Participants in the intervention group will be engaged in an online-delivered core stability exercise program. Sessions will be conducted via a secure video-conferencing platform three times per week, with each session lasting 40-50 minutes.

The exercise program will integrate both isometric and dynamic core stability tasks targeting the trunk flexors, extensors, lateral flexors, and hip musculature. Foundational exercises will include modified curl-up, bird-dog, side bridge, plank variations, and supine bridge. Dynamic components will incorporate controlled limb movements, diagonal patterns, and unstable support surfaces when appropriate. Exercise intensity and complexity will be progressively increased by adjusting lever length, base of support, repetition volume, and hold duration, while emphasizing proper breathing and pelvic floor engagement.

Participants in the control group will receive standard postpartum education delivered online once every two weeks over the 12 weeks. Education sessions will focus on general postpartum health, infant care, sleep hygiene, and psychological well-being, but will not include structured or supervised exercise. Control participants will be advised to maintain their usual daily activities and will not be restricted from engaging in light, unsupervised physical activity as recommended by their healthcare providers.

The intervention group participated in supervised, real-time sessions via a video-conferencing platform, three times per week for 12 weeks.

The lower quarter Y-Balance Test (YBT-LQ) will be used to assess dynamic postural control of the lower extremity. Participants will perform maximal reach in the anterior, posteromedial, and posterolateral directions while maintaining single-leg stance on a standardized YBT device or equivalent setup. Reach distances are normalized to leg length, and a composite score is calculated as the sum of the three directions divided by three times leg length, multiplied by 100.

Trunk endurance will be evaluated using three standardized tests: (a) the flexor endurance test (time holding a seated trunk flexion position against gravity); (b) the extensor endurance test (time maintaining the torso in a horizontal position in prone with the pelvis supported); and (c) the side bridge test (time maintaining a side plank position on each side). All endurance times will be recorded in seconds, with longer durations indicating better endurance.