Improving the Reproducibility of the Standing Forward Flexion Test After Specific Training: A Cross-Sectional Study

Area of Science:

• Osteopathic manipulative medicine
• Musculoskeletal assessment
• Clinical biomechanics

Background:

• The standing forward flexion test (SFT) is a common clinical tool for assessing sacroiliac joint (SIJ) mobility in osteopathic and manual therapy.
• Previous studies have reported inconsistent reliability of the SFT due to poor inter- and intra-examiner agreement.
• Variability in SFT results may stem from examiner training and methodological inconsistencies rather than inherent test limitations.

Purpose of the Study:

• To evaluate the impact of a structured palpatory training program on the reproducibility of the SFT.
• To identify which phase of the SFT (trunk flexion or standing) contributes most to measurement variability.
• To assess the potential of a modified 'reverse SFT' procedure for improved standardization.

Main Methods:

• A cross-sectional study involving 72 asymptomatic participants assessed by two senior osteopathy students.
• Examiner agreement was measured at baseline (T0), after 25 hours of specific SFT training (T1), and in a final assessment (T2).
• The SFT was performed classically, and separately for each phase (flexion and standing), with a 'reverse SFT' also evaluated. Reliability was quantified using weighted Cohen's kappa (κw), Gwet's AC2, and Brennan-Prediger kappa.

Main Results:

• Baseline SFT reliability was poor (κw ≈ 0.14).
• Following the 25-hour training program, both intra- and inter-examiner reproducibility significantly improved (κw = 0.60–0.83; AC2 = 0.60–0.82).
• Slightly higher agreement was observed during the flexion phase compared to the standing phase.

Conclusions:

• Palpatory variability in the SFT is largely attributable to insufficient training and inconsistent methodology.
• A structured, consensus-based palpatory training program of 25 hours can substantially enhance the diagnostic reproducibility of the SFT.
• The 'reverse SFT' procedure shows promise as a more stable and standardized approach for clinical and educational settings.