An investigation into the effects of a simulated effusion in healthy subjects on knee kinematics during jogging and running

Background Knee joint effusion can lead to changes in the activation of surrounding musculature and result in delayed return to baseline daily and sporting activity following injury. However, the effects of an isolated knee joint effusion on control of movement during cyclical activities such as gait are poorly understood. Methods Knee angular displacement and velocity was measured during treadmill jogging (8 km h−1) and running (12 km h−1) in 12 healthy subjects before and after a simulated knee joint effusion. Two separate pre-effusion recordings were taken to account for test–retest variability in gait measurement techniques. Findings Subjects demonstrated a small yet significant decrease in peak knee flexion following heel strike at 8 km h−1 as a result of the effusion (P < 0.05). However, there were no significant effects seen at 12 km h−1. Interpretation Previous work has suggested that knee joint movement during walking and jump landing is affected by an effusion. However, this work demonstrates that these effects are minimal during jogging and running. Our results suggest that it may be prudent to consider measurement variability in future studies of this nature.