Biomechanics; is the science of movement of a living body, part of the larger field of kinesiology that focuses specifically on the mechanics of movement. It helps us understand how muscles, bones, tendons and ligaments work together to produce movement. The forces that load the joints are produced by the muscles and transmitted by the tendons to other tissues. Bones rely on these forces.

Developments in the field of biomechanics of normal and pathological gait, biomechanics of sports injuries, neuromuscular control mechanics have improved our perspective on sports. Therefore, medical diagnosis, treatment methods and what can be done to prevent sports injuries are developing.

In the sport of triathlon, the biomechanical influence of the body varies for each branch. In this article, let’s talk about the relationship between swimming biomechanics and injury prevention methods.

Forces in Swimming:

There are several forces that affect the movement of a human body while moving in water. These forces are drag, gravity and buoyancy. Drag and lift are propulsion forces used by swimmers while swimming. Resistance (also known as drag) can be divided into three main groups: Pre-resistance, skin friction, and eddy resistance.

Pre-resistance; frontal resistance occurs when the body is too low in the water; producing a greater surface area that essentially pushes the water in the opposite direction of forward motion. To limit the effect of frontal resistance, the swimmer tries to position themselves as high on the water surface as possible to produce an effect similar to a booster. 

Skin friction is another factor, the kinetic friction of the swimmer’s skin and is compatible with water. This can be eliminated in several ways. The most popular method is to shave off all visible body hair, wax or use racing suits. 

Eddy resistance that creates eddy action is caused by poor technique and very low water ride (frontal resistance). Water cannot fill just behind the swimmer. This causes them to attract water and air bubbles with them; causing deceleration. Every time a swimmer exerts a pull on the water surface, he is exposed to a whirlpool. If the movement is not resolved, the vortex remains. If eddies build up around the swimmer’s body, water resistance increases.

One-Hour Training: Swimming Strength Set

In swimming, buoyancy can best be described by Archimedes’ principle: a body fully or partially immersed in a liquid is balanced by a force equal to the weight of the liquid displaced by the body. This essentially removes any effect that gravity might have on the swimmer. 

Buoyancy is the force exerted by an opposing fluid that corresponds to the weight of the object.

Buoyancy force is the upward force acting on the water, the swimmer. The pressure below the swimmer is much greater than the pressure above them, allowing the swimmer to float. There is less resistance on the water surface because it is more durable than liquid air. More buoyancy and staying close to the surface gives a greater advantage. For an object to float, the buoyant force must be equal to or greater than the weight of the water.

Drift is one of the main factors affecting the speed at which an athlete moves through the water. 

Drag is one of the main factors affecting the speed at which an athlete moves through the water, as active drag (similar to kinetic friction) acts against the movement of the athlete, reducing the net force acting in the desired direction.

Many athletes spend years improving their technique to produce the lowest amount of friction possible.

There are three main factors in swimming biomechanics; 

1- Newton’s laws of motion

2- Friction force of water = resistance

3- Lifting force

According to Newton’s laws of motion; An immobile object will remain so unless acted upon by a force.

It takes extra strength to move, and extra strength to stop moving, seen through static force and dynamic force.

Static Force: When a body is at rest, it wants to remain still and this must be overcome for fluid movement to occur. The drag felt when the movement starts is the static force the swimmer is trying to overcome. Since triathlon swimmers do not push with force using a wall, it is important to develop swimming technique and stroke with upper extremity isokinetic power.

Dynamic Force: When a body is in motion, it wants to stay in motion and is the reason why swimming becomes fluid after the initial movement. 

Water is significantly denser than air (773x) and this helps the athlete swim. The higher the swimmer is in the water, the more he reverts to all the frictional forces in swimming.

8 Tips for Easy Swimming

In swimming, the force produced by the swimmer is equal to the swimmer’s mass and multiplied by the swimmer’s acceleration in the water. This may explain why some people swim faster than others. In this case, since both swimmers have the same mass, the person who produces more force will accelerate more. Acceleration is directly proportional to force and inversely proportional to mass. This means that when you are pushed, the harder you are pushed, the faster you move (you gain acceleration)

For every action there is an equal and opposite action. In swimming, the hand can be associated with the standard hand/arm stroke when the hand moves down through the water and then forwards, to propel the swimmer forward. The swimmer is kept afloat and pushed forward while creating an equal and opposite reaction.

In addition to swimming biomechanics, it is wise to use isokinetic testing and exercise systems to reduce injury rates and improve performance. Strengthening the main muscles used in swimming with isokinetic exercise systems will support swimming training, reduce the risk of shoulder/hip injury and increase performance.

The adaptation of the palm and the whole arm to the water resistance as a closed kinetic chain exercise can be achieved by periodically adding the isokinetic system to the land training. In addition, the muscles will contract isokinetic, concentric and eccentric with the movement of the shoulder against the resistance at the same intensity at every angle. Thus, optimum fluid movement in and out of the water can be achieved. In addition, isokinetic testing and exercise systems are performance evaluation methods. This special test, which will be performed on the athlete in the company of your sports doctor, is very effective in quantitatively evaluating the difference at the beginning and end of the intense training period. There are scientific studies that prove the performance increase in athletes who are trained for a while with an isokinetic test and exercise system.

In addition to this, for injury prevention methods, conscious stretching and strengthening of the core (abdominal-back) muscles, the streamline position in the water, increases the success, thus the gliding and drifting movement in the water. Fascial stretching methods developed and trained by Sarah Mariano (thestretchtherapist) from Canada will be effective as stretching exercises.

In addition, neurokinetic therapy exercises should be especially utilized in order to improve the technique in swimming and to use the body biomechanics symmetrically while swimming.

Neurokinetic therapy exercises should be learned with the help of a specialist, starting from the eyes, fingertips and toes, all joints individually, and then combined (sport-specific) movements, and should be applied regularly in land and water training.

Click For Our Other Articles On Triathlon!

Deniz Alkan
Master Physiotherapist | Website

Having graduated from Hacettepe University in 2000, MSc. PT. Deniz Alkan has been actively working on everything regarding physiotherapy for over 20 years. In particular, the training of healthy life coaching in sports physiotherapy studies. The ability to use test and exercise systems, which are rare in Turkey, and the organising of many specific training courses can be applied. Research on sports are continuing with all manner of interest, and love. Deniz, from Antalya, is also an open water swimmer who crossed the strait in the Intercontinental Bosphorus swimming race. She is currently working as a consultant physiotherapist with the Turkish Ministry of Health.

Yorum Yap