A screening process was established to select participants based on medical records. We found 24 sedentary individuals (16 men and 8 women) with an age range of 40–64. Patients from one to seven years of follow-up type 2 diabetes were recruited by general practitioners of Dilla University Referral Hospital. In addition, the study participants were included when they were following physician check up in the clinic of the endocrinology unit of the hospital; those who would give their consent to participate in aerobic exercise and strength exercise according to the ADA (American Diabetic Associations) and ACSM (American College of Sports Medicine) joint position statement that Dilla University Community Gymnasium (DUCG) was using were included in the study . All 24 included participants with type 2 diabetes completed the study.
The researchers informed the subjects about the study objectives and that their information obtained before pretest and after 16 weeks of exercise training was treated as privileged and confidential. The subjects were also informed that their involvement in the study was voluntary, and they could opt out at any time. There was no financial incentive to attract participants in the study. Both verbal and written instructions on paper were given to confirm that the items were understood (i.e., honorably and without restrictions, the study participants should choose and circle what they believe to have recently existed; this is according to each item question of GHQ-12).
A quasi-experimental design was used to evaluate the effects of 4 months of aerobic and resistance exercises on selected psychological domains in individuals with type 2 diabetes mellitus in Dilla, Ethiopia.
Calculation of sample size
The sample size was determined using a cohort (follow-up) study as a foundation. For the computation of the sample size, we used the following presumptions: The outcome was and the intervention to control ratio was 1:2. (psychological well-being). When we used the adjustment factor, the maximum study population in the follow-up clinic was only 97, making the sample size incredibly tiny. Although this was done since the intervention group assumption was accepted  (“and lost to a follow-up rate of 10%”), the adjustment factor was still used. Then we decided to abandon this and use intentional sampling instead (study participants are divided into a control group and an intervention group). Also abandoned was the computation of the statistical sample size due to the study’s inclusion of all qualified participants.
Tools for data collection
A widely validated shortest form of the questionnaire (GHQ-12) was used [16, 17]. Our study used the translated version of the Amharic (the national language of Ethiopia) language.
The GHQ-12 is used in busy clinical settings and accepted as a screening tool by the international World Health Organization (WHO). The items of the GHQ-12 were selected from a pool of 60 items, including the original questionnaire, GHQ-60. The focus of items is on the inability to carry out normal activities and the appearance of new and distressing symptoms, i.e., depression, anxiety, and observable behaviors . The General Health Questionnaire (GHQ-12) has potential indicators to assess the severity of a psychological disorder that has recently been experienced using a 4-point scale (from 0 to 3). The score was used to mark a total score ranging from 0 to 36, with higher scores signifying worse conditions .
There is disagreement among some studies on the factor structure of GHQ-12 . However, the three-factor model (which is formed with factor I—anxiety and depression, factor II—social dysfunction, and factor III—loss of confidence) of GHQ-12, recognized by Graetz in 1991, was a better fit than the one-factor model (and others), and this factor structure was found to be the same for men and women in order to test meaningfully .
In our study, this has been evaluated by the effect of aerobic and resistance exercises on selected psychological domains, such as factor I-anxiety and depression, factor II-social dysfunction, and factor III-loss of confidence, independently. And the sum of these factors can measure psychological wellbeing in general among the four allocated groups of type 2 diabetes by using the GHQ-12 questionnaire .
The protocol for exercise intervention
Over the course of the intervention’s four months, walking a mile counted as aerobic exercise. With no more than a day between workouts, the aerobic exercise group engaged in exercises for up to 50 min per day, five days a week, with a moderate intensity set at a rate of felt effort. Free weights, biceps and abs, chest press, shoulder press, leg press, and leg extension were all forms of resistance training. Three times a week on days other than consecutive ones, the resistance exercise group engaged in exercises that lasted for forty minutes. The resistance exercise training load was determined using a percentage of 1RM, which was used in our study to evaluate each participant for each exercise.
The fitness experts at Dilla University Community Gymnasium (DUCG) created the aforementioned resistance and aerobic training routines, which were performed by the combined aerobic and resistance exercise groups for 40 min, four times per week. The control group, on the other hand, was maintained for a period of four months as a regular control (follow-up clinical case residing in the daily routine). Stretching, 10 min intervals of brisk walking, jogging, and stationary cycling served as warm-up exercises throughout each gym session. Each exercise group performed a 5-minute cool-down that included light stretching and waking after the warm-up.
A descriptive statistical analysis was performed to see the normality and homogeneity of some variables. A paired sample t test was used to compare means and the mean differences between the pretest and posttest of groups. To get a significant ANOVA by comparing the changes among groups, we also used Tukey’s post hoc test. Statistical analyses were performed using SPSS version 20 software.