Age-related differences in inter-joint coordination during stair walking transitions
Introduction
Stair negotiation is one of the most difficult and hazardous locomotor tasks for older adults [1], [2]. In a sample of 310 healthy older adults, more than 45% reported difficulties in stair negotiation [1]. While difficulties in stair ascending were associated with poor balance and gait abnormality, difficulties in stair descending were related to higher fall incidences [1]. Stair-related falls caused nonfatal injuries in more than 55,000 older adults in the United States and accounted for more than 10% of fatal fall accidents [2]. Additionally, falls induced by missteps during stair descending are especially dangerous and may result in serious injuries, such as head trauma or limb fractures [3].
In comparison to level ground walking, the capability to negotiate the stairs can be challenging for older adults due to the greater demands on motor functions. Many studies about the effect of age on stair negotiation have been focused on single joint kinematics, kinetics, muscle activities, or center of mass and center of pressure control. When negotiating the stairs, older adults show high variability in foot clearance [4], poor balance control during the stair to floor transition [5], reduced single joint motions [6], and difficulties in redistributing the joint moments [7]. They also tend to walk with a high proportion of maximal capacity, early activations of quadriceps, and increased muscle co-contraction which is described as a compensatory mechanism of increased joint stiffness for stability [8], [9].
Stair walking transitions were reported to be particular dangerous [10]. The mechanics of transition strides between stair and level ground have been recognized as unique features in anticipatory adjustments for the upcoming surfaces, requiring a greater effort in the ankle plantarflexor and increased lower limb range of motion compared to other strides on the staircase [10], [11]. Since declines in musculoskeletal functions may alter motor patterns in high demanding tasks and deficits in contrast sensitivity may hinder the detection of stair transition regions in older adults [4], [8], [12], further investigations on the transitions strides between stair and level ground may provide insightful information of stair-related falls in older adults.
High levels of neuromuscular control integrated with sensory inputs to produce coordinated limb movements are essential to regulate the initiation, termination, intensity, and adaptability of locomotion [13]. The neuromuscular controller has shown to take advantage of motor redundancy to provide a flexible control over motor tasks that requires good coordination among multiple joints [14]. As such, poor coordination among joints during gait could result in imbalance or tripping [15]. Aging is frequently accompanied with deteriorated central nervous system function and impaired proprioception which is critical in planning and updating inter-joint coordination when performing functional activities [16], [17]. Due to the degeneration of neuromuscular system, age-related differences in inter-joint coordination could be more pronounced than the differences in individual joints and were considered as one of the important functional features to reveal the declines in gait functions as well as the occasions of fall risks in older adults [18], [19]. However, to our knowledge, no study has yet reported the transition strides between stair and level ground from the perspective of neuromuscular control.
Certain aspects of inter-joint coordination of human movement have been successfully assessed by adopting phase portraits constructed by the motions of two joints or segments [20]. With the use of joint angle-velocity phase portraits, continuous relative phase (CRP) evaluates the differences in four quadrants arctangent phase angles between two joints or segments to provide a continuous measurement of the interaction between joints or segments throughout the gait cycle [21]. Investigating inter-joint coordination using CRP could provide insights into the essential timing and sequencing of movement control between joints, and the coordination variability could reflect the flexibility of this control [20], [21], [22]. The information could be used to enhance the safety of stair walking transitions in older adults and improve the development of rehabilitation interventions. The purpose of this study was to investigate the effects of age on the pattern and variability of lower limb inter-joint coordination in healthy adults during stair walking transitions. We hypothesized that during stair walking transitions (1) the patterns of inter-joint coordination of older adults would be different from that of young adults; (2) the variability of inter-joint coordination would be smaller among older adults than young adults.
Section snippets
Method
Forty adults were recruited: twenty healthy young adults (10 men, 10 women, age = 25.0 ± 4.5 yrs, height = 171.4 ± 8.6 cm, weight = 70.5 ± 10.9 kg, exercise time per week = 2.9 ± 2.1 h) and 20 healthy older adults (10 men, 10 women, age = 74.3 ± 5.9 yrs, height = 162.7 ± 8.5 cm, weight = 71.6 ± 17.4 kg, exercise time per week = 2.7 ± 1.8 h). Prior to participation, each study participant provided signed consent to the experimental procedure approved by the Institutional Review Board. All participants had no current or histories of
Results
During F-S and S-F walking transitions, older adults walked significantly slower (p < .001) with shorter stride length (p = .008 for F-S and p < .001 for S-F) when compared to young adults; however, significant group difference in step width was not detected (Table 1). For both young and older adults, the stride length and step width of F-S condition were significantly smaller than that of S-F condition (p ≤ .016; Table 1).
