Tactile acuity is typically measured by a two-point discrimination test (TPD) and a two-point estimation task (TPE). In the back area, they are only conducted in the lumbar and cervical regions of the spine. Considering that such measurements have not been conducted in the sacral regions, the purpose of this study was to assess the inter- and intra-examiner reliability of the TPD and TPE at the level of the S3 segment. The study included 30 pain-free subjects aged 20–30 years. Tests were performed with a pair of stainless hardened digital calipers. The TPD was measured in two locations: 5 and 15 cm from the midline; for TPE both, points were located inside the measured area. Session 1 involved assessments by two examiners in 10-min intervals. Session 2 was measured by one examiner, at analogous intervals between tests. The TPD inter-rater reliability was excellent for mean measurements (ICC_3.2: 0.76–0.8; ICC_3.3: 0.8–0.92); the intra-rater reliability was excellent for mean measurements (ICC_2.2: 0.79–0.85; ICC_2.3: 0.82–0.86). The TPE inter-rater reliability was good to excellent for mean measurements (ICC_3.2: 0.65–0.92; ICC_3.3: 0.73–0.94); the intra-rater reliability for all studies (ICC_2.1, ICC_2.2, ICC_2.3) was excellent (0.85–0.89). Two measurements are sufficient to achieve good reliability (ICC ≥ 0.75), regardless of the assessed body side.

Background: The phenomenon of fear of movement is called kinesiophobia. Kinesiophobia is a significant factor that complicates the treatment process. Fear of movement and physical activity is a risk factor for the transformation of acute pain into chronic pain. Therefore, the assessment of the level of kinesiophobia is a prognostic factor for disability and mental stress, thus having a significant impact on the quality of life of people with lower back pain. One of the psychometric diagnostic tools for assessing the level of kinesiophobia is the Kinesiophobia Causes Scale (KCS). The aim of the study was to assess the reliability of the KCS test used in people suffering from chronic nonspecific lower back pain (nsLBP). Methods: The study included a group of 112 people suffering from chronic nsLBP. The subjects completed the same Polish version of the KCS questionnaire 4 weeks apart. Results: Good internal consistency was recorded for both domains—the biological and psychological one—as well as the general KCS index (Cronbach’s alpha index α from 0.8 to 0.9). Reliability was excellent for both domains (95% CI of ICC_3.1 biological domain: 0.86–0.93 and for psychological domain: 0.92–0.96) and for the total score of the Kinesiophobia Causes Scale (95% CI of ICC_3.1: 0.91–0.93). Conclusions: These results indicate very good measurement reliability of the Polish version of the KCS questionnaire among people suffering from chronic nsLBP.