Trunk sway during walking among older adults: Norms and correlation with gait velocity

The aim of this study was to establish quantitative norms for trunk sway during walking for older male and female ambulatory adults at different age groups (65–70, 71–75, 76–80, ≥81). We also assessed the relationship between dynamic trunk sway and gait velocity in older individuals with clinically normal or abnormal gaits. Trunk sway in medio-lateral (roll) and antero-posterior (pitch) planes was measured using a body-mounted gyroscope (SwayStar) during walking on a 4.5 m long instrumented walkway. Of the 284 older adults (mean age 76.8, 54.6% women) in this sample, the mean ± SD value of roll and pitch angles were 6.0 ± 2.0° and 6.7 ± 2.2° respectively. Older women showed significantly greater trunk sway in both roll and pitch angles than older men (p < 0.01). In both men and women, there was no significant association of roll angle with age although gait velocity decreased with increasing age. The relationship between roll angle and gait velocity was U-shaped for the overall sample. Among the subgroup with clinically normal gait, increased roll angle was associated with increased gait velocity (p < 0.001). However, there was no significant relationship between roll angle and gait velocity among the subgroup with abnormal gait. Therefore, the relationship between medio-lateral trunk sway and gait velocity differs depending on whether gait is clinically normal.We conclude that trunk sway during walking should be interpreted with consideration of both gait velocity and presence of gait abnormality in older adults.     

Trunk sway during walking among older adults: Norms and correlation with gait velocity

The aim of this study was to establish quantitative norms for trunk sway during walking for older male and female ambulatory adults at different age groups (65–70, 71–75, 76–80, ≥81). We also assessed the relationship between dynamic trunk sway and gait velocity in older individuals with clinically normal or abnormal gaits. Trunk sway in medio-lateral (roll) and antero-posterior (pitch) planes was measured using a body-mounted gyroscope (SwayStar) during walking on a 4.5 m long instrumented walkway. Of the 284 older adults (mean age 76.8, 54.6% women) in this sample, the mean ± SD value of roll and pitch angles were 6.0 ± 2.0° and 6.7 ± 2.2° respectively. Older women showed significantly greater trunk sway in both roll and pitch angles than older men (p < 0.01). In both men and women, there was no significant association of roll angle with age although gait velocity decreased with increasing age. The relationship between roll angle and gait velocity was U-shaped for the overall sample. Among the subgroup with clinically normal gait, increased roll angle was associated with increased gait velocity (p < 0.001). However, there was no significant relationship between roll angle and gait velocity among the subgroup with abnormal gait. Therefore, the relationship between medio-lateral trunk sway and gait velocity differs depending on whether gait is clinically normal.We conclude that trunk sway during walking should be interpreted with consideration of both gait velocity and presence of gait abnormality in older adults.     

Rate of torque development and the risk of falls among community dwelling older adults in Japan

BackgroundRate of torque development (RTD) is defined as the slope of the torque-time curve obtained during an isometric contraction. Several studies have shown that RTD is lower in fallers than in nonfallers. However, these studies had small sample size and was not adjusted confounding factors.Research question: Is RTD associated with falls history in healthy community dwelling older adults.MethodsThis was cross-sectional study. In total, 122 participants aged ≥65 (mean, 71.3 ± 4.4) years were recruited for this study. We assessed RTD, muscle strength, functional capacity, and physical activity. We assessed RTD over the first 200 ms of the maximal isometric contraction, whereby the onset of contraction was deemed as the point at which torque had risen 4 Nm above the baseline. Differences between the 3 groups (no fall group, single fall group and multiple falls group) were examined using one-way analysis of variance or Kruskal-Wallis test. A post-hoc Bonferroni or Games-Howell test was used to assess the differences between the individual groups. A multivariate multinomial logistic model was built using the factors associated with the fall category.ResultsRTD was significantly different between the no fall group and multiple falls group (P = 0.047). Similarly, RTD was significantly different between the single fall group and multiple falls group (P = 0.016). RTD was associated with both the no fall group and single fall group (odds ratio = 2.05, 95% confidence interval: 1.06–3.97, odds ratio = 2.45, 95% confidence interval: 1.20–4.98, respectively) in multinomial logistic regression.SignificanceThis is the first study to investigate the relationship between RTD and falls history in community-dwelling older adults in multivariate analysis. RTD is more strongly associated with falls history than other performance measures in community-dwelling elderly.     

