In this study, the intra- and interexaminer reliability of the pennation angle and muscle thickness measurements of the medial gastrocnemius muscle was good to very good. Therefore, we suggest that the pennation angle and muscle thickness measurements of the medial gastrocnemius muscle obtained from rehabilitative ultrasound imaging would be useful for clinical assessment in poststroke patients.

Improvement of walking ability provides opportunities for stroke patients to participate in the community. Our finding, additional cognitive tasks can interfere with the independently basic activities of daily living in stroke patients, may provide basic information for use in development of rehabilitation programs for stroke patients. Spatio-temporal gait parameters under the dual-task condition measured using the GAITRite system may be useful for clinical assessment in post-stroke patients.

These finding demonstrate that measurements of the tibialis anterior muscle using USI can be useful for clinical assessment in stroke patients. In addition, objective and quantitative measurements of tibialis anterior muscle using USI may provide appropriate management for the walking recovery of stroke patients.

Objective: To investigate and compare the size of the rectus femoris (RF), tibialis anterior (TA), and medial gastrocnemius (GMM) using ultrasound (US) imaging in young, elderly, and very elderly groups. Design: Cross sectional study. Methods: This study consisted of 25 young (age 20 years), 24 elderly (age 65-74 years), and 25 very elderly (age 75-90 years) people with no physical dysfunctions. The cross sectional area (CSAs) of the RF and muscle thickness of the TA and GMM were measured at rest and during contraction using an US system. Results: The CSA of the RF and thickness of the TA and GMM were significantly smaller in the elderly and very elderly groups than in the young group (p<0.05). There was a significant difference of the CSA of the RF at rest and during contraction between elderly and very elderly group (p<0.05). In the comparison of the TA and GMM thickness between elderly and very elderly groups, there were no significant differences except for the TA thickness during contraction. There was a significant difference in the percentage change in RF CSA among the three groups (p<0.05). Conclusions: Our results revealed loss of muscle mass in the RF, TA, and GMM in elderly and very elderly people (≥65 years old). In particular, the greatest age-related decline in muscle mass was observed for the RF. Furthermore, the CSA of the RF declined with aging in the very elderly groups (≥75 years old).