ESPE Abstracts

Background: Obesity is characterized by insulin resistance of target tissues, such as skeletal muscle, adipose tissue and liver. Skeletal muscle tissue is responsible for approximately 75% of whole body insulin-stimulated glucose uptake. Previously, it has been shown that skeletal muscle strength is significantly associated with insulin resistance in type-2 diabetics and non-diabetics.

Objective and hypotheses: To examine the relationship between insulin resistance with isokinetic muscle strength, static and dynamic standing balances in obese adolescents.

Method: 192 obese (12–17 years old) adolescents and age-matched 75 healthy controls were recruited in this study. The isokinetic test protocol for measuring the strength of knee flexion-extension muscle groups was performed by using the Biodex System 3 Pro isokinetic dynamometer. In addition, dynamic and static standing balances were detected with Biodex® Balance System. HOMA-IR was calculated in all subjects. In patient group BMI, fasting insulin and HOMA-IR values were higher than controls.

Results: At all velocities, the isokinetic muscle strength of knee extensors and flexors were significantly higher in obese group without insulin resistance (P<0.05), but were lower in obese group with insulin resistance (P<0.05). Knee extensor peak torques bilaterally were positively correlated with BMI and age, but negatively correlated with insulin and HOMA-IR in both obese groups. Static standing balance was better in patient group than controls, but dynamic standing balance was worse in both patient groups and negatively correlated with insulin and HOMA-IR.

Conclusion: İsokinetic muscle strength was lower in obese adolescents with insulin resistance than those of controls and obese adolescents without insulin resistance, but dynamic standing balance was worse and both parameters were negatively correlated with insulin resistance in both obese groups. It was thought that insulin resistance can lead to impair the dynamic standing balance and muscle strenght.