A factor such as small sample size29 limits the con- clusions regarding non-specific neck pain and upper trapezius TrPs in patients treated with IC. The wide confidence intervals are also probably due to the small sample size. Further, we only examined the short-term effects of IC and TrPPR and post-treat- ment soreness possibly may have masked any posi- tive effects of treatment. However, we included a sham control group which also received hands-on intervention. This strengthens the evidence of clin- ical effectiveness because the placebo effect, which should not be underestimated,30 was accounted for. In our study, all measurements were made by a 4th year chiropractic student trained by a chiropractor with 28 years of clinical practice. Insuf- ficient time for practising examination procedures may act as another source of error. The examiner only had three practice sessions before the experi- ment. It has been established that the reliability of diagnosing TrPs by the use of palpation is acceptable when performed by appropriately trained and