Frontal plane hip and ankle sensorimotor function, not age, predicts unipedal stance time

A Non-Weight Bearing Method for Measuring Hip Abduction Strength Overestimates Hip Abductor Muscle Fatigue During One-Leg Stance

OCCUPATIONAL APPLICATIONSAssessing workers' strength capacities is a common practice prior to return to work following injury or illness, or assessing capabilities for strenuous jobs. Because it requires 50% or more of maximum strength capacity, hip abductor muscle strength is a strong predictor of both middle- and older-aged individuals' ability to reliably balance on one leg and of their risk of falls. Our results suggest subjects were able to augment their hip abductor moment during unipedal weight stance via gluteus maximus activity. Weight-bearing hip abduction strength measures are important for assessing worker capacity for jobs requiring reliable unipedal balance whether during lateral loading, while walking in gusty winds, on slippery footing or resisting lateral deck movements on board ship or train. Measurements of hip abductor strength should be made in a full unipedal weight bearing posture; non-weight-bearing measurements significantly underpredicted hip abductor strength as well as endurance.

The association of chemotherapy-induced peripheral neuropathy with reduced executive function in chemotherapy-treated cancer survivors: A cross-sectional study

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is common and disabling among cancer survivors. Little is known about the association of CIPN with other measures of the nervous system's integrity, such as executive dysfunction. We compared measures of executive function in older chemotherapy-treated cancer survivors with and without CIPN.

MATERIALS AND METHODS

This cross-sectional study enrolled 50 chemotherapy-treated cancer survivors (65.6 ± 11.5 years, 88% female) post-chemotherapy treatment who were previously referred for outpatient rehabilitation at the request of the cancer survivor or a medical provider. Twenty-two participants (44%) had CIPN defined by patient-reported distal paresthesia or numbness, which began with chemotherapy and continued to the time of cognitive testing. Measures of executive function included Trails-B, Stroop, and rapid reaction accuracy (RRA) and were evaluated between cancer survivors with and without CIPN using t-tests. Multivariable models were then used to determine whether CIPN was an independent determinant of the measures of executive function (Trails-B, Stroop Incongruent, and RRA). Models were adjusted for age, sex, history of anxiety, and benzodiazepine use due to their known associations with CIPN and executive function.

RESULTS

Cancer survivors with CIPN (CIPN+) had reduced executive function compared to survivors without CIPN (CIPN-) on Trails-B (CIPN+: 84.9 s ± 44.1 s, CIPN-: 59.1 s ± 22.5 s, p = 0.01), Stroop (CIPN+: 100.6 s ± 38.2 s, CIPN-: 82.1 s ± 17.3 s, p = 0.03), and RRA (CIPN+: 60.3% ± 12.9%, CIPN-: 70.6% ± 15.7%, p = 0.01). There were no differences in cancer stage severity or functional status by patient report or sit-to-stand function. The association between CIPN and reduced executive function was found in multivariable models after adjusting for age, sex, anxiety, and benzodiazepine use for Trails-B (ß:17.9, p = 0.046), Stroop (ß:16.9, p = 0.02), and RRA (ß:-0.072, p = 0.03).

DISCUSSION

In this population, CIPN is associated with reduced executive function in older cancer survivors treated with chemotherapy. Future research is required to further understand this preliminary association, the causality, and the potential risk factors.

Do increasingly unstable balance devices provide a graded challenge to bipedal stance in total hip arthroplasty patients?

BACKGROUND

Progressive balance exercises are critical to early functional rehabilitation after total hip arthroplasty (THA) but little is known regarding the challenge imposed by common balance devices.

RESEARCH QUESTION

Do progressively unstable balance devices provide a graded challenge to bipedal stance during early functional rehabilitation in THA patients?

METHODS

Postural control was evaluated in 42 patients (age, 63.7 ± 9.6 years; height, 1.72 ± 0.08 m and body mass, 78.9 ± 14.6 kg) approximately 3 weeks (23 ± 6 days) following unilateral primary THA. Patients were divided into two groups, based on their ability to complete a 20-second unipedal stance test (UPST) on the operated limb. A lumbar mounted inertial sensor monitored center of mass (COM) displacement during bipedal balance conditions involving three balance pads of progressive stiffness and an oscillatory platform, used in isolation and in combination with the most stable balance pad. COM displacement was normalised to bipedal stance on a hard surface. Differences between conditions and patient groups were assessed using a mixed-model analysis of variance.

RESULTS

Twenty patients (48%) were able to complete the UPST on their operated limb. There was a significant effect of balance condition on COM displacement during bipedal stance (F4,160 = 82.6, p < .01). COM displacement was lowest for the oscillatory platform but increased non-linearly across the three balance pads (p < .05). There was no significant difference in COM displacement between THA patients able and unable to complete the UPST.

SIGNIFICANCE

Increasingly compliant balance pads provided a progressive, though nonlinear, challenge to bipedal balance control in THA patients that was greater than that of an oscillating platform and independent of the ability to stand independently on the operated limb. These findings serve as a guide for the design of progressive training programs that enhance balance in THA patients.

