Effect of Trapezius Muscle Thickness on the One-Repetition Maximum (1RM) Strength

Abstract

Purpose: The objective of this study was to examine the impact of trapezius muscle thickness measurements on bench press single repetition maximum (1RM) power output. Material and Methods: The study included 13 male bodybuilders who participated in national and international professional natural bodybuilding competitions and 13 healthy sedentary male subjects. Body composition, 1RM values and ultrasonographic measurements of trapezius muscle thickness were obtained from the participants. Results: The findings revealed that both the skin-to-superficial muscle tissue (R1, L1) and skin-to-deep fascia (R2, L2) distances were significantly lower in sedentary individuals compared to bodybuilders (p<0.001). Additionally, 1RM strength output was significantly higher in bodybuilders than in sedentary individuals. In sedentary individuals, a moderate negative correlation was observed between the distance between superficial muscle and 1RM, and a low positive correlation was observed between the distance between deep fascia and skin surface. In contrast, a low negative correlation was found in both parameters in bodybuilders. Conclusion: Our findings indicate that trapezius muscle thickness is significantly lower in sedentary individuals compared to bodybuilders, both in superficial and deep tissue layers. We believe that the skin surface imaging method used in our study could be an effective tool for predicting injuries in athletes. Additionally, we believe that regular imaging follow-ups in athletes could provide important information about adaptations in muscle structures resulting from applied training stimuli.