This study proposes a squatting model that describes the relation between the center of gravity velocity and lower limb muscle forces that contribute to hip and knee flexion-extension and ankle dorsi-plantar flexion during squatting. Squatting exercises are experimentally monitored using a 3D motion analysis system and two force plates. Participants perform a squatting exercise with their feet shoulder-width apart without using a weight such as a barbell. Simulations using the musculoskeletal model calculate the lower limb muscle forces based on measured marker positions and floor reaction forces. The squatting model parameters are determined by a Kalman filter using the experimentally obtained center of gravity velocity, and lower limb muscle forces estimated by the simulations. The analysis results quantitatively demonstrate the contribution of each muscle to the center of gravity velocity during squatting. To verify the model accuracy, the root mean squared errors are calculated by using the center of gravity velocity that is obtained by the squatting model and the 3D motion analysis system. The root mean squared errors indicate that the contribution of each muscle to the center of gravity velocity may have differed between participants and between trials. The proposed method is expected to be utilized to evaluate the relation between the exercise velocity and muscle forces that is different among individual.

Currently, elderly people of 65 years and older constitute 29.1% of Japan's population. Frail patients are 8.7% of all elderly people 65 and older. Frailty is a weak state both physically and mentally. The probability of illness increases with age. Pole walking is an exercise designed to improve muscle strength and thereby prevent frailty in elderly people. This study applied musculoskeletal model analysis during pole walking and normal walking to clarify pole walking training effects and balance effects. Seven people with 35 plug-in gait markers attached to the body surface were examined for this study. Normal walking and pole walking were measured using a three-dimensional motion analysis system (Vicon Motion Systems) and two force plates. Position and force data were acquired at velocities of 58, 77, and 96 bpm. Measured data were analyzed using musculoskeletal model analysis software (OpenSim) procedures: scaling, inverse kinematics, residual reduction algorithm, inverse dynamics, and computer muscle control. Results obtained using a musculoskeletal model indicate details of muscle force, lower limb joint moments, and lumbar moments during pole walking. Pole walking is effective for the training of muscles working against gravity in cases of lower walking speed (58 bpm). However, cases with higher (96 bpm) walking speed were associated with better conditions for lumbar muscle training.

The purpose of this research is to verify the validity of the rotation mechanism theory of the SMA engine by experiment. The main results obtained by this research are as follows . We manufactured the equipment for the experiment to measure simultaneously rotation speed and torque, and obtained a maximum output power 1 .2W. We compared the experiment values of the rotation speed and the torque with the theoretical values , and partially verified the validity of the theory.We drew up the empirical formula which predicts the maximum output power of the SMA engine.

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