Clinical Considerations in Returning Pediatric and Young Adults With Cancer to Physical Activity

ABSTRACT

There is a gap in the literature on the best treatment of clinical sequelae within adolescent and young adult pediatric cancer populations. Children, adolescents, and young adults are at risk for a multitude of immediate and late effects of their disease and treatment that warrant a comprehensive, multidisciplinary team approach to optimize care. Sports medicine providers are well-equipped with their background to join the oncology rehabilitation team in diagnosing and managing cancer-related impairments to help these populations live a healthier and more active lifestyle. In this manuscript, four essential clinical components to consider when returning children, adolescents, and young adults with cancer history to physical activity are discussed: chemotherapy-induced peripheral neuropathy, cardiotoxicity, nutritional deficiencies, and deconditioning.

Effects of Motor Rehabilitation on Balance and Functional Activities in Elderly Patients with Peripheral Neuropathy and Recurrent Falls

To date, little is known about the effects of motor rehabilitation in peripheral neuropathy (PN) patients with a history of recurrent falls (RFH). This study aimed to assess balance and the activities of daily living (ADLs) in elderly lower limb PN patients with and without RFH and to verify the effects of motor rehabilitation on balance and ADLs in these patients. We collected data from 64 lower limb PN patients, who underwent a conventional motor rehabilitation program: 35 patients had a history of recurrent falls, and 29 did not. The Berg Balance Scale (BBS) and motor FIM, before and after rehabilitation, were the outcome measures. After rehabilitation, lower limb PN patients with RFH had significantly higher scores in BBS and motor FIM (p < 0.001, for both) than at entry. The final BBS score and effectiveness in the BBS score of lower limb PN patients with RFH were lower than those of patients without RFH (p < 0.05 and p = 0.009, respectively). The study shows that conventional motor rehabilitation improves both balance and ADLs in patients, but balance improvement is lower in those with RFH. Thus, motor rehabilitation can be a therapeutic option for the management of these patients.

Determinants of improvement in functional abilities in peripheral neuropathy patients undergoing rehabilitation: the role of Berg Balance Scale items

PURPOSE

This prospective observational cohort study aimed to verify whether single Berg Balance Scale (BBS) items were important determinants of improvement in functional abilities in patients with peripheral neuropathy (PN).

METHODS

Data were collected in 75 older patients with PN performing a standard motor rehabilitation program. Backward stepwise multiple regression analyses were performed to identify determinants of outcome measures. Gain in total and motor Functional Independence Measure (FIM) and gain in motor-FIM areas were the outcome measures.

RESULTS

Among BBS items, at the end of rehabilitation, the score was higher in "sitting unsupported" (3.94 ± 0.22) and lower in "standing on one foot" (1.18 ± 1.06). The gain was higher in "standing to sitting" (1.02 ± 0.67) and "standing unsupported" (1.00 ± 1.00), and lower in "sitting unsupported" (0.22 ± 0.60) and "standing on one foot" (0.65 ± 0.77). "Standing unsupported" was the only determinant of gain in motor-FIM (beta - 0.36, p = 0.002) and gain in self-care (beta - 0.37, p = 0.002). The R2 value of the models was 0.13 and 0.14, respectively. No independent variable was a determinant of gain in total-FIM.

CONCLUSIONS

The study shows that "unsupported standing" is an important determinant of results of ADL rehabilitation in PN patients and indicates that ability to stand without support for a fairly long time is an essential requirement to achieve with rehabilitation higher gain levels in functional abilities in PN patients.

The Effect of Breaking Up Sedentary Time with Calisthenics on Neuromuscular Function: A Preliminary Study

The ageing process results in reduced neuromuscular function. This alongside prolonged sedentary behaviour is associated with decreased muscle strength, force control and ability to maintain balance. Breaking up sedentary time with regular bouts of physical activity has numerous health benefits, though the effects on neuromuscular function are unknown. This study investigated the effect of breaking up sedentary time with calisthenic exercise on neuromuscular function. 17 healthy adults (33 ± 13.1 years), who spent ≥6 h/day sitting, were assigned to a four-week calisthenics intervention (n = 8) or control group (n = 9). The calisthenics intervention involved performing up to eight sets of exercises during the working day (09:00-17:00); with one set consisting of eight repetitions of five difference exercises (including squats and lunges). Before and immediately after the intervention, measures of knee extensor maximal voluntary contraction (MVC) and submaximal force control (measures of the magnitude and complexity of force fluctuations), and dynamic balance (Y balance test) were taken. The calisthenics intervention resulted in a significant increase in knee extensor MVC (p = 0.036), significant decreases in the standard deviation (p = 0.031) and coefficient of variation (p = 0.016) of knee extensor force fluctuations during contractions at 40% MVC, and a significant increase in Y balance test posterolateral reach with left leg stance (p = 0.046). These results suggest that breaking up sedentary time with calisthenics may be effective at increasing muscle strength, force steadiness and dynamic balance all of which might help reduce the effects of the ageing process.

The Impact of Diabetic Neuropathy on Activities of Daily Living, Postural Balance and Risk of Falls - A Systematic Review

OBJECTIVE

The objective of this review is to discuss a compilation of the currently available literature regarding the impact of diabetic neuropathy (DN) on activities of daily living (ADL), postural stability, and risk of falls.

