Profitable 10-second one-legged stance efficiency predicts survival in middle-aged and older people

Sadye Matula

Table of Contents IntroductionStrategiesDemographics, anthropometric and medical variablesOne-legged stance steadiness evaluationStatistical evaluationAffected person and public involvementOutcomes10-s OLS and all-cause mortality affiliation and danger predictionDialoguePrognostic dataComparability of present findings with the literatureStrengthsLimitationsConclusionKey messagesHow would possibly it influence on medical observe sooner or later?Information availability assertionEthics statementsAffected person consent for publicationEthics approvalAcknowledgments […]


Ageing is related to a progressive decline in bodily fitness1–3 and reductions or impairments in elements of aerobic4 5 and non-aerobic health, together with muscle energy/energy, flexibility, steadiness and physique composition.6–11 It’s also well-established that the mixture of sarcopenic weight problems and lack of flexibility and steadiness are detrimental for total well being, putting older adults with frailty extra susceptible to falls and different severe adversarial medical sequelae.12 Certainly, falls are the second main reason for unintentional injury-based deaths worldwide.13 Not like cardio health,2 14 muscle strength9 and suppleness,8 steadiness tends to be moderately preserved till the sixth decade of life, when comparatively, it begins to decrease rapidly.15 16

Nonetheless, steadiness evaluation just isn’t routinely integrated within the medical examination of middle-aged and older people.17 This can be partly attributable to the poor standardisation of steadiness testing in addition to to the relative paucity of data-relating steadiness outcomes to medical outcomes apart from falls, reminiscent of mortality, compared with, for instance, cardio health.16 18 19

On this context, the supply of straightforward, cheap, dependable and protected steadiness evaluation tools11 that might assist predict survival would probably be helpful to well being professionals evaluating and treating older adults. Due to this fact, the goals of our examine have been: (1) to evaluate whether or not the flexibility to finish a 10-s one-legged stance (10-s OLS) take a look at was independently related to all-cause mortality in middle-aged and older women and men and (2) whether or not the 10-s OLS added related prognostic data past bizarre demographic, anthropometric and medical knowledge. If the flexibility to carry out this easy bodily activity have been proven to be a superb prognostic indicator for danger of all-cause mortality, it is likely to be a helpful complement to routine evaluations amongst middle-aged and older topics.


This was a potential cohort examine utilizing knowledge from the CLINIMEX Train open cohort/analysis protocol (see on-line supplemental supplies).11 20 21 Briefly, the CLINIMEX Train cohort examine was arrange in 1994 to evaluate the relationships of assorted measures of bodily health and different exercise-related variables, in addition to standard cardiovascular danger components with all-cause and cause-specific mortality outcomes. The pattern dimension of 1593 members was calculated primarily based on the next parameter specs: (1) degree of significance, two-sided take a look at at α=0.05; (2) energy (1−β) of 80%; (3) 7% of examine members dying throughout follow-up; (4) an SD of 0.5 for the publicity (on condition that the binary publicity follows a Bernoulli distribution with the chance of a topic reaching success, p, assumed to be equal to 0.5, the SD was calculated from the formulation: (p*(1−p))0.5 and (5) impact dimension: the minimal HR thought of to be clinically vital, on this case, 1.7. The present evaluation included 1702 members aged 51–75 years at their first analysis performed between 10 February 2009 and 10 December 2020, who voluntarily sought the clinic for analysis to evaluate cardio and non-aerobic bodily health and/or to acquire train counselling.

Censoring of significant standing and mortality was up to date to mid-December 2020 from the regional official registry knowledge. All members learn and signed an knowledgeable consent and formally authorised the usage of their deidentified knowledge for scientific functions. The examine protocol was included in a Nationwide Analysis Registry and formally reviewed and accepted by an exterior Analysis Ethics Committee (Plataforma Brasil—CAAE: 40122320.8.0000.9433). Cohort knowledge are maintained in an institutional database.

