It is still a big challenge to construct a matured muscle tissue in vitro having applicable mass for tissue transplantation. It is well known that nutrient and oxygen supplies to seeded cells limit the scale of tissue-engineered constructs. In this study, a collagen sponge scaffold having uniaxial porous structure was prepared for the large-scaled tissue-engineered skeletal muscle. Unidirectional collagen sponge (US) was prepared from Type I collagen gel solution filled in PTFE tube by placing vertically and freezing with gradual immersion into liquid nitrogen from its bottom to top. Also, homogenous collagen sponge (HS) was prepared by freezing in deep freezer statically. The both of frozen collagen gel were freeze-dried and then crosslinked in a vacuum oven. The collagen scaffolds were observed by SEM and analyzed their pore orientation. C2C12 myoblasts were seeded in both scaffolds and cultured up to 5 weeks and then isometric contractile force of the constructs was determined. In addition, the constructs were studied histologically by HE staining. The isometric contractile force of tissue-engineered skeletal muscle of US was much higher than that of HS. Multinucleated myotubes were observed in both scaffolds, however many of cells located inside of the scaffold were dead probably because of a shortage of nutrients and oxygen supply resulting from shrinkage of the constructs. It may be important to keep the porous structure of sponge scaffold for long-term culture of tissue-engineered skeletal muscle.

The prevention of injuries during parasports is important for safety and to enjoy sports. However, in wheelchair rugby, there are few systematic studies on trauma precautions because of the differences in the physical function level of parasports athletes and the small number of players overall. We have proposed defensive motions to minimize injuries to the front and sides by analyzing videos of falls, a simulation using a multi-body model, and evaluating the injury to the head and upper limbs. By classifying the range of motion and muscular strength into three categories, the difference in disabilities was expressed using a multi-body model. The index, ULIC, was proposed to evaluate injuries to the upper limbs. It is calculated from the maximum moment value of the bones, using a simplified cylindrical model. The head injury criteria (HIC) and ULIC made it possible to evaluate the extent of injury by classification into one of four categories, depending on the presence or absence of injuries in the above regions. Furthermore, defensive actions not resulting in serious injuries and matching the difference between the degree of disability and fall, by predicting the potential injury to the head and upper limbs using the indexes, were proposed.

Rehabilitation systems for upper limbs that use robotic or virtual reality (VR) technologies have been expected not only to enhance the recovery of the motor function but also to realize quantitative and reproducible evaluation and motivation. Especially for quantitative evaluation of dexterity, the rehabilitation systems can be superior to conventional evaluation methods, however, few relevant researches have been reported. We developed a new application for a 2-DOF passive type rehabilitation robot, which was designed as for improving dexterity and quickness of post stroke patients by repetitive reaching exercise applied virtual reality technics. The application was designed to combine quantitative evaluation and amusingness during training. In this paper, we verified whether they were realized and its habituation effect according to age span. The result showed some habituation effect and difference on age span, but also showed quantitativeness and reproducibility of the evaluation indices. Difference between age span can advance into grading function of the evaluation indices. Elder subjects showed large individual differences despite no serious paralysis induced by like cerebrovascular diseases. Nevertheless, because their data also showed normal distribution property, statistical treatment and scoring are expected for typical values of the evaluation indices. High amusingness property was verified with questionnaire data.