The Concurrent Validity and Reliability of Single Leg Squat Among Physically Active Females with and without Dynamic Knee Valgus.
Nazatul Izzati Jamaludin, Farhah Nadhirah Aiman Sahabuddin, Nur Syahmina Rasudin and 1 others
PMID 35693857WHAT IT FOUND
Video analysis of the single leg squat is reliable for tracking knee alignment over time in active women.
However, it does not consistently match 3D motion capture for accuracy. Validity depends on which leg is used and the squat depth, so clinicians must choose the test setup carefully.
Key findings
01Both 2-D video and 3-D motion capture showed moderate to excellent reliability for measuring knee alignment during the single leg squat.
02The agreement between 2-D video and 3-D motion capture was inconsistent, depending on whether the dominant or non-dominant leg was tested and the depth of the squat.
03At 45 degrees of knee flexion, 2-D video matched 3-D data for the non-dominant leg in both groups, but failed to match for the dominant leg.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The study only included young, physically active females with a normal body mass index. Results may not apply to men, older adults, or those who are overweight. The foot position was fixed in a neutral position during the test, which may not reflect how patients move in real life. The sample size was small (34 participants), which limits the generalizability of the findings. The single leg squat may not place enough demand on the body to reveal subtle movement differences, potentially underestimating the value of more complex tasks like jumping.
Declared interests
The study was funded by a grant from Universiti Sains Malaysia. No other conflicts of interest were declared.
The easy way to misread this
Do not conclude that 2-D video analysis is a universally accurate substitute for 3D motion capture. The study found that agreement between the two methods was inconsistent across different legs and squat depths, meaning video may overestimate or underestimate knee valgus depending on the specific test setup.