METHODS

A systematic electronic search strategy was conducted on PubMed/MEDLINE database, Cochrane Library, and Embase in March 2020. This narrative review included clinical cross-sectional studies assessing ADL, postural balance, and falls in adults with DN. All studies underwent a quality assessment based on the Newcastle Ottawa scale developed to assess cross-sectional studies.

RESULTS

Forty-two studies were identified. A total of 37 studies evaluated postural stability in DN, 10 studies assessed fall accidents, and three studies assessed ADL in individuals with DN. Seven studies assessed both postural stability and fall accidents, and one study assessed postural stability and ADL. Each of the studied outcome variables was assessed separately. Based on a quality assessment, eight studies were excluded resulting in an evaluation of 34 studies.

CONCLUSIONS

Diabetic neuropathy has a negative impact on postural balance and gait kinematics combined with an increased fall risk. Because of the few number of studies available, we were unable to evaluate the impact of DN on ADL. Our findings are in concordance with previous reviews, supporting the evidence for DN as a critical measure negatively impacting postural stability and fall risk in individuals with diabetes. Further clinical investigative studies are needed.

High intensity power training in middle-aged women with Charcot–Marie–Tooth disease: a case series

Background/aims

High-intensity power training has been shown to be effective in improving muscular capabilities, functional performance and health-related quality of life in populations with physical impairments. However, the effectiveness of high-intensity power training in people with Charcot–Marie–Tooth disease remains uncertain. This case series investigated the effects of high-intensity power training on muscle performance, function and health-related quality of life in middle-aged women with Charcot-Marie-Tooth disease.

Methods

Four women (age 51–58 years) with Charcot–Marie–Tooth disease type 1A participated in 8 weeks of supervised high-intensity power training.

Results

All participants improved strength of the right hip abductors (46.7–109.7%) and left hip abductors (27.3–128.6%), maximal gait speed (2.3–9.1%), static balance (0.7–4.9%), tandem walk (−3.3 to −58.5%), and mental component scores on the Short Form 36 Health Status Survey (0.8–27.6%). Adherence to high-intensity power training was 100% and only one minor adverse event related to the intervention was reported.

Conclusions

Although promising, larger controlled studies are indicated to confirm the safety and efficacy of high-intensity progressive resistance and power training in this cohort.

Extensor digitorum brevis bulk and associations with fibular motor nerve conduction amplitude

INTRODUCTION

Prior work demonstrates that fibular compound motor action potential (CMAP) amplitude <4.0 mV predicts impairment of ankle proprioceptive precision and increased fall risk. Extensor digitorum brevis (EDB) inspection may present a simple clinical surrogate for CMAP amplitude.

OBJECTIVE

(1) To estimate the inter-rater reliability of assessment of EDB bulk. (2) To determine whether inspection of EDB bulk is associated with fibular CMAP amplitude.

DESIGN

Prospective inter-raterreliability study.

SETTING

Academic center outpatient Physical Medicine & Rehabilitation electromyography (EMG) clinics.

PARTICIPANTS

Fifty-two adult participants (102 feet).

MAIN OUTCOME MEASURES

(1) Inter-rater reliability of assessment of EDB bulk. (2) Mean fibular CMAP amplitude. (3) A binary measure of fibular CMAP amplitude at/above or below a 4.0 mV threshold.

RESULTS

Inter-rater reliability of EDB bulk grading was moderate (kappa: 0.65 [95% confidence interval (CI) 0.48-0.82]). The mean CMAP value was 5.9 ± 2.2 mV when bulk was normal, 3.4 ± 2.1 mV when diminished, and 0.6 ± 0.9 mV when atrophied. A multivariable analysis demonstrated that EDB bulk, distal symmetric polyneuropathy (DSP), and lumbar radiculopathy were all associated with CMAP amplitude. The sensitivity and specificity of grading muscle bulk as normal versus abnormal in detecting CMAP amplitude above or below 4.0 mV were 0.86 (95% CI 0.78-0.94) and 0.71 (95% CI 0.54-0.88), respectively. An atrophied EDB was a highly specific indicator that CMAP amplitude was abnormal (<4.0 mV) in 100% of cases (8/8).

CONCLUSIONS

EDB bulk was associated with fibular CMAP amplitude. Atrophy was a highly specific indicator for CMAP amplitude below 4.0 mV. Evaluation of EDB bulk may represent a quick and easy clinical surrogate marker for CMAP amplitude and distal neuromuscular impairment.

Falls in older people with diabetes: Identification of simple screening measures and explanatory risk factors

AIMS

To identify risk factors for falls in older people with diabetes mellitus (DM) and to develop a low-cost fall risk screening tool.

METHODS

Older adults with DM (n = 103; age = 61.6 + 6.0 years) were recruited from diabetic clinics. Demographic, DM specific factors, lower limb strength and sensation, cognition, fear of falling, hand reaction time, balance, mobility and gait parameters were assessed using validated methods. Falls were prospectively recorded over six months.

