Low back pain (LBP) is a common musculoskeletal symptom in athletes. More than 40% percent of high school baseball players reported incidents of LBP during the previous year. University baseball athletes were 3.23 times more likely to have lumbar intervertebral disk degeneration than the nonathletic university students. According to the regional interdependence model, a patient's chief complaints may be directly or indirectly related to or influenced by physical impairments from various body systems and regardless of proximity to the primary symptom(s). Athletes with a chief complaint of LBP frequently demonstrate with mobility restrictions in the thoracic spine and hips, which may contribute to compensatory hypermobility in the lumbar spine and subsequently lead to LBP. Few studies have examined the relationship between thoracic spine mobility and LBP, while many studies investigating the relationship between hip joint mobility and LBP in athletes showed inconsistent results. The inconsistent results may be due to different types of sports and measurement methods. Therefore, the objectives of this research project are to: (1) examine if baseball players with a history of LBP have mobility restriction in the thoracic spine and hips and movement coordination within the spine and hip regions during baseball batting that are different from those without a history of LBP; (2) identify thoracic spine and hip joint mobility and coordination related predictors for batting velocity and LBP in baseball players. This 2-year research project plans to recruitment a total of 110 male baseball players aged between 18 and 30 years from university and community recreational league baseball teams (55 players with a history of LBP and 55 age-matched players without a history of LBP). Participants will receive physical examination for the thoracic spine and hip joints (joint mobility and muscle stiffness) and 3D motion analysis for baseball batting. The results of this research project will guide the development of more specific and effective treatment and preventative training for baseball players with LBP and enhance their batting performance.

Inclusion Criteria:

• Baseball players who had experienced at least 2 episodes of LBP that limits their performance for a period of greater than 3 days in the previous year.

Exclusion Criteria:

• Current LBP symptoms including weakness and numbness in the lower extremities
• Previous surgery to the back, upper or lower extremities
• Marked spinal deformity (e.g., scoliosis, or kyphosis)
• Any other orthopedic or medical problem that would have limited their ability to fully participate in baseball training and competition in the last year.

university and recreational leagues baseball teams