Single Leg Stance Test

Abstract

The Single Leg Stance Test (SLST) is a widely recognized and standardized performance test utilized across clinical and research settings to assess an individual’s static balance capabilities. This test requires the patient to maintain equilibrium while standing on one leg for a defined period.

The methodology of the SLST is flexible, often administered under two conditions: with eyes open or eyes closed, which allows clinicians to differentiate between reliance on visual versus somatosensory and vestibular inputs for postural control. The test is also known by several synonyms, including unipedal stance, single limb stance, and one leg stance or balance test.

Keywords

Single Leg Stance Test, SLST, Static Balance, Postural Control, Performance Test, Mobility, Geriatrics, Falls Risk Assessment, Lower Extremity.

Authors

Freeman MAR, Dean MR, Hanham IW (1965)

Purpose

The primary purpose of the SLST is to provide an objective, quantifiable measure of postural stability and static balance. It serves as a rapid screening tool for identifying deficits in balance control, particularly those related to the integration of sensory information necessary for maintaining an upright posture on a narrow base of support.

Clinically, the SLST is invaluable in assessing fall risk, tracking rehabilitation progress, and evaluating the functional status of the musculoskeletal system and the central nervous system. It is commonly applied in populations recovering from orthopedic injuries, neurological disorders, or those experiencing age-related declines in stability.

Construct

The SLST primarily measures the construct of static postural control, which is the ability to maintain the center of mass within the base of support when the body is not in motion. This ability relies heavily on the integration of three main sensory systems: the visual system, the vestibular system, and the somatosensory system.

When performed with eyes open, the test reflects the combined efficiency of all three systems. When performed with eyes closed, the test isolates the reliance on the vestibular and somatosensory systems, making it a powerful diagnostic tool for identifying specific sensory impairments contributing to instability. The time an individual can maintain the stance serves as the metric for the quality of balance control.

Validity

The validity of the Single Leg Stance Test has been extensively studied, particularly its criterion and predictive validity concerning fall risk. Numerous studies confirm that shorter single-leg stance times are significantly correlated with an increased risk of falls in elderly populations, establishing strong predictive validity for this demographic.

Furthermore, the SLST demonstrates good concurrent validity when compared against more complex laboratory-based measures of balance, such as force plate analysis. Its simplicity and high correlation with objective measures make it a clinically pragmatic and valid tool for assessing functional mobility and balance deficits related to the lower extremity.

Reliability

The SLST exhibits generally strong inter-rater and intra-rater reliability, provided standardized testing protocols are strictly followed. Factors that can influence reliability include consistent instruction regarding arm and non-stance leg positioning, and precise timing methods.

Test-retest reliability is typically high, especially in healthy adult populations. However, reliability may decrease slightly in individuals with significant balance impairments or cognitive deficits due to increased variability in performance. Standardizing the conditions (e.g., surface type, footwear, and whether eyes are open or closed) is critical for ensuring reliable outcomes.

Factor Analysis

As a single-item performance measure (time held), the SLST does not typically undergo traditional factor analysis in the same manner as multi-item questionnaires. Instead, research often focuses on its relationship with latent factors underlying overall physical function, such as general mobility or neuromuscular control.

Studies incorporating the SLST into larger batteries of physical function tests (e.g., the Berg Balance Scale or the Timed Up and Go) often show that single-leg stance time loads highly onto a common factor representing static postural stability, distinct from dynamic balance or gait speed factors.

Instrument

Test Type: Performance Test

Format: Timed motor task (Seconds held)

Language Available: Standardized protocol is generally language-independent, but instructions are available in English (based on provided documents).

Population Group: Clinical and General Populations

Age Group: Children, Adults, and the Elderly (Geriatric populations)

Population Details: Applicable across a wide range of individuals, including those with conditions affecting the Musculoskeletal System and the Nervous System (e.g., post-stroke, orthopedic injury, peripheral neuropathy).

Test Methodology: The patient stands unsupported on one leg for as long as possible. The test is typically terminated when the stance leg moves, the lifted foot touches the ground, or the maximum time limit (often 30 seconds) is reached. Testing is performed on both the dominant and non-dominant legs, usually under both eyes-open and eyes-closed conditions.

The original PDF document explaining the procedure (Toelichtingsformulier) can be downloaded here: SLST-form.pdf

The original PDF document containing the measurement instrument (Meetinstrument) can be downloaded here: SLST-meetinstr-Eng.pdf

Keywords

Unipedal Stance, Single Limb Balance, Postural Stability, Fall Prediction, Neuromuscular Function, Orthopedics, Geriatrics, Nervous System, Time Limit.

Authors

Author ORCID Identifier: Information not provided in source content.

Affiliation Email addresses: Information not provided in source content.

Correspondence Address: Information not provided in source content.

Permissions & Fee and Test Year

The Single Leg Stance Test (SLST) was first described by Freeman, Dean, and Hanham in 1965. As a fundamental, non-proprietary physical performance measure, the SLST is generally considered to be in the public domain and does not typically require specific licensing or incur fees for clinical or research use.

Users are encouraged to consult the specific reference material (Freeman et al., 1965) or subsequent standardized protocols to ensure strict adherence to the original methodology and scoring criteria.

Reference’s

The foundational reference for the Single Leg Stance Test is:

• Freeman MAR, Dean MR, Hanham IW. (1965). The etiology and prevention of functional instability of the foot. Journal of Bone and Joint Surgery. British volume, 47-B(4), 678-685.

Items of the Single Leg Stance Test

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

The primary item instruction for the Single Leg Stance Test is:

• Sta op één been zo lang mogelijk.
• De tijd wordt gestopt zodra de patiënt de grond aanraakt met de andere voet, de armen gebruikt om te balanceren door de handen op de heupen te plaatsen, of de maximale tijdslimiet is bereikt.