The primary purpose of this study is to determine the effectiveness of foot-ankle exercise and walking exercise on foot neuropathy, stress, and quality of life (QoL) among people with diabetes mellitus (PWDM). At the same time, the secondary purpose of this study is to determine the effectiveness of foot-ankle exercise and walking exercise on body mass index (BMI), fasting blood glucose (FBG), blood pressure (BP), and ankle-brachial index (ABI) among PWDM at baseline (before intervention/0 week), at 6-weeks and 12-weeks.

The research questions in this study include the following:

• Is foot-ankle exercise effective for foot neuropathy, stress, QoL, BMI, FBG, BP, and ABI for PWDM?
• Is walking exercise effective for foot neuropathy, stress, QoL, BMI, FBG, BP, and ABI for PWDM?
• Are there any differences in the mean scores of foot neuropathy, stress, QoL, BMI, FBG, BP, and ABI of PWDM within and between the foot-ankle exercise, walking exercise and control group at baseline, 6 weeks, and 12 weeks?
• Are there any mediators/moderators effect of BMI, FBG, blood pressure, ABI, and stress for influencing foot exercise and walking exercise interventions on foot neuropathy and QoL for PWDM?

Participants in the foot-ankle exercise group will be given health education about DM and foot-ankle exercise, as well as leaflets and videos. Participants will be taught how to practice foot-ankle exercises before the instructor. Afterwards, participants will practice foot-ankle exercises independently without supervision for 2-3 sessions every day for 12 weeks. Participants in the walking exercise group will be given health education about DM, walking exercises and leaflets. Participants will practice walking exercises independently without supervision for 12 weeks. Participants are advised to do walking exercises with a minimum duration of 10 minutes for each session and 150 minutes/week. Two consecutive days without walking exercise are not allowed. Participants in the control groups will be treated as active control and given health education on general DM topics and leaflets. All groups received usual care according to standards provided by public health services. Researchers will compare the groups to see the effect of the interventions on foot neuropathy, stress, QoL, BMI, FBG, BP, and ABI at three different time points: at baseline, 6 weeks, and 12 weeks.

Intervention Development

This study focused on foot-ankle exercises modified from previous research and adapted to exercises developed by the Indonesian Endocrinology Association. Providing health education about DM in general and foot-ankle exercise is intended to increase participants' basic knowledge about DM and the importance of foot-ankle exercises. Foot-ankle exercise simulation and practice aim to ensure participants can do it well and independently. The leaflet contains the material presented during health education and is given to participants. A video was made containing the steps to do foot-ankle exercises. Researchers will upload videos of the foot-ankle exercises to YouTube. Participants will be given the video in soft file form and informed that they can access it via the researcher's YouTube channel. Walking exercises in this study adapted and modified from previous research. Providing health education about DM in general and walking exercises is intended to increase participants' basic knowledge about DM and the importance of walking exercise exercises. The leaflet contains the material presented during health education and is given to participants in walking exercise groups.

Content Validity

The content validity test in this study aims to validate the intervention procedures used during the research process. The details are: detail intervention of foot-ankle exercise and walking exercise, health education materials and leaflets for the control group, foot-ankle exercise groups, and walking exercise groups, videos of foot ankle exercises, standard operational procedures for measuring foot sensation and foot vibration, height and weight, BP, and ABI. The criteria for Experts: 1) Willing to be involved in the content validity study, 2) Doctor/nurse, 3) Have experience working in the clinical or research area on the topic of diabetes mellitus for more than 5 years. In this study, six experts are needed to achieve a content validation index (CVI) satisfaction of 0.83. Researchers will send formal invitations via email to experts. The files include an application letter, a cover letter containing the research objectives, expert panel criteria, intervention procedures to be assessed, and an assessment sheet. Assessment of each item uses a 1-4 Likert scale. Item with score <3 will be asked to provide comments or suggestions to help further refine the intervention protocol. Researchers will use item-level CVI (I-CVI) and the scale-level (S-CVI). The CVI value is satisfactory if I-CVI ≥0.80 and S-CVI ≥0.83. Items with a low CVI value will be revised according to the comments and suggestions of experts until the CVI value becomes satisfactory.