Demographics, anthropometric and medical variables

Intercourse, age, date of analysis, date of dying (if it occurred), censored date and follow-up time have been obtainable for all members. Anthropometric measurements have been obtained with members barefoot and utilizing minimal clothes and included top, weight, sum of six skinfolds—triciptal, subscapular, suprailiac, stomach, thigh and medial calf – and waist girth measured on the umbilical degree, in addition to two calculated values—physique mass index (BMI) and waist-height ratio. Scientific knowledge have been obtained by medical historical past, contemplating the presence or absence of identified related ailments and/or use of normal drugs. Weight problems was outlined as a BMI ≥30 kg/m2. Lower than 1% of anthropometric or medical knowledge have been lacking. All members have been totally ambulatory and people presenting with unstable gait or having indicators of any identified acute vestibular or otoneurological disturbance have been excluded.

One-legged stance steadiness evaluation

As a part of the analysis, members have been requested to face on a flat platform. Static steadiness was assessed as the flexibility to finish 10 s in OLS, both left or proper foot, below shut face-to-face supervision of a doctor and/or a nurse assistant as a precaution to stop falls or accidents. To minimise the affect of muscle energy and suppleness and to enhance standardisation, barefoot members have been instructed to position the dorsal a part of the non-support foot on the again of the other decrease leg, as naturally as attainable (determine 1). Moreover, members have been requested to maintain their elbows prolonged, the arms naturally positioned near their physique and instructed to repair their gaze on an eye-level level at a 2-m distance.22 As soon as the participant assumed the proper place, a rely of 10 s was began and as much as three makes an attempt have been allowed. A quite simple criterion was utilized—capability to finish 10-s OLS on both foot, maintaining the proper preliminary place and with out every other help—and members have been accordingly labeled as capability (YES) or lack of ability (NO) to finish the 10-s OLS take a look at.

Profitable 10-second one-legged stance efficiency predicts survival in middle-aged and older people
Determine 1

Physique place to the 10-s one-legged stance take a look at.

Statistical evaluation

For descriptive statistics, quantitative variables have been described utilizing imply±SD or median and IQR, relying on the character of distribution, and categorical variables have been summarised utilizing frequencies and percentages. Pattern dimension calculations employed the Stata command “stpower cox” which implements the strategies of Hsieh and Lavori23 and Schoenfeld.24 The Cochran–Armitage take a look at was used to check for temporal traits in deaths throughout the follow-up interval. Outcomes for YES and NO 10-s OLS have been in contrast by two-tailed Scholar’s t-tests or χ2 take a look at, after checking, respectively, for the normality of distribution and homogeneity of variance and for the inexistence of anticipated cell rely lower than 1 and not more than 20% of cell counts lower than 5, relying on the variable. Spearman rank correlation coefficients have been used to calculate associations. Kaplan-Meier curves have been constructed and log-rank checks have been used to analyse survival occasions for the YES and NO 10-s OLS teams.

Whereas the CLINIMEX Train cohort contains women and men from 6 to 99 years of age, solely members aged between 51 and 75 years have been included on this mortality examine, as survival curves (see on-line supplemental supplies) calculated at every 5 years of age interval beginning at 41–45 years indicated that the mixture of related numbers of deaths and failures to finish the 10-s OLS take a look at may very well be recognized solely utilizing the 51–75 years of age vary. The connection between 10-s OLS outcomes and all-cause mortality was modelled by Cox univariate and multivariable analyses, after affirmation of no departure from the proportionality of hazards assumptions utilizing Schoenfeld residuals.25 The proportionality take a look at of every covariate in addition to a worldwide take a look at was finished. The take a look at was not statistically vital for every of the covariates, and the worldwide take a look at was additionally not statistically vital. Changes have been made for age, intercourse, BMI and medical variables (as beforehand described), utilizing the 10-s OLS YES group because the reference. For every participant, follow-up time was obtained utilizing the variety of days between the analysis and dying or censoring dates. Not one of the members have been misplaced to follow-up.

