Author(s): GUARASCIO, G., GRECO, F., IRACE, C., GNASSO, A., CUTRUZZOLÀ, A., QUINZI, F., TARSITANO, M.G., EMERENZIANI, G.P., Institution: UNIVERSITY , Country: ITALY, Abstract-ID: 2738

INTRODUCTION:
Type 1 diabetes (T1D) is associated with microvascular and macrovascular complications; however, increasing evidence indicates that skeletal muscle impairment represents an overlooked complication [1]. Although reductions in maximum voluntary contraction (MVC) have been consistently reported, little is known about explosive muscle strength in T1D, particularly the rate of torque development (RTD), which reflects the ability to rapidly generate force [2]. Given the early neural impairments and increased fatigability observed in T1D, the assessment of RTD may provide new insights into muscular dysfunction. Therefore, this study aimed to compare knee extensor RTD between adults with T1D and healthy individuals and to investigate its association with Continuous Glucose Monitoring (CGM) metrics.
METHODS:
Seventy-seven individuals with T1D (T1D_G, age=40.1 ± 14.8 yrs; BMI=25.98± 4.6 kg/m²; disease duration= 20.7 ± 12.5 yrs; insulin dose= 0.60 ± 0.18 U/kg) and sixty-nine healthy individuals (Control Group, CC, 37.5 ± 13.5 yrs; BMI= 25.2 ± 4.4 kg/m²) performed three maximal isometric knee extensions (90°). RTD was calculated as the slope of the torque–time curve between 20–80% of peak torque and normalized to body mass. In T1D_G, 14-day CGM metrics were collected: Time In Range (TIR), Time Below Range (TBR), Time Above Range (TAR), and Glucose Management Indicator (GMI). Group comparisons and correlations were analysed using parametric or non-parametric tests.
RESULTS:
Knee extensor RTD normalized for kg of body mass was significantly lower in T1D_G compared with CG (8.37 ± 4.06 vs 9.55 ± 3.53 Nm·s⁻¹·kg⁻¹, U = 3163, p =0.047). In the T1D_G, RTD was positively correlated with TIR (Spearman’s ρ = 0.366, p = 0.001). RTD was negatively correlated with TAR (Pearson’s r = −0.363, p = 0.001) and with GMI (Spearman’s ρ = −0.441, p < 0.001). No significant correlation between TBR and RTD was observed (ρ = 0.221, p = 0.059).
CONCLUSION:
The lower RTD in T1D_G compared to CG may indicate possible impairment of muscular function.Furthermore, better glycemic control was associated with superior RTD performance. These findings suggest that chronic glycemic dysregulation may contribute to early muscular impairment, even in the absence of clinically evident neuropathy. Therefore, RTD may represent a sensitive functional marker of subclinical muscular dysfunction in individuals with T1D.

REFERENCES:
1 Andreo-López et al. Nutrients (2023): 4914.
2 Maffiuletti et al. European journal of applied physiology. 2016: 1091-1116.