We intended to investigate in this pilot-study if long-term glycemic control stands in close relationship with muscle function in children and adolescents with type 1 diabetes mellitus (T1DM). Muscle function (MIGF, maximal isometric grip force; PJF, peak jump force; PJP, peak jump power) was investigated in 40 children and adolescents (males 20, females 20; age 13.5-/+2.5 yr) affected with T1DM. Muscular parameters were correlated with anthropometric parameters (age, height, weight) and with glycosylated hemoglobin (HbA1c) of the presence and the past. Standard deviation scores (SDSs) of weight and MIGF indicated significantly higher weight (mean 0.75-/+1.83 (SD)) and lower MIGF (mean -1.06-/+1.76 (SD)) in individuals with T1DM. When the study group was divided into two groups by the criteria that the actual HbA1c (HbA1c0) was lower (N=25) or higher (N=15) than 8.5%, the comparison showed significantly higher muscular parameters (PJF-SDS, PJP-SDS and MIGF-SDS) in individuals with higher HbA1c0. Multiple regression analyses demonstrated that body weight and height primarily predicted muscle force (MIGF, PJF) in T1DM. In conclusion, skeletal growth is an important determinant for the development of muscle function in children and adolescents with T1DM.