iomechanics can be defined as the study of the structure and function of biological entities by application of biological principles coupled with the principles of mechanics. Basically it serves to unify two vastly different disciplines -biology and mechanics. It also utilizes the concepts of physics, aerodynamics and material sciences among other subjects. In biomechanics, the human body is analogously treated as a mechanical system i.e. the concept of links, degrees of freedoms, equilibrium of forces, etc. can be applied to a living body as it can be applied to any inanimate object. For example, the human body has 244 degrees of freedom. There are 230 joints in the body, most of which have 1 degree of freedom (exceptionhips and shoulders that have 3 degrees of freedom), so in totality, there are 244 degrees of freedom controlled by 630 muscles. These concepts are very pivotal in the making of prosthetics, orthotics and building humanoids.
Soft Body Mechanics deals with the motion and properties of deformable objects.
It is the combination of kinetics and physiology. It governs the physiological, mechanical and psychological mechanisms of living bodies. Application areas include strength and conditioning of athletes and refinement of sport exercises.
This subject deals with the relationship of body size to shape or in scientific terms it deals with the statistical shape analysis. Study of insect species is conducted by utilizing its principles.
Orthotics are externally applied systems that support a deformity or deficiency of a subject. They are used to restrict movement in a particular direction or assist movement in a particular direction. Prosthetics are artificial limbs that help a subject to perform normal human functions which would otherwise not have been possible due to its absence.
It deals with the reduction of injuries in the workplace, thereby creating an environment of maximum comfort and ease which in turn optimizes their workplace efficiency. For example, the ideal distance between a person's sight and the computer screen on which they work should be 26 inches. There should provisions on the chairs so that the person can rest their arms, the computer screen should me moveable so as not to strain the person's neck.
The fundamental aspect of any sport is movement and through effective gait analysis optimization of musculoskeletal functions is highly possible. It not only improves the performances of the athletes but also helps in their career longevity and reduction of injuries. In this case, I have proceeded to show how the high jump technique has evolved over the years leading to a gradual increase in the world record heights. In the above four figures the gradual evolution of the high jump technique is shown. Figure 1 denotes the earliest technique, known as the scissors technique. The main advantage of the scissors technique was that parts of both legs are well below the level of the bar at the peak of the jump. This increases the height of the pelvis and consequently the height of the bar that can be cleared. The world record was set at 1.97 m. Figure 2 shows the next technique that came about, known as the eastern cut-off. In this technique the body is in the horizontal position at the peak and thus the pelvis is lifted higher than in the scissors technique. But the main disadvantage of this technique is that it requires tremendous flexibility. The world record was set at a rather modest 2.01 m. Figure 3 shows the straddle technique in which the athlete cleared the bar face down. Parts of leg and pelvis is higher and effective bar clearance is more. The athlete cleared the bar by virtue of the angular momentum generated due to movement of hip and lower back. The world record increased from 2.01 m to 2.13 m and finally to 2.28m. The technique's main drawback was that it depended very much on the strength of the athlete and caused a burnout. Figure 4 shows the current technique that has completely dominated the sport since its inception. The Fosbury Flop has now emerged as the most successful of the 4 techniques. The athlete arches back in this case, thus the bending lifts the belly higher than all the previous techniques. For this reason the present world record has shot up to 2.45m. The edges of the blades are also rounded off so to decrease stress concentration and effectively manoeuvre around tight corners. It has been found that 5% more power is utilized by clap skates than the regular skates.
Various sports are played on grass turfs (or plastic pitches) like football, rugby union, rugby league, etc. Yet in spite of the similarities of conditions the demands and dynamics of the sports vary from one to the other. Here comes the need for development of sport specific equipments.
The above figure shows the stresses that are developed on the foot of a professional footballer. Highest stresses are recorded in the ball of the foot as shown (1700 KPa). These soaring stresses are tremendously detrimental for the health and career longevity of the footballer. Therefore in case of football boots polyfoam urethane is provided in that section to minimize the build-up of such high stresses. But at the same time one may argue that for a game like rugby union which involves a lot of running like football, normal football boots would suffice for the rugby players. But in reality it is not so.
A Review of applications and Developments of Biomechanics in Sports Ossur. These blades act as a spring and a shock absorber. As the unit is compressed on impact, the energy is stored and the stress is absorbed within it, which eventually propels the athlete forward. They are made of layers of carbon-fibre -mainly 30-90 layers depending upon the athlete's weight and the impact levels to which he will subject them to. The apex of the J-curve is fitted with more layers of carbon-fibre to resist high stress and those in need of greater flexibility are fitted with less. Vertical forces generated at the heel contact are stored and translated into linear motion. It benefits more natural gait and reduced walking effort. Deflection of carbon-fibre heel and forefoot components are proportional to the user's weight and impact levels. It optimizes walking efficiency.
However, the Cheetah returns only 80% of the energy stored during compression which is a far cry from the 249% a normal able bodied runner's foot and ankle system delivers. Oscar Pistorius has to generate twice the amount of power from his hips and gluteal muscles than a normal sprinter.
There has been a lot of activity in the field of biomechanics particularly in the last 20-30 years. A brief illustration of some of them have been described below:
A Review of applications and Developments of Biomechanics in Sports
The area of prosthetic development has improved manifold by the application of biomechanical principles. People who are differentially abled can now rub shoulders with the best able-bodied athletes because of the advancements and availability of a wide variety of prosthetics.
The International Rugby Board have funded a research programme for the improvement of scrummaging in the sport. The research is being conducted at the University of Bath, England where researchers are trying to minimize the forces on the necks and spinal cords of players in the game. Peak engagement forces have been recorded at 16.5 kN (men's elite international level) to 8.7 kN (women's elite international level). The new research has refined the technique of scrummaging whereby they have decreased the forces by 25% in elite level competitions. Yet, this has not been declared as the finished product and continuous research is still going on.
SPEEDO's Aqualab in Nottingham, England has developed a new set of swimsuit and swimgear. The latest swimsuits compresses the swimmer's body into a streamline tube, traps air to add buoyancy. It has vertically stitched or ultrasonically welded seams to reduce drag.
University of Texas is in the process of making artificial muscles from carbon nanomaterials. These artificial muscles can contract about 30000% per second while an ordinary muscle contracts about 20-40% per second.
University of Delaware are developing a new kind of reactive padding that seeks to significantly reduce the impact stresses and harmful injuries like concussion. In the initial stages of research Kevlar was used because of its lightness and durability.
Besides these there have been many more developments like the developments of various softwares like SIMM, Quintic Biomechanics V26, etc.
The future of Biomechanics looks even brighter than it was a couple of decades back. The 18th World Congress on Biomechanics is to be held at Dublin in 2018. The University of Omaha in Nebraska has developed a $6 million stand-alone facility specifically for Biomechanical research which is also the first of its kind research facility in the world. These examples and many more bear witness to the fact that this subject will only flourish in the future. This in turn will cause tremendous advancements in the field of sports biomechanics, development of sports equipment and injury management and might someday lead to the development of the perfect athlete.
We, Koustav Kanjilal and Sudipto Shekhor Mondol, are indebted to a number of people, who helped and motivated us to bring out this project. I would like to thank all the faculty members of the department of mechanical engineering of Heritage Institute of Technology specially Dr. Siddhartha Ray who constantly motivated and guided us.
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