Award Date


Degree Type


Degree Name

Doctor of Physical Therapy (DPT)


Physical Therapy

Advisor 1

Daniel Young

First Committee Member

Merrill Landers

Second Committee Member

Daniel Young

Number of Pages



Objective: To examine the reliability and validity of using a movement analysis application (MAA) to measure knee valgus angle during three functional activities used to assess return-to-sport after ACL reconstruction (ACLR). Design: Reliability and validity study Setting: University laboratory Participants: Twelve ACLR participants with a non-contact mechanism of injury and 20 healthy individuals. Independent Variables: Each subject performed single-leg drop landing, single-leg hop, and 90º cut with simultaneous 3-dimensional (3D) motion capture and video recording in the frontal plane on an iPad. Main Outcome Measures: Peak knee valgus angle during the landing phase of each task was measured using a MAA and 3D analysis. To obtain reliability, peak knee valgus angle was measured in 2 days with at least 7 days apart. Reliability was determined using intra-class correlation coefficients (ICCs) and standard errors of measurement (SEMs). Validity was assessed using Pearson correlation coefficients by comparing peak knee valgus angles between the MAA and 3D analysis. Results: Our data revealed excellent intra- and inter-rater reliability with low SEMs of using a MAA for evaluating peak knee valgus angle in both groups. Significant, moderate to large associations were found in comparing peak knee valgus angles between the MAA and 3D analysis in both groups. Conclusions: Our findings suggest that a MAA is reliable for measuring peak knee valgus angle for both healthy and ACLR participants. The actual values obtained by a MAA should be viewed with caution given that the comparison against the 3D motion analysis is moderate to large.


Reliability; Validity; Anterior cruciate ligament; Movement analysis application; Knee valgus


Physical Therapy

File Format


File Size

1.241 Kb

Degree Grantor

University of Nevada, Las Vegas




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