Participants Recruitment Process

Researchers will ask the District Health Service for information about public health centers (PHCs) with active Chronic Disease Management Program (PROLANIS) activities. Researchers will contact and collaborate with PHCs for participant recruitment. The research team will contact each potential participant and explain the research process. Researchers will also put-up posters in PHCs and also distribute these posters through social media. Potential participants willing to become participants can contact the contacts listed on the poster. For potential respondents who are willing, after signing the informed consent, they will be included in the chat group. Participants will be given a transportation fee of IDR 25,000 for each arrival during the data collection process.

Sample Size Calculation

Samples were calculated using G*Power sample size calculator v.3.1. using F test with an analysis of variance based on some criteria. Researchers will use small effect size (0.1), an α error probability of 0.05, and a power of 0.95; Number of groups 3 (foot-ankle exercise, walking exercise, and control group); and number of measurements 3 (baseline, 6-weeks, and 12 weeks). Based on the calculation, 312 participants were needed; and added an anticipated dropout of 20% (63 people), so the total sample size was 375. The total sample was divided into three groups; each group had 125 participants.

Randomization and Allocation Concealment

Eligible participants will be randomized by independent staff not involved in the recruitment and data collection process, with a ratio of 1:1:1 for each group. After baseline measurements, the randomization process will be carried out using the computer-generated randomization method. The method that will be used is random permuted blocks with size 3, 6, 9. The random numbers will be packaged in sequence, stored and locked in opaque envelopes to guarantee allocation concealment. This sequence will be kept private and stored in a place that assessors cannot access.

Intervention Delivery

Control group: The active control group was given health education on the topic of DM for 30 minutes and then given a leaflet.

Foot-ankle exercise group: Participants will be given health education on DM and foot-ankle exercise after the allocation procedure, followed by simulation and practice lasts 60 minutes. Participants were also given leaflets and videos to take home. Afterward, participants will practice independently without supervision for 12 weeks. Foot-ankle exercise consists of 10 movements. When doing foot exercises, participants sit comfortably without leaning, and the soles of their feet touch the floor and barefoot. These movements are:

A 1)Lift the soles of the feet with heels still touching the floor.2)Toes are bent to grip like chicken claws in this position.3)Repeat this movement 10x.

B 1)Lift the soles of the feet with heels still touching the floor. 2)Lower the soles of feet and raise heels with toes touching the floor. 3)Repeat this movement 10x.

C 1)Lift the soles of the feet with heels still touching the floor.2)Do circular movements from the inside to the outside for the soles of both feet.3)Repeat this movement 10x.

D 1)Lift the heels of both feet with toes still touching the floor.2)Do circular movements from the inside to the outside for the soles of both feet.3)Repeat this movement 10x.

E 1)Lift right knee and straighten it. The left leg remains in its original position.2)Move toes forward and backward.3)Repeat this movement 10x.4)Do the same for the left leg.

F 1)Lift right knee and straighten it.2)The left leg remains in its original position.3)Move toes towards face.4)Repeat this movement 10x.5)Do the same for the left leg.

G 1)Lift both knees of the right and left legs, then straighten them.2)Move toes towards face at the same time.3)Repeat this movement 10x.

H 1)Lift both knees of the right and left legs, then straighten them.2)Move both legs forward.3)Repeat this movement 10x.

I 1)Lift their right knee and straighten it. The left leg remains in its original position.2)Write the numbers 1-10 with feet.3)Do the same movement for the left leg.

J 1)Place newspapers as a base for the soles.2)Shape the newspaper into a ball using both feet.3)Open the newspaper ball again to become sheet-like before using both feet.4)Divide the newspaper into two parts using both feet.5)Tear one part of the newspaper into small pieces and collect it on top of the other part of the newspaper.6)The newspaper sheet containing small shreds is made into a ball using both feet.7)Throw the newspaper ball into the trash.

Walking exercise group: Participants will be given health education for 30 minutes, on DM and walking exercises and leaflet after the allocation procedure. Participants will practice walking exercises independently for 12 weeks.

