Maintaining Resistance Training in Older Prediabetic Adults

The aim of this Phase II Clinical Trial is to demonstrate the efficacy of social cognitive
theory (SCT) based intervention for initiating, and most importantly, maintaining resistance
training in older adults with pre-diabetes (i.e., impaired glucose tolerance or impaired
fasting glucose) to improve glucose homeostasis. The overall aim is consistent with NIDDK's
Behavioral/Prevention Research Program's focus on individual, family, and community-based
strategies for prevention of diabetes and its complications. Resistance training is
particularly applicable to older, pre-diabetic adults given the loss of lean body mass and
worsening of glucose tolerance with aging. The proposed research program evaluates a
15-month SCT based intervention for maintenance of resistance training with older adults.
Men and women 50-69 (N=180) with pre-diabetes, defined as exhibiting either impaired glucose
tolerance (IGT; 2-h glucose 140-199 mg/dl) or impaired fasting glucose (IFG; 100-125 mg/dl),
will first follow the same standard, supervised 3-month initiation period with resistance
training. All people completing the Initial Phase will be randomly assigned to 1 of 2
maintenance conditions: 1. a long-term SCT based, ASPIRE intervention, emphasizing
self-regulation and other SCT strategies to optimize training, with faded contact; 2. a
Standard intervention with minimal contact. The primary outcome measures are indices of
pre-diabetes (glucose tolerance and fasting glucose concentration) and strength. Secondary
measures include adherence; ß-cell responsivity, insulin sensitivity, and disposition index,
as determined by the oral glucose and C-peptide minimal model; fat free mass, other
indicators of health and metabolic fitness, and SCT measures. Assessments will occur at
baseline, at the end of the Initiation Phase (3 months), at the end of the different
interventions (9 months) and 6 months after all contact has ended (15 months from baseline).
It is hypothesized that SCT based resistance training with faded contact will produce
better outcomes than the Standard-based resistance training at 9 month and 15 month
assessments. It also is hypothesized that improvements in glucose homeostasis and in
strength from resistance training will be mediated by adherence, self-efficacy, and use of
self-regulation strategies. Resistance training has become an important component in the
treatment and prevention of diseases and disabilities, and especially so for Type 2
diabetes. Critical to public health and a focus of NIDDK are theory-based interventions that
enable, effective long-term resistance training with minimal supervision after an initiation
phase and where improvements in adherence and outcomes are facilitated by theoretical
constructs.

Inclusion Criteria:

- prediabetes,

- overweight or obese,

- aged 50-69 years,

- otherwise good health,

- physician clearance for exercising,

- sedentary (< 150 min/wk of moderate intensity physical activity).

Exclusion Criteria:

- diagnosed with diabetes or other conditions that would preclude an individual from
safely resistance training (eg, heart disease),

- currently engaging in RT (for > 1 year),

- smokers,

- uncontrolled hypertension,

- retinopathy,

- recent cataract surgery,

- recent head trauma.