Estimating the Reliability and Validity of the Quadrant Hop Test in the Assessment of the Functional Stability of the Knee.

Background Many sporting activities demand multidirectional skills and movements, emphasizing the importance of various fitness components such as functional stability, strength, power, endurance, and range of motion. These aspects must be thoroughly assessed before athletes can return to sports safely following an injury. Although the single-leg hop test (SHT) is widely used as the gold standard for evaluating joint stability, it has limitations in assessing multidirectional movements. Therefore, further research is necessary to explore whether increasing the dynamicity of the hop test in different directions enhances its sensitivity in assessing knee joint stability across all four directions. The objective of this study was to investigate the applicability of a new functional assessment tool, the quadrant hop test (QHT), for evaluating lower limb functional stability. Methodology One hundred nineteen amateur sportsmen who are in the age group of 18-25 years with a limb symmetry index of the lower limb calculated through SHT of >80% were included. All the participants performed the SHT, a triple hop test (THT), a crossover hop test (CHT), and the QHT on two different days, with two investigators assessing the QHT on different days and then recording the measurements of Hop distance. Results The mean difference between SHT, THT, and CHT with QHT was 4.59%, with a moderate correlation between all the hop tests. The Cronbach's alpha revealed good intra-rater (0.917) and inter-rater reliability (0.912) of the QHT. Conclusion The QHT proves to be a reliable and valid measure for assessing the functional stability of the lower limb and is 4.59% more sensitive than SHT, THT, and CHT in assessing knee stability and in return to sports criteria.