名古屋大学博士学位論文 学位の種類:博士(リハビリテーション療法学) (課程) 学位授与年月日　平成22年9月30日

The purpose of this project was to explore the possibility of using the accelerometer in a mobile device to measure acceleration instead of professional laboratory equipment. Five subjects performed ten vertical jumps each. The equipment used for the purpose of this project was a mobile device, force plate and a motion capture system, of which the last one mentioned was used as a reference for comparison against the others. The data from the mobile device was split into two groups of datasets, where the first one was the nominal acceleration from the raw data and the second one the acceleration when the phones orientation was taken into consideration. The height was calculated by using the double summation, take-off velocity and flight-time. All the data was compiled where the mean deviation, standard deviation, R-value and R-Squared was calculated for each method. The take-off velocity was later used as the final method to give it a fair and equal comparison. The result showed that the force plate was significantly better and more reliable than the mobile device. When comparing the different datasets from the phone, the orientation adapted data performed better than the raw data. The conclusion made from this project was that the force plate is still significantly better than the mobile device regardless of the type of data, but the orientation adapted data demonstrates a result in the right direction.

Objective: We quantified, via complexity analysis, the postural stability of healthy people from a wide age range. Approach: Thirty-five healthy people aged 18-72 performed three tasks while balancing on one foot on a force plate: standard balancing task, mental task (balancing while answering basic arithmetic questions), and knot-tying task (balancing while tying two knots in a piece of ribbon). Mediolateral force trajectories were analyzed to determine control strategy via Hurst exponents, Lyapunov exponents, Kolmogorov complexity, root mean square, and phase-space plots. Main results: We found increased pattern repetition in balancing with increased age, as evidenced by the emergence of a double attractor pattern in phase-space plots and the increase of Hurst exponents with age from approximately 0.3 to 0.8. Significance: As people age, they tend to develop strong feed-forward control strategies for balancing, and lose the complexity of micro movements intrinsic to young age. There is an open-loop control strategy for balancing that emerges in older adulthood, and there are attractors inherent to balancing which begin to develop in middle age.

No description available.

Autologous chondrocyte implantation (ACI) is a cell based therapy for the treatment of articular cartilage defects. Numerous studies have reported outcomes following ACI using a variety of patient reported outcomes (PROs), but no clear recommendations exist regarding which PRO is the most responsive to changes following ACI. Few studies have documented changes in performance based assessments (PBAs) following ACI. Response shift theory proposes that residual changes in self-report measures occur over time. Failing to account for response shift may result in over or under reporting of outcomes from which clinical decisions are made. The purposes of this dissertation were 1) review the literature concerning ACI outcomes to determine the responsiveness of PROs to changes in self-reported function following ACI, 2) evaluate the reliability of PBAs among ACI patients, 3) develop a descriptive timeline for the return of function 1 year following ACI using both PROs and PBAs, and 4) utilize PROs and PBAs to evaluate patients undergoing ACI for evidence of response shift. All PRO and PBA measures were collected preoperatively and 3, 6, and 12 months postoperatively. A retrospective then-test PRO evaluation of function prior to surgery was completed at 6 and 12 months. Response shift was calculated by subtracting the original pre-test score from the then-test score. A systematic review and meta-analyses of existing ACI outcome studies resulted in the recommendation of the International Knee Documentation Committee Subjective Knee Form (IKDC) and Lysholm Knee Scale as highly responsive PROs among ACI patients of varying activity levels. Despite significant increases in PRO scores as early as 6 months following ACI, improvement in PBAs at 12 months following ACI were limited to stride length, walking speed, and step-up force. Finally, no evidence of a group level effect for response shift was observed. These results support the validity of traditional pre-test/post-test research designs with no need to account for response shift when evaluating treatment effects of ACI on the group level. However, the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) did show evidence of a measurable response shift on a patient by patient basis.

