Periodization-Based Strength Exercise Training in İndividuals With Type 2 Diabetes

Type 2 diabetes mellitus is associated with reduced exercise capacity, decreased muscle strength, impaired quality of life, and metabolic dysfunction. Exercise training is recommended as an important component of diabetes management; however, the comparative effectiveness of different strength training periodization approaches remains unclear.

This randomized controlled trial aims to compare the effects of non-linear periodization and linear periodization strength training programs in individuals with type 2 diabetes mellitus. Participants will be randomized into three groups: a non-linear periodization training group, a linear periodization training group, and a control group receiving usual care.

The intervention will be conducted for 8 weeks, three times per week. Outcomes including exercise capacity, muscle strength, body composition, quality of life, and metabolic parameters will be evaluated before and after the intervention period.

• Non-linear Periodization-Based Strength Training (Behavioral): Participants will perform supervised non-linear periodization-based strength training three times per week for 8 weeks.
• Linear Periodization-Based Strength Training (Behavioral): Participants will perform supervised linear periodization-based strength training three times per week for 8 weeks.
• Usual Care (Other): Participants will receive usual care and no structured exercise intervention during the study period.

Primary outcomes

• Exercise Capacity [Baseline and after 8 week]: Exercise capacity will be assessed using the 6-Minute Walk Test (6MWT)

Secondary outcomes

• Change in Peripheral Muscle Strength [Baseline and after 8 weeks]: Peripheral muscle strength will be assessed using handheld dynamometry for upper and lower extremity muscle groups and reported in Newton (N).
• Change in Hand Grip Strength [Baseline and after 8 weeks]: Hand grip strength will be assessed using a hand dynamometer and reported in kilograms (kg).
• Change in Diabetes Quality of Life Questionnaire Score [Baseline and after 8 weeks]: Change in the Turkish version of the Diabetes Quality of Life Questionnaire (DQOL) total score and subscale scores from baseline to 8 weeks will be evaluated. The DQOL consists of 45 items assessing treatment satisfaction, psychological impact, concerns about future effects of diabetes, and social/vocational concerns. Each item is scored on a 1-5 scale, and higher scores indicate better diabetes-related quality of life.
• Change in Body Fat Percentage [Baseline and after 8 weeks]: Body fat percentage (%) will be assessed using bioelectrical impedance analysis (BIA).
• Change in Skeletal Muscle Mass [Baseline and after 8 weeks]: Skeletal muscle mass (kg) will be assessed using bioelectrical impedance analysis (BIA).
• Change in Resting Metabolic Rate [Baseline and after 8 weeks]: Resting metabolic rate (kcal/day) will be assessed using indirect calorimetry (COSMED Fitmate Pro, Rome, Italy).
• Change in Hemoglobin A1c (HbA1c) [Baseline and after 8 weeks]: Glycemic control will be assessed by measuring glycated hemoglobin (HbA1c) levels (%).
• Change in Fasting Blood Glucose [Baseline and after 8 weeks]: Glycemic control will be assessed by measuring fasting blood glucose levels (mg/dL).

Sex: All, ages: 18 Years to 65 Years

Inclusion Criteria:

* Adults aged between 18 to 65 years
* Diagnosis of Type 2 Diabetes Mellitus (T2DM)
* Not having participated in any structured exercise program within the last 6 months
* Willingness to participate in the study and provide written informed consent

Exclusion Criteria:

* Presence of nephropathy, retinopathy, or peripheral neuropathy
* Presence of neurological, cognitive, or orthopedic disorders that may affect outcome measurements
* Severe respiratory disease (Forced Expiratory Volume in the first second \[FEV1\] <35% or Forced Vital Capacity \[FVC\] <50%)
* Presence of ischemic heart disease or peripheral arterial disease
* History of any cardiovascular event within the last 6 months
* Current malignancy

• Neslihan Duruturk, PhD, Principal investigator, Baskent University