The Multiple Tasks Test as a predictor of falls in older adults

PURPOSE: Falls are among the most common and serious problems facing the elderly. The Berg Balance Scale (BBS) is the gold standard in measuring falls risk. With higher functioning elders, a ceiling effect is often evidenced using the BBS. The purpose of this study was to determine if the Multiple Tasks Test (MTT) when used in high functioning community dwelling elderly correlated with the BBS. Secondly, this study assessed the unidimensionality of the MTT. If a relationship existed between the performance of multiple tasks and the potential loss of balance resulting in falls, then the MTT would be more appropriate than the BBS at predicting falls in higher functioning individuals. METHODS: Twenty-two independent community dwelling older adults were tested using both the MTT and the BBS on the same day at a senior center. DATA ANALYSIS: Correlations between the BBS and the MTT ranged between -0.765 and -0.79. The results of the Guttman's scalability analysis were a plus percentage ratio of 0.75 and an index of reproducibility of 0.93. Scales with these values are regarded as having evidence of unidimensionality. SUMMARY: All of the MTT tests correlated with the BBS. In addition, the MTT was found to be unidimensional. CONCLUSION: Although the MTT correlated with the BBS and was found to be a good cumulative measure, it would benefit from continued study to examine quantifiability, validity and reliability. With further refinement and study, the MTT may be useful at discriminating fallers from non-fallers in high functioning older adults.     

Differences between trunk sway characteristics on a foam support surface and on the Equitest ankle-sway-referenced support surface

Clinicians have sought ways to increase trunk sway so that it is easily observed and a balance deficit more easily identified. One technique often used for this purpose is to reduce the efficacy of ankle proprioceptive inputs on sway. To achieve this reduction either a foam mat is used as an unstable support surface or the subject stands on a surface made unstable with servo-driven ankle-sway-referencing. The purpose of the current study was to investigate differences in trunk pitch and roll sway characteristics using these techniques. Trunk sway while standing quietly on two legs was measured in 25 normal subjects in the age range 20–35 years for three support-surface conditions. Each condition was tested twice for 20 s, once with eyes open and once with eyes closed. The three conditions were standing on a foam support surface, standing on a support surface with pitch (fore-aft) ankle-sway-referencing as used for the standard Sensory Organization Test (SOT) of the Neurocom Equitest System (SOT 4 and 5), and standing with roll (lateral) ankle-sway-referencing. The latter was achieved by having the subjects stand turned 90° to the standard SOT position. Two angular velocity sensors mounted on a belt measured trunk sway in the pitch and roll directions. Trunk roll angle and angular velocity amplitudes for pitch sway-referencing were reduced compared to either the foam or roll sway-referencing conditions, but trunk pitch angle and angular velocities amplitudes were greater. For roll sway-referencing, the trunk roll angle was greater than for the other stimulus conditions. Analyses of the trunk sway velocity in the frequency domain indicated that ankle-sway-referencing in the pitch direction increased trunk pitch sway at 1 Hz and decreased trunk roll sway between 2 and 5 Hz compared to foam support frequency spectra. Roll ankle-sway-referencing decreased trunk roll between 2 and 4 Hz only. These results indicate that using a foam support surface provides multidirectional trunk sway with velocity content across all frequencies in the range 0.8–5.2 Hz. Roll ankle-sway-referencing, but not pitch ankle-sway-referencing, yields trunk sway with similar characteristics to those with foam. Pitch ankle-sway-referencing forces pitch trunk resonance to be around 1 Hz and yields very different trunk sway from that obtained with a foam support surface. Roll sway-referencing is an alternative means to test multidirectional control of sway. Clinically though, foam is simpler to use and provides a more difficult balance task for the patient.     