Commercial technologies for the objective assessment of balance exist in clinical settings. Training requires integration of sensory information to produce a coordinated motor response related to balance. These systems have had measurable phase delays of up to 250ms in the visual feedback provided to the patient. This provokes an unnatural response, requiring prediction from the subject. The proposed research investigates the impact of visual feedback phase delays on the performance of weight shift tracking tasks in a population of individuals with no known balance deficits.Visual feedback delays were investigated by simulating popular balance training software which utilizes force plates to measure center of pressure and display the results in a stimulus and response study. Ten healthy young-adult subjects with no known balance deficits were recruited to participate in this study. Subjects were asked to stand on a pair of force platforms that were linked to a computer. The system was designed to provide visual feedback corresponding to lateral weight shifts. A computer generated target provided a moving stimulus the subjects attempted to match. The stimulus files presented approximately 20 seconds of movement in a periodic (sinusoidal) or non-periodic pattern. Stimulus frequencies ranged between 0.2 and 1.0 Hz with amplitude sufficient to require the subject to move safely within 50% of his/her base of support. Stimulus presentation was randomized and included both normal (control) and phase delayed (experimental) trials. Results of the experiment point to a noticeable improvement of performance with repeated trials. Regardless of introduced phase delays, study participants improved their performances as they were exposed to more trials, suggesting learning and predictive behavior. Random stimuli produced no noticeable improvements in performance across days of testing, as expected. Visual biofeedback systems may skew performance assessments of balance training because they contain periodic stimuli that are predictable.

Examining a countermovement jump (CMJ) force-time curve related to net impulse might be useful in monitoring athletes' performance. This study aimed to investigate the reliability of alternative net impulse calculation and net impulse characteristics (height, width, rate of force development, shape factor, and proportion) and validate against the traditional calculation in the CMJ. Twelve participants performed the CMJ in two sessions (48 hours apart) for test–retest reliability. Twenty participants were involved for the validity assessment. Results indicated intra-class correlation coefficient (ICC) of ≥ 0.89 and coefficient of variation (CV) of ≤ 5.1% for all of the variables except for rate of force development (ICC = 0.78 and CV = 22.3%). The relationship between the criterion and alternative calculations was r = 1.00. While the difference between them was statistically significant (245.96 ± 63.83 vs. 247.14 ± 64.08 N s, p < 0.0001), the effect size was trivial and deemed practically minimal (d = 0.02). In conclusion, variability of rate of force development will pose a greater challenge in detecting performance changes. Also, the alternative calculation can be used practically in place of the traditional calculation to identify net impulse characteristics and monitor and study athletes' performance in greater depth.

