Resistance Training Added to Aerobic Interval Training to Improve Aerobic Capacity and Muscle Mass in Women With Coronary Artery Disease (VAKAR)

January 14, 2026 updated by: Borut Jug, University Medical Centre Ljubljana

Resistance Training Among Women With Coronary Artery Disease

The goal of this clinical trial is to find out whether partly replacing aerobic interval training (AIT) with resistance training (RT) leads to greater improvements in physical fitness and muscle mass in women with coronary artery disease (CAD) during cardiac rehabilitation.

The main questions this study aims to answer are:

  • Does combining RT (squats and pulling exercises with weights) with a reduced amount of AIT (cycling) improve aerobic fitness in the same way as AIT alone?
  • Does the combined training lead to greater improvements in muscle mass compared with AIT alone?
  • Does slow-speed RT (slower lowering phase) result in lower heart rate and blood pressure during exercise compared with normal-speed RT?

Researchers will compare three exercise programs:

  • AIT only (control group),
  • AIT combined with normal-speed RT (1-second lifting, 2-second lowering),
  • AIT combined with slow-speed RT (1-second lifting, 5-second lowering).

Participants will take part in a 12-week cardiac rehabilitation program and will train three times per week.

At the start and end of the program, participants will complete a cycling fitness test, body composition assessment, blood sampling, two strength tests, and quality-of-life questionnaire.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

CAD remains one of the leading causes of death among women worldwide. Although cardiac rehabilitation programs with AIT are well established, the optimal way to include RT in this population remains unclear. Historically, RT was limited in patients with heart disease due to concerns about excessive blood pressure responses and cardiovascular risk. However, recent evidence shows that properly prescribed RT is safe and may significantly improves muscle strength, aerobic fiitness, and overall quality of life.

The study consists of two sequential phases. The first is a crossover feasibility phase designed to compare the acute hemodynamic responses (blood pressure, heart rate) and rate of perceived exertion between two RT protocols: (1) traditional high-load RT (1-second lift, 2-second descent) and (2) high-load RT with a prolonged eccentric phase (1-second lift, 5-second descent). The goal of this phase is to confirm the feasibility and short-term safety of both approaches before inclusion in the main trial.

The second phase is a three-arm, parallel-group randomized controlled trial. After baseline assessments, participants are randomized into one of three groups using block randomization with variable block sizes to ensure balanced allocation throughout recruitment.

The 12-week intervention includes three supervised sessions per week, totaling 36 visits. AIT follows a structured progression based on heart rate reserve, alternating between high- and low-intensity cycling intervals on a stationary ergometer. RT sessions consist of compound lower-body and upper-body movements (hex-bar squat and horizontal cable pull), performed at approximately 80% of one-repetition maximum. Training intensity, load progression, and repetition tempo are standardized across groups, ensuring equivalent time under tension per set.

To maintain participant safety, all exercise sessions are supervised by medical and rehabilitation staff, including a physiotherapist, nurse, and kinesiologist, with a cardiologist on call. Continuous heart rate monitoring and pre- and post-exercise blood pressure measurements are performed during each session. Any adverse events will be recorded and reviewed by the study physician.

Statistical analyses will follow the intention-to-treat principle.

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Slovenia
      • Ljubljana, Slovenia, 1000
        • Recruiting
        • University Medical Centre Ljubljana (Department of Vascular Diseases, Division of Internal Medicine)
        • Contact:
        • Principal Investigator:
          • Borut Jug, MD, Ph.D.
        • Sub-Investigator:
          • Marko Novaković, MD, Ph.D.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • documented CAD,
  • stable clinical status (at least 1 month since myocardial infarction and/or elective percutaneous coronary intervention, at least 3 months since cardiac surgery).

