Driving Force and Frontal Drag in Swimming .
All swimmers are equally affected by the three laws of dynamics of Sir Isaac Newton, formulated by him several centuries ago. For me, the easiest way to describe their action is as follows: the force that moves us through the water (propulsion forces), the force that slows us down (frontal resistance) and the law of inertia, which says that the most effective way to maintain a constant speed is to strike a balance between propulsion and frontal resistance with lifeguard course.
Axial rotation in crawl and backstroke .
The advancement of the swimmer in the water occurs progressively due to strokes and kicks. However, in front crawl and backstroke, another movement is used to move forward, which is equally important for achieving high speed, namely the axial rotation of the body from side to side.
Freestyle and backstroke .
Although many coaches and swimmers often believe that one of the reasons fast freestylers and spinners rotate their body along the axis of their movement is to reduce resistance during the slide, I disagree with this opinion. If this were the case, then we would swim much faster on our side than we would allow lying in the water on our stomachs or on our backs, fortunately, in practice this is not at all the case. Another widely held misconception about why we rotate our bodies during freestyle and backstroke is the theory that by doing this movement we help ourselves to reach a little further with each stroke. This is partly true, at the finish line of the distance (especially in freestyle), however, I don’t think
Mechanics and Biomechanics in Swimming .
There are two reasons why we rotate the body around the axis during crawl and backstroke. One of them lies in the laws of mechanics, the other is based on the principles of biomechanics. Everything can be explained from the point of view of biomechanics as follows: by rotating the torso, we create a kind of traction, bringing the body into the most convenient position for using the back muscles, in particular its latissimus dorsi. This makes the grip stronger.
Mechanics explains everything a little differently: by rotating the torso around the axis, we transfer energy to our body, which allows us to overcome the force of water resistance. In other words, we do not move against almost completely static water molecules, but move forward with them, using the force generated by the reverse rotation of the torso. The amount of energy required depends on the mass of our body (weight) and its speed of rotation. The rotation of the body does not occur by itself. It must be performed by the swimmer himself, applying additional effort by tensing the muscles of the core. If the axial rotation of the body is fast enough and coordinated enough, the swimmer will be able to cover a much greater distance with each new stroke. Nobody says that swimming fast is easy.