Reliability and validity of the medial standing overhead arm reach (SOAR) test as a measure of functional hip adduction motion.

OBJECTIVE: The Posterior Standing Overhead Arm Reach (SOAR) test has been previously reported as a reliable clinical measure of closed chain hip extension motion. The proposed Medial SOAR test expands on that testing approach to provide a similar measure of functional hip adduction motion. This was a preliminary intrarater and interrater reliability and validity study of the Medial SOAR test as a measure of functional hip adduction. DESIGN: Cross-sectional. SETTING: University motion analysis laboratory. PARTICIPANTS: Fifty hips were assessed in 25 (22 female) asymptomatic participants (mean age = 23.4 years, SD = 0.8). MAIN MEASURES: Maximum hip adduction during the Medial SOAR test was measured with a standard goniometer independently by two examiners. The test was also performed using three-dimensional motion capture. The intrarater and interrater reliability of the goniometric measure was determined using intraclass correlation coefficients, and the relationship between measures obtained via goniometry and three-dimensional motion capture was assessed with Pearson correlations and Bland-Altman analysis. RESULTS: Intrarater reliability (ICC2,3) was 0.88 (95% CI = 0.80-0.92) for Examiner 1 and 0.87 (95% CI = 0.79-0.92) for Examiner 2. The standard error of measurement and minimal detectable change were less than 3.0°. Interrater reliability demonstrated an intraclass correlation coefficient = 0.62 (95% CI = 0.28-0.79). Pearson correlations were significant with low-to-moderate associations (r = 0.49, P < 0.001; r = 0.24, P = 0.045). CONCLUSIONS: Similar to the previously reported Posterior SOAR test, the Medial SOAR test demonstrated acceptable intrarater and interrater reliability, along with low-to-moderate associations with three-dimensional motion capture. The Medial SOAR test has the potential to provide a reliable and accurate assessment of closed chain hip adduction.

Mechanics of the foot and ankle joints during running using a multi-segment foot model compared with a single-segment model.

The primary purpose of this study was to compare the ankle joint mechanics, during the stance phase of running, computed with a multi-segment foot model (MULTI; three segments) with a traditional single segment foot model (SINGLE). Traditional ankle joint models define all bones between the ankle and metatarsophalangeal joints as a single rigid segment (SINGLE). However, this contrasts with the more complex structure and mobility of the human foot, recent studies of walking using more multiple-segment models of the human foot have highlighted the errors arising in ankle kinematics and kinetics by using an oversimplified model of the foot. This study sought to compare whether ankle joint kinematics and kinetics during running are similar when using a single segment foot model (SINGLE) and a multi-segment foot model (MULTI). Seven participants ran at 3.1 m/s while the positions of markers on the shank and foot were tracked and ground reaction forces were measured. Ankle joint kinematics, resultant joint moments, joint work, and instantaneous joint power were determined using both the SINGLE and MULTI models. Differences between the two models across the entire stance phase were tested using statistical parametric mapping. During the stance phase, MULTI produced ankle joint angles that were typically closer to neutral and angular velocities that were reduced compared with SINGLE. Instantaneous joint power (p<0.001) and joint work (p<0.001) during late stance were also reduced in MULTI compared with SINGLE demonstrating the importance of foot model topology in analyses of the ankle joint during running. This study has highlighted that considering the foot as a rigid segment from ankle to MTP joint produces poor estimates of the ankle joint kinematics and kinetics, which has important implications for understanding the role of the ankle joint in running.

A preliminary study of the reliability and validity of the Posterior Standing Overhead Arm Reach (SOAR) test as a measure of functional hip extension motion.

BACKGROUND: Current clinical tests do not provide a method to reliably measure closed chain hip extension. We developed the Posterior Standing Overhead Arm Reach (SOAR) test for this purpose. OBJECTIVES: This was a preliminary intrarater and interrater reliability and validity study of the Posterior SOAR test as a measure of functional hip extension. DESIGN: Cross-sectional. METHOD: Hip extension on the Posterior SOAR test was measured with a standard goniometer independently by two examiners. The test was then repeated using three-dimensional (3D) motion capture. Intraclass correlation coefficients (ICC) were used to determine the intrarater and interrater reliability of the goniometric measure and Pearson correlations were used to assess the relationship between measures obtained via goniometry and 3D motion capture. RESULTS: Fifty hips were assessed in 25 (14 female, 11 male) asymptomatic participants (mean age = 24.0 years, SD = 1.1). Intrarater reliability (ICC2,3) was 0.80 (95% CI = 0.68-0.88) for Examiner 1 and 0.77 (95% CI = 0.64-0.86) for Examiner 2, indicating excellent reliability. The standard error of the measure (SEM90) ranged from 2.5° to 3.0° with a minimal detectable change (MDC90) of 3.5° to 4.2°. Interrater reliability was good with ICC = 0.65 (95% CI = 0.36-0.80). Pearson correlations were significant with low to moderate associations (r = 0.36, P = 0.009; r = 0.51, P < 0.001). CONCLUSIONS: The Posterior SOAR test demonstrated excellent intrarater reliability, good interrater reliability, and low to moderate associations with 3D motion capture. The Posterior SOAR test has the potential to provide a reliable and accurate assessment of closed chain hip extension.

Elastic energy within the human plantar aponeurosis contributes to arch shortening during the push-off phase of running.

During locomotion, the lower limb tendons undergo stretch and recoil, functioning like springs that recycle energy with each step. Cadaveric testing has demonstrated that the arch of the foot operates in this capacity during simple loading, yet it remains unclear whether this function exists during locomotion. In this study, one of the arch׳s passive elastic tissues (the plantar aponeurosis; PA) was investigated to glean insights about it and the entire arch of the foot during running. Subject specific computer models of the foot were driven using the kinematics of eight subjects running at 3.1m/s using two initial contact patterns (rearfoot and non-rearfoot). These models were used to estimate PA strain, force, and elastic energy storage during the stance phase. To examine the release of stored energy, the foot joint moments, powers, and work created by the PA were computed. Mean elastic energy stored in the PA was 3.1±1.6J, which was comparable to in situ testing values. Changes to the initial contact pattern did not change elastic energy storage or late stance PA function, but did alter PA pre-tensioning and function during early stance. In both initial contact patterns conditions, the PA power was positive during late stance, which reveals that the release of the stored elastic energy assists with shortening of the arch during push-off. As the PA is just one of the arch׳s passive elastic tissues, the entire arch may store additional energy and impact the metabolic cost of running.