Relationships between Patellofemoral Pain, Fear-Avoidance Beliefs, and Time Spent Walking and Sitting.

Walking and sitting are frequent activities of daily living and necessary functions for service members. Patellofemoral pain (PFP), one of the most common knee conditions in the military, can be exacerbated by these activities and therefore, impact return to duty and warfighter performance. The purpose of this study was to assess relationships between baseline PFP levels, fear-avoidance beliefs, and weekly walking and sitting frequency in individuals participating in a large clinical trial for PFP. Sixty-one individuals with PFP enrolled in the trial (20 males, 41 females) completed visual analog scales rating 0-100 their current and worst PFP in the past week. The Fear-Avoidance Beliefs Questionnaire (FABQ) was also administered, in addition to the International Physical Activity Questionnaire (IPAQ). FABQ-Total and sub-scales for physical activity (FABQ-PA) and for work (FABQ-W) were scored, and time spent walking at least 10 min (days/week and minutes/day) and sitting (hours/day) in the past week were recorded from the IPAQ. Spearman's rho (ρ) correlation coefficients were calculated to determine relationships between current pain, worst pain, FABQ-PA, FABQ-W, FABQ-Total, and time spent walking and sitting. Current pain (25.30 ± 23.45) had weak positive relationships with worst pain experienced (52.48±22.08) (ρ = .384, P =.002) and walking minutes/day (102.1±127.6) (ρ = .304, P = .017). There were no significant associations between pain, walking, or sitting with FABQ-PA (17.33±54.76), FABQ-W (11.85±6.39), or FABQ-Total (38.84±9.95). Hours spent sitting per day (6.11±3.70) also did not exhibit any significant relationships with pain or fear-avoidance beliefs. As walking and sitting are expected in daily life and work for the general population and military personnel, understanding their relationship to PFP is important. Weak, yet statistically significant relationships indicated that higher current levels of PFP were associated with worst pain experienced and with more time spent walking. Challenges with walking for extended timeframes are important to consider when evaluating return-to-duty and optimal performance for those reporting higher levels of PFP. Fear-avoidance beliefs in regard to physical activity were high. Yet, the lack of relationships between FABQ scores and walking or sitting highlights the need for future investigation into how more vigorous activities impact PFP and fear-avoidance beliefs.