A Pilot Randomized Controlled Trial Comparing Core Exercise, Aerobic Exercise, and Combined Exercise in Patients Undergoing Phase II Cardiac Rehabilitation.

The peak oxygen uptake (VO₂peak) is measured using a cardiopulmonary exercise testing (CPET).

Participants are instructed to walk back and forth as quickly as possible along a flat, hard-surfaced indoor corridor for six minutes. The total distance walked within six minutes is recorded.

Participants stand barefoot on one leg, keeping the opposite leg lifted without touching the supporting leg. Hands are placed on the hips, and eyes are open, gazing forward. The maximum duration of stable standing is recorded. Each leg is tested twice, and the best score is used for analysis.

Participants assume a forearm plank position, maintaining a straight trunk with core engaged. The duration for which the position is held is recorded. The body must remain in a straight line from head to heels, with no sagging of the hips.

Participants perform side planks on the left and right sides, supporting the body with one forearm while keeping the body in a straight line. The holding time for each side is recorded separately.

Performed using McGill's trunk flexor endurance protocol. Participants sit on a 60-degree inclined board with hips and knees bent at 90 degrees and arms crossed over the chest. The support board is then removed, and participants are asked to maintain the trunk at a 60-degree angle from the ground for as long as possible. The test ends when the participant can no longer hold the position.

Participants lie supine in a crook-lying position (knees bent) with a pressure biofeedback unit placed under the third lumbar vertebra, inflated to 40 mmHg. Participants are instructed to slowly lift both legs to 90° hip flexion. If the pressure change is less than 10 mmHg during lifting, it is considered a success, indicating stable lumbar control; a change greater than 10 mmHg indicates failure due to uncontrolled lumbar flexion. Participants then lower both legs from 90° to 45° hip flexion. If the pressure change is less than 10 mmHg, it is considered a success, indicating good lumbar stability; a change greater than 10 mmHg indicates failure due to uncontrolled lumbar extension.

Participants sit on an armless chair with arms crossed over the chest and are instructed to stand up and sit down as many times as possible within 30 seconds. The total number of full sit-to-stand repetitions is recorded.

Participants sit with the dominant arm relaxed at the side, elbow flexed at 90°, and hold a hand dynamometer. They are instructed to squeeze maximally for 2-3 seconds. Three trials are performed with 30-second rest intervals, and the highest value is recorded as the maximal handgrip strength.

Based on the results of the baseline cardiopulmonary exercise test, participants perform a constant-load exercise at 80% of their VO₂peak until volitional exhaustion or until reaching test termination criteria. The total exercise time to exhaustion is recorded.

Body fat percentage and lean body mass are measured using bioelectrical impedance analysis (BIA).