## 4 Discussion and Conclusions
The generated specific movement compensation is closely related to the movement trajectory and the placement of objects reached for by a patient [27]. The study of movement trajectory appears to be a promising stroke assessment tool. Further research is still necessary to assess the relationship between its outcome variables and clinical measures of upper extremity impairment. This type of research proves the need to use the tools we use to support the diagnostic process of rehabilitation; however, the researchers are aware that there is still a long way to go, due to the cost and process of processing the collected information. We are also aware that the development of modern information technology will significantly simplify this system. The study of surface electromyography in patients after stroke raises a lot of controversy and reservations as to the reliability associated with disorders of the central nervous system. The central nervous system uses various mechanisms to improve the patterns of muscle activation needed for movement after a stroke [28,29]. The impairment in muscle activation depends on both the degree of impaired motor control and the movement (compensation) strategy to compensate for the impairment. The conducted research showed the level of co-activation, but after the rehabilitation process, no statistically significant changes were found in this parameter. The findings of [30] suggest that increased activation of the triceps as an agonist and better coordination between the triceps and biceps muscles could mediate the observed changes in shoulder function. Changes in EMG activity were relatively small compared to changes in arm function, indicating that they could also be related to factors such as the involvement of other muscles in the compensation of movement [30,31]. The created specific movement compensation is closely related to the direction of movement and the location of the objects that the patient must use [27]. Co-activation is noticeable in new tasks performed by patients; however, with learning a new task, its activity decreases [32]. This type of research confirms the need to use the tools used by authors to support the diagnostic process of rehabilitation; however, we are aware that there is still a long way to go for their widespread use, due to the costs as well as the procedure of processing the collected information. We are also aware that the development of modern information technology will significantly simplify the described system. We are also aware of the limitations resulting from the inability to test each of the patients admitted for rehabilitation. The low popularity of the sEMG examination and the OptiTrack or other motion capture systems may also seem problematic. However, the authors are aware that there is great progress in simplifying these devices and, thanks to such research, adapting them to the needs of the hospital. Our research will allow to improve and verify the general process of rehabilitation and show the usefulness of the performed motor activities. Conceptualization, M.K. and P.P. ; methodology, M.K., P.P. and A.K.-S.; software, M.K. and P.P. ; validation, M.K., P.P., P.D. and A.K.-S.; formal analysis, M.K., P.P. and A.K.-S.; investigation, M.K., P.P., M.B. and P.D. ; resources, M.K., P.P. and M.B. ; data curation, M.K., P.P., M.B. and P.D. ; writing--original draft preparation, M.K., P.P., P.D. and A.K.-S.; writing--review and editing, M.K., P.P., P.D. and A.K.-S.; visualization, M.K., P.P. and A.K.-S.; supervision, M.K., P.P., M.B. and A.K.-S.; project administration, M.K., M.B. and P.P. ; funding acquisition, M.K. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. Data Availability Statement: Data available upon written request.