OBJECTIVE: To compare the muscle strength of children and adolescents with growing pains, with and without joint hypermobility, to healthy controls by means of quantitative tests. METHOD: Forty-seven children and adolescents were monitored because of growing pains: 24 with joint hypermobility (GP-JH group) and 23 without joint hypermobility (GP group). These cases, along with 47 healthy controls matched for age and gender, underwent two quantitative tests for muscle strength evaluation: the Childhood Myositis Assessment Scale (CMAS) and the Manual Muscle Strength Test (MMT). Anthropometric data such as height, weight, body mass index, triceps skinfold, mean arm circumference and arm muscle area were compared between the three groups. RESULTS: The three groups did not present any statistical differences in anthropometric measurements. There were significant differences in median CMAS scores, which were lower in the GP (47; range 39-52) and GP-JH (46; range 40-51) groups than the control group (50; range 45-52; p<0.0001). Two of the timed CMAS exercises (head lift and leg lift duration) had significantly lower scores among the patients than among the controls (p<0.0001). The median MMT scores in the GP (79; range 73-80) and GP-JH (78; range 32-80) groups were also significantly lower than the control group (80, range 78-80; p<0.0001). The best correlation between the CMAS and MMT scores was in the GP-JH group (Spearman r=0.65, p=0.0007). Application of CMAS and MMT on two occasions produced good agreement, with intraclass correlation coefficients of 0.87 (95% CI: 0.64-0.96; p<0.0001) and 0.92 (95% CI: 0.76-0.97; p<0.0001), respectively. CONCLUSION: Patients with growing pains, with and without joint hypermobility, presented mild to moderate muscle weakness, compared with healthy controls.
adolescents; children; muscle strength; pain; joint hypermobility
