. It is most definitely worth giving economic movement patterns some attention. For example, economic running enables longer running and therefore faster running. It means using less oxygen on the same distance at the same speed. And that leads to less heat development which is a limiting performance factor. Training surveys confirm that an improvement of running economics has a major effect on training in well trained athletes. Running faster with the equal use of oxygen, means to run economically. A high aerobic capacity is an indication of poor running economics. The best marathon runners have a VO2max-level between 63-74 ml/kg/min. Higher VO2max values are not necessarily connected to greater success.

The cheetah - an example for excellent and ideal running

Reduce weight - improve running economics

This feline predator is said to be the fastest land animal. It can reach a maximum speed of up to 112 km/h, but can only keep up this pace for about 400 m or under one minute. Its head and torso length amounts to about 150 cm, added by a 70 cm long tail. Its shoulder height is 80 cm. Regardless of its stately size it only weighs about 60 kg.
  Its spine is highly flexible and gives the cheetah an amazing elasticity. In a condition of isometric tension, its whole body gives the impression of a spring. When in full sprint, it will reach the 60 km/h mark within 2 seconds. Laboratory experiments have shown that the cheetah will immediately stop running after reaching a rectal temperature of 40, 5 to 41°C. It will simply lie down on the treadmill, stretch all fours and refuse any from of movement.

Fatigue of the shortening stretching cycle

Repeated high speed and short excentric muscle contractions while running induce a specific kind of fatigue, which can last up to seven days after a marathon. A reduced contractive capacity combined with a lower stretching tolerance and a delayed transit from stretching to contracting is typical for this kind of fatigue. The muscle looses its elasticity because the nervous reflexes can not function properly. Movement becomes stiff and rigid. This fatigue is caused by reversible micro injuries (inflammatory regions) in the muscle and especially the neuromuscular spindle (sensors for measuring the length changes inside the muscles). The healing process can take up to one week.

Back to Africa

Kenyans generally train harder than other top athletes on other continents. Volume and intensity are incomparable especially in the early years of age. The result of the hard training is a structural change in the connective tissue around the calf muscles and the ankle. The shortening stretching cycle - which is based on a reflex - is basically "deadened". Because of the greater passive elasticity and the connective tissue structure, they can move with less contraction and more storage of potential energy.
  In addition they mostly weigh less, even though they are not necessarily smaller. This improves their running economics as well. At least it is an explanation for their extraordinary running performance and why these athletes do not experience a drop out in a marathon, like a hobby athlete does, when the shortening stretching cycle collapses. Without hard training for at least ten years, this kind of performance is simply not possible.