Extended Abstract
Background and Aim: Age-related decrease in physical abilities and muscle weakness are contributing factors for increasing metabolic disorders such as type II diabetes (T2DM). The T2DM is characterized by impaired glucose metabolism and insulin resistance, frequently associates with non-alcoholic fatty liver disease (NAFLD), and can lead to liver dysfunction. Early detection of liver disease in elderly patients with type 2 diabetes is of considerable clinical importance. Liver enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and Alkaline Phosphatase (ALP) are considered important indicators of liver injury in these patients. Both aerobic and resistance trainings have been shown to improve liver health indices in elderly diabetic patients. Resistance training, such as pilates band exercises, is an effective method for improving muscle function and increasing muscle mass in the elderly. Therefore, the aim of the present study was to investigate the effect of 12 weeks of resistance training using pilates bands on liver enzymes levels, body composition and, leg muscle strength, in elderly women with type II diabetes.
Materials and Methods: This experimental study included 26 elderly women with T2DM (65–80 years), who were randomly assigned to control (n=13) and exercise (n=13) groups. All participants provided written informed consent. Measurements were performed 24 hours pre‑intervention and 48 hours post‑intervention. After 8–12 hours fasting, blood samples were drawn to assess serum liver enzymes (AST, ALT, ALP) via standard enzymatic methods. Body weight was measured using a Porsa ZT‑120 scale, and height using a wall stadiometer. Body composition was measured using an Omron BF‑302 analyzer. Dynamic lower limb strength was evaluated using the 30‑second chair stand test (CST), recording the number of complete sit‑to‑stand repetitions within 30 seconds.
Exercise intervention: The 12‑week resistance training program was designed according to American College of Sports Medicine (ACSM) guidelines for older adults, was performed three sessions/week using elastic bands (yellow, green, pink, red). Each session consisted 10 min warm‑up, 40 min resistance exercises (seated chest press, row, shoulder press, knee extension/flexion, hip flexion/extension, leg press), and 5 min cool‑down. Intensity was progressively increased by changing band colors every two weeks and increasing repetitions, monitored by the Borg RPE scale (score 13= moderate intensity). Participants completed at least 75% of sessions for final analysis.
Statistical analysis: Paired t‑tests, ANCOVA (with pretest scores as covariates), and the Mann‑Whitney U test were used, with significance set at p<0.05.
Findings: At baseline, the exercise and control groups were homogeneous in terms of mean age (72.08±4.71 years vs. 72.3±5.75 years) and height (167.68±4.94 cm vs. 164.15±6.30 cm) (p>0.05). Data were analyzed using analysis of covariance (ANCOVA). To be eligible for the post-test phase, participants were required to complete at least 75% of all training sessions. Throughout the intervention period, the participants’ general condition was monitored both visually and verbally to ensure that the exercise intensity remained within their individual tolerance levels.
Body Composition: The results indicated a reduction in body weight in the resistance training group, whereas body weight increased in the control group. ANCOVA revealed a statistically significant between-group difference in post-intervention body weight (p=0.004, F=10.40, η²=0.34). Regarding body fat mass, a sig nificant reduction was observed within the exercise group compared with baseline (p=0.04). However, the between-group difference in the post-test was not statistically significant (p=0.16, F=2.00, η²=0.09).
Liver Enzymes: Concerning AST levels, both groups showed within-group decreases, but these reductions were not significant, and no between-group difference was observed in the post-test (p=0.75, F=0.005, η²=0.005). Additionally, no significant difference was found between the two groups in ALT levels (p=0.69, F=0.16, η²=0.008). However, both groups demonstrated a significant within-group increase in ALT compared to baseline (p<0.05). Regarding ALP, due to the violation of ANCOVA assumptions, the Mann–Whitney U test was employed for between-group comparisons. The results indicated no significant difference between the groups (p=0.11, Z=-1.58, U=36.00). Furthermore, both groups showed non-significant within-group increases in ALP relative to baseline (p>0.05).
Functional Test: The results of the paired-samples t-test also revealed a significant increase in lower limb functional strength in the Pilates band resistance training group compared to baseline (p=0.02), whereas the control group did not showed any significant decrease (p=0.06). Moreover, the results of ANCOVA, with pre-test scores entered as the covariate, demonstrated a significant difference between the two groups in post-test mean scores (p=0.004, F=10.75, η²=0.38), indicating a significant effect of Pilates band resistance training on improving lower limb functional strength compared to the control group (Table 1).
Conclusion: The findings of the present study indicated improvement in body composition and muscle strength; specifically, for weight, body mass index, and fat mass in the exercise group compared to the control group that indicate the effective role of resistance training in metabolic management of diabetic patients due to the reducing obesity-related risk factors and insulin resistance. Furthermore, a significant 9% improvement in the CST performance in the exercise group suggests increased functional strength and muscular endurance of the lower limbs that can be considered as a key factor in maintaining functional independence, reducing the risk of falls and fractures, and ultimately enhancing the quality of life in the elderly. This finding is consistent with the results of previous studies that have introduced resistance training with elastic bands as effective in improving functional fitness in older adults, although the intensity, volume, and duration of training, as well as the characteristics of the study population, may justify slight differences in the effectiveness between various studies. However, the implementation of resistance training did not create significant changes in the levels of liver enzymes (ALT, AST, ALP). These results can emphasize that the 12-week intervention duration, as well as confounding factors such as medications, diet, and the long history of diabetes in the subjects, may have contributed to the lack of change in liver enzymes. Therefore, to establish sustainable changes in liver enzymes, longer intervention periods or different training intensities may be required.
Ethical Considerations: All stages of the present research were approved by the Ethics Committee of Kharazmi University, Tehran (Approval Code: IR.KHU.REC.1403.108) and the Iranian Registry of Clinical Trials (Trial ID: IRCT20241008063290N1).
Conflict of Interest: The authors declare that there is no conflict of interest.
Funding: This research was supported by Grant No. 4026206 from the Iran National Science Foundation (INSF).