A method to investigate discrepancies between perceived and actual balance in older women

Despite the established relationship between low balance confidence and poorer balance and gait performance, discrepancies may occur between an individual's perceived and actual abilities. This study determined if trunk sway measures could assist in identifying potential discrepancies between perceived and actual balance. Older women completed the Activities-specific Balance Confidence (ABC) scale and performed a series of 16 stance, gait and tandem gait tasks. Duration (or completed steps for tandem gait tasks) and trunk pitch and roll angle and angular velocity were calculated. Low (mean ABC score ≤ 70%, n = 33) and high (mean ABC score ≥ 90%, n = 99) balance confidence groups were identified from a pool of 204 participants. The low balance confidence group had greater stance trunk pitch and roll sway, shorter one leg stance durations, reduced gait trunk roll sway, longer gait durations, less tandem gait trunk roll sway and completed fewer tandem gait steps compared to the high balance confidence group. Stepwise linear discriminant analysis identified four variables that were used to achieve a classification accuracy of 75.8% for low and 90.9% for high balance confidence groups. This study reinforces the influence of low balance confidence on stance and gait control and provides direction for the identification and treatment of individuals with discrepancies between perceived and actual balance.     

Effect of painful keratoses debridement on foot pain, balance and function in older adults

BACKGROUND: Painful feet in older people can detrimentally affect balance and are a risk factor for falls. Pain is often associated with plantar hyperkeratoses, which are easily treated by podiatrists. Currently, there is no data defining the effect this treatment has on balance or functional ability. OBJECTIVE: To determine the effects of scalpel debridement of painful plantar hyperkeratoses on pain, balance and functional ability in older people aged 65 years and over. SUBJECTS: Nineteen men and women aged 65-84 years (mean age 72, standard deviation 5.6). METHODS: Pain resulting from plantar hyperkeratoses was measured using a visual analogue scale. Static balance and functional ability were measured using tests of postural sway, co-ordinated stability and timed walking and stepping tests. Painful plantar hyperkeratoses were debrided with a scalpel then all tests were repeated, immediately and 7 days later. RESULTS: Following scalpel debridement, pain levels (sensory and afferent) were significantly reduced (P<0.0001) and functional ability was significantly increased (P<0.0001). There was no change in static balance ability. One week after debridement the improved performance in functional ability tests was maintained. CONCLUSIONS: Debridement of painful plantar hyperkeratoses reduces pain and improves functional ability in older people. Its effect on static balance was inconclusive.     

Effect of sensorimotor training on balance measures and proprioception among middle and older age adults with diabetic peripheral neuropathy

PurposeThe aim of the study was to evaluate the effect of sensorimotor training on balance measures, and proprioception, among middle-aged and older adults with diabetic peripheral neuropathy (DPN).MethodsA randomized controlled study with four parallel arms (two intervention groups and two control groups) was conducted at CPRS, Jamia Millia Islamia. Thirty-seven individuals were selected on the basis of inclusion and exclusion criteria. Of these, 16 middle-aged and 21 older adults were randomly allocated to intervention and control groups, respectively. Subjects in the intervention group were administered eight weeks (3days/week) of sensorimotor training, involving 10 different types of exercises, progressed from easy to hard every two weeks, along with diabetes and foot care education; subjects in control group received diabetes and foot care education only. Outcomes measures involved static and dynamic balance measures, centre of pressure (COP) range, COP sway, and proprioception, measured before and after eight weeks.ResultsBaseline measures showed significant age effect for timed up and go test (TUG) (p = 0.002), one leg stance (OLS) in eyes open (EO) and eyes closed (EC) (p ≤ 0.041), COP range in front (p = 0.007), back (p = 0.009) and right direction (p = 0.013), COP sway with visual feedback in front-back direction (p = 0.027), COP sway without visual feedback in left-right direction (p = 0.028), and proprioception in right direction (p = 0.026). After intervention, OLS EO and EC on both legs showed significant time effect (p ≤ 0.003), group effect as well as time×group interaction (p < 0.05), and age effect and time×age interaction (p ≤ 0.04). Functional reach test, TUG, COP range, COP sway, and proprioception were found with significant time effect (p < 0.03), group effect, and time×group interaction (p ≤ 0.035). Age effect and time×age interaction were found to be non-significant for all COP ranges and COP sway.ConclusionSensorimotor training improved static and dynamic balance as well as proprioception measures after eight weeks of exercise intervention. Static balance showed greater improvement in the middle-aged than older aged adults, while dynamic balance and proprioception showed similar results for both.     