Exclusion Criteria:

  • based on the American Heart Association guidelines for resistance training in patients with CAD,
  • pregnancy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Aerobic Interval Training
Other: Aerobic Interval Training
Interval cycling, performed at 70-80% of the heart rate reserve (HRR) as determined during the cardiopulmonary exercise test. The training is structured as alternating high- and low-intensity intervals.
Experimental: Combined Training 1
Other: Aerobic Interval Training
Interval cycling, performed at 70-80% of the heart rate reserve (HRR) as determined during the cardiopulmonary exercise test. The training is structured as alternating high- and low-intensity intervals.
Other: Traditional Resistance Training
Resistance training with traditional tempo (1-second ascent, 2-second descent) - squat exercise and horizontal pull.
Experimental: Combined Training 2
Other: Aerobic Interval Training
Interval cycling, performed at 70-80% of the heart rate reserve (HRR) as determined during the cardiopulmonary exercise test. The training is structured as alternating high- and low-intensity intervals.
Other: Prolonged Eccentric Phase Resistance Training
Resistance training with prolonged eccentric phase tempo (1-second ascent, 5-second descent) - squat exercise and horizontal pull.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Maximal Aerobic Capacity
Time Frame: From enrollment to the end of treatment at 12 week.
Maximal aerobic capacity (VO2peak) will be assessed using a modified Ramp protocol on the Schiller ERR 911 cycle ergometer in combination with the Cardiovit CS-200 Excellence ergo-spirometer (Schiller, Switzerland). Following baseline spirometry, participants will perform a warm-up phase of unloaded cycling for up to three minutes, after which the workload will increase incrementally by 10-25 W every minute until exhaustion or the appearance of clinical indications for test termination. Throughout the test, the supervisor will monitor for any signs or symptoms warranting termination, in accordance with the American Heart Association guidelines.
From enrollment to the end of treatment at 12 week.
Lean Body Mass
Time Frame: From enrollment to the end of treatment at 12 weeks.
Body composition, including lean body mass (also called fat-free mass; calculated by subtracting body fat weight from total body weight) and fat mass, will be assessed using whole-body dual-energy X-ray absorptiometry (DXA) (Hologic, USA), which is considered the gold standard for evaluating body composition due to its high accuracy and reproducibility .
From enrollment to the end of treatment at 12 weeks.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Blood Biomarkers
Time Frame: From enrollment to the end of treatment at 12 weeks.
As part of routine clinical blood draws, fasting blood samples will be obtained before the first and last training sessions. They will be analysed for standard clinical parameters (including blood lipids and others).
From enrollment to the end of treatment at 12 weeks.
Handgrip Strength
Time Frame: From enrollment to the end of treatment at 12 weeks.
Handgrip strength will be assessed using a hand dynamometer (Jamar). Participants will hold the dynamometer with the arm alongside the body and the elbow flexed at 90 degrees, and will be instructed to squeeze as hard as possible for 3-5 seconds. Three measurements will be performed for each hand, with 1 minute of rest between trials. The highest value obtained will be used for analysis.
From enrollment to the end of treatment at 12 weeks.
30-Second Sit-to-Stand Test
Time Frame: From enrollment to the end of treatment at 12 weeks.
Lower-limb functional strength will be assessed using the 30-second sit-to-stand test. Participants rise from and return to a seated position as many times as possible within 30 seconds, using a standard chair (43 cm) without armrests, with arms crossed over the chest and feet flat on the floor. The outcome is the number of fully completed stands in 30 seconds. If the participant is unable to stand without using the arms, the score is recorded as 0.
From enrollment to the end of treatment at 12 weeks.
Quality of Life Measure
Time Frame: From enrollment to the end of treatment at 12 weeks.
Health-related quality of life will be assessed using the Heart Quality of Life Questionnaire (HeartQoL). The questionnaire yields scores ranging from 0 to 3, with higher scores indicating better health-related quality of life. The overall HeartQoL score is calculated as the mean of all item responses and includes one global scale and two subscales (physical and emotional).
From enrollment to the end of treatment at 12 weeks.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University Medical Centre Ljubljana

Investigators

  • Principal Investigator: Borut Jug, MD, Ph.D., University Medical Centre Ljubljana, Slovenia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 26, 2025

Primary Completion (Estimated)

October 1, 2026

Study Completion (Estimated)

November 1, 2026

Study Registration Dates

First Submitted

December 8, 2025

First Submitted That Met QC Criteria

January 14, 2026

First Posted (Actual)

January 21, 2026

Study Record Updates

Last Update Posted (Actual)

January 21, 2026

Last Update Submitted That Met QC Criteria

January 14, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • UKCLRehabVAKAR

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Coronary Artery Disease With Myocardial Infarction

Clinical Trials on Aerobic Interval Training

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Sri Lanka

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe