Association between insulin resistance, lean mass and muscle torque/force in proximal versus distal body parts in healthy young men.

OBJECTIVES The purpose of this study was to investigate whether there is already an association of insulin resistance (IR) with muscle mass and -force/torque in an adult population and whether this relationship is the same in distal and proximal body parts. METHODS 358 Healthy young men were divided into a more insulin sensitive (MIS) (n=89) and a less insulin sensitive (LIS) group (n=89), respectively using lower and upper quartiles of HOMA-IR index (Homeostasis Model Assessment of IR). Muscle force/torque and lean mass, were compared between the two groups. RESULTS LIS subjects had higher absolute thigh lean mass, but not higher thigh muscle torque, resulting in a lower torque per kg muscle. In upper arm, lean mass was higher in LIS subjects, but also absolute muscle torque resulted higher. For handgrip force, the LIS and MIS group had similar results, despite a trend towards higher forearm lean mass in LIS subjects. Lean mass % of total lean mass is lower in LIS subjects in more distal body parts. CONCLUSIONS Already in a young healthy population, IR seems to be associated with lower force/torque per muscle mass and lower lean mass % of total lean mass predominantly in more distal body parts.