To evaluate whether or not including data on 10-s OLS to standard danger components was related to enchancment within the prediction of all-cause mortality, three statistical approaches have been employed. First, the development in danger discrimination ensuing from including data on 10-s OLS to a mannequin containing established danger components (age, intercourse, BMI, medical historical past of coronary artery illness, hypertension, diabetes and dyslipidaemia) was quantified utilizing Harrell’s C-index.26 Comparability of the C-index for fashions together with and never together with data on the 10-s OLS was carried out based on the methodology of DeLong.27 The 95% CIs for C-indices and their adjustments have been derived from jackknife SE. The C-index is acceptable for time-to-event knowledge and supplies the chance that the mannequin accurately predicts the order of failure of randomly chosen pairs of people. A C-index of 1.0 signifies good prediction of the order of failure (on this case, mortality), whereas a C-index of 0.5 is achieved purely by likelihood. Second, the continual internet reclassification enchancment (NRI) was calculated,28 which determines whether or not danger will increase instances making use of a brand new mannequin in contrast with a longtime or reference mannequin. Moreover, the built-in discrimination enchancment (IDI) was calculated, which integrates the NRI over all attainable cut-offs.29 Along with Harrel’s C-index which might be insensitive in detecting variations as a result of it’s primarily based on ranks moderately than on steady knowledge and never with the ability to assess calibration,30 31 we examined for variations within the −2 log chance of prediction fashions with and with out inclusion of 10-s OLS. The −2 log chance take a look at has been really helpful as a extra delicate danger discrimination methodology.30 31 Statistical significance degree was set at 5%, and 95% CIs have been calculated for all outcomes. Calculations have been carried out and figures ready utilizing both Prism (V.8.4.3; GraphPad, USA) or STATA (V.16; USA) statistical packages.

Affected person and public involvement

This analysis was finished with out affected person or public involvement within the examine design, knowledge evaluation, writing or modifying.


The imply±SD age of the members was 61.7±6.8 years and 68% have been males. No adversarial medical occasions or accidents occurred throughout the 10-s OLS testing. A complete of 348 (20.4%) members did not go the take a look at and have been labeled as NO. The lack to finish the take a look at, that’s, 10-s OLS with both the suitable or left foot, growing with growing older, virtually doubling at every subsequent 5-year age-group intervals starting at age group of 51–55 years. The proportion of NO responders was 4.7% amongst these 51–55 years, 8.1% at 56–60 years, 17.8% at 61–65 years and 36.8% at 66–70 years. Within the age group of 71–75 years, the vast majority of the members (53.6%) have been unable to efficiently full the 10-s OLS (determine 2). Throughout a median (IQR) follow-up time of seven (4.16–9.41) years, 123 members (7.2%) died, largely on account of most cancers (32%), cardiovascular causes (30%), ailments of the respiratory system (9%) and COVID-19 problems (7%) with no clear temporal traits within the deaths (p=0.77). Given a pattern of 1702 people together with 123 all-cause mortality occasions, we had 92% energy to detect a clinically vital HR of 1.84. The proportion of deaths within the NO group was increased than that within the YES group (17.5% vs 4.6%; p<0.001), reflecting an absolute distinction of 12.9%, however the distribution of the foremost underlying causes of dying didn’t differ considerably between the YES and NO teams (p=0.45).

Figure 2
Determine 2

YES= capability or NO= lack of ability to finish the take a look at to 10-s one-legged stance take a look at based on age teams. This determine consists of data from people of a wider age vary than the one included for evaluation on this examine as talked about beforehand.

A comparability of key variables for all members and individually for 10-s OLS YES and NO teams is offered in desk 1. Whereas intercourse distribution didn’t completely different considerably between the YES and NO teams, (p=0.76), a number of different variables together with age, BMI and waist-height ratio differed between the 2 teams (p<0.001). Generally, NO members had an unhealthier profile with the next share of members having coronary artery illness, hypertension, dyslipidaemia and weight problems. Probably the most putting distinction was for diabetes mellitus, which was 3 times extra frequent within the NO group (37.9%) as in contrast with the YES group (12.6%) (p<0.001).

