|
Nowadays a large number of people around the world participate in sports and physical activities, at different levels and on a regular basis. However regardless of the different level and types of involvement in sports and physical activities, participation in sports conveys a risk of injury to all the participants. The scientific challenge of prevention, reduction and rehabilitation of injury in sports, force the sport scientists to discover new methods, and improve old techniques in order to achieve the best biomechanical analysis of the human body.
The types of sport injuries can be categorized into two ways, according to how they occur: a) Traumatic injury. The cause of a traumatic injury can be located to a specific incident or event. For example, spraining an ankle after a jump shoot in a basketball game, or dislocation of the shoulder after colliding with the opponent during a rugby game. b) Gradual overuse injury. This kind of injury may be developed during a training session. Alternative it may develop over a period of weeks. An example of a gradual overuse injury is when the performer experience slight tenderness in her/his gastrocnemius muscle after a training session. The pain often goes away after an overnight relaxation, but it may return greater and dangerously after a subsequent training session. There are a number of parameters targeting prevention, reduction and rehabilitation of these sport injuries. Those parameters are: i) appropriate warm up, ii) appropriate training, iii) biomechanical balances and anatomical factors, iv) adequate skill/technique, v) appropriate recovery, vi) appropriate footwear and clothing, vi) invention of protective equipment and vii) appropriate environment. Currently, evidences through biomechanical analyses on sport activities have greatly expand the scientific knowledge about the mechanical bases for human movement function. The key points, which develop the prevention, reduction and rehabilitation of sport injuries, arrived from the knowledge concerning the function of human joints, the role of muscle action on human skeletal levers during sporting movements, the internal and external forces that applied on the human body during motion, and the improvement and the appropriate usage of the sport equipment.
During the last decades there was an outstanding improvement of biomechanical techniques for recording and analysis of sport movements. As a result, in this day and age, sport scientists have a variety of techniques to choose from in order to achieve better and more accurate results. The most popular techniques for biomechanical analysis are: Cinematography, two and three dimensional video analysis, automatic opto-electronic motion analysis system, electrogoniometry, plus equipment for force measurement such as; force platforms and electromyography. Although, some of the techniques have a larger range of use than the others, the major objective is to reduce, prevent and rehabilitate athletic injuries, in order for the athlete to achieve elite performances.
Two of the most practical techniques that are used for sport biomechanical analysis are the cinematography and the two or three-dimensional video analysis. Through cinematography and video analysis scientists can calculate kinetic variables for joints and body segments. Cinematography provides excellent picture quality, high resolution and digitizing accuracy. Scientists use cinematography for example to exam the stress on ankle joint (synovial saddle joint) and metatarsophalangeal joints (synovial ellipsoid joints) during running barefoot and running with shoes (appendixes 1,2). In spite the excellent picture quality, high resolution and digitizing accuracy of cinematography, a number of sport biomechanists use the video analysis to perform their experiments. Video technology provides standard framing rate, immediately playback facility and ability to deal with lower light levels. An additional technique for the calculation of kinetic variables for joints and body segments is the Automatic opto-electronic motion analysis system. This technique is used mostly for clinical and laboratory studies than outdoors activities. Electrogoniometry is an additional method and inexpensive technique that scientists use in order to measure joint angles. Scientists believe that the understanding of the physiological movement of the joints under different circumstances is an important element that leads on the reduction and prevention of sport injuries. Sport scientists also use force platforms in order to measure contact forces between sports performers and the ground (or other surfaces). The measurements for contact forces can be used for example, to evaluate the footstrike pattern of runners and help to identify and minimize injury potential. Electromyography (EMG) is a method for measurement of muscles activity during sports movements. Through EMG scientist can estimate the activation time of a muscle, the force produce by the muscles and the fatigue rate of the muscles. Human movement comprises a complex and multidimensional action. That is the reason, which lead sport biomechanists to use a number of simple and more sophisticated biomechanical devices simultaneously, aimed the prevention, reduction and rehabilitation of sport injuries.
In 1996 Dr. Mariusz Ziejewski using a video analysis, a sophisticated computer stimulation software and an instrumented crash test dummies, he examined whether the forces of the head impacts in soccer (appendix 3) are capable of producing sufficient stresses to potentially cause permanent damage to the brain. The next step was to exam whether foam materials worn on the head as part of a headband (appendix 3) could reduce the stress of impacts encountered in soccer game. Based on his findings Dr. Mariusz Ziejewski concludes that, a head impact could cause from minor to major head injuries depending on the severity of the impact. He also added that there was a significant reduction of the risk of head injury using a protective head device. Headgears are worn for the protection of the wearer in a number of contact sports, both to reduce the severity or likelihood of injury to the head and to prevent reinjury to an athlete. Depending on the needs of the sports, Biomechanists through biomechanical analyses have provided a variety of protective headgears (appendix 4).
