4.1 Strengths and weaknesses
Type-1 errors
We used 8 weeks and 6 months’ follow-up with several outcomes to register the development of improvement after different interventions. The clinical setting and the choice of ordinary, well known physiotherapeutic approach ensured the external validity. This study strictly adhered to the CONSORT guidelines for randomized controlled trials. Randomization, concealed allocation and blinding strategies were performed, as these features are known to minimize bias. There were a few dropouts and the adherence to the intervention was good. We chose the apt statistical tests that would minimize Type-1 errors, since this is a non-serious and self-limiting condition. Only male subjects were included in the study. Including both genders may provide information about these interventions for both sexes and can generalize the results. A strict physiotherapy guideline, prohibited an individual adjustment of treatment and may have influenced the results. Although much research could be done on Mill’s manipulation alone, it would be interesting to study the efficacy on acute and sub-acute conditions, using similar inclusion criteria as in our study.