Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Abstract: Measurement characteristics of two constant velocity dynamometers (Cybex II, Lumex, Inc., NY) were evaluated at 11 selected speeds (0 to 5 rad X s-1) under various conditions of inert gravitational loading. A linear accelerometer was affixed to the lever arm. Speed settings were standardized percentages of each machine's maximum tachometer feedback voltage (0 to 100% Vfb max). Regression of Cybex transducer-observed voltages (V0) on true, i.e., expected, torques (Me) revealed that, for any static loading condition or angle, the measurement system was essentially linear and valid, although greater variance was evident for smaller torques. However, different calibrations, i.e., regression lines, were required for different speed settings. The error in predicting Me from V0 increased substantially with increased % Vfb max. Methodologies which assume constant velocity dynamic loading induce questionable, often invalid, results and inferences. Dynamic V0 represents both gravitational and inertial components. Considerable fluctuations in lever arm instantaneous velocity were ascribed to the combined influence of load and % Vfb max upon the servomotor. After computing inertia-corrected Me, calibration variability and prediction error were markedly reduced. Unexplained variability may be due to poor proximity of the Cybex transducer to the force application point. We concluded that: Cybex II should be calibrated only statically; use of an optimal filter will avoid false estimates of joint torque; inertial corrections must be applied in order to minimize potentially serious errors due to system angular acceleration; and reported muscle function relationships might be usefully re-assessed in view of these findings.
Biomechanics

Abstract: Computed tomography measurements of tibial torsion were evaluated in 85 patients with medial-type osteoarthritic knees and in 24 normal adults. Although there were no differences in the degrees of femoral torsion or knee joint rotation, external tibial torsion was observed to have a mean value of 11.3 degrees, significantly smaller than the 23.5 degrees observed in the normal adults (p less than 0.01). The more advanced the osteoarthritic stage, the greater was the reduction in external tibial torsion. Reduction of external torsion of the tibia was most severe at the proximal tibial metaphysis.
Adult

Abstract: A medical and engineering study was made of 1074 car accidents involving 2520 vehicle occupants. The injuries they sustained were correlated with details of the crash and with contact points inside the cars. Where possible the forces which were generated in the crash were estimated and related to the injuries. In all, 39 car occupants suffered femoral shaft fracture, with an incidence of 1.7% and 0.8% for front and rear seat occupants respectively. Of these, 31 had associated injuries to other regions of the body; these were the cause of 13 of the 14 deaths in this group. Associated injuries were more severe in car occupants who were not wearing seat belts but the incidence of femoral fracture was not significantly different. The mean velocity change (delta-V) causing femoral fracture was 26 mph (42 km/h) and there was a higher incidence of femoral shaft fracture when delta-V was over 30 mph. Estimates of forces needed to cause fracture were higher than those found in cadaver studies. The time to union of femoral fractures did not correlate with the severity of the crash but was longer (mean 19 weeks) than the average for other femoral fractures.

Accidents, Traffic

