Influence of scapular position on the pressure pain threshold of the upper trapezius muscle region

A position of scapula depression will maintain the upper trapezius muscle region in a lengthened position, causing excessive strain. This strain could lead to peripheral nociceptive nerves sensitization in the affected area, changing the pressure pain threshold (PPT). Thus, people with a faulty alignment of scapular depression may have lower PPT levels in the upper trapezius region when compared to subjects with normal vertical scapular position. The purpose of this double-blind study was to assess the influence of scapular position on the PPT of the upper trapezius region in a young healthy population. Fifty two physical therapy students of the Catholic University of Minas Gerais - PUC-Minas, Brazil, with normal shoulder (NS group, n = 26, 6 men and 20 women) or depressed shoulder (DS group, n = 26, 6 men and 20 women) volunteered to participate in this study. An electronic pressure algometer was used to measure the PPT on the upper trapezius muscle region. The results showed a significant difference between groups, with the DS group (19.0 ± 9.0 N/cm²) demonstrated lower mean PPT values when compared to NS group (26.1 ± 9.6 N/cm²) (p < 0.01). Our results showed that healthy young subjects with depressed scapula position had significant lower upper trapezius PPT values when compared to subjects with normal scapula position.