Base of Support
Original Editor - The Open Physio project
Top Contributors - Sheik Abdul Khadir, Sonal Joshi, Admin, Rachael Lowe, Garima Gedamkar, Kim Jackson, Scott Buxton, Simisola Ajeyalemi, Wanda van Niekerk, Lucinda hampton, WikiSysop, Claire Knott, Jess Bell and Olajumoke Ogunleye
Introduction
The base of support (BOS) refers to the area beneath an object or person that includes every point of contact that the object or person makes with the supporting surface. These points of contact may be body parts e.g. feet or hands, or they may include things like crutches or the chair a person is sitting in.
Measurement
Inertial and Infrared wearable systems assist in estimation of base of support along with step length and stride width during gait cycle.[1]
Significance
BOS & Balance: Balance by definition is the ability to maintain the line of gravity (passing through the Centre of Gravity) within the BOS. Therefore, the BOS is an important concept to understand an individual's ability to Balance.
BOS & Gait Cycle: In the gait cycle, BOS has been defined as the horizontal stride width during the double-support phase when both feet are in contact with the ground.[2]
BOS & Fall Risk: The dynamical nature of gait increases fall risk for older People as the Center of Mass (COM) is constantly displaced inside and outside the BOS.[3]Dynamic balance requires the ability to maintain the vertical projection of the COM within a small BOS (feet) during standing and walking[4]A wide base of support (BOS) has long been believed to be a hallmark of unsteady gait. [5]
Physiotherapy Implications
A knowledge of the variations in BOS is essential when assessing balance, both dynamic and static. The majority of the gait cycle is spent in single leg support during which the BOS is minimised to the width of the supporting foot.[2] Thus when a patient presents with an unstable gait a wider base of support can be provided by walking aids (eg walker, crutches, cane) giving more stability and a larger BOS. As the condition of the patient improves, the BOS can be reduced.
Variations in body position have an effect on the BOS. A decreased stride width is found to closely correlate with fall frequency and dynamic stability[2]. Balance training aims to increase an individuals ability to maintain their stability within there BOS and prevent falls.
When progressing exercises using changes in the the BOS, focus on BOS manipulation and step width. Research supports that it leads to improvement in dynamic stability and postural control, including in conditions such as Cerebral Palsy and Cerebellar ataxia in which balance impairments primarily present[8][9].
References
- ↑ Rossanigo R, Caruso M, Bertuletti S, Deriu F, Knaflitz M, Della Croce U, Cereatti A. Base of support, step length and stride width estimation during walking using an inertial and infrared wearable system. Sensors. 2023 Apr 12;23(8):3921.
- ↑ 2.0 2.1 2.2 Krebs DE, Goldvasser D, Lockert JD, Portney LG, Gill-Body KM. Is base of support greater in unsteady gait?. Physical Therapy. 2002 Feb 1;82(2):138-47.
- ↑ Siragy T, Russo Y, Horsak B. Mediolateral Margin of Stability highlights motor strategies for maintaining dynamic balance in older adults. Plos one. 2024 Oct 31;19(10):e0313034.Available: https://pubmed.ncbi.nlm.nih.gov/39480769/ (accessed 16.2.2025)
- ↑ Baptista RR, Peyré-Tartaruga LA, Granacher U. Spotlight on aging: physiology, prevention and management of gait and balance. Frontiers in Physiology. 2024 Sep 17;15:1477957.Available: https://pmc.ncbi.nlm.nih.gov/articles/PMC11443459/(accessed 16.2.2025)
- ↑ Nutt JG, Marsden CD, Thompson PD. Human walking and higher-level gait disorders, particularly in the elderly. Neurology.1993 ;43:268–279.
- ↑ Carol Doehler. Biomechanics: Centre of Gravity & Base of Support. Available from : https://www.youtube.com/watch?v=MGObbsKpbVM&t=2s [last accessed 19/05/2025]
- ↑ Muscle and Motion. Mastering Balance: The Science of Centre of Gravity and Base of Support. Available from: https://www.youtube.com/watch?v=5s1gEi5wfLg [last accessed 19/05/2025]
- ↑ da Conceição GZ, Gardinal M, Kreutz GM, Rocha NA, Pavão SL. How Does Postural Control of Children with CP Deal with Manipulations on Base of Support and Support Surface? A Systematic Review. Developmental Neurorehabilitation. 2024 May 18;27(3-4):93-105.
- ↑ Conte C, Serrao M, Cuius L, Ranavolo A, Conforto S, Pierelli F, Padua L. Effect of restraining the base of support on the other biomechanical features in patients with cerebellar ataxia. The Cerebellum. 2018 Jun;17:264-75.