History of falls,balance performance,and quality of life in older cancer survivors

Older cancer survivors may be predisposed to falls because of the sequalae associated with cancer and its treatments. This study examined the association between the fall history, balance performance, and health‐related quality of life (QoL) in older, community‐dwelling cancer survivors who had completed primary cancer treatments. Forty-one cancer survivors (age = 67.9 ± 8.8 years) participated in the study. Balance performance was examined using the Activities-specific Balance Confidence Scale (ABC) and the Balance Evaluation Systems Test (BESTest). Scores from the Physical Component Summary (PCS) and Mental Component Summary (MCS) of the SF‐36v2 were obtained to assess the QoL. The demographics and health status were comparable between the fallers and non-fallers. While 54% of the participants had experienced at least one fall in the past 12 months, 30% had experienced two or more falls. Spearman's correlation analysis revealed a significant relationship between the outcomes from the ABC and the PCS (p < 0.001), and between the BESTest and the PCS (p < 0.001). Only the PCS significantly differentiated fallers from non-fallers (p < 0.01). Logistic regression analysis estimated that a one-unit increase in the PCS score significantly reduced the odds of falling by 13% (p < 0.01). The results demonstrate that in older cancer survivors, falls are a significant problem and balance control is a determinant of perceived physical function and well-being. Older cancer survivors reporting a poor QoL in the physical health domain may have higher risks of falling. Future studies are needed to examine the risk factor profiles of falls and the interventions to prevent falls in older cancer survivors.     

Dual tasking affects lateral trunk control in healthy younger and older adults

Assessing the effects of attention-demanding tasks on trunk movement provides useful insights into postural control while walking in an attention-split situation, such as occurs in daily life. The coefficient of attenuation of acceleration (CoA) at the trunk is a useful gait index to assess whole trunk movements. We investigated the effect of attention-demanding tasks on CoA to assess the role of attention on trunk control during walking. Thirty healthy, community-dwelling older adults (70.1 ± 5.6 years) and 38 younger adults (22.1 ± 3.4 years) participated in this study. Participants walked 20 m at a self-selected speed (slow, normal, fast) and while performing an attention-demanding cognitive task. Trunk acceleration was measured using triaxial accelerometers attached to the lower (L3 spinous process) and upper (C7 spinous process) trunk and used to compute CoA (the reduction in acceleration from the lower to upper trunk). Results showed that an attention-demanding task significantly decreased CoA in the medio-lateral (ML) direction in both age groups (p < 0.001), whereas it did not affect CoA in the vertical (VT) and anterior–posterior (AP) directions. Our findings suggest that the priority of whole trunk control in the ML direction may be higher than in other directions and be strongly associated with attention, whereas whole trunk control in the VT and AP directions may be passively regulated and require minimal attentional control.     

Old adult fallers display reduced flexibility of arm and trunk movements when challenged with different walking speeds

Specific patterns of pelvic and thorax motions are required to maintain stability during walking. This cross-sectional study explored older-adults’ gait kinematics and their kinematic adaptations to different walking speeds, with the purpose of identifying mechanisms that might be related to increased risk for falls. Fifty-eight older adults from self-care residential facilities walked on a treadmill, whose velocity was systematically increased with increments of 0.1 meters/second (m/s) from 0.5 to 0.9 m/s, and then similarly decreased. Thorax, pelvis, trunk, arms, and legs angular total range of motion (tROM), stride time, stride length, and step width were measured. Twenty-one of the subjects reported falling, and 37 didn’t fall. No significant effect of a fall history was found for any of the dependent variables. A marginally significant interaction effect of fall history and walking speed was found for arms’ tROM (p = 0.098). Speed had an effect on many of the measures for both groups. As the treadmill’s velocity increased, the non-fallers increased their arm (15.9 ± 8.6° to 26.6 ± 12.7°) and trunk rotations (4.7 ± 1.9° to 7.2 ± 2.8°) tROM, whereas for the fallers the change of arm (14.7 ± 14.8° to 20.8 ± 13°) and trunk (5.5 ± 2.9° to 7.3 ± 2.3°) rotations tROM were moderate between the different walking speeds. We conclude that walking speed manipulation exposed different flexibility trends. Only non-fallers demonstrated the ability to adapt trunk and arm ROM to treadmill speed i.e., had a more flexible pattern of behavior for arm and trunk motions, supporting the upper-body’s importance for stability while walking.     

