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This paper discusses the development of adequate criteria and evaluation methods for seat belt restraint design. These criteria should include the effect of seat belts in abdominal injury as well as head injury. It is concluded that belt load limiters and energy-absorbing devices should limit head-to-vehicle contact, ensure that the lap belt maintains proper contact with the bony pelvic girdle, and limit the belt loads. Studies are made of pulse shape and belt fabrics. Currently available mathematical models are used for the studies included in the paper.

Expenditure of energy under several simultaneous forms (mechanical, chemical, etc.) is associated with all muscular activity. The energy is directly related to what is commonly called exertion or effort. This paper defines “muscular effort” quantitatively in terms of some of the elements of the dynamics of the human (and animal) body. It postulates that in all likelihood the individual will, consciously or otherwise, determine his motion (or his posture, if at rest) in such a manner as to reduce his total muscular effort to a minimum consistent with imposed conditions, or “constraints”. The principle, formulated in mathematical terms, is sufficient to ascribe to the moments at all body joints—a matter generally of free choice on the part of the individual—their most likely magnitudes. It therefore renders the equations of human (and animal) motion determinate within this context. The paper also describes briefly an iteration method for the solution of these equations, once they have been made determinate. A simple illustrative application of the principle is included.

Experimental evidence is presented to document the load-bearing capability of the articular facets which join the vertebrae of the spine together posteriorly. Contrary to the general opinion that these facets carry no vertical load, this paper gives qualitative as well as quantitative data to show that there exists a dual load path along the vertebral column. Extensively instrumented human cadavers were used as test subjects. Strain gages were used to provide qualitative evidence of facets load while a unique intervertebral load cell supplied quantitative information of the load-bearing role of the facets. The results of this study led to a clearer understanding of the mechanism of injury to the vertebral column during +Gz impact acceleration.

Following the classification of tissues according to their “dominant” and “interactive” components the paper surveys their load-deformation behavior, highlighting in particular the significance of time dependence. This leads to a discussion of the implant/tissue interaction in which the complexity that could be created by varying load and deformation time rates at the interface is explored.

This paper begins with a brief historical review of the field of biomechanics applied to oral implantology. Based on the current status of development, a set of generalized biomechanical requirements are presented covering analytical, experimental and clinical considerations. The current biomechanics status and requirements are then used to derive a three part role for the biomechanics of oral implantology. The expected benefits to be gained from implementing this role are outlined.

This paper provides a review of the principles and procedures of workspace design for engineers. It emphasizes that human body size, anthropometry, and muscle force capability, biomechanics, are both essential for the efficient sizing of equipment. The proper method of workspace design, the “design limits concept”, is described, and the fallacy of the “average man” concept is demonstrated. General methods of gathering body size and strength data are outlined, and major information sources noted. The author's ideas on human muscle strength in the weightless state are included.

This paper attempts to present an overall picture of the various biomechanics problems in a synovial joint. Of particular interest is the lubrication mechanism between the articulating surfaces. A survey of pertinent information in regards to the constituents, i.e., the cartilage and the synovial fluid, indicates the possible types of constitutive equations which one must use to approximate their mechanical behavior. The approach is phenomenological. Further, the results of some of the lubrication theory are applied to the system under consideration. Using realistic physiological limits upon the loading and the speed of operation, the results seem to indicate that the mode of lubrication is elastorheodynamic. This is a term which describes the theory of lubrication in which the deformation of the cartilage and the non-Newtonian nature of the synovial fluid are considered. Finally, a list of problems is proposed. Their solutions are invaluable in settling the question of the proper description of the mechanism of synovial joints. Presently, research is under way in attacking one of these problems.

The investigation reported in this paper is concerned with an experimental and theoretical study conducted to explain the changes of the knee joint mechanics in degenerative joint disease. The major thrust of the study is to determine the resultants of the pressure distribution on both lateral and medial plateaus in normal and abnormal knee joint configurations. Up to 5° of varus and valgus deformity is applied to a normal femorotibial angle of a strain-gaged test specimen which is connected through the femur and the tibia to the jaws of a specially designed loading apparatus. Strains are obtained for various loads and deviated femorotibial angles from the strain gages implanted on the femur and the tibia. Utilization of these strains as data for a three-dimensional theoretical analysis yielded the following results for the normal and abnormal knee joint configurations: (a) contact forces on both lateral and medial plateaus; (b) medial and lateral collateral ligament forces; (c) anteroposterior and lateral-medial moments.

The problem of assisting or substituting for lost functions of human extremities, by applying various manipulators, lies in the field of interest of modern biomechanics. This paper deals with some biomechanical, thechnical and medical problems encountered during a selection of type of device and a control system of such manipulators as orthosis, prosthesis and implant stimulator. A few examples of designs of such apparata are given.

Although many books and papers describing bowling techniques have been published, there is little information dealing with the mechanics of bowling. The present study was undertaken to investigate bowling performances by analyzing with cinematography the motion of the bowling ball during the approach and delivery.

Mechanical properties of bone tissue have been studied to determine the viscoelastic behavioral characteristics. Whole bones, however, have not been examined to determine the effect of loading rate on ultimate properties. This paper presents results obtained from torsional tests of fresh dog tibiae and femora tested at both high and low loading rates. The data which is presented includes energy absorption required for failure, maximum torque, and maximum angular deformation before failure. A comparison of these properties is made between paired specimens tested at high rates of loading and at low rates of loading. The findings indicate increased energy absorption, increased maximum torque, and slightly increased angular deformation under rapid loads. In addition there is a strong suggestion of a different fracture pattern.

The present paper describes an investigation designed to examine the relationship(s) between (1) the physiological characteristics of muscles as reflected in electrical activity, and (2) the mechanical characteristics to power output in the human forearm. Electromyographic responses were recorded from the biceps, brachialis, and brachioradialis muscle groups while subjects were performing on a specially constructed inertial dynamometer. Mechanical analysis included a resolution of forces acting on the forearm. This procedure included the calculation of muscle forces through the use of geometrical considerations and the principle of moments. Results were suggestive of the existence of a linear relationship between power output and electrical activity, and (2) the mechanical characteristics to power output in the human forearm. In addition, statistical analysis revealed that power production and calculated muscle force were related at higher inertial loads.