Impact of Fatigue on Balance and Gait Function in Older Adults

Abstract

Considerable attention has been given to falling in older adults and balance has frequently been used as a predictor of fall risk. Much of this research, however, has assessed balance only in a rested state rather than in a fatigued condition that many older adults find themselves in from activities of daily living. PURPOSE: To determine whether static and dynamic balance differs following a fatigue bout in older adults. METHODS: Subjects were 55 older adults (69 ± 5.4y: 35 Female). Static balance was assessed under six conditions using computerized dynamic posturagraphy. The conditions manipulated the input a participant received from their somatosensory, vestibular, and visual senses. Dynamic balance was measured via gait using a battery of tests including the timed up-and-go test (UPGO), 7-meter walk without obstacle (WALK), and 7-meter walk with an obstacle (OBWALK). A counter-balanced design was used and subjects completed the balance tests in a rested state and after fatigue bouts immediately preceding tests. The fatigue bouts were designed to produce fatigue representative of the activities of daily living that older adults might experience prior to facing a challenge to their balance. Before the fatigued static balance assessment, subjects walked up three flights of stairs on a Stairmaster Stepmill while carrying a bag weighted at 5% of body mass. Speed of climbing was set to match their previously timed normal stair ascent to create local muscular fatigue. Prior to the fatigued dynamic balance assessments, subjects walked 15 minutes on a treadmill at 50% of their heart rate reserve maximum. RESULTS: The fatigue condition reduced the average static balance score by 1.4% in the first condition where the participant could utilize all senses for balance (p=0.007). The remaining five conditions were not significantly different between the fatigue and rested conditions (p>0.05). The measures of dynamic balance were not statistically different between the rested and fatigued state for the UPGO, WALK, and OBWALK (p>0.05). CONCLUSIONS: Local muscular fatigue had an immediate impact on static balance but the effect was transient. Dynamic balance was not impacted by systemic fatigue. These results suggest that balance in older adults may be compromised by activities of daily living that result in local muscular fatigue and may place them at a greater risk of falling. Supported by: NIH/NIA AG18861 (PI: Woods) and UIUC Research Board (PI: Evans).