Does a Temporary Leg Length Discrepancy have an Influence on Upper Body Posture and Lower Jaw Position in Competitive Athletes?

Introduction: The purpose of this study was to examine the linkage between the musculoskeletal and the craniomandibular system in competitive athletes. Therefore the upper body posture and lower jaw position were investigated while a temporarily induced leg length discrepancy (LLD) during standing was induced. Material and Methods: In this study 34 competitive athletes (2 women/32 men) who had no signs of temporomandibular dysfunction according to their own statements were investigated. The measurement of the upper part of the body posture was performed with a three-dimensional back scanner. Afterwards the condylar position was registered by using a homologated and approved electronic registration device. In order to induce the leg length discrepancy, wooden panels measuring 1 and 3 cm thickness were placed unilaterally under one foot. Results: The statistical analysis of the three-dimensional back measurement was carried out using the Friedman and Wilcoxon matched pairs tests with Bonferroni-Holm correction. The results showed in comparisons of the lateral trunk a decline (p <= 0.05), of the height of the shoulder girdle (p <= 0.05) and, in every pair comparison, of the height of the pelvis area significant correlations between the body posture and the experimentally induced leg length discrepancy. The biggest changes can be observed in the area of the height of the pelvis in the transverse plane. The alterations in statics can be found at the ipsilateral as well as the contralateral side of the body, whereby changes are dependent of the parameter. Moreover, the position of the left condyle in space changes significantly (p <= 0.05). Discussion: The results illustrate functional correlations of the musculoskeletal system through muscular, neurological and fascia based processes. Furthermore, they show that athletes who have a distinctive supporting and postural musculature possess a good body demeanor as well as a fast musculoskeletal compensation by way of the sensorimotor system correspondent to the heightened side of the body. The theory of the ascendant chain spanning from limb to shoulder girdle and further to mandibular condyles can be demonstrated. Athletes with strong postural muscles can quickly compensate through the use of the somatic nervous system.