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The Role of Energetic Cost in the Age‐Related Slowing of Gait Speed
Author(s) -
Schrack Jennifer A.,
Simonsick Eleanor M.,
Chaves Paulo H.M.,
Ferrucci Luigi
Publication year - 2012
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/j.1532-5415.2012.04153.x
Subject(s) - medicine , preferred walking speed , gait , physical medicine and rehabilitation , confounding , energy expenditure , balance (ability) , power walking , physical therapy
Objectives To determine whether slow gait represents a compensatory strategy to reduce the energetic cost of walking with age. Design Cross‐sectional analysis. Setting Community‐dwelling volunteers from the B altimore L ongitudinal S tudy of A ging ( BLSA ). Participants Four hundred twenty community‐dwelling persons aged 32 to 96 (mean 68.1 ± 12.5) who underwent a physical examination, physical function testing, and energy expenditure assessment. Measurements Energy expenditure per minute (mL/kg/min) and per meter (mL/kg/m) during 2.5 minutes of overground walking at customary speed and usual gait speed over 6 m (m/s) were examined. General linear regression models were used to assess the relationship between customary walking energy expenditure and usual gait speed, adjusted for potential confounders including smoking, medical diagnoses, walking‐related pain, and balance difficulty. Results Usual gait speed was slower with increasing age after age 65. Energy expenditure per minute during customary walking averaged 13.0 ± 2.8 mL/kg/min and was independent of age (ρ < 0.01, P = .88). In contrast, energy expenditure per meter walked was progressively higher after age 65 (ρ = 0.35, P < .001) and heightened after age 80 ( r = 0.57, P < .001), mirroring the observed pattern of usual gait speed. This relationship remained significant after adjusting for multiple impairments and comorbidities. Conclusion These observations support the hypothesis that slower gait at older ages may reflect a compensatory action to offset the greater energetic cost of walking associated with aging and chronic conditions. Future studies should evaluate the specific mechanisms that contribute to this phenomenon as novel targets for clinical intervention.