La postura del tronco durante il cammino è un miglior indicatore rispetto alla velocità dell’andatura del declino della funzione e della successiva fragilità?

R.A. Merchant, S. Banerji, G. Singh, E. Chew, C.L. Poh, S.C. Tapawan, Y.R. Guo, Y.W. Pang, M. Sharma, R. Kambadur, S. Tay

J Am Med Dir Assoc. 2016;17(1):65-70

Gait speed is considered a strong predictor of a wide range of outcomes in older adults, including falls and fractures, hospitalization, cognitive decline, and mortality. Hence, many recent guidelines and consensus  definitions of sarcopenia have been based on gait speed, but without addressing posture adaptation to maintain gait speed in the face of weakness or joint stiffness.

Older adults are known to compensate well for declining physiological reserve through environmental modification and posture adaptation. This study aimed to analyze and identify significant posture adaptation in older adults that is required to maintain gait speed in the face of increasing vulnerability.

The study team recruited 90 community-dwelling Chinese older adults between the ages of 60 and 80 years with body mass index (BMI) in the normal range (18.5-23.5 according to Asian standards). Additional 20 adults between 21 to 50 years were recruited as a reference group. All the participants underwent handgrip strength testing, 6-minute walking test, timed up-and go (TUG) test, and motion analysis for gait characteristics. Low function was characterized by slow walking speed (< 1.0 m/s) and/or slow TUG (> 10 seconds), whereas low strength was determined by hand grip dynamometer testing (< 26 kg). The degree of frailty was classified using the Canadian Study for Health and Ageing Clinical Frailty Scale (CSHA-CFS) to differentiate between healthy and vulnerable older adults. Posture adaptation were evaluated by analyzing joint and limb segment kinematics.

Results showed that vulnerable older adults had lower functional performance and strength compared with the healthy older adults group. However, a significant number demonstrated posture adaptations in walking in all 3 groups, including those who maintained a good walking speed (> 1.0m/s). The extent of such adaptation was larger in the vulnerable group as compared with the healthy group.

Comment: This study suggests that trunk posture adaptation precedes decline in gait speed and it might be useful to track this adaptation during walking to identify at-risk older adults earlier, before gait speed decline takes place. Identifying trunk posture adaptation before the onset of a decline in gait speed may help in planning interventions in the at-risk community-dwelling older adults, before gait speed declines. However, further prospective studies are needed to see if healthy older adults with trunk posture adaptation and normal gait speed develop impaired gait speed earlier than those without such adaptation and if this decline can be prevented with posture correction and motion exercises.