Patellofemoral joint loading during the forward and backward lunge.
Level 3 - non-randomized controlled study
Controlled within-subject laboratory biomechanical study
PubMed 33310585 · doi:10.1016/j.ptsp.2020.12.001
What was done
Twenty asymptomatic females performed six trials each of forward lunges (FL) and backward lunges (BL) to a standardized depth of 75% leg length in a university biomechanics laboratory. Three-dimensional motion capture and force platforms were used to collect kinematic and kinetic data, which were analyzed using a musculoskeletal model to estimate quadriceps force, patellofemoral joint (PFJ) reaction force, PFJ stress, PFJ loading rate, trunk tilt, and knee flexion angles across movement phases (Down vs. Up).
What was found
Multivariate analysis showed significant differences in PFJ loading variables and joint angles between movements and phases. Quadriceps force, PFJ reaction force, knee flexion angle, and PFJ loading rate were all greater during the forward lunge compared to the backward lunge, and were higher during the Up phase compared to the Down phase. The forward lunge was also performed with a lower forward trunk tilt. The abstract did not report specific numerical values, point estimates, or confidence intervals.
Why it matters
Selecting a backward lunge instead of a forward lunge substantially reduces biomechanical loading on the patellofemoral joint, suggesting a potentially safer progression in rehabilitation.
Limits
The study evaluated a small sample of 20 asymptomatic females, limiting generalizability to males or individuals with symptomatic patellofemoral pain. Joint loading parameters were derived from musculoskeletal modeling rather than direct measurement, and clinical outcomes or pain responses were not evaluated.