Cognitive tasks promote automatization of postural control in young and older adults

Researchers looking at the effects of performing a concurrent cognitive task on postural control in young and older adults using traditional center-of-pressure measures and complexity measures found discordant results. Results of experiments showing improvements of stability have suggested the use of strategies such as automatization of postural control or stiffening strategy. This experiment aimed to confirm in healthy young and older adults that performing a cognitive task while standing leads to improvements that are due to automaticity of sway by using sample entropy. Twenty-one young adults and twenty-five older adults were asked to stand on a force platform while performing a cognitive task. There were four cognitive tasks: simple reaction time, go/no-go reaction time, equation and occurrence of a digit in a number sequence. Results demonstrated decreased sway area and variability as well as increased sample entropy for both groups when performing a cognitive task. Results suggest that performing a concurrent cognitive task promotes the adoption of an automatic postural control in young and older adults as evidenced by an increased postural stability and postural sway complexity.     

Striatal dopamine denervation and sensory integration for balance in middle-aged and older adults

The dopaminergic system of the basal ganglia has been implicated in the integration of sensory information important for balance based on studies in patients with Parkinson's disease. Striatal dopaminergic activity decreases with normal aging.

Objective

To investigate the relationship between regional striatal dopaminergic denervation and sensory information integration important for balance in middle-aged and older adults.

Methods

Community-dwelling subjects (N = 35; age 41–83) with no clinical diagnoses of conditions affecting balance underwent dynamic posturography testing (Sensory Organization Test/SOT) and C-11-beta-CFT dopamine transporter positron emission tomography.

Results

Reduced ventral striatal dopamine was significantly correlated with increased anterior–posterior sway in three SOT conditions. Specifically, during quiet standing (SOT Conditions #1, 2) and when repeatedly to sway-referenced visual environments (SOT Condition #3, Trial #3), pre-synaptic dopaminergic denervation in the anteroventral striatum explained over 20–25% of the variability in sway magnitude above and beyond that explained by age (p ≤ 0.01). Striatal dopaminergic denervation did not impact balance in sway-referenced floor conditions.

Conclusions

The SOT Condition #3 findings suggest that, in normal aging, the central ability to inhibit balance destabilizing vision-related postural control processes depends at least partially on striatal dopaminergic pathways. In contrast, striatal dopaminergic denervation does not appear to impair the ability to disengage destabilizing proprioceptive inputs and to trigger the vestibular control system during challenging sensory perturbations (SOT Conditions #4–6). Finally, quiet standing results (SOT Conditions #1, 2) justify the need to further investigate the impact of striatal dopaminergic denervation on the ability to tune muscle tone in healthy adults.     

Foot and ankle biomechanics during walking in older adults: A systematic review and meta-analysis of observational studies

BackgroundThe foot and ankle complex undergoes significant structural and functional changes with advancing age.Research questionThe objective of this systematic review and meta-analysis was to synthesize and critique the research literature pertaining to foot and ankle biomechanics while walking in young and older adults.MethodsElectronic databases (Web of Science, PubMed, Scopus and Embase) were searched from inception to April 2019 for cross-sectional studies which compared kinematics, kinetics and plantar pressure differences between young and older adults. Screening and data extraction were performed by two independent assessors, with disagreements resolved by consensus.ResultsA total of 39 articles underwent full-text screening, and 19 articles met the inclusion criteria and were included. Meta-analysis showed that older adults had less ankle joint plantar flexion (5 studies; weighted mean difference [WMD]: −5.15; 95 %CI: −6.47 to −3.83; P < 0.001) and less ankle joint power generation (6 studies; standardized mean difference [SMD]: −0.62; 95 %CI: −0.82 to −0.41; P < 0.001) during propulsion compared to young adults. These differences persisted in subgroup analyses comparing different walking speeds. Plantar pressure findings were highly variable due to differences in data collection protocols and meta-analysis was not possible.SignificanceOlder adults have unique foot and ankle kinematics and kinetics during walking characterized by reduced ankle joint plantarflexion and power generation during propulsion.     