In most sports, athletes produce extreme force loading on the their lower limb. In sports like cycling, basketball and climbing the risk of a lower limb injury is very high. In 1994 van der Putten et al examined the Biomechanical factors associated with shoe/pedal interfaces and the Implications for injury. Cyclists, due to high reactive forces between the foot and pedal, experience high loads on the joints. These loads may adversely affect joint tissues and contribute to overuse injuries, e.g. ankle and knee pains. Shoe/pedal interface can either create smooth transfer of energy or abnormally high repetitive loads, which are potentially injurious to the body. Through kinematics and kinetics analysis biomechanists designed cycling pedals which, allowing varying degrees of float. This form of transmission intended to enhance power transfer from rider to bike as well as to minimize trauma to the legs by permitting the foot to rotate during the pedaling cycle in a toe-in/heel-out or heel-in/toe-out movement pattern. Recent evidence suggests that, this type of pedal design reduce the risk of injury and maintain power output. In sports like basketball the risk of ankle sprain injury is very high. Barlow, J and Miller, S 2001 referred on the effectivity of the two most common methods by which the ankle may be supported; the ankle brace and the ankle taping. According to their findings, tape support provided a greater protection for the ankle. However, following a training session the brace demonstrated a greater retention of its support properties. Their final suggestion was that the brace might be superior in preventing ankle injuries. In 2001, van der Putten et al focused on the shoe design for prevention of injuries in sport climbing. Foot injuries in elite climbing are accepted as unavoidable since shoes must be tight, formatting an unnatural shape. Based on biomechanical analyses, van der Putten et al designed a different type of climbing shoes. They used thinning sole to produce easier flexion and extension of the toes. Basically, the shape of the shoes had closer relationship to the natural form of the foot and the shoes closure provided a close fit for feet with width differences of up to 20 mm. After biomechanical testing on prototypes, they concluded that the new shoe design could contribute to the prevention of foot injuries in sport climbing. Shoes designing is also essential for recreational athletic activities like aerobic. Aerobic instructors have identified their shoes as the second possible cause of injury. Based on biomechanical researches, it is recommended that aerobic instructors must select their shoes by taking into consideration the insole and sock absorption properties of the mid-sole and not just the brand name (Davis, M et al 2001).
In some other sport events, athletes produce extreme force loading on their upper limb. In throwing and racquet events the risk of shoulder and elbow injuries is very high. Biomechanists, through biomechanical remodeling techniques expand their knowledge of the forces, loads, and motions on the shoulder and the elbow joints during high intensive events. Kibler, W B in 1994, examined the stress on the elbow joint during a tennis game. Kibler, W B supported that a biomechanical based evaluation framework can be used for the understanding of the anatomical and biomechanical alterations on the elbow joint during powerful and high-speed movements. As a result, it will be easier for the scientists to produce new training techniques in order to prevent, reduce the risk of injury in shoulders and furthermore to improve rehabilitation methods. Portus, M in 2001 referred on the relationship between cricket fast bowling technique and trunk injuries. Based on his findings, he supported that shoulder count-rotation has been clearly show to be a major predisposing factor to lumbar spine stress fractures.
The privileges of sports activities are not only encountered by healthy people, but also by people with special needs. A number of biomechanical analyses have been done on players with special needs in order to prevent and reduce the risks of injury. Escamilla, R F et al in 2001 focused on the biomechanical analysis of the powerlifting events during the 1999 Special Olympics World Games. The aim of their study was to compare and contrast biomechanical parameters between high and low skilled lifters who participated in the powerlifting event. A biomechanical analysis was based on two synchronized video cameras. Escamilla, R F et al suggestions was that improper lifting techniques might increase injury risks and also decrease performance.