Desk 1

Demographic and medical traits of women and men aged 51–75 years based on the flexibility to finish 10-s one-legged stance take a look at

Correlation coefficients between a NO 10-s OLS response and age and a number of other anthropometric variables of potential curiosity are proven in determine 3. Apart from top, lack of ability to finish the 10-s OLS was considerably related to all the opposite variables (p<0.001). The 2 highest correlation coefficients between NO and chosen steady variables have been 0.40 for age and 0.26 for waist-height ratio.

Figure 3
Determine 3

Spearman correlation coefficients between the shortcoming to finish the 10-s one-legged stance take a look at and demographic and anthropometric variables. Values of r>0.048 (constructive or unfavourable) have been vital at 5% of chance.

10-s OLS and all-cause mortality affiliation and danger prediction

Kaplan-Meier survival curves have been considerably completely different for YES and NO responders (p<0.001) (determine 4). Cox proportional hazard evaluation indicated that lack of ability to finish the 10-s OLS was related to a considerably increased danger for all-cause mortality. An age-adjusted and a multivariable-adjusted—age, intercourse, BMI and medical comorbidities (together with historical past of coronary artery illness, hypertension, diabetes, weight problems and dyslipidaemia) confirmed HRs (95% CI) of two.18 (1.48 to three.22; p<0.001) and 1.84 (1.23 to 2.78; p=0.003)), respectively (desk 2). A directed acyclic graph displaying a minimally enough set of confounders for adjustment can be offered (determine 5).

Figure 4
Determine 4

Kaplan-Meier survival curves of members aged 51–75 years previous divided by capability (YES) and lack of ability (NO) to finish the 10-s one-legged stance take a look at.

Figure 5
Determine 5

Directed acyclic graph (DAG) of affiliation between demographic and anthropometric variables, presence of comorbidities, the flexibility to finish 10-s one-legged stance (10-s OLS) and all-cause mortality. The inexperienced field is the publicity variable (10-s OLS). The blue field ‘I’ is the result variable (all-cause mortality). The gray bins are potential cofounding variables. Different potential however unmeasured confounders have been omitted from the determine for simplicity. Gender, 10-s OLS, comorbidities, medical standing (wholesome or unhealthy) and very important standing have been used as dichotomous variables. This DAG reveals 4 confounding paths: the trail through age, intercourse, physique mass index (BMI) and medical standing (wholesome vs unhealthy). Thus, the minimally enough adjustment to get the whole impact of the publicity on the result is to regulate for age, intercourse, BMI and medical standing.

Desk 2

Associations of capability to finish 10-s one-legged stance steadiness take a look at (10-s OLS) with all-cause mortality in 1702 women and men aged 51–75 years previous (123 deaths, 7.2%; median follow-up time=7 years)

An all-cause mortality mannequin containing established danger components yielded a C-index of 0.7990 (0.7563, 0.8417). After addition of the 10-s OLS binary outcomes, the C-index was 0.8090 (0.7678, 0.8503), a rise of 0.0100 (–0.0005, 0.0205; p=0.06). The −2 log chance mannequin confirmed vital enchancment after addition of the 10-s OLS binary outcomes to the mannequin (p for comparability=0.002). The continual NRI and IDI have been 17.50% (95% CI −1.46 to 36.45; p=0.07) and 0.0143 (95% CI 0.0019 to 0.0267; p=0.024), respectively, suggesting additive worth of the shortcoming to finish the 10-s OLS take a look at.