Fig. 1 illustrates the mean hip-knee and knee-ankle CRP curves of young and
Discussion
Older adults walked with more in phase hip-knee coordination pattern during stair walking transitions. Such differences between age groups were less notable in the knee-ankle coordination pattern, as its difference was only observed in swing phase of the trailing limb during stair to floor walking transition. These findings partially support our first hypothesis that the patterns of inter-joint coordination of older adults would be different from that of young adults.
The locked in phase pattern
Conclusion
The study demonstrated that the inter-joint coordination during stair walking transition was different in young and older adults. The pattern and variability of inter-joint coordination was consistent and reduced in older adults relative to young adults. Our findings suggest that examining and facilitating lower limb inter-joint coordination of older adults during stair walking transition could be an important factor in the development of stair-related fall prevention program.
Conflict of interest
There are no conflicts of interest associated with this research.
Acknowledgements
We thank Niall O’Brien, Jacob Banks, Amanda Rivard for helping with the data collection and the assistance of Rick Holihan and Peter Teare in stair construction. Funding for this project included the Liberty Mutual Harvard School of Public Health Occupational Safety and Health Post-doctoral Program.
References (30)
- et al.
Self-reported difficulty in climbing up or down stairs in nondisabled elderly
Arch Phys Med Rehabil
(2008) - et al.
Foot clearance during stair descent: effects of age and illumination
Gait Posture
(2005) - et al.
Balance control during stair negotiation in older adults
J Biomech
(2007) - et al.
Kinematics of stair descent in young and older adults and the impact of exercise training
Gait Posture
(2007) - et al.
Sagittal and frontal lower limb joint moments during stair ascent and descent in young and older adults
Gait Posture
(2011) - et al.
Older adults employ alternative strategies to operate within their maximum capacities when ascending stairs
J Electromyogr Kinesiol
(2009) - et al.
Comparison of ground reaction forces and antagonist muscle coactivation during stair walking with aging
J Electromyogr Kinesiol
(2008) - et al.
Stair walking transitions are an anticipation of the next stride
J Electromyogr Kinesiol
(2011) - et al.
Biomechanical demands differentiate transitioning vs. continuous stair ascent gait in older women
Clin Biomech
(2014) - et al.
Motor abundance supports multi-tasking while standing
Hum Mov Sci
(2012)
Proprioceptive sensibility in the elderly: degeneration, functional consequences and plastic adaptive processes
Neurosci Biobehav Rev
Effect of walking speed on inter-joint coordination differs between young and elderly adults
J Biomech
Relative phase quantifies interjoint coordination
J Biomech
A Fortran package for generalized, cross-validatory spline smoothing and differentiation
Adv Eng Softw
Limitations in the used and interpretation of continuous relative phase
J Biomech
Cited by (28)
Impacts of mobile phone texting on vertical ground reaction forces during stair negotiation
2023, International Journal of Industrial ErgonomicsMuscle co-contractions are greater in older adults during walking at self-selected speeds over uneven compared to even surfaces
2021, Journal of BiomechanicsCitation Excerpt :Three-dimensional marker trajectories were reconstructed, labeled, and gap filled in Cortex (Motion Analysis Corp., Santa Rosa, USA). The marker data were filtered using a fourth-order low-pass Butterworth filter with a cut-off frequency of 8 Hz (Chiu et al., 2015). Although marker data were collected from both legs, only marker data from the leg used for EMG measurements was included in this study.
Adults with knee osteoarthritis use different coordinative strategies to transition from swing to stance compared to young asymptomatic adults
2021, Gait and PostureCitation Excerpt :Individuals are thought to have preferred coordination patterns and some level of variability that allows them to alter their preferred pattern in response to perturbation. These coordination patterns may differ by age [12–14] and have been associated with clinical balance measures, falls history, or falls incidence [15–17]. Differences in coordination or its variability with age or knee OA could put individuals at risk of a fall should they encounter a challenge during gait.
Comparison of the lower limb inter-segmental coordination during walking between healthy controls and people with multiple sclerosis with and without fall history
2020, Multiple Sclerosis and Related DisordersCitation Excerpt :Some studies have suggested that in PwMS, elevated gait variability could be due to muscle weakness, spasticity, fatigue, and balance impairment (Socie et al., 2013). On the one hand, increased shank-thigh coordination variability found in PwMS may indicate high demand on neuromuscular system for gait control; on the other hand, proper coordination between proximal segments plays an essential role in maintaining balance control during walking (Chiu et al., 2015). Increased coordination variability may decrease the ability to control center of mass trajectory and lead to deficits in dynamic balance and mobility (Lacquaniti et al., 1997; Winter, 1992).