Flexibility: A Hidden But Trainable Morbidity in Pediatric Patients with Congenital Heart Disease.

Flexibility is important for range of motion, muscular performance, and injury prevention with exercise. Promoting exercise is important for patients with congenital and pediatric acquired heart disease (CHD), yet there are a paucity of data addressing flexibility in this population. We hypothesized that flexibility was worse in pediatric patients with CHD than the general population but could be improved with directed training. Patients at Boston Children's Hospital who participated in the pediatric Cardiac Fitness Program between 09/2016 and 11/2022 were retrospectively analyzed. Flexibility was assessed via sit-and-reach (SaR) box. Data from baseline and 60 days into the fitness program intervention were compared to age-matched population norms, and changes over time were assessed. Analyses were also stratified by sex and history of sternotomy. Patients with paired baseline and 60-day data were analyzed (n = 46, age 8-23 years old, 52% male). The mean SaR at baseline for CHD patients was 24.3 cm, significantly lower than the population norm (p = 0.002). The mean for male (n = 24, 21.2 cm) and female (n = 22, 27.2 cm) CHD patients was significantly lower than their respective population norms (p = 0.017 and p = 0.026, respectively). After the fitness intervention, flexibility in CHD patients significantly improved to normal, including patients with a history of sternotomy. Flexibility was significantly lower in CHD patients than the general population, but normalized with training. Further research is warranted to investigate associations of flexibility with other measures of fitness, cardiovascular status, and quality of life, as well as benefits gained with training.