Postural control in response to unilateral and bilateral external perturbations in older adults

BackgroundBalance is an important determinant of physical function and falls risk. The ability to withstand external perturbations is important when walking on icy or uneven surfaces, whether the perturbations are bilateral or unilateral.Research questionThis study sought to determine the effect of unilateral and bilateral standing perturbations on leg muscle activity in healthy older adults.MethodsParticipants experienced unilateral and bilateral standing perturbations of the treadmill. Surface electromyography (EMG) from lower limb muscles was recorded unilaterally. EMG onset latency and root mean square (RMS) amplitude of the muscle bursts were calculated.ResultsOlder adults demonstrated a combined ankle/hip strategy, along with pre-activation and co-contraction of muscles in response to unilateral and bilateral stance perturbations. As well, older adults demonstrated higher levels of EMG, but no difference in the latency of burst onset, in bilateral than unilateral perturbation types.SignificanceWhen the stance limb was perturbed in the bilateral condition, the older adults responded with a Gastrocs EMG burst nearly 100% of the maximum EMG. The high level of EMG used, especially in the Gastrocs, during the bilateral perturbations may reduce the safety factor for falls in older adults. Older adults responded to the different perturbation demands by modulating EMG amplitude as opposed to the onset timing of EMG.     

Trunk sway measures of postural stability during clinical balance tests: effects of a unilateral vestibular deficit

This research evaluated whether quantified measures of trunk sway during clinical balance tasks are sensitive enough to identify a balance disorder and possibly specific enough to distinguish between different types of balance disorder. We used a light-weight, easy to attach, body-worn apparatus to measure trunk angular velocities in the roll and pitch planes during a number of stance and gait tasks similar to those of the Tinetti and CTSIB protocols. The tasks included standing on one or two legs both eyes-open and closed on a foam or firm support-surface, walking eight tandem steps, walking five steps while horizontally rotating or pitching the head, walking over low barriers, and up and down stairs. Tasks were sought, which when quantified might provide optimal screening for a balance pathology by comparing the test results of 15 patients with a well defined acute balance deficit (sudden unilateral vestibular loss (UVL)) with those of 26 patients with less severe chronic balance problems caused by a cerebellar-pontine-angle-tumour (CPAT) prior to surgery, and with those of 88 age- and sex-matched healthy subjects. The UVL patients demonstrated significantly greater than normal trunk sway for all two-legged stance tasks especially those performed with eyes closed on a foam support surface. Sway was also greater for walking while rotating or pitching the head, and for walking eight tandem steps on a foam support surface. Interestingly, the patients could perform gait tasks such as walking over barriers almost normally, however took longer. CPAT patients had trunk sway values intermediate between those of UVL patients and normals. A combination of trunk sway amplitude measurements (roll angle and pitch velocity) from the stance tasks of standing on two legs eyes closed on a foam support, standing eyes open on a normal support surface, as well as from the gait tasks of walking five steps while rotating, or pitching the head, and walking eight tandem steps on foam permitted a 97% correct recognition of a normal subject and a 93% correct recognition of an acute vestibular loss patient. Just over 50% of CPAT patients could be classified into a group with intermediate balance deficits, the rest were classified as normal. Our results indicate that measuring trunk sway in the form of roll angle and pitch angular velocity during five simple clinical tests of equilibrium, four of which probe both stance and gait control under more difficult sensory conditions, can reliably and quantitatively distinguish patients with a well defined balance deficit from healthy controls. Further, refinement of these trunk sway measuring techniques may be required if functions such as preliminary diagnosis rather than screening are to be attempted.     

Effects of age,sex and task on postural sway during quiet stance

BackgroundPostural sway during quiet standing has been shown as a useful task to assess risk of falling in older adults. While the risk of falling is consistently reported to be higher in older females than males, the sex-related differences in postural sway are not consistent across the studies.Research questionWhat are the effects of age and sex on postural sway during quiet standing during different stance conditions?MethodsWe examined the effects of age (40 young and 34 older adults), sex (37 males and 37 females), and their interaction on the postural sway during different stance conditions. We compared the center of pressure (CoP) velocity, amplitude and frequency during parallel (eyes open and eyes closed) and semi-tandem (eyes open) stances.ResultsOur results suggest that postural sway is similar between sexes in young participants, while older males exhibit larger postural sway than older female participants (10/21 outcomes). Older female participants exhibited lower CoP amplitude (but larger total and anterior-posterior CoP velocity) compared to young female participants. We also found that the increase in the postural sway with increasing task difficulty is more pronounced in older vs. young adults.SignificanceThis study shows that ageing-related changes in postural sway are sex- and task-specific. Researchers and clinicians need to be aware of these effects when comparing groups or monitoring changes in time.     

