Impact of controlled type 2 diabetes on muscle-tendon mechanics

Aims: This study aimed to investigate the impact of type 2 diabetes (T2D) on muscle and tendon mechanics by comparing individuals with controlled diabetes to a healthy cohort matched for age, BMI, and physical activity level. A secondary aim was to investigate the possible association between muscle-tendon proprieties and glycated haemoglobin (HbA1c) or advanced glycated end products (AGE, RAGE) as determined in blood and skin biopsies. Methods: Twenty-eight patients and eighteen controls were recruited for this study. Achilles tendon stiffness (kT), muscle-tendon stiffness (kM, in gastrocnemius medialis) and the rate of torque development (RTD) were evaluated by combining dynamometric and ultrasound data. Results: Diabetic patients showed increased tendon stiffness and reduced tendon elongation compared to controls, but similar RTD and kM values. No differences in advanced glycation end products (in serum or biopsies) were observed between cohorts, but a significant positive correlation was observed between kT and HbA1c (r = 0.610, N = 46, P < 0.001). Conclusion: Our data indicate that muscle, but not tendon, properties can be preserved in controlled and physically active diabetic patients and that higher tendon stiffness does not result in a functional deficit (i.e., same explosive capacity between cohorts). Although this study is cross-sectional and has a limited sample size, our data suggest a potential role of HbA1c as a non-invasive biomarker of altered tendon mechanics in people with diabetes. ClinicalTrials.gov, protocol number: NCT05585502.