Biomechanics studies the process of kinematics and develops artificial limbs and footwear specifically to aid the body in performance. The study of biomechanics also includes the stress testing on crash dummies in car accidents and any sport where stress is placed on the body in order to produce performance. The type of stress specifically is the joint stimulation and bone modeling stress.
The most common use of biomechanics is in the development of prosthetic limbs used for the handicapped. Most work on prosthetics is done in laboratories where scientists use calibrated machines to test stress and wear of artificial limbs. These days, prosthetics, are made of titanium and lightweight fiberglass to make a near perfect match with most people. The most common prosthesis is the replacement in a below the knee amputation. The American Society of Biomechanics (ASB) held a meeting at Clemson University of 1997 in order to develop a sports prosthesis that would stand up to every day flexing of the knee for performance in sports.
In order to develop this prosthesis they had to go through two main phases, the analysis of a jogger wearing a standard walking prosthesis and computer simulation of the flexing of the knee on this walking prosthesis. They had to measure rotation, weight bearing, moments, and the stress of the joints acting on this limb. After the mechanical actions were mapped out they had to use many mathematical equations to spring force and spring stiffness. All of this was accomplished and the conclusion was that by varying the placement and orientation of the spring, the moment arm values could be adjusted in an attempt to linearize the spring stiffness. Biomechanics is also used in the study of sports actions, such as the motion of throwing a baseball.
This process involves three major steps. First, an engineer must take photos of every separate motion in the release. Also the ground must be fitted with sensors to effectively sense the affects of a player upon the ground. Second, the engineer must determine the kinematics from marker positions, which involves drawings and calculations to find stress and rotation points in the body. Finally, they must create animated models or structural diagrams with labeled motions, stresses, and moment in the arm and rest of the body.
The diagram below, obtained from a John Hopkins University Study, illustrates his action. Another use of biomechanics is in the subject of crash simulation, human stress testing, and collision testing. In the attempt to develop safer cars, cars with special sensors were crashed to find out what stress occurs where and how the body of a person reacts to the crashes. Of course paying a person to drive into a wall at forty miles an hour is ridiculous, so test dummies were invented where all the joints, bones, and miscellaneous points on the body had sensors to read out what support was needed in different places. This has been the project of the U.S. Department of Transportation since computers were invented in an effort to reduce bodily harm and vehicle damage.
Each year every car is tested in order to make sure that the car is up to standards of the Department of Transportation. Again, body stress measured in tension and compression, and moments of the body are measured in order to better the restraints in a car for safety. Biomechanics is a well-developed area in science and engineering where studies are performed. Many universities have a biomechanics lab in which advancements in technology are accomplished so that we may understand and operate our human bodies with greater knowledge of how to do so in the future.