RESULTS

Past falls and female gender were identified as significant predictors of falls: history of falls and female gender increased fall rates by 4.62 (95% CI = 2.31-9.27) and 2.40 (95% CI = 1.04-5.54) respectively. Fall rates were significantly associated with Diabetic Neuropathy scores, HbA1c level, contrast sensitivity, quadriceps strength, postural sway, tandem balance, stride length and Timed Up and Go Test times. A multi-variable fall risk tool derived using five measures, revealed that absolute risk for multiple falls increased from 0% in participants with zero or one factor to 83% in participants with all five risk factors.

CONCLUSIONS

Simple screening items for fall risk in people with DM were identified, with parsimonious explanatory risk factors. These findings help guide tailored interventions for preventing falls in DM.

On the importance of the hip abductors during a clinical one legged balance test: A theoretical study

Background

The ability to balance on one foot for a certain time is a widely used clinical test to assess the effects of age and diseases like peripheral neuropathy on balance. While state-space methods have been used to explore the mechanical demands and achievable accelerations for balancing on two feet in the sagittal plane, less is known about the requirements for sustaining one legged balance (OLB) in the frontal plane.

Research question

While most studies have focused on ankle function in OLB, can age and/or disease-related decreases in maximum hip abduction strength also affect OLB ability?

Methods

A two-link frontal plane state space model was used to define and explore the ‘feasible balance region’ which helps reveal the requirements for maintaining and restoring OLB, given the adverse effects of age and peripheral neuropathy on maximum hip and ankle strengths.

Results

Maintaining quasistatic OLB required 50%-106% of the maximum hip abduction strength in young and older adults, and older patients with peripheral neuropathy. Effectiveness of a ‘hip strategy’ in recovering OLB was heavily dependent on the maximum hip abduction strength, and for healthy older women was as important as ankle strength. Natural reductions of strength due to healthy aging did not show a meaningful reduction in meeting the strength requirement of clinical OLB. However deficits in hip strength typical of patients with peripheral neuropathy did adversely affect both quasistatic OLB and recoverable OLB states.

Significance

The importance of hip muscle strength has been underappreciated in the clinical OLB test. This is partly because the passive tissues of the hip joint can mask moderate deficits in hip abduction strength until it is needed for recovering OLB. Adding a follow up OLB test with a slightly raised pelvis would be a simple way to check for adequate hip abductor muscle strength.

Strength deficits in lower limb prosthesis users: A scoping review

BACKGROUND

Strength deficits may play a central role in the severity of balance, mobility, and endurance impairments in lower limb prosthesis users. A body of literature detailing the scope and specifics of muscle weakness in lower limb prosthesis users is emerging, but has yet to be summarized. A synopsis of strength deficits, and their impact on functional abilities in lower limb prosthesis users, may inform rehabilitation and research needs.

OBJECTIVES

Synthesize reported strength deficits in lower limb prosthesis users, and discuss possible causes, consequences, and solutions.

STUDY DESIGN

Scoping review.

METHODS

A search of biomedical databases was performed, and inclusion/exclusion criteria were applied to identify publications relevant to the purpose of the review.

RESULTS

In all, 377 publications were identified, of which 12 met the inclusion/exclusion criteria. When compared with the controls and the intact limb, the primary strength outcome, peak torque, was lower in transtibial residual limb knee flexors and extensors, as well as transfemoral residual limb hip muscles.

CONCLUSIONS

The reviewed studies provide evidence of strength deficits in lower limb prosthesis users. These deficits appear to be consequential, as they may contribute to balance, mobility, and endurance impairments. Additional research exploring alternative strength metrics, clinical tests, and causal links to functional impairments is required.

CLINICAL RELEVANCE

Evidence of muscle weakness among lower limb prosthesis users, and its influence on balance, mobility, and endurance, suggests that greater clinical attention and scientific inquiry into physical conditioning of lower limb prosthesis users is merited and required.

The Role of Hip Abductor Strength in Identifying Older Persons at Risk of Falls: A Diagnostic Accuracy Study

Background/Objectives

Early detection of fall risk in persons older than 65 is of clinical relevance, but the diagnostic accuracy of currently used functional tests (eg short physical performance battery [SPPB] and timed up and go test [TUG]) to assess older persons' fall risks remains moderate. Recent literature highlights the importance of strong hip abductors to prevent falls. We thus aimed to assess the diagnostic accuracy of hip abductor strength measures to assess older persons' fall risks.

Methods

Hip abductor maximum voluntary isometric strength (ABD MVIS), rate of force generation (ABD RFG), and the SPPB and TUG functional fall risk assessments were assessed in 60 persons aged over 65 years (82.0 ± 6.1 years). The diagnostic accuracy (area under the curve [AUC], sensitivity [sens], specificity [spec], positive predictive value [PPV], negative predictive value [NPV], and positive and negative likelihood ratios [LR⁺, LR^-]) was evaluated at a clinically important 90% sensitivity level. Cut-off values for clinical use were calculated.

Results

In our population, hip ABD MVIS (AUC 0.8, sens 90.6%, spec 57.1%, PPV 70.7%, NPV 84.2%, LR+ 2.1, LR- 0.2, and cut-off value ≤ 1.1 N/kg) and hip ABD RFG (AUC 0.8, sens 90.6%, spec 46.4%, PPV 65.9%, NPV 81.3%, LR+ 1.7, LR- 0.2, and cut-off ≤ 8.47 N/kg/s) show diagnostic accuracy comparable to other fall risk assessments (SPPB and TUG) and a high net sensitivity when used in a test battery.

