About this trial
Pre-diabetes (Pre-D) is a precursor to type 2 diabetes (T2D) and characterized by increased exercise fatigability of lower limb muscles, that can impede exercise performance. The cause for the increased fatigability in people with Pre-D is not known. Given the profound vascular disease present in people who have had uncontrolled diabetes for several years, we will determine whether dynamic, fatiguing contractions of the lower limb muscles in people with Pre-D are limited by vascular dysfunction at multiple levels along the vascular tree including the artery, arteriole, and/or capillary. This clinical trial involves a novel exercise training regime involving blood flow restriction to the exercising limb will be used as a probe to further understand the vascular mechanisms for increased fatigability in people with Pre-D and T2D. The long-term goal is to better understand what limits exercise and functional performance in people with diabetes to help develop targeted, more effective exercise programs.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Men and women adults 30 years to 85 years or less
Pre-diabetes [glycosylated hemoglobin (HbA1c) of 5.7-6.4% and fasting plasma glucose 100-125 mg/dL at the time of initial screening]
Controls [normoglycemic with a HbA1c level ≤5.6% and fasting blood glucose ≤ 99 mg/dL (5.5 mmol/L)]
Type 2 Diabetes Mellitus [elevated glycosylated hemoglobin (HbA1c) >6.5% and <10%]
Disqualifiers
Signs or symptoms of neuropathy
Medications associated with advanced stages of T2D including insulin
Poor glycemic control (HbA1c>10%)
Peripheral edema
Trial design
Parallel
Treatments tested in this trial
Control Exercise
Other interventionEach participant will attend 3 sessions per week for 8 weeks. Participants will perform low-load knee extension resistance training (20% of 1-RM) without blood flow restriction on the designated leg for 4 sets of contractions with 15 contractions per set of contractions with a 30 second rest between each set of contractions.
Blood Flow Restriction Exercise
Other interventionEach participant will attend 3 sessions per week for 8 weeks. Participants will perform low-load knee extension resistance training (20% of 1-RM) with blood flow restriction on the designated leg for 4 sets of contractions with 15 contractions per set of contractions with a 30 second rest between each set of contractions.
Treatment groups
Trial outcomes
Primary outcomes
Fatigability - Reduction in Power
Reduction in limb power and maximal force in response to a dynamic fatiguing contraction.
Strength - 1 Repetition Maximum
Reduction in limb power and maximal force in response to a dynamic fatiguing contraction
Strength - Maximal Voluntary Contraction (MVC)
Changes in MVC after 8 weeks resistance training. MVC is the greatest force generated during a brief isometric contraction.
Leg Blood Flow
Femoral artery mean blood velocity and femoral artery diameter will be measured using Doppler ultrasonography before and immediately after the fatiguing task in each leg.
Sponsors and contacts
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University of Michigan
Lead sponsor
University of Illinois at Chicago
Collaborator
Medical College of Wisconsin
Collaborator
University of Wisconsin, Madison
Collaborator
National Institute on Aging (NIA)
Collaborator
Marquette University
Collaborator