Gross anatomy of the gluteal and posterior thigh muscles in koalas based on their innervations

There are not many descriptions of the muscle morphology of marsupials, despite the fact that they should show diversity according to the adaptation and dispersal to a variety of environments. Most of the previous studies regarding the gross anatomy of marsupials were conducted in the 1800 - 1900’s, and many issues still remain that need to be reexamined. For instance, the muscle identification had been performed based only on their attachments and thus, muscle descriptions are often inconsistent among the studies. These classic studies often do not include figures or photographs, so the discrepancies in the descriptions of the muscles could only be verified by performing the muscle identification again with a more reliable method. This problem can be solved by performing muscle identification by innervation. This method, which focuses on the ontogenic origin of the muscle as opposed to the attachment site, is prone to individual and interspecies variation and is a common technique in recent anatomical research. This technique is more reliable than previous methods and is suitable for comparison with other taxa (i.e., eutherians). In this study, we first conducted muscle identification based on innervation in the gluteal and posterior thighs of koalas in order to reorganize the anatomical knowledge of marsupials. This is because the gluteus and posterior thighs of koalas are the areas where previous studies have been particularly inconsistent. We dissected five individual koalas and clarified discrepancies in previous studies, as well as investigated the unique muscle morphology and their function in koalas. Specifically, the koala's gluteal muscle group is suitable for abduction, while the posterior thigh muscles are particularly suitable for flexion. In the future, we will update the anatomical findings of marsupials in the same way to clarify the adaptive dissipation process of marsupials, as well as to contribute to the understanding of the evolutionary morphology of mammals.

Assessment of the Maximal Range of Motion from Initial Sensation of Stretching to the Limits of Tolerance

The aim of this study was to determine whether the first sensation of stretching (ROMFSS) may predict the maximum range of motion (ROMMAX) in male (N = 37) and female (N = 32) volunteer subjects, and to assess the reliability of the ROM perceived by subjects in relation to a pre-determined ROM (ROM50%). Subjects attempted three experimental sessions with 48 hours between sessions 1 and 2 and 28 days between sessions 1 and 3. Within each session, five trials were performed with isokinetic equipment to assess posterior thigh muscle flexibility. The results revealed a strong and significant correlation between ROMMAX and ROMFSS for both sexes, females (r = 0.96, p < 0.001, R2 = 0.92) and males (r = 0.91, p < 0.001; R2 = 0.82). The accuracy of the model verified by the standard error of estimate (SEE) was high in the equations proposed for both female (SEE = 4.53%) and male (SEE = 5.45%). Our results revealed that ROMFSS may predict the ROMMAX for both male and female subjects. The ROMFSS may contribute to the development of evaluation methods that do not subject the individuals to conditions that may include unnecessary risk of injury and is well suited to monitor the training process of stretching exercises with submaximal loads.

Characteristics of Muscle Work in Track and Field Athletes with Intellectual Disability, Hearing Impairment and Cerebral Palsy

In persons with disabilities, the underlying impairment affects the functioning of other organs and systems. Special attention is drawn to athletes of adaptive sports, in particular, the main impairment influence to the work of the musculoskeletal system, and, accordingly, the sports result. Is it possible to correct and change training programs, knowing the peculiarities of muscles work of various nosological groups athletes. Aim. To analyze the work of the musculoskeletal system in athletes with intellectual disability, hearing impairment and cerebral palsy. Material and methods. The study was carried out on the multifunctional simulator Humac Norm on the basis of the State Autonomous Institution “Sports Adaptive School”of the Sverdlovsk region. It was attended by 21 athletes aged from 16 to 22 years: with intellectual impairment of the slight mental retardation degree (n = 7: 1 m., 6 days), with infantile cerebral palsy in the form of spastic hemiparesis (n = 7: 4 m., 3 days), athletes with hearing impairment (n = 10: 7 m., 3 days) with congenital deafness (n = 3) and 3-4 degree hearing loss (n = 7). the athletes underwent testing of the lower extremities muscles, in particular, the muscles of the anterior and posterior thigh surfaces; internal and external lower leg muscles in concentric (overcoming) and eccentric (yielding) modes of muscle work. The muscles of the anterior and posterior thighs were tested in the sitting position at angular velocity of 45 degrees/s on a simulator. The internal and external muscles of the lower leg were tested in the reclining position with a fixed knee joint, at the angular velocity on the simulator of 30 degrees/s. The result was evaluated 15 times for performing a given movement in concentric and eccentric modes and the average values of the general muscle working capacity were revealed. Results. When analyzing the results, it was revealed that athletes with cerebral palsy and hearing impairment have interaction in muscle work. Thus, the weakness of the front thigh part muscles corresponds to or entails the weakness of the lower leg external muscles. Hypotension of the posterior thigh surface muscles entails (or is a consequence of) weakness of the lower leg internal muscles. In athletes with intellectual disabilities, there is no clear interaction in muscle work. In different athletes, asymmetry is detected in completely different indicators, which may be associated with incomplete understanding of the attitudes to test performance or with the overlap syndrome presence. Conclusion. The athletes’ testing revealed the muscle work imbalance and asymmetry. A greater deficit was observed in the concentric mode of work in athletes with intellectual disability and cerebral palsy. The calf muscles need to be worked out in athletes of all nosological groups.