Conclusion

Hip ABD MVIS or RFG shows good diagnostic accuracy to differentiate between older fallers and nonfallers compared to the chosen external criterion history of falls. The high net sensitivity when hip ABD MVIS or RFG is combined with currently used fall risk assessments shows promise in contributing value to a test battery and should be investigated further in longitudinal studies.

Differences in postural sway among healthy adults are associated with the ability to perform steady contractions with leg muscles

Upright standing involves small displacements of the center of mass about the base of support. These displacements are often quantified by measuring various kinematic features of the center-of-pressure trajectory. The plantar flexors have often been identified as the key muscles for the control of these displacements; however, studies have suggested that the hip abductor and adductors may also be important. The purpose of our study was to determine the association between the force capabilities of selected leg muscles and sway-area rate across four balance conditions in young (25 ± 4 years; 12/19 women) and older adults (71 ± 5 years; 5/19 women). Due to the marked overlap in sway-area rate between the two age groups, the data were collapsed, and individuals were assigned to groups of low- and high-sway area rates based on a k-medoid cluster analysis. The number of participants assigned to each group varied across balance conditions and a subset of older adults was always included in the low-sway group for each balance condition. The most consistent explanatory variable for the variance in sway-area rate was force control of the hip abductors and ankle dorsiflexors as indicated by the magnitude of the normalized force fluctuations (force steadiness) during a submaximal isometric contraction. The explanatory power of the regression models varied across conditions, thereby identifying specific balance conditions that should be examined further in future studies of postural control.

Positive verbal suggestion optimizes postural control

Balance is a very important function that allows maintaining a stable stance needed for many daily life activities and for preventing falls. We investigated whether balance control could be improved by a placebo procedure consisting of verbal suggestion. Thirty healthy volunteers were randomized in two groups (placebo and control) and asked to perform a single-leg stance task in which they had to stand as steadily as possible on the dominant leg. The task was repeated in three sessions (T0, T1, T2). At T1 and T2 an inert treatment was applied on the leg, by informing the placebo group that it was effective in improving balance. The control group was overtly told that treatment was inert. An accelerometer applied on participants’ leg allowed to measure body sways in different directions. Subjective parameters, like perception of stability, were also collected. Results showed that the placebo group had less body sways than the control group at T2, both in the three-dimensional space and in the anterior-posterior direction. Furthermore, the placebo group perceived to be more stable than the control group. This study represents the first evidence that placebo effect optimizes posture, with a potential translational impact in patients with postural and gait disturbances.

Development of postural control during single-leg standing in children aged 3-10 years

BACKGROUND

The ability to control the center of mass (COM) during single-leg standing (SLS) is imperative for individuals to walk independently. However, detailed biomechanical features of postural control during SLS performed by children remain to be comprehensively investigated.

RESEARCH QUESTION

We aimed to investigate the development of postural control during SLS in children aged 3-10 years.

METHODS

Forty-eight healthy children (26 boys and 22 girls) aged 3-10 years and 11 young adults participated in this experiment. The child population was divided into four groups by age: 3-4, 5-6, 7-8, and 9-10 years. The SLS task included standing on a single leg as long and as steady as possible for up to 30 s. A three-dimensional motion capture system and two force plates were used for calculating the COM and center of pressure (COP). The task was divided into three phases (accelerated, decelerated, and steady) on the basis of the relationship between COM and COP.

RESULTS

COP-COM distances in the 5-6 years' and 7-8 years' groups were significantly increased during the acceleration phase when compared with those in the adult group. Furthermore, COP-COM distances during the decelerated phase were significantly higher in all children's groups compared with those in the adult group. Lastly, COP-COM distance during the steady phase was significantly higher in the 3-4 year age group than in the 9-10 year age and adults groups.

SIGNIFICANCE

These results suggest that postural control during the acceleration and steady phases mature by 9 years. Conversely, children ∼10 years did not attain adult-like levels of postural control during the decelerated phase. The developmental process for postural control at each phase possibly plays a significant role in the basic biomechanics of movement and does not display a monotonic pattern.

Why Do Individuals with Cirrhosis Fall? A Mechanistic Model for Fall Assessment, Treatment, and Research

Falls are prevalent for people with cirrhosis and commonly lead to loss of independence, reduced quality of life, and mortality. Despite a critical need for fall prevention in this population, cirrhosis-specific fall-related mechanisms are not well understood. We posit that most falls in this patient population are due to a coalescence of discrete subclinical impairments that are not typically detected at the point of care. The combined effect of these subtle age- and disease-related neurocognitive and muscular impairments leads to the inability to respond successfully to a postural perturbation within the available 300 to 400 ms. This article provides a conceptual model of physiological resilience to avoid a fall that focuses on attributes that underlie the ability to withstand a postural perturbation and their clinical evaluation. Evidence supporting this model in cirrhosis and other high fall risk conditions will be synthesized and suggestions for fall assessment and treatment will be discussed.

