Effects of hip stability training versus standard care on Q-angle and pain in marathon runners with patellofemoral pain syndrome: A retrospective cohort study.
Hip stability training and standard care were each associated with improvements in static Q-angle, running pain, and function, but Hip-STAB was not superior to standard care in marathon runners with patellofemoral pain syndrome.
Key Findings
Results
Both hip stability training and standard care produced significant improvements over 16 weeks in Q-angle, running pain, and knee function, but neither treatment was superior to the other.
Linear mixed-effects models showed significant time effects for Q-angle, VAS-Run, and AKPS (all p < 0.001)
No significant time-by-group interactions were found for Q-angle (p = 0.190), VAS-Run (p = 0.302), or AKPS (p = 0.317)
Bonferroni-adjusted post-hoc comparisons did not identify significant between-group differences at W16
Outcomes were assessed at baseline (W0) and at 4, 8, and 16 weeks (W4, W8, W16)
Results
Q-angle reduction was significantly correlated with improvement in running pain in both treatment groups.
In the Hip-STAB group, the association between Q-angle reduction and VAS-Run improvement was r = 0.35 (95% CI 0.16 to 0.52, p < 0.001)
In the Control group, the correlation was r = 0.44 (95% CI 0.26 to 0.59, p < 0.001)
The authors cautioned that this correlation 'should be interpreted as an association rather than evidence of a causal biomechanical mechanism'
Methods
After 1:1 propensity score matching, 94 runners were retained in each group from an initial pool of 312 eligible participants.
487 marathon runners with PFPS were initially identified
312 met the eligibility criteria
1:1 propensity score matching resulted in 94 runners per group (Hip-STAB and Control)
This was a retrospective cohort study design
Background
The clinical relevance of static Q-angle changes in the context of patellofemoral pain syndrome remains uncertain.
The study used standing (static) Q-angle as a primary outcome measure
Primary outcomes included standing Q-angle, visual analog scale pain during running (VAS-Run; 0–100 mm), and Anterior Knee Pain Scale (AKPS; 0–100 points)
The authors noted that 'the clinical relevance of static Q-angle changes remains uncertain' in the abstract
What This Means
This research suggests that marathon runners with patellofemoral pain syndrome (commonly known as 'runner's knee') improved over 16 weeks regardless of whether they received hip stability training or standard care. Both groups showed reductions in knee pain during running and improvements in knee function, and neither approach proved to be clearly better than the other. The study used a statistical technique called propensity score matching to make the two groups as comparable as possible before comparing outcomes.
The study also found that decreases in the Q-angle — a measurement of knee alignment — were associated with less running pain in both groups. However, the researchers cautioned that this relationship does not necessarily mean that changing the Q-angle directly causes pain relief; the two measures simply moved together over time, which could reflect many overlapping factors. The clinical importance of changes in static (standing) Q-angle is still not well established.
This research suggests that standard care may be just as effective as adding specialized hip stability exercises for this population of marathon runners, at least over a 16-week period. This finding could be relevant for clinicians and athletes deciding how to prioritize rehabilitation resources, though the retrospective design of the study limits the strength of causal conclusions that can be drawn.
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Bai D, Cao X, Feng S. (2026). Effects of hip stability training versus standard care on Q-angle and pain in marathon runners with patellofemoral pain syndrome: A retrospective cohort study.. PloS one. https://doi.org/10.1371/journal.pone.0357057