Single-leg horizontal jump is more suitable for assessing lower limb function compared to single-leg vertical jump in patellofemoral pain patients.

Background: The single-leg vertical jump (SLVJ) and single-leg horizontal jump (SLHJ) are commonly used assessments for individuals with lower limb injuries. Despite previous studies comparing these tasks across various individuals, their comparative effectiveness in evaluating lower limb function in individuals with patellofemoral pain (PFP) and any potential sex differences in these functional tests remain uncertain.

Research Question: The purpose of this study was to determine which jump task is more suitable for functional assessment in PFP patients by comparing the differences in jump performance and biomechanical variables between PFP patients and healthy individuals during the SLVJ and SLHJ. Furthermore, the study aimed to determine whether the more suitable functional assessment for male and female PFP patients is consistent.

Methods: A total of 24 PFP patients (15 males, 9 females) and 17 healthy individuals (9 males, 8 females) were recruited. Three-dimensional kinematic and kinetic data were collected during the propulsion and landing phases of the SLVJ and SLHJ. Two-way ANOVA was used to compare each dependent variable between groups (PFP vs. healthy controls) and sex (male vs. female).

Results: Both male and female PFP groups presented a reduced jump distance than the control group in the SLHJ (p = 0.002), but no significant difference was detected in the SLVJ. Both male and female PFP groups displayed increased hip work (p = 0.005) and contribution (p = 0.009) and reduced knee work contribution (p = 0.034) during the propulsion phase of the SLHJ compared to the control group. Moreover, female participants of PFP and control groups performed shorter jump distances (p ≤ 0.001) and had less knee work (p < 0.001) during the propulsion phase of vertical and horizontal jumps than males.

Conclusion: Single-leg horizontal jump is more suitable for assessing lower limb function in PFP patients, characterized by reduced knee work contribution impacting jump performance, and this applies to both male and female PFP patients.