Abstract and Introduction
Background: falls are common in older adults, and any fall from standing height onto a rigid surface has the potential to cause a serious brain injury or bone fracture. Safe strategies for falling in humans have traditionally been difficult to study.
Objective: to determine whether specific 'safe landing' strategies (body rotation during descent, and upper limb bracing) separate injurious and non-injurious falls in seniors.
Design: observational cohort study.
Setting: two long-term care homes in Vancouver BC.
Methods: videos of 2,388 falls experienced by 658 participants (mean age 84.0 years; SD 8.1) were analysed with a structured questionnaire. General estimating equations were used to examine how safe landing strategies associated with documented injuries.
Results: injuries occurred in 38% of falls, and 4% of falls caused injuries treated in hospitals. 32% of injuries were to the head. Rotation during descent was common and protective against injury. In 43% of falls initially directed forward, participants rotated to land sideways, which reduced their odds for head injury 2-fold. Upper limb bracing was used in 58% of falls, but rather than protective, bracing was associated with an increased odds for injury, possibly because it occurred more often in the demanding scenario of forward landings.
Conclusions: the risk for injury during falls in long-term care was reduced by rotation during descent, but not by upper limb bracing. Our results expand our understanding of human postural responses to falls, and point towards novel strategies to prevent fall-related injuries.
Falls are common in older adults. Approximately 30% of adults over age 65 years living independently, and 60% of older adults residing in long-term care (LTC) will fall at least once per year, and many will fall repeatedly.[1,2] Fortunately, most falls in older adults do not cause serious physical injuries. In the LTC setting, ~20–30% of falls cause some sort of injury, and 5% result in injuries treated in hospitals.[1,3–5]
The reasons why most falls are non-injurious are not well understood. Any fall from standing height onto a rigid surface has the potential to cause serious injury, even in young healthy adults.[6,7] The energy available is more than sufficient to cause head impacts that lead to skull fracture or brain injury,[8–11] or pelvis impacts that cause hip fracture.[7,12,13]
Mechanisms must be acting during falls to absorb and distribute the impact energy in a way that prevents contact forces (and tissue stresses and strains) from exceeding injury thresholds. The nature of safe landing responses has been investigated in cats and other animals.[14–16] However, only a small number of studies have employed methods for eliciting falls in humans, with no restraint harness, and little chance for balance recovery.[17–19] Furthermore, participants in these studies have been restricted to young, healthy individuals.
The limited evidence suggests that two mechanisms used by humans for safe landing during falls are upper limb bracing and body rotation during descent. Upper limb bracing involves impacting the ground (or an object in the environment) with the hand(s) and/or forearm(s), to arrest downward movement of the torso, and thereby prevent impact and injury to the head.[6,20,21] Young adults who experienced unexpected falls in the lab environment consistently exhibited upper limbs bracing.[17,18] A recent analysis of falls in babies captured on video shows that upper limb bracing emerges early in childhood, and tends to be tailored to the context of the fall.
Body rotation during descent involves altering the direction of a fall. Young adults are able to rotate the body after being unexpectedly released into a fall. Judo practitioners are taught to rotate backward during the descent stage of a (forward or sideways) fall, and safely absorb energy through impact to the thigh, buttock(s) and torso.[24,25]
There is scant evidence on the prevalence and effectiveness of rotation or bracing in preventing injuries during falls in older adults. In a study of falls and fractures in community-dwelling older women, approximately 46% of women self-reported falling on their hand/wrist, and those who landed on their hand had a decreased risk for hip fracture[26–28] and an increased risk for distal radius fracture.[27,29] It is unclear whether upper limb bracing persists as a protective response during falls in the more frail LTC population. Furthermore, no study has reported on whether rotation during descent is common and protective for falls in older adults.
We addressed these knowledge gaps by linking documented injuries to video evidence on the movement patterns of older adults during falls in LTC, and testing whether the odds for injury associate with upper limb bracing and body rotation during descent.
Age Ageing. 2022;51(12):afac273 © 2022 Oxford University Press
Copyright 2007 British Geriatrics Society. Published by Oxford University Press. All rights reserved.