Developing a toolkit for the assessment and monitoring of musculoskeletal ageing

The complexities and heterogeneity of the ageing process have slowed the development of consensus on appropriate biomarkers of healthy ageing. The Medical Research Council–Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA) is a collaboration between researchers and clinicians at the Universities of Liverpool, Sheffield and Newcastle. One of CIMA’s objectives is to ‘Identify and share optimal techniques and approaches to monitor age-related changes in all musculoskeletal tissues, and to provide an integrated assessment of musculoskeletal function’—in other words to develop a toolkit for assessing musculoskeletal ageing. This toolkit is envisaged as an instrument that can be used to characterise and quantify musculoskeletal function during ‘normal’ ageing, lend itself to use in large-scale, internationally important cohorts, and provide a set of biomarker outcome measures for epidemiological and intervention studies designed to enhance healthy musculoskeletal ageing. Such potential biomarkers include: biochemical measurements in biofluids or tissue samples, in vivo measurements of body composition, imaging of structural and physical properties, and functional tests. This review assesses candidate biomarkers of musculoskeletal ageing under these four headings, details their biological bases, strengths and limitations, and makes practical recommendations for their use. In addition, we identify gaps in the evidence base and priorities for further research on biomarkers of musculoskeletal ageing.

Intra-rater reliability of hip abductor isometric strength testing in a standing position in older fallers and non-fallers

Background

Reduced hip muscle strength has been shown to be a major factor related to falls in older persons. However, comprehensive assessment of hip abduction strength in the clinical setting is challenging. The aim of this study was to investigate the feasibility and intra-rater reliability of a quick and simple hip abductor strength test in a functional standing position.

Methods

Individuals over 65 years of age were recruited from the geriatric department of a university hospital and an outpatient clinic. Thirty-two older subjects, including 16 fallers (≥1 fall during the last 12 months) and 16 non-fallers were included. Maximum voluntary isometric strength (MVIS) and rate of force generation (RFG) of the hip abductors of the right leg were evaluated in a standing position using a hand-held dynamometer. Two test-sessions were carried out. All hip strength values were normalized to participants’ weight. Reliability was determined using the intra-class correlation coefficient agreement (ICC_agreement), the standard error of measurement (SEM) and a Bland and Altman analysis (BA).

Results

All participants completed the strength tests, which took a mean 2.47 ± 0.49 min (one limb). Intra-rater reliability was higher for MVIS (0.98_{[0.95–0.99]}) than RFG (ICC = 0.93_{[0.87–0.97]}) for the entire sample. In the non-fallers, ICC was 0.98_{[0.95–1.00]} (SEM = 0.08 N.kg^− 1) for MVIS and 0.88_{[0.75–0.96]} for RFG (SEM = 1.34 N.kg^-1.s^-1). In the fallers, ICC was 0.94_{[0.89–0.98]} (SEM = 0.11 N.kg^− 1) for MVIS and 0.93_{[0.84–0.98]} (SEM = 1.12 N.kg^− 1.s^− 1) for RFG. The BA plot showed that the MVIS and RFG values did not differ across test-sessions, showing that no learning effect occurred (no systematic effect). The mean differences between test-sessions were larger and the LOA smaller in the fallers than in the non-fallers.

Conclusion

Assessment of hip strength in a standing position is feasible, rapid and reliable. We therefore recommend this position for clinical practice. Future studies should investigate the diagnostic value of hip abductor strength in standing to discriminate between fallers and non-fallers, and to determine if change in strength following a falls prevention program reduces the risk of falls.

Hip muscle and hand-grip strength to differentiate between older fallers and non-fallers: a cross-sectional validity study

Background

Hip muscle weakness in older people seems to be an influencing factor of falls. Currently, it is unclear which muscles out of the hip muscle group play an important role in older people. A validating process in the measurement regarding muscle strength related to falls is necessary before answering that question.

Objective

Firstly, we aimed to investigate which hip muscle group strength shows an acceptable level of distinction between older adult fallers and non-fallers compared to a predefined external criterion regarding falling. Secondly, we aimed to compare the same outcomes and questions for hand-grip strength in relation to the same external criterion.

Design

This study was a cross-sectional validity study.

Methods

The maximum voluntary isometric strength (MVIS) and the rate of force generation of hip abductors (ABD), adductors, internal and external rotators, extensors, and flexors were measured with a dynamometer fixed to a custom-made frame as well as hand-grip strength with a Martin Vigorimeter in 60 older people aged over 65 years (38 females and 22 males).

Results

The area under the curve (AUC) and the results of the mean decrease in Gini index assessed by random forest approach show that of all the assessed parameters, hip ABD MVIS showed the highest discriminative value regarding the chosen external criterion in older people (AUC ABD MVIS 0.825, 95% confidence interval: 0.712-0.938).

Conclusion

Results indicate that ABD MVIS is a useful measure to distinguish between older adult fallers and non-fallers regarding the chosen external criterion.

Complex and Simple Clinical Reaction Times Are Associated with Gait, Balance, and Major Fall Injury in Older Subjects with Diabetic Peripheral Neuropathy

OBJECTIVE

The aim of this work was to identify relationships between complex and simple clinical measures of reaction time (RTclin) and indicators of balance in older subjects with and without diabetic peripheral neuropathy (DPN).

