Functional Reach: A New Clinical Measure of Balance

TLDR

Functional reach (FR) is a clinically accessible balance measure defined as the difference between arm length and maximal forward reach with a fixed base of support. The study aimed to validate FR against the laboratory measure COPE, assess its reliability and precision, and identify factors such as age and anthropometrics that influence it. FR was measured in 128 volunteers aged 21–87 using a precise electronic device and a simple yardstick apparatus. FR correlated strongly with COPE (r = 0.71), exhibited high precision (CV = 2.5%) and stability (ICC = 0.81), was influenced by age and height, and proved to be portable, inexpensive, reliable, and a useful clinical proxy for the margin of stability, aiding detection of balance impairment, monitoring changes, and informing environmental modifications for older adults.

Abstract

A new clinically accessible measure of balance, functional reach (FR), is the difference between arm's length and maximal forward reach, using a fixed base of support. The purposes of this study were to (a) establish FR as a measure of the margin of stability versus the laboratory measure, center of pressure excursion (COPE); (b) test reliability and precision, and (c) determine factors that influence FR, including age and anthropometrics. We evaluated FR in 128 volunteers (age 21-87 years). FR was determined with a precise electronic device and a simple clinical apparatus (yardstick). FR correlates with COPE (Pearson r = .71) and is precise (coefficient of variation = 2.5%) and stable (intraclass correlation coefficient across days = .81). Age and height influence FR. FR is portable, inexpensive, reliable, precise, and a reasonable clinical approximator of the margin of stability. FR may be useful for detecting balance impairment, change in balance performance over time, and in the design of modified environments for impaired older persons.