The aim of this interventional study was to evaluate the immediate effects of a single bout of 30 squats performed on an unstable surface versus a stable surface on postural stability, bilateral coordination, and dynamic balance in healty subjects. We hypothesized that performing squats on an unstable surface would result in significantly greater improvements in these parameters compared to squats on a stable surface. By comparing the immediate effects under randomized conditions, this study seeks to contribute novel insights into the role of surface stability in acute exercise-induced balance adaptations.

Despite the growing interest in instability training, there remains a lack of evidence regarding the acute effects of squats performed on stable versus unstable surfaces on key balance-related outcomes, including postural stability, bilateral coordination, and dynamic balance. Filling this gap is essential for informing clinical decision-making and optimizing performance and rehabilitation strategies. The study recruited young, relatively healthy, and physically active individuals-students (n = 42). Inclusion criteria were: 1) age between 18 and 35 years, and 2) voluntary consent to participate. Exclusion criteria were: 1) history of lower limb injury within the past six months, and 2) inability to maintain postural balance during testing.The study applied the following procedures: Participant Data Collection, Leg Length Measurement, Determination of Dominant Leg, Postural Stability Assesment, Dynamic Stability Assessment, and Bilateral coordination assessment.

All assessments were performed under controlled laboratory conditions by the same examiner to ensure reliability. Participants were instructed to avoid caffeine, strenuous exercise, and alcohol consumption for at least 12 hours prior to testing. and their hands placed on their hips.

Participants performed 30 bodyweight squats while standing with their feet shoulder-width apart and their hands placed on their hips. Each squat was executed to approximately 90° of knee flexion at the lowest point. The movements were paced using a metronome, with participants completing 30 squats within 45 seconds to ensure a consistent tempo and intensity.

The test was conducted under two conditions: on a stable surface and on an unstable surface, with a 48-hour interval between the two sessions.

Inclusion Criteria:

1. age between 18 and 35 years,
2. voluntary consent to participate in the study.

Exclusion Criteria:

1. history of lower limb injury within the past six months,
2. inability to maintain postural balance during testing.

There are no plans to share individual participant data, as the consent obtained from participants does not include permission for data sharing with other researchers.

No masking is applied in this study. This is a single-arm, open-label trial; therefore, no participants, care providers, investigators, or outcome assessors are masked.