Table 1

List of items that will be extracted from all the eligible studies

Background informationStudy ID/author
Title of the study
Year of publication
Country of study
Source of funding
Aims/objectives of the study
MethodologyStudy design
Sample size
Patient population characteristics - age, gender, diagnosis, confounding factors (like restriction of activity level)
Control population characteristics - age, gender, any confounding factors
Spinal pain characteristics - average duration of pain, laterality, severity
Biopsy samples - type of biopsy done and how muscle sample was obtained (eg, surgical, ultrasound guided,), from which muscle, landmark site/location taken from, unilateral or bilateral region
Synthesis of resultsAnalysis and outcome measures - fibre type (I, IIa, IIb/IIc, IIx) slow, intermediate or fast twitch, fibre type percentage/ distribution, fibre size, area occupied by fibre types, any other fibre characteristics if mentioned
Study limitationsConfounding factors, observational bias, measurement techniques