Study uncovers extent of muscle weakness in people with type 2 diabetes

Patients with type 2 diabetes have muscle weakness in more areas of the leg than previously thought, according to new research.
It is well known people with diabetes can suffer from muscle weakness of the lower limbs, such as the calf muscle, which increases the risk of falling.
In this new study, researchers at Manchester Metropolitan University assessed muscle strength in 20 patients with type 2 diabetes. They were measured for severity of neuropathy, intramuscular noncontractile tissue (IMNCT), and vitamin D deficiency. The participants were then matched with 20 healthy control subjects matched by age, sex and BMI.
Using Magnetic Resonance Imaging (MRI) scans, the researchers found that people with diabetes had an increased amount of intramuscular fat in the lower leg muscles. This was due to an “infiltration” of fat within muscles that inhibited diabetic participants from producing muscle force relative to the muscle size.
This increased fat meant that type 2 diabetes participants had significantly reduced knee extensor strength, reduced muscle volume of both knee extensors, and substantial muscle weakness further up in the leg, including the quadriceps.
Patients with diabetic neuropathy had significantly less knee extensor strength than those without, but no significant differences were observed in knee extensor volume and ankle strength. Additionally, no muscle differences were found among patients with or without vitamin D deficiency.
Professor Neil Reeves, Professor of Musculoskeletal Biomechanics at Manchester Metropolitan University, explained: “This muscle weakness with diabetes has important implications, meaning that patients may find everyday tasks more difficult and struggle to meet the demands of some tasks, thereby initiating a negative cycle of reduced activity, which negatively affects their diabetic condition.
“Therefore, people with diabetes not only have smaller muscles capable of producing lower forces, but their lower leg muscles are also infiltrated by fat, which causes a further reduction in the force that can be produced, compounding their weakness.”
The findings appear in the online journal Diabetes Care.