Effect of Squats on Postural Stability, Bilateral Coordination and Dynamic Balance

IMMEDIATE EFFECTS OF SQUATS PERFORMED ON STABLE AND UNSTABLE SURFACES ON POSTURAL STABILITY, BILATERAL COMPARISON AND DYNAMIC BALANCE

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.

Study Overview

• Status: Completed
• Conditions: Healthy Subjects
• Intervention / Treatment: Other: Condition - no exercise before testing; Other: Condition - exercise on unstable surface; Other: Condition - exercise on stable surface

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 42
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Lithuania
  • Kauno M. Sav.
    • Kaunas, Kauno M. Sav., Lithuania, 44221
      • Department of health promotion and rehabilitation

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Healthy student volunteers; 42 students were tested under three conditions	Other: Condition - no exercise before testing; Participants were tested without any exercise; Other: Condition - exercise on unstable surface; Participants performed 30 squats on unstable surface before testing; Other: Condition - exercise on stable surface; Participants performed 30 squats on stable surface before testing

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postural stability	Individuals were asked to stand on the platform with both feet barefoot; the platform's instabil-ity level was set to 11 (with 11 representing a predefined setting on the system). Foot position was determined using the Biodex Balance System (BBS) platform, with the cuboid bones serv-ing as anatomical landmarks to ensure that the foot was centred; subjects' arms were positioned on their hips throughout testing. Postural stability tests were measured in 10-second trials with a 10-second rest period between tests, with a total of three trials conducted.; Stability index (the lower the index, the better the stability). Overall stability index (Overall), sagittal plane's stability index (Forward/Backward) and frontal plane's stability index (Left/Right).; Sway index (the lower the index, the lower the sway); Time in Zone (four zone sizes in percentage provided).; Time in Quadrant (percentage of time).	Under three conditions (Condition 0, condition 1 an Condition 3) at least 48 hours apart
Bilteral Coordination	Using the Biodex machine the following parameters were measured: Sway index in sagittal plane (Anterior/Posterior direction) while standing on a left leg, hand placed on hips. Lower index meant greater results.; Sway index in sagittal plane (Anterior/Posterior direction) while standing on a right leg, hands placed on hips. Lower index meant greater results.; Differences in the sway index in the sagittal plane between the two legs. Lower index meant greater results.; Sway index in frontal plane (Medial/Lateral direction) while standing on a left leg, hands placed on hips. Lower index meant greater results.; Sway index in frontal plane (Medial/Lateral direction) while standing on a right leg, hands placed on hips. Lower index meant greater results.; Differences in the sway index in the frontal plane between the two legs. Lower index meant greater results.; Overall sway index on the left leg.; Overall sway index on the right leg.	Under three conditions (Condition 0, condition 1 an Condition 3) at least 48 hours apart.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dynamic balance	For Dynamic balance Y Balance test was used. Three attempts each leg were conducted, to anterior, poster-omedial and posterolateral directions. The mean of all three reaches were analysed. Participants were instructed to stand barefoot, maintain a single-leg stance and extend the contralateral leg to reach as far as possible along specified lines. The supporting leg could not move, hands were placed on the hips. Y Balance test's score was calculated using this formula: Normalized Reach Distance = (Sum of reach distances in three directions: Limb length) × 100.	Under three conditions (Condition 0, condition 1 an Condition 3) at least 48 hours apart
Body hight	in cm	Befor testing
Body weight	in kg	Before testing

Collaborators and Investigators

• Sponsor: Lithuanian Sports University

Study record dates

Study Major Dates

• Study Start (Actual): February 15, 2025
• Primary Completion (Actual): April 1, 2025
• Study Completion (Actual): April 1, 2025

Study Registration Dates

• First Submitted: January 6, 2026
• First Submitted That Met QC Criteria: January 6, 2026
• First Posted (Estimated): January 14, 2026

Study Record Updates

• Last Update Posted (Actual): January 15, 2026
• Last Update Submitted That Met QC Criteria: January 14, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: exercise; postural balance; coordination
• Additional Relevant MeSH Terms: Behavior; Motor Activity
• Other Study ID Numbers: Lithuanian Sports University28

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No