Background: Muscle quality (MQ) is an important metric to predict future declines in muscle function. Ultrasonographic measures of muscle thickness (MT) and shear wave velocity (SWV) are clinically accessible, inexpensive, and may offer insight into age-related MQ changes. Currently, there is a lack of consensus on the utility of shear wave elastography to detect age-related changes in muscle stiffness and on protocol standardization. Methods: MT, MQ, and SWV were assessed in the tensor fascia latae (TFL), rectus femoris (RF), vastus lateralis (VL), and gluteus medius (GM) using ultrasonography across three groups: Low Fall Risk Young Adults (N=21), Low Fall Risk Older Adults (N=15), and High Fall Risk Older Adults (N=17). Maximal isometric contractions of knee extensors and hip abductors were performed, as well as the 5 times Sit to Stand test and Four Square Step Test (FSST). The High Fall Risk Older Adult group also received Computed Tomography (CT) scans in the hip abductors and knee extensors to compare ultrasound muscle quality measures to CT-based measures. Results: Knee extensor MQ was lower in high fall risk older adults than low fall risk younger adults (P<0.05). Hip abductor MQ was lower in high fall risk older adults compared to both low fall risk older and younger adults (P<0.05). SWV was lower in both low and high fall risk older adults in the TFL only. High fall risk older adults who performed above the mean of the group on physical function tests showed more variability in SWV measurements in both the TFL (P<0.05) and the GM (P<0.05) than those who fell below the mean. SWV did not change in response to an acute maximal isometric contraction, and there were no significant correlations between ultrasound-based and CT-based measures of MQ. Interpretation: Age-related changes in MT and SWV may be muscle-specific and influenced by the functional capacity and biomechanical role of the muscle. Ultrasonography is a valuable tool to assess changes in MT, quality, and stiffness when used in conjunction with other non-invasive rehabilitation testing, however SWV did not show significant correlations with CT-based measures of MQ in a cohort of high fall risk older adults. More research is needed to improve shear wave elastography imaging protocols and interpretation in context with age-related physiological changes.