Study Design

This non-randomised pilot study aimed to determine safety and feasibility of targeted exercise commencing during an acute inpatient setting. Ethics approval was granted by the South Metropolitan Health Service Human Research Ethics Committee (RGS 4173). Study data were collected and managed using Research Electronic Data Capture (REDCap) [20, 21].

Participants

Patients admitted to hospital under the care of the Multidisciplinary DFU team between October 2020 to April 2021 were screened for eligibility. Participants were eligible if they were over the age of 18, had a diagnosis of diabetes mellitus and requiring admission to hospital for DFU of any type or severity. People were excluded from participation if they were unable to consent due to language or cognitive impairment, had an acute myocardial infarction, unstable angina, severe heart failure (New York Heart Association Functional Classification IV), cardiac arrhythmias causing haemodynamic compromise, musculoskeletal or neurological conditions precluding exercise or it was otherwise determined not to be in their best interest to participate. Written consent was obtained for all participants. The resources available for this study limited patient screening and recruitment to one day per week.

Study procedures

Demographic information was collected, surveys and physical assessments (described in Outcomes section below) were completed. Participants completed an individually prescribed inpatient exercise session under supervision. Following this, they were provided with an individualised daily home exercise programme to complete for two weeks post discharge (see Intervention section below). Podiatric wound offloading recommendations were observed at all times during this study.

After completion of the inpatient phase of the study, participants were reviewed at their routine outpatient follow-up clinic, scheduled for two weeks after discharge. Adherence to their home exercise programme was assessed by review of a home exercise diary. Final surveys and physical outcome measurement were also completed. Participants were also offered an outpatient exercise session at this review. Participants who could not attend in-person after discharge were followed up via telephone and surveys were emailed to participants for completion using REDCap. Upon exit from the study, participants were provided a short survey asking about acceptability and satisfaction of the exercise intervention. Adverse events, participant comments and any reasons for withdrawal were collected throughout the study.

Intervention

Exercise was commenced during hospital admission. Where a participant required surgery for their DFU, clearance from the treating team was obtained for the patient to commence exercise. The treating team made weight bearing orders in relation to the DFU location for each participant to follow. Participants who were able to weight bear but in offloading footwear were prescribed this by the Podiatrist. These included removable ankle high and knee high devices. Otherwise, participants who were ordered to be non-weight bearing were able to participate in exercise whilst adhering to this restriction. Blood glucose levels (BGL) were assessed prior to and during exercise sessions. Exercise was not commenced, or was stopped, where BGL < 5 mmol/L.

Supervised exercise sessions were comprised of both aerobic and strength training components. These exercises were individualised for each participant to maintain weight bearing orders given by the treating team. For example, participants who were ordered to be heel weight bearing undertook exercises weight bearing through the heel only. Participants ordered to be toe weight bearing completed exercises weight bearing through the toe only. Where a patient was strictly non-weight bearing on one leg, exercises were performed weight bearing on the opposite leg and non-weight bearing on the affected leg. Exercise selection was completed with respect to the participant’s ability to achieve the full range of movement of the selected exercises. This was assessed at the time of exercise by the supervising Physiotherapist.

The mode of aerobic exercise was selected using a combination of patient preference and adherence to wound offloading requirements. Participants completed five to 20 min of upper limb ergometry (Monark Exercise AB, Dalarna, Sweden), single leg or two-legged cycling on an upright exercise bike (Monark Exercise AB, Dalarna, Sweden), or recumbent exercise bike (SportsArt, Washington, United States of America). The amount of time for the aerobic component was based on exercise tolerance. Participants were instructed to exercise at a moderate intensity using Borg’s Rating of Perceived Exertion Category-Ratio scale (CR-10) [22].

Strength training exercises were completed as a circuit using body weight, resistance bands (Performance Health ANZ, Sydney, Australia), free weights and ankle weights, or pin-loaded cable weight machines (Cybex International, Illinois, USA). Exercises were selected based on weight bearing orders as described above. Participants were instructed to work to a moderate intensity on the CR-10 scale. Each participant completed a total of 2–3 sets of 8–15 repetitions of each exercise. Exercises targeted key muscles groups in both lower and upper limbs in standing, sitting or unilateral positions. Examples of some of the common exercises utilised were; bicep curl, shoulder press, deltoid fly, seated or bent over row, leg press, sit to stands, squats, bridging, heel raise, side lying or standing hip abduction and seated knee extensions. Participants were asked to rate the intensity of the full exercise session using the CR-10 scale at 10 min after their session.

