Skeletal muscle properties, gross motor performance, and quality of life in survivors of childhood hematologic and oncologic health conditions

Abstract

Background: Gross motor skills such as running, hopping, and jumping are important for age-appropriate activities and sports throughout the lifespan. Difficulty with gross motor skills negatively affects one’s quality of life (QoL). Gross motor skills require the activation of the large lower-extremity skeletal muscles and the muscle properties of these muscles such as strength, size, and neuromuscular activation contribute to gross motor performance. Children with chronic hematologic and oncologic health conditions, such as sickle cell disease (SCD) and musculoskeletal sarcoma (MSS), are at risk for impairments in skeletal muscle properties, limitations in gross motor performance, and reduced QoL. However, there remains a lack of knowledge of skeletal muscle properties and their relationships to gross motor performance and QoL in children with chronic hematologic and oncologic health conditions. Methods: Quadriceps skeletal muscle properties (strength, size, and neuromuscular activation), gross motor performance, and quality of life were measured in children with SCD and adolescent, young adult MSS survivors of childhood cancer (CCS), and healthy controls. The effect of functional strengthening (PT-STRONG) was assessed in a sub-population of MSS CCS. Results: Children with SCD and adolescent and young adult MSS CCS presented with impairments in muscle properties including decreased knee extension strength and lower quadriceps rate of muscle activation (RoA), poorer gross motor performance, and reduced QoL compared to controls. MSS CCS demonstrated decreased surgical limb knee extension strength, and quadriceps muscle thickness and RoA compared to their non-surgical limb, and decreased bilateral knee extension strength, gross motor performance, and physical QoL compared to normative values. In children with SCD, positive relationships between RoA, strength, gross motor performance, and quality of life were identified. In MSS CCS, positive correlations between muscle thickness and strength, and between strength and gross motor performance were identified. In response to PT-STRONG, MSS CCS participants demonstrated individual improvements in neuromuscular activation, gross motor performance, and physical QoL. Conclusions: Children with SCD and adolescent and young adult MSS CCS demonstrate changes in muscle properties that are associated with limitations of gross motor performance and reduced quality of life.