Effect of gait retraining for reducing ambulatory knee load on trunk biomechanics and trunk muscle activity

The purpose of this study was to test the hypothesis that walking with increased medio-lateral trunk sway is associated with lower external knee adduction moment and lower extremity muscle activation, and higher external ipsilateral trunk moment and trunk muscle activity than walking with normal trunk sway in healthy participants. Fifteen participants performed walking trials with normal and increased medio-lateral trunk sway. Maximum trunk sway, first maximum knee adduction moment, lateral trunk bending moment, and bilateral vastus medialis, vastus lateralis, gluteus medius, rectus abdominis, external oblique and erector spinae muscle activity were computed. Walking with increased trunk sway was associated with lower maximum knee adduction moment (95% confidence interval (CI): 0.50–0.62 Nm/kg vs. 0.62–0.76 Nm/kg; P < .001) and ipsilateral gluteus medius (−17%; P = .014) and erector spinae muscle activity (−24%; P = .004) and greater maximum lateral trunk bending moment (+34%; P < .001) and contralateral external oblique muscle activity (+60%; P = .009). In all participants, maximum knee adduction moment was negatively correlated and maximum trunk moment was positively correlated with maximum trunk sway. The results of this study suggest that walking with increased trunk sway not only reduces the external knee adduction moment but also alters and possibly increases the load on the trunk. Hence, load-altering biomechanical interventions should always be evaluated not only regarding their effects on the index joint but on other load-bearing joints such as the spine.     

The effects of short term balance training on the postural control of older adults

The purpose of this study was to determine and contrast the effect of five weeks of balance training on the postural stability of elderly adults with a history of falls (F) and those who have not previously fallen (NF). Twelve F subjects, 12 NF subjects, and 14 control subjects participated. Balance training consisted of exercises designed to stress balance and coordination performed three times per week for five weeks. Postural stability was evaluated with an ADL test resembling activities of daily living and force-platform-based postural sway measurements. In general F and NF reflected similar improvements in postural stability following training. F and NF demonstrated small improvements (5–10%) on the ADL tests with respect to the control group. The postural sway measures provided only moderate support for the effectiveness of training, with the control subjects exhibiting improvements similar to those of the training groups (approximately 15–30%). Overall the data provide moderate support for the effectiveness of short term balance training for functionally independent elderly adults.     

A comparison of turn and straight walking phases as predictors of incident falls

BackgroundWhile gait assessments are recommended to evaluate fall risk in older adults, these often involve walking in a straight line, even though one-third of steps taken throughout the day involve turning. Falls that occur during a turn tend to be more serious than falls that occur during a straight walk, but little is known about how gait variables collected during a turn can predict falls.Research questionHow do gait characteristics collected from straight and turning walking phases predict falls in older adults?MethodsWe prospectively examined the association between six quantitative gait variables measured during normal walking turn and straight walking phases as predictors of incident falls in a community-based sample of older adults (N = 253; mean age 78.5; 51% women). Cox regressions adjusted for multiple potential confounders were used to examine the associations.ResultsParticipants had significantly slower stride velocity (57.81 vs 83.26 cm/s), shorter stride length (74.76 vs 101.81 cm,), lower swing (30.1 vs 32.41%), higher double support (39.79 vs 35.19%), and more swing (30.09 vs 32.41%) and stride length variability (31.86 vs 6.35 %) during turns compared with straights. Higher swing percent in both turns (adjusted hazard ratio; HR 0.92, 95% CI 0.87, 0.97) and straights (HR 0.89, 95% CI 0.84, 0.96) was associated with reduced risk of falls. Higher double support percent during both turns (HR 1.04, 95% CI 1.01, 1.07) and straights (HR 1.06, 95% CI 1.02, 1.09) was associated with increased risk of falls. More swing variability during turns (HR 1.03, 95% CI 1.00, 1.06), but not straights, was associated with increased risk of falls.SignificanceGait variables collected during turning and walking straight were similar in their predictions of future falls. In the future, clinical research that builds on these findings could improve identification and prevention of falls.