DESIGN

Prospective cohort design. Complex RTclin accuracy, simple RTclin latency, and their ratio were determined using a novel device in 42 subjects (mean ± SD age, 69.1 ± 8.3 yrs), 26 with DPN and 16 without. Dependent variables included unipedal stance time (UST), step width variability and range on an uneven surface, and major fall-related injury over 12 months.

RESULTS

In the DPN subjects, the ratio of complex RTclin accuracy to simple RTclin latency was strongly associated with longer UST (R/P = 0.653/0.004), and decreased step width variability and range (R/P = -0.696/0.001 and -0.782/<0.001, respectively) on an uneven surface. Additionally, the 2 DPN subjects sustaining major injuries had lower complex RTclin accuracy:simple RTclin latency than those without.

CONCLUSIONS

The ratio of complex RTclin accuracy:simple RTclin latency is a potent predictor of UST and frontal plane gait variability in response to perturbations and may predict major fall injury in older subjects with DPN. These short latency neurocognitive measures may compensate for lower limb neuromuscular impairments and provide a more comprehensive understanding of balance and fall risk.

Evaluation of hip abductor and adductor strength in the elderly: a reliability study

BACKGROUND

In elderly individuals an increased muscle strength contributes to the diminution of the falls risk and associated adverse events. An increasing interest in lateral control exists due to the fatal consequences of postero-lateral falls. Therefore a proper assessment of frontal plane hip muscle strength in elderly is important but remains challenging. Therefore we aimed to investigate the feasibility and repeatability of a hip abductor and adductor maximum voluntary isometric strength (MVIS) and rate of force generation (RFG) test in elderly. This represents an initial step in the development process of a new and clinically relevant test that could lead to more specific treatment protocols for this population.

METHODS

In this measurement focused study hip abduction (ABD) and adduction (ADD) MVIS and RFG were tested twice within one to three hours with a dynamometer fixed to a custom made frame in a geriatric population including fallers and non-fallers. Intraclass correlation coefficient (ICCagreement), standard error of measurement (SEM), and smallest detectable difference (SDD) were determined.

RESULTS

All recruited persons (N = 76; mean age (SD) 80.46 (7.05) years old) completed the tests. The average time needed to complete the strength tests was 10.58 min. (1.56) per muscle group. The reliability of the hip ABD and ADD was high with ICC'sagreement ranging from 0.83 to 0.97. The SDD varied between 18.1 and 81.8% depending on the muscle group and type of strength that was evaluated.

CONCLUSION

Hip abductor and adductor strength measures in older person are feasible and reliable. However, the significance of moderate changes in these measurements may be limited by the large SDD and SEM. Therefore, physical therapist should be careful when using this measure for assessing the progress of an individual person in a daily clinical use.

Assessing Somatosensory Utilization during Unipedal Postural Control

Multisensory-visual, vestibular and somatosensory information is integrated for appropriate postural control. The primary goal of this study was to assess somatosensory utilization during a functional motor task of unipedal postural control, in normal healthy adults. Assessing individual bias in the utilization of individual sensory contributions during postural control may help customization of rehabilitation protocols. In this study, a test paradigm of unipedal stance control in supine orientation with and without vision was assessed. Postural control in this test paradigm was hypothesized to utilize predominantly contributions of somatosensory information from the feet and ankle joint, with minimal vestibular input. Fourteen healthy subjects "stood" supine on their dominant leg while strapped to a backpack frame that was freely moving on air-bearings, to remove available otolith tilt cues with respect to gravity that influences postural control when standing upright. The backpack was attached through a cable to a pneumatic cylinder that provided a gravity-like load. Subjects performed three trials each with Eyes-open (EO) and Eyes-closed (EC) while loaded with 60% body weight. There was no difference in unipedal stance time (UST) across the two conditions with EC condition challenging the postural control system greater than the EO condition. Stabilogram-diffusion analysis (SDA) indicated that the critical mean square displacement was significantly different between the two conditions. Vestibular cues, both in terms of magnitude and the duration for which relevant information was available for postural control in this test paradigm, were minimized. These results support our hypothesis that maintaining unipedal stance in supine orientation without vision, minimizes vestibular contribution and thus predominantly utilizes somatosensory information for postural control.

Are falls prevention programs effective at reducing the risk factors for falls in people with type-2 diabetes mellitus and peripheral neuropathy: A systematic review with narrative synthesis

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a common complication of type-2 diabetes mellitus (T2DM) that predisposes the elderly to a higher falls risk. Falls prevention programs with a component of weight-bearing exercises are effective in decreasing future falls in the elderly. However, weight-bearing exercise was only recently recommended in guidelines for exercise for people with T2DM and DPN. Since then, there have been an increasing number of studies to evaluate the effectiveness of falls prevention programs on this targeted population.

OBJECTIVES

A systematic literature review was undertaken to determine the effectiveness of falls prevention programs for people with T2DM and DPN.

MAJOR FINDINGS

Nine published studies that investigated the effect of exercise training on falls risk among people with T2DM and DPN were included in the review. Interventions included lower limb strengthening, balance practice, aerobic exercise, walking programs, and Tai Chi.

