# Development of a Simplified Human Body Model for Movement Simulations
## 4 Discussion
This would enable kinematic and dynamic parameters to be calculated without the use of Adams or any other multibody simulation software. It would be enough to use a mathematical calculation program such as Matlab or Excel after prior validation and comparison of the obtained results. Another issue is whether the internal/external rotation of the wrist joint should be included in the model. This is generally recognized by biomechanics, but does not occur in everyday activities; therefore, omitting it may be a way to further simplify the model. In addition, in future attempts to link the model motion simulations with the results from the IMU sensor system, it is necessary to eliminate the need to apply corrections to the obtained values. These corrections, according to the manufacturer, resulted from the method of calculating the biomechanical angles in the joints. One solution could be to use more sensors to measure movements in problematic places or to use data on the orientation of human body segments (directly exported quaternions from the IMU system) instead of data on joint angles. This study aimed to explore the potential of using IMU-based data for the developed model. However, it should also be considered that besides offering certain advantages in terms of portability and ease of use, IMU-based systems have drawbacks. Their accuracy can be influenced by factors such as sensor noise, drift, and signal processing. Due to the limitations of IMU systems, data from optical motion capture systems should be incorporated in future studies. Moreover, the current study focuses on a single subject with specific characteristics (height 187 cm and mass 70 kg), which may significantly limit the reliability of the current findings and generalizability for broader applications. Therefore, a plan for future research to assess the model's performance and accuracy should include the following steps. Firstly--Trials with diverse groups of volunteers to obtain more representative results:  
* Recruit volunteers varying in height, weight, body shape, age, and gender to ensure statistically significant results;
* Include a variety of daily activities and tasks;
* Couple volunteers should perform the same activities to assess inter-subject variability and improve the generalizability of the findings;
* Incorporate data from optical motion capture systems (e.g., Vicon) as the gold standard to provide more accurate data for evaluation;
* Collecting data simultaneously with IMU sensors would allow us to directly compare and validate IMU results and their applicability to the model;
* Obtaining human body torques with proper measurement equipment (e.g., torque sensors, Biodex system, and measurement exoskeletons) would allow us to assess the model's correctness in this aspect. Secondly--Simulations for a wider range of anthropometric data:
* Include variations in height, weight, and body proportions for the model. This would allow us to assess the model's sensitivity to these variations and evaluate the model's generalizability across a more diverse population;
* Compare the model results with those measured for volunteers representative of a particular set of weight and height in order to evaluate the model's accuracy. Thirdly--Statistical analysis to assess the accuracy and reliability of the model:
* Compare model predictions with experimental data using appropriate metrics (e.g., root mean square error and correlation coefficients);
* Determine the sensitivity and the universality of the model in predicting different aspects of human movement. Performing these planned experiments and simulations in the future will allow us to assess the model's accuracy and significantly enhance its validity, reliability, and generalizability for a broader application. Until this validation is completed, the model's applicability is limited in the main aspects concerning its usage for a wide range of individuals (sets of height and weight) and for performing various movements and tasks.