Table 2 Quality items, explanation, and scoring key for included studies

Was PPT measured correctly, and was reliability pre-tested?

Valid/reliable technique includes taking 3 measures and averaging all 3 or last 2.

Both = 1, Valid technique only = 0.5, Pre-tested reliability only = 0.5, Neither = 0

Was the assessor blinded?

–

Yes = 1, No = 0

Was there appropriate random number generation and concealment?

Random sequence generation, e.g. random number generator. Adequate concealment until randomisation occurs, e.g. sequential opaque envelopes.

Method appropriate = 1, Method for one component but not both reported and appropriate = 0.5, Method NR = 0

Were active and control interventions well described?

–

Yes = 1, No = 0

Were practitioners appropriate and sufficiently experienced?

Practitioner with training in spinal manipulative therapy, ≥3 years clinical experience.

Yes = 1, No/NR = 0

Were attempts made to keep participants naïve to study aims? If sham-controlled, were they blinded, and confirmed?

If sham group: Blinded? Confirmed? Naïve to study aims?

If no sham group: Naïve to study aims?

If sham: Blinding confirmed = 1, Blinding attempted but not confirmed and/or naïve = 0.5, Not blind/naïve = 0

If no sham: Naïve = 1, Not naïve/NR = 0

Were study conditions controlled?

An effort to control temperature, room, interactions, expectations

Yes = 1, No/NR = 0

Was there control for psychosocial modifiers/confounders?

Statistical control

Yes = 1, No = 0

Was a sample size calculation performed and met?

Performed based on PPT estimates?

Yes = 1, Performed and met but NR based on what = 0.5, Not performed, not performed based on PPT, or not met = 0

Were losses and exclusions reported clearly?

–

Yes = 1, No = 0

Missing data reported? Imputation method reported and appropriate, if required?

–

Yes = 1, No/NR = 0

Were estimates and p-values/CIs reported for between-group differences?

–

Yes = 1, Estimates/CIs NR but p-values non-significant = 1, No = 0