Health education for all groups is provided by persons who have certificates as DM educators and carried out in subgroups with 7-10 members in each group. To avoid contamination, health education was implemented at different times, Fridays for control group, Saturday for foot-ankle exercise group, and Sunday for walking exercise group, with flexible implementation hours according to the agreement of each group. All group participants were included in the chat group (Whatsapp Messenger) so that researchers could communicate and monitor the implementation of the intervention.

Interventionist dan Outcome Investigators

Each research location has 1 health professional who carries out the intervention with criteria: having a master's degree in nursing, working as a health worker/health educator for at least 5 years, and having a certificate as a DM educator. Each research location has at least of 1 outcome investigator with the criteria of a health worker with a registration certificate.

Plan for Data Management/Analysis

Data analysis will use the intention to treat (ITT) principle. In addition, an analysis using the per-protocol (PP) principle will be carried out. Then, Researchers will compare the analysis results using ITT and PP and conduct a sensitivity test. The data analysis process uses the SPSS V.27 program. Researchers will conduct a normality test using the Kolmogorov Smirnov test; the data distribution is normal if the value is> 0.05. Researchers will use the Generalized Estimating Equation (GEE) test to analyze changes in outcomes between the foot-ankle exercise group vs control group, walking exercise group vs control group, and foot-ankle exercise group vs walking exercise group over time (baseline, six weeks, and 12 weeks). Baseline measurement and control group as reference. The significance value uses p value <0.05.

Comparison data of baseline respondents between the 3 groups for categorical data will be analyzed by the Chi-square/Fisher Exact test; for numerical data, ANOVA test for normal distributed or Friedman test for non-normally distributed. If a significant imbalance is found, an appropriate covariance adjustment analysis will be carried out in the data analysis. Analysis within group for each measurement time (baseline vs six weeks, baseline vs 12 weeks, six weeks vs 12 weeks) will use the Paired T-test if normally distributed or the Wilcoxon test if non-normally distributed. Meanwhile, the analysis between groups for each measurement time (T0, T1, and T2) will use the Independent T-test for normally distributed or the Mann-Whitney test for non-normally distributed.

Researchers will use path analysis to analyze the mediation/moderator of BMI, FBG, BP, ABI, and stress on the effects of foot-ankle exercise and walking exercise on foot sensitivity and QoL. The mediation analysis will use the bootstrap technique as a nonparametric procedure to test the statistical significance of various Partial Least Squares-Structural Equation Model (PLS-SEM) results, such as path coefficients. Researchers will use the software program SmartPLS 3 (SmartPLS GmbH, Bo¨nningstedt, Germany) to analyze the mediation effects. For PLS-SEM, Standard Root Mean Square Residual/SRMR can be used as a goodness-of-fit test to prevent model specification errors. SRMR is the difference between the observed correlation and the model's implied correlation matrix. As a result, it is possible to use the average magnitude of the difference between measured and predicted correlations as an absolute measure of (model) goodness-of-fit. A good fit is described as a value smaller than 0.10 or 0.08. The statistically significant level was set at 0.05 and 95% confidence intervals (CI) to test indirect effects. The result indicates a significant level if the 95% CI does not contain zero.

Monitor for Adverse Events

Adverse events that have the potential to occur include fatigue, muscle aches, pain and dizziness. Participants will record for themselves if adverse events occur and report to the team. The research team also monitored by telephone once a week, asking whether any adverse events had occurred and recording them. If excessive adverse events occur, investigators will immediately stop the intervention and carry out treatment.

Inclusion Criteria:

• People with type 2 diabetes
• Aged 20-70 years
• Diagnosed with DM for at least 1 year
• Can walk without assistance
• Able to communicate well
• Can read and write
• Willing to be a respondent

Exclusion Criteria:

• Has a history of leg amputation
• Have a diagnosis of heart failure, kidney failure, pulmonary TB, stroke
• Patients with a history or under-treatment of mental disorders
• DM patients with foot ulcers
• DM patients with fractures or difficulty using the lower extremities

Particular data will be shared: Individual participant data that underlie the results reported in this article after identification (text, tables, figures, and appendices).

Beginning 9 months and ending 60 months following article publication.

Investigators whose proposed use of the data has been approved by an independent review committee ("learned intermediary") identified for this purpose, for example, for a meta-analysis or other study.

Data collectors who assess the outcomes and statistician who analyse the data are blinded.