Browsing by Author "Arena, Sara Louise"

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    Differences in Movement and Loading Variability Between ACLR and Healthy Athletes During Bilateral and Unilateral Landings
    Mesisca, Jenna Kellie (Virginia Tech, 2023-05-31)
    The continual increase in anterior cruciate ligament (ACL) injuries in sports makes it the most common ligament injury and leads the athlete down a difficult road with reconstruction surgery (ACLR) and months of rehabilitation. Specifically, females are at a greater risk of both primary and secondary ACL injuries compared to males. The purpose of this research was to understand the differences in movement and loading variability between ACLR and healthy athletes during unilateral and bilateral landings while utilizing limb symmetry to understand between group differences. It was hypothesized that females with an ACLR would have greater variability compared to males with an ACLR and healthy female athletes. 40 ACLR and 67 healthy athletes were asked to complete seven stop jumps and 25 ACLR and 30 healthy athletes completed seven single hop trials to assess intra-subject variability. The stop jump task utilized embedded force plates and motion capture technology while the single hop task used loadsol® in-shoe force sensors. The measures studied with the stop jump included posterior and vertical ground reaction force (GRF), knee/hip abduction/adduction angles, and loading rate. The single hop measures included peak force, loading rate, and impulse. To assess variability and limb symmetry, coefficient of variation (CV) and the limb symmetry index (LSI) were calculated for each of outcome measure. A linear mixed effects model was completed in JMP (SAS Institute Inc., Cary, NC) with p<0.05 to see the effects of group, sex, and limb. During the stop jump task, the ACLR athletes showed higher variability for both posterior GRF (p<0.001), posterior GRF LSI (p<0.001), and loading rate (p=0.027) compared to controls. Females with an ACLR had higher variability in vertical GRF (p<0.001) and vertical GRF symmetry (p=0.029) compared to HC females. Additionally, females with an ACLR had higher variability in the vertical GRF (p=0.033) when compared to males with an ACLR. Knee abduction angle (p=0.024) showed males with an ACLR to have higher variability compared to females with an ACLR. For the single hop task, there was a significant difference between sex for loading rate (p<0.001), loading rate LSI (p=0.004), impulse (p=0.006), and impulse LSI (p=0.001) with males producing a higher mean CV compared to females in all measures regardless of group. Overall, these results support the hypothesis that group and sex differences exist and that females with an ACLR will have higher variability and asymmetrical movements than male ACLR patients and healthy females during bilateral landings, which could lead to increased injury risk. In unilateral landings, the results suggest that females are landing with less variability compared to males. With increased variability on the surgical limb of an athlete with an ACLR, it is likely that the athlete will have a more successful return to sport as they can react and adapt to changes in landing during sports. Future work should report reinjury rates to investigate the potential role of movement variability in injury risk and potentially determine variability thresholds for injury risk. The evaluation of bilateral and unilateral landings revealed the need to include both landing tasks in return to sport testing as well as a limb symmetry metric to understand an athlete's functional readiness to react to changing conditions during sports related movement.
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    Quantification of the Elastic and Relaxation Properties of Human Tunica Albuginea under Biaxial Loading
    Hou, Sindy Siyuan (Virginia Tech, 2019-09-20)
    Peyronie's disease (PD) affects the tunica albuginea of the penis with a formation of dense and fibrous plaques. The plaques can cause a variety of symptoms in the patient such as pain during erection, erectile dysfunction, and penile disfigurement. There are many treatment options available, though none without disadvantages. Quantification of the material properties of the tunica tissue can inform potentially improved treatments. In this study tunica tissue (n=5) from donors were tested biaxially along the circumferential and longitudinal directions to a specified load magnitude and maintained at a fixed displacement for 30 minutes to allow for stress relaxation. The loading and relaxation were then repeated for a second time. Stiffness, Young's Modulus, strain at inflection point between the toe region and linear region on the stress-strain curve, as well as percent stress relaxation after 30 minutes were compared between anatomic directions and ramp number. Only stiffness and percent relaxation showed a statistically significant difference between ramps 1 and 2, regardless of direction (p = 0.012). The results from this study report the baseline data of the biaxial mechanical properties of the tunica albuginea to be used for future comparisons to the properties of PD and graft tissue.
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    Validation and Examination of Upper Extremity Kinematics in Typically Developing Children During the Box and Blocks Functional Test using Marker-based and Markerless Technology
    Hansen, Robyn Michelle (Virginia Tech, 2023-06-30)
    Joint kinematics of upper extremity (UE) impairments in a pediatric population are often difficult to examine using marker-based motion capture. As a result of the cost and availability of tools such as marker-based motion capture in clinical settings, clinicians use functional tasks to examine improvement in movement quality. However, some of these tasks, such as the Box and Block test (BBT), which is examined in this study, rely on scoring to assess motor improvement. This scoring method can be misleading due to the possibility of movement compensation to improve scores. Therefore, finding kinematic correlations that can lead to improved BBT scores could improve the quality of functional assessments by providing discrete measures for clinicians. Understanding human motion using marker-based motion capture has been the accepted standard in biomechanics. However, it is not without its drawbacks, especially in upper extremity examination due to complex anatomical positioning. The introduction of markerless motion capture software could drastically alter how human biomechanics is analyzed in various settings. Additionally, avoiding possible errors due to clothing and skin movement could greatly improve reported results. Therefore, examining similarities in UE joint kinematics between accepted marker-based and markerless software could introduce markerless motion capture as a method for examining complex kinematics. This study aims to examine UE joint kinematics in a typically developing pediatric population while they complete the BBT, as well as validate Theia3D (Theia Markerless Inc., Kingston, ON, Canada). Marker-based motion capture was used to capture UE kinematics during the BBT. This study was performed on typically developing children aged 7, 9, and 11. Average and peak joint angles were determined, as well as hand segment velocity and path length. Significant correlations to BBT scores were found in peak shoulder flexion (FLEX) angle (r = -0.556, p-value = 0.009), peak (r = -0.479, p-value = 0.028), and average (ρ = -0.535, p-value = 0.012) wrist extension (EXT) angle, average mediolateral (ML) hand segment velocity (r = 0.494, p-value = 0.023), and path length (r = -0.522, p-value = 0.015). Additionally, significant differences between BBT scores (p-value = 0.005), peak shoulder FLEX (p-value = 0.024), and peak shoulder abduction (ABD) angle (p-value = 0.022) were found between the 7- and 11-year-old age groups. Peak elbow FLEX angle was significantly different (p-value = 0.049) between 9- and 11-year-old age groups. These results show that the BBT score could be related to the shoulder and wrist angle, as well as hand segment velocity and path length for typically developing children. Furthermore, root mean square deviation (RMSD) values less than 6° existed in all joint angles. Intraclass correlation coefficients (ICCs) greater than 0.75 were found in shoulder ABD (ICC = 0.79), forearm pronation (ICC = 0.81), wrist EXT (ICC = 0.75), and radial deviation (ICC = 0.87). Additionally, validation results between the marker-based and markerless systems show that there are differences in pose estimations and joint calculations based on rotation sequences. Overall, UE joint kinematics are shown to have correlations to BBT scores, so scores alone may not be indicative of movement quality in other patient populations. Markerless motion capture shows many benefits, however, it should be noted that, due to the complexity of upper extremity motion analysis, understanding what joint rotation sequences align the best with task-specific motions is important.