Abstract:

Understanding the structure and function of a complex biological system as well as simplifying its kinematic and kinetic analysis is the main task of biomechanical modeling. The representation simplification of a complex biological system facilitates, for example: the assessment of muscle and joint biomechanics, arterial flows and soft tissue mechanics. Biomechanical modeling requires defining the system, reviewing existing knowledge, choosing a model together with the research method, establishing simplifications, developing a mathematical solution, estimating the model and discussing it. The multi-stage modeling may not ensure the success of the final results. One of the most important elements of building biomechanical models is not only having knowledge (from general to detailed) and experimental data (from detailed to general) but also correct measurement of input parameters. During laboratory classes, some students often do not pay much attention to measuring accuracy and precision in modeling, which results in the lack of reliability and validity of parameter results. Parameter measurement should reflect actual results, not based on poor predictive value.

The article discusses issues of bio-mechanical modeling and measurements in motion recording systems. The key issues and measurement limitations in biomechanical modeling encountered by students were presented. Example measurements of parameters in selected motion registration systems were made, focusing on measurement attributes. The analysis of measurement issues in biomechanical modeling allowed to confirm the independence of precision and accuracy from each other. The measurement can be precise but inaccurate if the spread of the results is small and their average is far from true (or predicted or standard). Similarly, in the case of low precision - results with a large dispersion can be accurate if the average of these results corresponds to the true (or reference or theoretical value). It can be stated that precision and measurement accuracy should be determined by students in the field of individual laboratory installation. Both of them depend on various factors, for example: test equipment configurations, lighting conditions, camera resolutions. Motion analysis systems have different accuracy. In biomechanical modeling it is also important that many estimation models rarely take into account the individual characteristics of the subjects and mathematical models use the so-called purposeful functions to optimize the solution. Still, it is important in research that both students and teachers strive for credibility and validity of results in obtaining real models that will find application in facilitating many areas of life.

Keywords:

biomechanical modeling, measurements, accuracy and measurement precision, measurement, motion capture