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Trial registered on ANZCTR

Registration number
Ethics application status
Submitted, not yet approved
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
“HIITing” the Mark: The developing an optimal high-intensity interval training (HIIT) protocol for improving fitness before abdominal surgery
Scientific title
“HIITing” the Mark: The developing an optimal high-intensity interval training (HIIT) protocol for improving fitness before abdominal surgery
Secondary ID [1] 294857 0
Universal Trial Number (UTN)
Trial acronym
Linked study record
This study is a continuation of a pilot study, ACTRN12617000587303.

Health condition
Health condition(s) or problem(s) studied:
Prehabilitation 307803 0
Abdominal Surgery 307804 0
Complications after surgery 307805 0
Condition category
Condition code
Physical Medicine / Rehabilitation 306853 306853 0 0
Other physical medicine / rehabilitation
Surgery 306854 306854 0 0
Other surgery

Study type
Description of intervention(s) / exposure
A full pre-operative anaesthetic assessment will be performed for each participant, and this is part of the standard treatment that they receive if they are patients scheduled for abdominal surgery. Participants will be categorised as either fit or unfit, by means of the Duke Activity Survey, initial cardiopulmonary exercise testing (CPET), and a modified frailty index. CPET will be performed on an electromagnetically braked ergometer using individualised stepped protocols based on the individual’s fitness levels. This will be supervised by a senior researcher with medical staff also on site. Peak VO2, anaerobic threshold, respiratory exchange ratio and the workloads required to elicit 60% and 90% maximal heart rate will be documented. CPET will be repeated throughout the exercise program to test for changes in Peak VO2.
The exercise program will include 24 sessions, 3-4 times a week, over approximately eight weeks. This will include five sessions of CPET (sessions 1,6,10,14 and 24) and 19 of HIIT. The HIIT sessions, which will be supervised by a trained exercise physiologist, will be performed on Monarch cycle ergometers, with monitoring of pulse and blood pressure. The HIIT sessions will aim to achieve ten 1-minute intervals of high-intensity cycling (against resistance) followed by ten 1-minute intervals of active rest (gentle cycling against no resistance) and will then progress to five 2-minute intervals of high-intensity work followed by 2-minutes of active rest. Intense exercise may be for shorter periods of time in unfit participants. The sessions will be individualized, with differences in the duration of intense exercise on starting HIIT, progression of exercise intensity over time, and adherence to exercise targets (such as reaching a heart rate of 90% of an age defined maximal heart rate) being noted. Whilst the session is individualised, we may have groups of up to 4 patients undertaking a HIIT session at a time, and this will take place at Dunedin Hospital in an exercise room. If the participant’s surgery is delayed, he or she will be invited to complete one additional HIIT session per week up until surgery. Each session will last approximately 30 minutes. After surgery, patients will complete a postoperative morbidity survey and quality of life questionnaire.
Intervention code [1] 301166 0
Intervention code [2] 301167 0
Treatment: Other
Comparator / control treatment
No control group
Control group