Annually an estimated 684 000 people die from falls globally, of which over 80% are in low/middle-income nations.13 Whereas it’s identified that good ranges of steadiness are related for a lot of day by day life actions,32 there’s appreciable proof that lack of steadiness can be detrimental for well being and that some train interventions could enhance steadiness.12 32–37 Nonetheless, it’s presently unsure if the outcomes of repeated 10-s OLS checks can be amenable to intervention, that’s, train or steadiness coaching, and if adjustments in 10-s OLS over time would affect mortality danger.38

In our 13 years of medical expertise routinely utilizing the 10-s OLS static steadiness take a look at in adults with a large age vary and various medical situations,39 the take a look at has been remarkably protected, well-received by the members, and importantly, easy to include in our routine observe because it requires lower than 1 or 2 min to be utilized.

Prognostic data

The power to finish the 10-s OLS take a look at begins to progressively diminish with ageing, roughly halving at every subsequent 5-year age group interval. Acknowledged otherwise, the members within the oldest age group—71–75 years—have been greater than 11 occasions extra prone to be a NO responder as in contrast with these simply 20 years youthful and belonging to the youngest age group within the examine—51–55 years. The power to finish the 10-s OLS tended to point out each a ceiling and a ground by way of an age profile, with very uncommon (<1%) youthful members (<45 years of age) failing and comparatively few members older than 80 years in a position to full the take a look at (see on-line supplemental materials).

Univariate evaluation indicated {that a} NO 10-s OLS response was considerably and immediately related to age, with a excessive waist-height ratio and the prevalence of diabetes mellitus. Our outcomes are concordant with these of Neri et al40 who discovered that adiposity measures, specifically waist circumference, have been related to postural instability and better danger of falls in older adults. As well as, the upper share of members with diabetes mellitus within the NO 10-s OLS group means that a few of these members have subclinical central or autonomic nervous system dysfunction, as has been not too long ago reported.41

Our knowledge present that middle-aged and older members unable to finish the 10-s OLS had decrease survival over a median of seven years in contrast with these in a position to full the take a look at, with an 84% increased danger of all-cause mortality, even when different probably confounding variables reminiscent of age, intercourse, BMI and medical comorbidities or danger components, together with presence of coronary artery illness, hypertension, weight problems, dyslipidaemia and diabetes mellitus, have been taken under consideration. The utility of the 10-s OLS take a look at for mortality danger evaluation is additional corroborated by the truth that it offered an enchancment in mortality danger discrimination utilizing measures together with IDI and distinction in −2 log chance.

Comparability of present findings with the literature

A examine revealed in 200715 proposed normative values for OLS timing primarily based on outcomes obtained in 549 males/ladies divided into six age teams starting from 18 to 80+ years. Much like our examine, they discovered that OLS efficiency was strongly and negatively influenced by age however unaffected by intercourse.15 There’s restricted data within the literature relating steadiness to all-cause mortality. In a latest Japanese examine with 1085 aged members (65–89 years),22 it was noticed that OLS timing was strongly related to all-cause mortality, with an adjusted-relative danger worth much like the present examine utilizing related covariates (1.91 (95% CI 1.39 to 2.63)). In a latest cohort examine, Cao et al42 evaluated static steadiness in 5816 women and men older than 40 years who have been adopted for a median of 12.5 years and noticed that these with a steadiness dysfunction had a 44% increased danger of all-cause mortality compared with these having regular leads to the 4 situations assessed within the modified Romberg take a look at of standing steadiness on agency and compliant help surfaces.

It ought to be identified that OLS has been used to evaluate steadiness for greater than 50 years; Fregly et al16 have been the primary to report normative requirements for OLS primarily based on a wholesome pattern of navy women and men. It’s notable that in most research OLS outcomes have been expressed as time in seconds, typically restricted to 30 or 60 s, reflecting the length that members have been in a position to keep the OLS place.15 16 43–45 Whereas that is attainable for younger adults, it turns into progressively harder with ageing. Certainly, our knowledge point out that almost all of members aged >70 years have been unable to finish 10-s OLS. Furthermore, whereas plainly reliability is average to good for timing OLS research,46 it’s attainable that in a medical setting with older members timing measurements are typically much less reproducible on account of excessive intraparticipant and interobserver variation, probably limiting the validity of the OLS outcomes. Moreover, there are distinct methods wherein OLS has been assessed, with variations in arm/hand positions, whether or not arm actions for stabilisation are allowed and place of the other leg and foot, with a few of the research permitting a swing leg that comes with a muscle energy part.18 38 47–49

Due to this fact, our outcomes are usually not solely confirmatory of the research talked about above, however they lengthen these observations and make them sensible for routine medical use. Certainly, it’s easier and sure extra reproducible to have a transparent time reference reminiscent of 10 s as used within the present examine, as in contrast with recording the time wherein the topic is ready to stay in OLS.