Based on the number of studies that have been done in the past years, there are strong links between biomechanical analyses and prevention, reduction and rehabilitation of injuries in sports. Biomechanical works have been completed in many sports activities, covered all the different types and levels of participation. Biomechanists have worked on collision forces between players, impacts forces between performers and surfaces, links between athletes, athletic environments and sport equipments, even on people with special needs. However, despite the various and numerous biomechanical analyses, the explanation and verification of biomechanical results is inefficient without the knowledge and interference of interrelated sciences. Sport biomechanists possess knowledge on science like human physiology, human anatomy, physics, ergonomics and engineering. Although, some times the complexity of the experimental procedure, and the understanding of the experimental output requires additional knowledge from experts with a different scientific backgrounds. As a result, in many occasions sport biomechanists cooperate with scientists like, exercise physiologist, physiotherapist, ergonomists, engineers and physicians. Through their cooperation scientist aimed to produce validate biomechanical analyses in order to reduce, prevent athletic injuries and additional to invent/improve rehabilitation techniques for already injured athletes.
To sum up, unquestionably there is a strong relationship between injuries and sport activities. Sport biomechanists, through biomechanical analyses trying to identify and minimise the links between sport activities and athletic injuries. Although, sports scientists must cooperate with scientists from a variety of scientific perspectives in order to obtain significant results. Based on scientific cooperation and the improvement of biomechanical analysis techniques, scientists can achieve prevention, reduction and rehabilitation of injuries in sport.
Appendix 1,2: http://allserv.rug.ac.be/~ddclerc/biom/rx.html
Apendix 3: http://www.soccerdocs.com/research.htm
Appendix 4: http://www.wasupply.com/indexwel.htm http://www.fightgear.com/cartsnap/cartsnap.cgi?Head_Gear
http://www.velotique.com/helm.htm
REFERENCES
Barlow, J., Miller, S. 2001. Effect of ankle brace and tape support on foot and ankle motion on basketball-specific performance. Biomechanics symposia 2001/University of San Francisco.
Bartlett, R., 1997. Introduction to sport biomechanics. Great Britain: E & FN Spon, an imprint of Chapman & Hall
Bird, S. et al, 1997. Sports injuries causes, diagnosis, treatment and prevention. Great Britain: Stanley Thornes (publishers) Ltd.
Davis, M et al. 2001. Shock absorption characteristics of footwear worn by aerobic instructors. Biomechanics symposia 2001/University of San Francisco.
Deusinger, R H. 1984. Biomechanics in clinical practice. Physical Therapy, 64(12), 1860-1868. Accessed from sport discus, University of Portsmouth 08-12-01
Escamilla, R F. et al, 2001. Biomechanical analysis of the deadlift during the 1999 Special Olympics World Games. Medicine and Science in Sports and Exercise, 33(8), 1345-1353. Accessed from sport discus, University of Portsmouth 08-12-01.
Gregor, R J; Wheeler, J B, 1994. Biomechanical factors associated with shoe/pedal interfaces. Implications for injury. Sports Medicine, 17(2), 117-131. Accessed from sport discus, University of Portsmouth 08-12-01
Gunn, C., 1999. Bones and joints a guide for students. 3rd edition. China: Churchill Livingstone.
Hrysomallis, C, and Morrison, W, E., 1997. Sport injury surveillance and protective equipment. Sport medicine, 24(3), 181-183.
Kibler, W B, 1994. Clinical biomechanics of the elbow in tennis: implications for evaluation and diagnosis. Medicine and Science in Sports and Exercise, 26(10), 1203-2994. Accessed from sport discus, University of Portsmouth 08-12-01.
Portus, M, 2001. Relationship between cricket fast bowling technique, trunk injuries, and ball release speed. Biomechanics symposia 2001/University of San Francisco.
Van der Putten. Et al, 2001. Shoe design for prevention of injuries in sport climbing. Applied Ergonomics, 32(4), 379-387. Accessed from sport discus, University of Portsmouth 08-12-01.
Renstrome., 1993. The encyclopaedia of sport medicine. Great Britain: Blackwell.
Ziejewski M., 1996. Protective headgears in soccer [Online]. Available from: http://www.soccerdocs.com/research.htm [accessed: 10 December 2001.
Cinematographic sequence [Online]. Available from: http://allserv.rug.ac.be/~ddclerc/biom/rx.html [accessed: 03 April 2001].
Boxing headgear [Online]. Available from: http://www.fightgear.com/cartsnap/cartsnap.cgi?Head_Gear [accessed: 12 December 2001].
Helmets for cycling [Online]. Available from: http://www.velotique.com/helm.htm [accessed: 12 December 2001].
Hockey headgears, baseball & softball supplies [Online]. Available from: http://www.wasupply.com/indexwel.htm [accessed: 12 December 2001].
|