Primary outcome [1] 305847 0
The primary outcome of the study is to document a ‘dose-response’ curve for peak oxygen consumption (y-axis), which is compared to the number of pre-operative exercise sessions (x-axis). This will be measured with a cardiopulmonary test on a stationary cycle ergometer. During this test, we will use spirometry to measure the exchange of respiratory gasses to determine the patient's oxygen consumption during cycling on a stationary cycle ergometer. After 3 minutes of resting (for resting spirometry and to let gas exchange variables stabilise), the test will proceed with a ramp protocol of incremental resistance on the stationary cycle ergometer until termination, followed by 5 minutes of active recovery against no resistance. Heart rate, 12-lead electrocardiogram, blood pressure and pulse oximetry are assessed throughout the procedure in order to provide safety monitoring and will not be considered outcomes. An automated external defibrillator is present on site and there is a phone line to a designated arrest team in case of any cardiac event. The peak oxygen consumption (peak VO2) will be measured using online gas analysis (Quark B2), part of the Cosmed Cardio-Pulmonary Exercise Testing system (Cosmed, Rome, Italy).
Timepoint [1] 305847 0
The peak oxygen consumption will be measured 5 times for participants who complete the exercise program, at the 1st, 6th, 10th, 14th and 24th exercise session.
Secondary outcome [1] 346743 0
Quality of Life- measured via the short form health questionnaire (SF-36). This validated questionnaire has been used by our research group previously and gives an indication of the patient's perceived quality of life. The first SF-36 questionnaires will be administered at the time of the HIIT sessions, subsequent questionnaires will be mailed out to the participants.
Timepoint [1] 346743 0
The SF-36 will be administered 4 times: After allocation and prior to the first CPET, after the last HIIT session, 6 weeks after the last HIIT session, and 12 weeks after the last HIIT session.
Secondary outcome [2] 346744 0
Exercise: All participants will keep an exercise diary and will be provided with a pedometer. These will be used to capture their overall level of exercise over the time period they are included in the study and up to the time of surgery. The exercise will be both that of the study and the participant's own, individual activity level.
Timepoint [2] 346744 0
Exercise will be recorded from the time of the first CPET and for the following eight weeks up to the time of their final CPET.
Secondary outcome [3] 346745 0
Clinical Outcomes: length of hospital stay. This will be determined from a review of the medical records and discussion with the surgical team managing the patient.
Timepoint [3] 346745 0
Length of stay is defined as the number of postoperative days stayed in hospital, with day one being the day of surgery.
Secondary outcome [4] 352444 0
Clinical outcomes: Post Operative Morbidity Survey. This is a validated questionnaire used to assess postoperative adverse events in 9 different categories.
Timepoint [4] 352444 0
For patients undergoing surgery, this will be recorded at the hospital 5 days after the operation.
Secondary outcome [5] 352445 0
Clinical outcomes: complications. Complications will be assessed in two ways. Inpatient complications will include a review of the medical records and discussion with the surgical team managing the patient. Complications after discharge will be assessed by a previously validated telephone questionnaire (Journal of Surgical Research 206:77-82, 2016)
Timepoint [5] 352445 0
For patients who have surgery: five days after surgery and 6 weeks after surgery.

Key inclusion criteria
One of the following: 1.) Patients on the surgical waiting list for the following elective operative procedures: major bowel surgery, incisional hernia repair, cholecystectomy, hysterectomy and prostate surgery. 2.) Patients referred by a cardiologist, respiratory physician or geriatrician. Participants must be able to attend multiple supervised exercise sessions at the hospital and be identifiable from surgery waiting lists approximately two months before the estimated time of surgery.
Minimum age
55 Years
Maximum age
85 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1) Inability to exercise or to perform CPET
2) Contraindication to exercise diagnosed on CPET
3) Uncontrolled hypertension (Blood Pressure >180/100),
4) Active clinical angina (This does not include patients with a history of ischaemic heart disease who have no symptomatic angina on appropriate medical treatment, or no angina following a successful revascularization procedure)
5) myocardial infarction in the past three months,
6) uncontrolled cardiac arrhythmias,
7) aortic aneurysm >6.5cm,
8) severe obstructive pulmonary disease with a FEV1 < 1.0 litres,
9) inability to provide consent,
11) preoperative chemotherapy or radiotherapy which overlaps with the period of preoperative exercise.