There are a number of strengths to our examine. The ten-s OLS testing was carried out in well-controlled conditions and below direct well being skilled surveillance. The ten-s OLS take a look at was straightforward to clarify to the participant, to use and to acquire the binary consequence used within the examine (YES or NO responder). Median follow-up time and the share of deaths within the pattern offered acceptable statistical energy for evaluation and to handle the purpose of the examine. As well as, there have been knowledge obtainable from a number of anthropometric and medical variables that have been used for clinically related multivariable modelling.


Some limitations are notable. First, this CLINIMEX Train cohort is primarily composed of members of white race and belonging to increased socioeconomic strata in Brazil. Any extrapolation of those findings to populations distinct from this profile ought to be interpreted with warning. It’s also attainable {that a} extra subtle measure of OLS steadiness, reminiscent of centre of stress displacement in a given time frame, would offer higher discrimination and enhance the worth of this evaluation by way of survival. Nonetheless, this may make testing rather more troublesome to include as a easy medical routine observe. Second, use of HRs could also be uninformative as a result of they make direct comparisons between danger components troublesome to interpret. In addition they implies a continuing relative hazard all through the follow-up, which is often not the case.50 As well as, they’ve a built-in choice on account of conditioning on those that have survived. Third, a number of potential confounder variables weren’t obtainable for the members, together with latest historical past of falls, sample of bodily exercise or train and sports activities observe, weight-reduction plan, smoking and the usage of drugs that will intrude with steadiness. Fourth, since we didn’t have repeat measurements of the publicity, we have been unable to handle time-varying confounding in addition to time-varying confounding affected by prior publicity as potential confounders and to offer us the possibility to right for potential regression dilution bias and, lastly, we have now not used the Okay-fold cross-validation’s strategy, as a result of comparatively restricted pattern dimension of our examine. Future research ought to discover whether or not 10-s OLS outcomes add prognostic data when knowledge can be found for different elements of bodily health.

Lastly, investigation of the organic mechanisms that will clarify the noticed associations between poor OLS steadiness and all-cause mortality is required. It’s also of curiosity to analyze whether or not extra detailed or subtle assessments of static steadiness, reminiscent of together with a measurement of the centre of stress displacement, variety of trials required, completely different arm or foot positions and/or utilizing closed eyes throughout the OLS, might contribute to much more highly effective survival analyses.


Our examine signifies that the shortcoming to finish a 10-s OLS in middle-aged and older members is expounded to the next danger of all-cause mortality and, consequently, to a shorter life expectancy.

Key messages

How would possibly it influence on medical observe sooner or later?

  • 10-s OLS supplies speedy and goal suggestions for the affected person and well being professionals relating to static steadiness.

  • The routine software of a easy and protected static steadiness take a look at—10-s OLS—provides helpful data relating to mortality danger in middle-aged and older women and men.

Information availability assertion

Information can be found on cheap request. Deidentified knowledge can be found on cheap request.

Ethics statements

Affected person consent for publication

Ethics approval

This examine entails human members and was accepted by the Ethics Committee CONEP Brazilian Authorities (reference no: 4.459.555). Contributors gave knowledgeable consent to take part within the examine earlier than participating.


The authors thank all members who voluntarily permitted us to anonymously use their knowledge and to the Secretary of Well being of Rio de Janeiro state for offering the very important knowledge data to the members of CLINIMEX Train cohort.

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