• tendinopathy
• statistics
• lower limb
• upper extremity

Systematic reviews can provide evidence that informs clinical practice. However, in order to allow valid comparisons, researchers, reviewers and clinicians need to know what was done, and how similar or different study populations were (clinical heterogeneity). The importance of considering clinical heterogeneity when comparing data sets becomes evident when considering the topical issue of central sensitisation in tendinopathy. Central sensitisation refers to the increased responsiveness of the central nervous system.1 Central sensitisation encompasses such features as altered sensory processing in the brain, malfunctioning of descending antinociceptive mechanisms, and increased activity of pain facilitatory pathways, among others.2 Central sensitisation is frequently present in various chronic musculoskeletal pain disorders, including chronic low back pain,3 and rheumatoid arthritis.4 A recent systematic review reported the presence of central sensitisation in tendinopathy; however, these findings were based mainly on upper limb tendons, so data cannot be generalised to the lower limb.5 In fact, it is often argued that unlike upper limb tendinopathy, individuals with lower limb tendinopathy do not display evidence of central sensitisation. There is evidence to support this assertion, with studies appearing to confirm the absence of central sensitisation in the lower …