# Influence of Thoracolumbar Mobility on Running Performance: A Comparative Study
## 2 Methods and Materials
Lateral flexion was measured when the participant bent sideways; the goniometer was placed at the back of the trunk, with one arm aligned with the spine and the other with the midpoint of the iliac crests to measure the angle. For extension, the participant bent backward, and the goniometer followed the imaginary line of the lumbar vertebrae and aligns with the greater trochanter (\") [21]. Lumbar Extensor Tightness: Lumbar extensor tightness was evaluated by having a physiotherapist push the participant's legs towards their chest. The distance between the knees and the chest was measured with a tape measure and recorded in centimeters (cm) [21,22]. The TLF length test with a goiometric platform (TLF flexibility): During the assessment, the participant's posterior superior iliac spine and pelvis were stabilized by a physiotherapist. Verbal instructions were given to ensure that the arms followed the trunk rotation. The degree of trunk rotation was recorded by marking the goniometric platform with a wooden pencil held between the hands, which were clsaped in front of the body with 90\({}^{\circ}\) shoulder flexion following the rotation. Rotation measurements were performed three times in the same direction, and the values were recorded. The same evaluation method was repeated for both right and left trunk rotation [15] (Figure 1). Modified Schober Test: Lumbar spine flexibility was measured by means of the Schober test. A mark was placed at the midpoint of the line connecting the superior iliac posterior spine (SIPS), with additional marks 10 cm above and 5 cm below this midpoint. The distance between the points served as a reference for the measurements: the participants, from standing in an upright position, performed a full flexion of the lumbar spine. A distance of less than 5 cm indicated decreased lumbar flexibility [23] (Figure 2). Figure 1: Measurement using a goniometric platform. Myoton [Myoton-3 myotonometer (Muometria AS, Estonia, EU; ICC: 0.80-0.93)]: The device assesses three biomechanical tissue parameters: muscle tone (Hz), elasticity and stiffness (N/m). These parameters provide insights into muscle function and mechanical behavior. Muscle tone reflects passive muscle tension in a relaxed state, derived from its viscoelastic properties. A higher oscillation frequency indicates greater muscle tone, with typical relaxed values between 11 and 16 Hz, which increase during contraction [24; 25]. Elasticity represents the tissue's ability to regain its shape after deformation. A lower oscillation reduction indicates better elasticity, while higher values suggest reduced elasticity and greater energy dissipation. Normal values range from 1.0 to 1.2 [25]. Stiffness measures resistance to shape deformation by external forces. A higher stiffness implies greater force requirements and increased movement energy expenditure. At rest, stiffness values range between 150 and 300 N/m and rise with muscle contraction [23]. Higher values indicated increased muscle tone and stiffness and reduced elasticity [26; 27]. Participants lay prone with a thin rolled towel under their foreheads and their arms positioned in 180\({}^{\circ}\) flexion for a fifteen-minute rest period. A point 5 cm below the lower tip of the scapula along the imaginary line of the LD was marked. After the rest period, the myotonometer probe was positioned at a 90\({}^{\circ}\) angle to the skin at the marked point, and measurements were taken ten times at one-second intervals. The average values were recorded [28; 29] (Figure 3). All analyses were performed using the IBM SPSS Statistics 23.0 software package. Descriptive statistics of demographic variables for the included participants were calculated. Before conducting significance tests, all variables were assessed for normality using the Kolmogorov-Smirnov test and for homogeneity of variances using [PERSON]'s test.