Examining a countermovement jump (CMJ) force-time curve related to net impulse might be useful in monitoring athletes' performance. This study aimed to investigate the reliability of alternative net impulse calculation and net impulse characteristics (height, width, rate of force development, shape factor, and proportion) and validate against the traditional calculation in the CMJ. Twelve participants performed the CMJ in two sessions (48 hours apart) for test–retest reliability. Twenty participants were involved for the validity assessment. Results indicated intra-class correlation coefficient (ICC) of ≥ 0.89 and coefficient of variation (CV) of ≤ 5.1% for all of the variables except for rate of force development (ICC = 0.78 and CV = 22.3%). The relationship between the criterion and alternative calculations was r = 1.00. While the difference between them was statistically significant (245.96 ± 63.83 vs. 247.14 ± 64.08 N s, p < 0.0001), the effect size was trivial and deemed practically minimal (d = 0.02). In conclusion, variability of rate of force development will pose a greater challenge in detecting performance changes. Also, the alternative calculation can be used practically in place of the traditional calculation to identify net impulse characteristics and monitor and study athletes' performance in greater depth.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The evolution of techniques for the development of equipment capable of translating the results taken from a diverse and complex set of tasks carried out by the human body, has become an important item on the scientific communities agenda. Within the context of such equipment, the force plate has shown itself capable of being implemented for the task of measuring phenomena, which before could only be observed visually. This work has as its objective to describe and develop an extensometric, multiaxial force plate, for use as a biomedical assistance apparatus. Sensors for the detection of forces such as strain gauges were used and fixed in predetermined areas on the four transducers, which are an integral and fundamental part of the force plate apparatus. The cell design was completed using geometry capable of coupling with the minimum of interference the two different forces present within the structure. In this manner it is possible to quantify the forces in three orthogonal directions. The prototype developed can be utilized, for example as an evaluation tool for both gait and stability research. In parallel to the development of the force plate, equipment for carrying out the conditioning and digitalization of signals originating from the load cells was designed and constructed. The control of the acquisition processes as well as the processing of signals received from the force plate is carried out by the use of a specific applicative, which makes the quantitative values of the forces, strength and momentum available, allowing for the calculation of the parameters used for the respective biomedical evaluations, especially those dealing with the oscillation of the human body in an erect near static posture. Still further the applicative provides a confidence ellipse obtained from the stability evaluations carried out along with the coordinates of pressure center and standard stability indexes obtained instantaneously. / A evolução das técnicas para desenvolver equipamentos capazes de traduzir o resultado de diversas tarefas complexas exercidas pelo corpo humano, tornou-se evidente para a comunidade científica. Dentre esses equipamentos, a plataforma de força mostrou ser uma ferramenta capaz de ser empregada para a mensuração de fenômenos antes só observados. Este trabalho tem por objetivo descrever o projeto e o desenvolvimento de uma plataforma de força extensométrica, multiaxial, para uso em instrumentação biomédica. Sensores para detecção de esforços, do tipo strain gauge, foram utlizados e fixados em regiões previamente determinadas nos quatro transdutores que compõem o conjunto da plataforma. O projeto das células considera uma geometria capaz de desacoplar, com mínima interferência, dois esforços diferentes, presentes na mesma estrutura. Assim, pode-se quantizar esforços em três direções ortogonais. O protótipo desenvolvido pode ser utilizado como ferramenta para avaliações de marcha e estabilidade, por exemplo. Paralelamente ao desenvolvimento da plataforma, um equipamento para realizar o condicionamento e digitalização dos sinais provenientes das células de carga foi projetado e construído. O controle dos processos de aquisição e processamento dos sinais advindos da plataforma de força é realizado através de um aplicativo específico que disponibiliza os valores quantitativos dos esforços de força e momento, os quais permitem o cálculo de parâmetros relevantes às avaliações biomédicas, particularmente em avaliações a cerca da oscilação do corpo humano na postura ereta quasi-estática. O aplicativo fornece ainda as elipses de confiança obtidas a partir das avaliações de estabilidade realizadas, juntamente com as coordenadas do centro de pressão e índices de estabilidade padrão e instantâneos obtidos. / Mestre em Ciências

The ability to produce force rapidly has the potential to directly influence sprinting performance through changes in stride length and stride frequency. This ability is commonly referred to as the rate of force development (RFD). For this reason, many elite sprinters follow a combined program consisting of resistance training and sprint training. The purpose of this study was to investigate the strength, endocrine and body composition adaptations that occur during distinct phases of a block periodized training cycle in a 400 m Olympic level sprinter. The athlete is an elite level 400 m male sprinter (age 31 years, body mass: 74 kg, years of training: 15 and Personal Best (PB): 45.65 s). This athlete completed four distinct training phases of a block periodized training program (16 weeks) with five testing sessions consisting of testosterone:cortisol (T/C) profiles, body composition, vertical jump, and maximum strength testing. Large fluctuations in T/C were found following high volume training and the taper. Minor changes in body mass were observed with an abrupt decrease following the taper which coincided with a small increase in fat mass percentage. Jump height (5.7%), concentric impulse (9.4%), eccentric impulse (3.4%) and power ratio (18.7%) all increased substantially from T1 to T5. Relative strength increased 6.04% from T1 to T5. Lastly, our results demonstrate the effectiveness of a competitive taper in increasing physiological markers for performance as well as dynamic performance variables. Block periodization training was effective in raising the physical capabilities of an Olympic level 400 m runner which have been shown to directly transfer to sprinting performance.