ABSTRACT
[Purpose] The aim of this study was to use ultrasound imaging equipment for in vivo observation of the popliteus muscle thickness during rest and exercise to examine its functional characteristics and to establish a training method for this muscle. [Subjects and Methods] The subjects included 30 healthy adults (15 men and 15 women). The measurement tasks, consisting of isometric knee flexion and extension and internal rotation of the lower leg were performed in an arbitrary order. The popliteus muscle thickness was measured using an ultrasound. [Results] The popliteus muscle thickness significantly increased in the internal rotation in 27 subjects (90%), whereas, it remained unchanged in the remaining three subjects (10%). [Conclusion] This study differed from most of the previous studies because it involved in vivo observation of the popliteus muscle. We found that ultrasound was an effective method for the measurement of popliteus muscle thickness. The results suggest that internal rotation of the lower leg is the most effective exercise for working the popliteus muscle.
ABSTRACT
[Purpose] The purpose of this study was to investigate and evaluate the timing and amount of muscle activity during forward-stepping motion. [Subjects and Methods] Seven healthy subjects participated in this study. The task was to step forward from a static standing position. Timing and amount of muscle activity were measured during the task. Muscle activities of the stance leg and the swing leg were measured using surface electromyography (EMG). [Results] A high negative correlation was found between the rate of change in the amount of tibialis anterior muscle activity of the stance leg and the reaction time. High positive correlations were found between the rates of change in the gastrocnemius and soleus muscles and the reaction time of the swing leg. [Discussion] Forward-stepping motion can be accomplished using two strategies. One is to swing the leg out taking a step forward using the gastrocnemius and soleus muscles of the swing leg. The other is to take a step forward using the tibialis anterior muscle of the stance leg. Increasing the activity of the tibialis anterior muscle of the stance leg may lead to taking a step forward rapidly.
ABSTRACT
[Purpose] The purpose of this study was to perform kinematic and kinetic analyses of the ankle during both forward and backward walking using three-dimensional motion analysis. [Subjects] The subjects were 11 healthy adults. [Methods] Measurements of forward and backward walking motions were taken using a three-dimensional motion analysis device and 3 ground reaction force plates. The analysis segment was the standing phase and the items analyzed were walking time, maximum dorsal flexion of the ankle, maximum angle of plantar flexion, peak ankle power in the sagittal plane, workload of the ankle, and work rate. Statistical analysis consisted of comparisons using the t-test for each of the items measured during both forward and backward walking. [Results] The backward walking group had significantly lower ankle power, workload, and work rate. [Conclusion] The propulsive force in backward walking must come from some factor other than the ankle. The analysis of joint power is an important index for understanding the motion.
ABSTRACT
Few studies have examined balance training of elderly people using wobble boards. This study assessed the effects of wobble board balance training on physical function in institutionalized elderly people. This study examined 23 subjects (age 84.2 ± 5.9 years) who lived in a nursing home. The exercise program for the training group comprised balance training standing on a wobble board for 9 weeks, twice a week. In all, 11 training group subjects and 11 control group subjects completed this study. After 9 weeks, standing time on a wobble board, standing time on a balance mat, and maximum displacement distance of anterior-posterior center of pressure in the training group were significantly greater than those of the control group. Frequency analysis revealed that the power spectrum in 0.1-0.2 Hz significantly increased in the training group. These results suggest that wobble board training is effective for elderly people to improve their standing balance, by which they frequently control their center of gravity and maintain a standing posture on unstable surface conditions.