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
Patients will be categorised as fit or unfit based on their modified frailty index scores.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
For the primary endpoint, the Peak VO2 v number of exercise sessions ‘dose-response’ curve, we aim to assess if separate curves can be developed for average and high-risk patient groups. Based on our current study, the improvement in Peak VO2 after 14 sessions (with a combination of those who would fit into the low and high-risk groups) is approximately 2.5ml/kg/min with a standard deviation of 1.9ml/kg/min. Non-linear mixed models will be used to compare changes over time (including slopes) in the dose-response curves between the two exercise groups. Comparison of specific aspects of the exercise program, such as duration of intense exercise on starting HIIT, progression of exercise intensity over time and adherence will be summarised and directly compared. Categorical variables will be compared using the chi-square test or Fisher’s exact test depending on frequency, and continuous variable will be compared using the Student’s t-test or the Mann-Whitney U test depending on the distribution. Changes in peak VO2 after completing the 24 sessions of HIIT will be assessed using analysis of covariance (ANCOVA) statistics. Patient demographics will be described using appropriate descriptive statistics (mean and standard deviation for approximately normally distributed continuous variables, median and inter-quartile range for other continuous variables, count and percentage for categorical variables). For secondary endpoints, differences in complications for average and high-risk groups will be compared using the chi-square test or Fisher’s exact test, and differences in the length of stay, POMS and the SF-36 scores will be compared using the Mann-Whitney U test. Statistical significance will be set at p<0.05. Complications in frail and non-frail participants will be summarised.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 10390 0
New Zealand
State/province [1] 10390 0

Funding & Sponsors
Funding source category [1] 299445 0
Name [1] 299445 0
University of Otago
Address [1] 299445 0
University of Otago
362 Leith Street
North Dunedin
Dunedin 9016
Country [1] 299445 0
New Zealand
Funding source category [2] 299446 0
Name [2] 299446 0
Maurice and Phillis Paykel trust
Address [2] 299446 0
PO Box 110008
Auckland Hospital
Auckland 1148
Country [2] 299446 0
New Zealand
Primary sponsor type
Dunedin Hospital
201 Great King Street, Dunedin 9016
New Zealand
Secondary sponsor category [1] 299529 0
Name [1] 299529 0
Address [1] 299529 0
Country [1] 299529 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 300352 0
Health and Disability Ethics Committee
Ethics committee address [1] 300352 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 300352 0
New Zealand
Date submitted for ethics approval [1] 300352 0
Approval date [1] 300352 0
Ethics approval number [1] 300352 0

Brief summary
Many of us will require a major operation during our lifetime. Complications after surgery are common, and medical staff continue to explore ways to reduce this. Although many risk factors, such as our health problems and the operation required cannot be changed, it has been demonstrated that we can improve fitness over 4-6 weeks before surgery. In our first study, we have achieved a greater than 10% improvement in fitness before surgery. In this study, we will examine what an ideal aerobic preoperative exercise program, including for patients with different levels of fitness, should look like.

This study will compare two groups of participants, a high risk and an average risk group, who are scheduled for abdominal surgery. Fitness, defined as peak oxygen consumption (peak VO2), will be measured by cardiopulmonary exercise testing (CPET). The exercise program will include 24 sessions over eight weeks (19 exercise sessions and 5 CPET). The changes in peak VO2 will be compared against the number of exercise sessions to construct ‘dose-response’ curves, which will be used to recommend evidence-based preoperative exercise programs for both average and high-risk patients. Postoperative outcomes including complications, recovery from surgery, and quality of life will also be compared.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 83366 0
Dr John Woodfield
Address 83366 0
Dunedin School of Medicine
University of Otago
201 Great King Street
Dunedin 9016
Country 83366 0
New Zealand
Phone 83366 0
+64 34740999
Fax 83366 0
Email 83366 0
Contact person for public queries
Name 83367 0
Dr John Woodfield
Address 83367 0
Dunedin School of Medicine
University of Otago
201 Great King Street
Dunedin 9016
Country 83367 0
New Zealand
Phone 83367 0
+64 34740999
Fax 83367 0
Email 83367 0
Contact person for scientific queries
Name 83368 0
Dr John Woodfield
Address 83368 0
Dunedin School of Medicine
University of Otago
201 Great King Street
Dunedin 9016
Country 83368 0
New Zealand
Phone 83368 0
+64 34740999
Fax 83368 0
Email 83368 0

No information has been provided regarding IPD availability
Summary results
No Results