# Influence of Thoracolumbar Mobility on Running Performance: A Comparative Study
## 1 Introduction  
Running is a fundamental motor skill, and motor control strategies may evolve over time. The level of experience can influence coordination patterns and their variability. Greater years of running experience can contribute to the development of coordination patterns that reduce the cumulative load on the musculoskeletal system and allow for flexibility in response to changing task demands. Coordination refers to the organization of multiple degrees of freedom--such as muscles, joints, and joint movements--into aunified control unit. During the process of motor skill specialization, established movement patterns (e.g., joint movements and muscle engagement levels) may undergo changes [1; 2]. A study suggested that the gluteus medius functions to control the downward acceleration of the body's center of mass after foot contact and subsequently elevate the contralateral pelvis. This action occurs at the lumbopelvic junction. During the late stance phase, the lumbar spine exhibits lateral flexion toward the contralateral leg relative to the pelvis. Simultaneously, it works to limit trunk extension (in the sagittal plane) and actively rotate the thorax relative to the pelvis. This active rotation results in greater thoracic motion compared to the pelvis [3; 4]. Previous studies have identified consistent patterns of pelvic, lumbar, and thoracic movements among runners with varying levels of experience [5]. Based on these findings, it is recommended that runners focus on thoracic angles during technical development and training to optimize mid-distance running mechanics [6; 7; 8]. The position and mobility of the thorax and upper extremities have been shown to vary among athletes with differing running intensities. Dysfunction in the lumbar spine has been identified as a contributing factor to lower extremity injuries in runners, and such injuries are thought to be associated with specific kinematic parameters of the lumbopelvic-hip complex [8; 9]. Constraints in spinal mobility are often attributed to muscles, ligaments, tendons, and neurological control mechanisms. However, studies are highlighting the critical role of fascia in joint movement, neurological regulation of motion, and energy transfer between joints. The thoracolumbar fascia is a large, connective tissue structure located in the lower back and extends across the back. It helps support and stabilize the spine, muscles, and organs. Think of it as a tough, fibrous sheet that covers and connects the muscles in the lower back, extending from the thoracic (upper) spine down to the lumbar (lower) spine. It plays a role in movement, posture, and helps transmit forces when you bend, twist, or lift objects [10; 11; 12; 13]. The thoracolumbar fascia (TLF) plays a vital role in load transmission between the trunk and extremities and in maintaining lumbosacral stability. Through its connection with the latissimus dorsi muscle, the TLF facilitates energy transfer during contralateral limb movements, playing a significant role in lumbosacral function, especially during walking and running [14; 15]. The LD is a large, flat muscle located on the dorsolateral aspect of the torso. The muscle originates from the T7-T12 vertebrae, TLF, iliac crest, the lower 3 rd-4 th ribs, and the inferior angle of the scapula. The latissimus dorsi facilitates horizontal abduction, extension, and internal rotation of the shoulder joint. It also plays a synergistic role with the lumbar vertebrae in extension and lateral flexion movements. [PERSON]'s research further emphasizes the spine's role as an energy generator, with potential energy stored in connective tissues during tension and released to enhance movement efficiency during gait [16]. A study has demonstrated that participants were required to have engaged in regular running for at least six months per year, with both groups reporting running for over 10 months annually. This approach ensured that participants consistently developed specific movement patterns over their running years [17].