Show simple item record

dc.contributor.authorBuckley, John*
dc.contributor.authorCooper, G.*
dc.contributor.authorMaganaris, C.N.*
dc.contributor.authorReeves, N.D.*
dc.date.accessioned2016-10-07T14:29:47Z
dc.date.available2016-10-07T14:29:47Z
dc.date.issued2013-02
dc.identifier.citationBuckley JG, Cooper G, Maganaris CN and Reeves ND (2013) Is stair descent in the elderly associated with periods of high centre of mass downward accelerations? Experimental Gerontology. 48(2): 283-289.
dc.identifier.urihttp://hdl.handle.net/10454/9630
dc.descriptionNo
dc.description.abstractWhen descending stairs bodyweight becomes supported on a single limb while the forwards-reaching contralateral limb is lowered in order to make contact with the step below. This is associated with lowering of the centre of mass (CoM), which in order to occur in a controlled manner, requires increased ankle and knee joint torque production relative to that in overground walking. We have previously shown that when descending steps or stairs older people operate at a higher proportion of their maximum eccentric capacity and at, or in excess of the maximum passive reference joint range of motion. This suggests they have reduced and/or altered control over their CoM and we hypothesised that this would be associated with alterations in muscle activity patterns and in the CoM vertical acceleration and velocity profiles during both the lowering and landing phases of stair descent. 15 older (mean age 75 years) and 17 young (mean age 25 years) healthy adults descended a 4-step staircase, leading with the right limb on each stair, during which CoM dynamics and electromyographic activity patterns for key lower-limb muscles were assessed. Maximum voluntary eccentric torque generation ability at the knee and ankle was also assessed. Older participants compared to young participants increased muscle co-contraction relative duration at the knee and ankle of the trailing limb so that the limb was stiffened for longer during descent. As a result older participants contacted the step below with a reduced downwards CoM velocity when compared to young participants. Peak downwards and peak upwards CoM acceleration during the descent and landing phases respectively, were also reduced in older adults compared to those in young participants. In contrast, young participants descended quickly onto the step below but arrested their downward CoM velocity sooner following landing; a strategy that was associated with longer relative duration lead-limb plantar flexor activity, increased peak upwards CoM acceleration, and a reduced landing duration. These results suggest that a reduced ability to generate high eccentric torque at the ankle in the forward reaching limb is a major factor for older participants adopting a cautious movement control strategy when descending stairs. The implications of this CoM control strategy on the incidences of falling on stairs are discussed.
dc.relation.isreferencedbyhttp://dx.doi.org/10.1016/j.exger.2012.11.003
dc.subjectAcceleration
dc.subject; Accidental falls
dc.subject; Adult
dc.subject; Age factors
dc.subject; Aged
dc.subject; Aging
dc.subject; Analysis of variance
dc.subject; Ankle joint
dc.subject; Biomechanical phenomena
dc.subject; Electromyography
dc.subject; Female
dc.subject; Humans
dc.subject; Linear models
dc.subject; Locomotion
dc.subject; Male
dc.subject; Muscle contraction
dc.subject; Muscle strength dynamometer
dc.subject; Muscle
dc.subject; Postural balance
dc.subject; Range of motion
dc.subject; Time factors
dc.subject; Torque
dc.subject; Young adult
dc.titleIs stair descent in the elderly associated with periods of high centre of mass downward accelerations?
dc.status.refereedYes
dc.date.Accepted2012-11-08
dc.date.application2012-11-22
dc.typeArticle
dc.type.versionNo full-text available in the repository


This item appears in the following Collection(s)

Show simple item record