A home exercise programme was prescribed and consisted of a selection of pre-determined exercises similar to those utilised in the inpatient session (Additional file 1). These accounted for individual ability and wound offloading requirements. These exercises were aimed at strength training and utilised hand weights (or water bottles / other common household items) or resistance bands (Performance Health ANZ, Sydney, Australia) which were provided. Home exercises were demonstrated by a Physiotherapist who ensured these were able to be completed safely prior to discharge. A home exercise diary was provided to participants and checked at the two week follow up. Where a patient was unable to attend in person, this was reported subjectively on the phone to the researcher.

OutcomesPrimary outcome

The primary outcome of this study was the feasibility and safety of undertaking exercise in the study population (Table 1) and was assessed at the end of the study. These criteria and acceptability limits were agreed upon by the study team during development of this project.

Table 1 Feasibility and safety outcome measurement and acceptability levels

Adverse events in this study were defined as BGL < 5.0mmol/L during exercise, any event related to the exercise session which required a referral for an unplanned medical review, unplanned repeat debridement of index ulcer during the enrolment period or unplanned amputation involving the index ulcer during the enrolment period.

Secondary outcomes Current levels of physical activity

Current participation in physical activity and exercise was assessed using the International Physical Activity Questionnaire (IPAQ) - short. This is a seven-item questionnaire which can be self-administered, or telephone administered. It is a validated tool to obtain data on health-related physical activity [23]. The questionnaire quantifies how much vigorous, moderate or walking based activity on an average week and converts this to a weighted estimate of total physical activity. This estimate is then used to classify participant’s physical activity level as low, moderate or high [23]. This was assessed at initial review and two week follow up.

Benefits and barriers to physical activity

Perceived benefits of and barriers to physical activity and exercise was assessed using the Exercise Benefits/Barriers Scale (EBBS) [24]. This is a 43 item four-choice Likert scale in which the respondent rates their agreement with perceived barriers or benefits of exercise [24, 25]. The EBBS can be scored as a Benefits scale and a Barriers scale, where a higher score indicates the responder has greater perception of benefits or barriers to exercise respectively. In addition to the EBBS, we asked participants whether they believed that having a foot ulcer was a barrier to them participating in exercise. This was as a “yes/no” question format. This was assessed at initial review and two week follow up.

Muscle strength

Grip strength was assessed in kilograms using a Jamar handheld dynamometer (Surgical Synergies, SI Instruments, SA, Australia). Grip strength has been demonstrated to be useful as a predictor for muscle mass and physical functioning [26]. This was assessed at initial review and two week follow up.

Exercise Intensity and load

The intensity of exercise was rated using the CR-10 scale. This is a 0–10 scale used to grade exercise intensity [27]. This scale allows individuals to rate their exertion and monitor the intensity of exercise. The overall intensity of the exercise session was assessed by asking the patients for a session RPE (sRPE) score to quantify the intensity of the exercise session [28]. The sRPE is a multiplication of the intensity score for the session as a whole by the duration of the session in minutes. This was assessed 10 min after at the end of an exercise session.

Satisfaction

An exit survey was given to participants at the end of enrolment in this study asking about the participant’s satisfaction with the intervention. It was based on previous research and investigated participant’s perceptions of benefit and safety [29]. A five-point Likert scale was used asking participants to rate their level agreement with the following statements, from strongly disagree [1] to strongly agree [5]:

1.

I found the exercise sessions in hospital useful

2.

I felt safe completing exercise in the hospital

3.

I felt that the supervision with exercise in hospital was adequate

4.

I was able to do the home exercise programme easily in my home

5.

I found the home exercise programme useful

6.

I would recommend participation in an exercise programme like this

Sample size

The enrolment target was 30 participants.

Statistical methods

Descriptive statistics were used to describe the demographic data, primary and secondary outcomes. Primary outcomes were compared to pre-determined criteria displayed in Table 1. Paired data from 15 participants who completed both study phases for the EBBS and IPAQ were analysed. The EBBS data were compared using a Wilcoxon signed-ranked analysis whilst data from the IPAQ was compared using a chi-square analysis. We have chosen to display the Likert data in chart form to highlight the frequency of answers in these fields.