Tomoyuki YAMAUCHI

The relationship of the Functional Reach Test (FRT) value with the Center of Pressure Excursion (COPE) and physical function remains unclear, and would be influenced by different population characteristics and movement patterns used in the FRT. Therefore, we explored the relationship between the FRT value and the COPE and physical function in healthy young and older individuals classified according to movement patterns. In 21 healthy young participants (42 sides) and 20 older participants (40 sides), three-dimensional motion analysis was performed during the FRT and physical function assessments. The participants were assigned to two clusters after performing a motion analysis during the FRT. Kinematic and kinetic parameters during the FRT and physical function assessment results were compared between the clusters for both groups. Correlation analysis was performed to investigate the relationships of the FRT value with COPE and physical function parameters in each cluster, in young and older individuals separately. The results showed that the hip strategies could be divided into two groups according to the degree of use (Small Hip Strategy, SHS Group; Large Hip Strategy, LHS Group). In the older SHS group, the FRT values were significantly correlated with the COPE (r = 0.75), toe grip strength (r = 0.62), and the five-times sit-to-stand test time (r = -0.52). In the older LHS group and in both groups of young individuals, there were no significant correlations of the FRT value with any parameters. The FRT value reflects the COPE and physical function only in older individuals using the SHS. This could explain previous discrepant results. As there is no simple relationship between the FRT value and physical function, it is important to include movement strategy assessment when using the FRT in clinical evaluations.

Abstract Background: There is no comprehensive report on quadriceps femoris muscle parameters’ association with isokinetic knee extensor strength, and no study has comprehensively clarified the relationship with motor function. To investigate the relation of isokinetic knee extensor strength and motor functions with phase angle, muscle echo intensity, and muscle thickness, to find alternative methods for knee extensor strength assessment. Methods: This cross-sectional study evaluated the associations between phase angle (PA) (measured using bioelectrical impedance analysis), muscle echo intensity (EI), and muscle thickness (MT) (measured using ultrasound) and isokinetic knee extensor strength (measured as maximum torque at 60 degree/s using an isokinetic dynamometer), and motor functions evaluated by gait speed (usual and maximum), five chair stands time, and stand up score.Results: The study comprised of 33 young healthy adults (12 males and 21 females; mean age, 22.2 years). Both sexes showed a significant correlation between isokinetic knee extensor strength and PA (males, r = 0.65, females, r = 0.54), muscle EI (males, r = -0.53, females, r = -0.54), and MT (males, r = 0.34, females, r = 0.38). In addition, a significant correlation was found between PA and maximum gait speed (males, r = 0.64, females, r = 0.44), five chair stands time (males, r = -0.69, females, r = -0.62), and stand up score (females, r = 0.45), and between muscle EI and maximum gait speed (males, r = -0.34, females, r = -0.42), five chair stands time (males, r = 0.37, females, r = 0.33), and stand up score (females, r = -0.30).Conclusions: The study suggests the potential of phase angle and muscle echo intensity as alternative assessment methods for isokinetic knee extensor strength.