Core Stability and Respiratory Parameters in Children With Thoracic Hyperkyphosis

Hyperkyphosis, defined as an excessive curvature of the thoracic spine beyond normal limits, is among the factors that reduce chest wall mobility and lung function. In modern society, increased sitting durations contribute to increased thoracic kyphosis. Studies have indicated that an increase in thoracic kyphosis and a decrease in thoracic spinal mobility are associated with reduced respiratory functions, such as forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). The diaphragm forms the upper part of the core stability system. When contracted, it increases intra-abdominal pressure, contributing to core stability. The diaphragm also contracts in advance of and during limb movements to assist in postural control. Additionally, the diaphragm is the primary respiratory muscle responsible for inspiration. Any functional loss in the diaphragm, which alone accounts for 65-80% of vital capacity, can significantly reduce inspiratory capacity. During forced expiration, muscles such as the rectus abdominis, transversus abdominis, internal obliques, and external obliques play an active role. Specifically, the transversus abdominis, like the diaphragm, increases intra-abdominal pressure and supports trunk stabilization. However, the relationship between respiratory muscle strength and the endurance of core stability muscles remains unclear. In light of this information, this study aims to investigate the relationship between the endurance of core muscles, which contribute to trunk stabilization, and respiratory parameters in children with thoracic hyperkyphosis.