CONCLUSIONS

The preliminary evidence presented in this review suggests that people with T2DM and DPN can improve their balance and walking after a targeted multicomponent program without risk of serious adverse events. There is insufficient long-term follow-up data to determine whether the improvements in balance or strength resulted in a decrease falls risk in the community setting.

Balance and mobility assessment for ruling-out the peripheral neuropathy of the lower limbs in older adults

The peripheral neuropathy of the lower limbs (PNLL) is an important cause of balance and mobility impairment in older adults. The nerve conduction study (NCS) is the gold standard for PNLL diagnosis. Aim of this work is to establish the sensitivity (Sn) and the specificity (Sp) of the balance and mobility examination for the PNLL in older adults. This study consecutively recruited 72 participants (>65years) who accessed to the clinical neurophysiology outpatient clinic for suspected PNLL. Participants were given the NCS and four clinical tests. Mobility was evaluated by the Timed Up and Go (TUG) test, the Performance Oriented Mobility Assessment (POMA) and the de Morton Mobility Index (DEMMI). In addition the Clinical Evaluation of Static Upright Stance (CELSIUS) scale was developed for a selective evaluation of static balance. Based on the NCS, 36% of participants had PNLL. The CELSIUS scale (cutoff: 19.5/24), the TUG test (cutoff: 9.6s) and the DEMMI scale (cutoff: 17.5/19) have high Sn (0.92÷0.96), but low Sp (0.28÷0.43) for the PNLL in the older adult. POMA scale (cutoff: 14.5/16) has low Sn (0.73), but acceptable Sp (0.85). In addition, CELSIUS, DEMMI and TUG negative likelihood ratios are 0.13, 0.17 and 0.12, respectively. Balance and mobility examination have high sensitivity for PNLL. CELSIUS score>19/24, DEMMI score>17/19 or TUG time≤9.6s substantially reduce PNLL likelihood. These clinical measures are thus recommended for ruling-out PNLL in the older adult.

Robot-aided assessment of lower extremity functions: a review

The assessment of sensorimotor functions is extremely important to understand the health status of a patient and its change over time. Assessments are necessary to plan and adjust the therapy in order to maximize the chances of individual recovery. Nowadays, however, assessments are seldom used in clinical practice due to administrative constraints or to inadequate validity, reliability and responsiveness. In clinical trials, more sensitive and reliable measurement scales could unmask changes in physiological variables that would not be visible with existing clinical scores.In the last decades robotic devices have become available for neurorehabilitation training in clinical centers. Besides training, robotic devices can overcome some of the limitations in traditional clinical assessments by providing more objective, sensitive, reliable and time-efficient measurements. However, it is necessary to understand the clinical needs to be able to develop novel robot-aided assessment methods that can be integrated in clinical practice.This paper aims at providing researchers and developers in the field of robotic neurorehabilitation with a comprehensive review of assessment methods for the lower extremities. Among the ICF domains, we included those related to lower extremities sensorimotor functions and walking; for each chapter we present and discuss existing assessments used in routine clinical practice and contrast those to state-of-the-art instrumented and robot-aided technologies. Based on the shortcomings of current assessments, on the identified clinical needs and on the opportunities offered by robotic devices, we propose future directions for research in rehabilitation robotics. The review and recommendations provided in this paper aim to guide the design of the next generation of robot-aided functional assessments, their validation and their translation to clinical practice.

Gait Efficiency on an Uneven Surface Is Associated with Falls and Injury in Older Subjects with a Spectrum of Lower Limb Neuromuscular Function: A Prospective Study

OBJECTIVE

The objective of this study was to determine which gait measures on smooth and uneven surfaces predict falls and fall-related injuries in older subjects with diabetic peripheral neuropathy.

DESIGN

Twenty-seven subjects (12 women) with a spectrum of peripheral nerve function ranging from normal to moderately severe diabetic peripheral neuropathy walked on smooth and uneven surfaces, with gait parameters determined by optoelectronic kinematic techniques. Falls and injuries were then determined prospectively over the following year.

RESULTS

Seventeen subjects (62.9%) fell and 12 (44.4%) sustained a fall-related injury. As compared with nonfallers, the subject group reporting any fall, as well as the subject group reporting fall-related injury, demonstrated decreased speed, greater step width (SW), shorter step length (SL), and greater SW-to-SL ratio (SW:SL) on both surfaces. Uneven surface SW:SL was the strongest predictor of falls (pseudo-r = 0.65; P = 0.012) and remained so with inclusion of other relevant variables into the model. Post hoc analysis comparing injured with noninjured fallers showed no difference in any gait parameter.

CONCLUSION

SW:SL on an uneven surface is the strongest predictor of falls and injuries in older subjects with a spectrum of peripheral neurologic function. Given the relationship between SW:SL and efficiency, older neuropathic patients at increased fall risk appear to sacrifice efficiency for stability on uneven surfaces.

Stance Postural Strategies in Patients with Chronic Inflammatory Demyelinating Polyradiculoneuropathy

Introduction

Polyneuropathy leads to postural instability and an increased risk of falling. We investigated how impaired motor impairment and proprioceptive input due to neuropathy influences postural strategies.

Methods

Platformless bisegmental posturography data were recorded in healthy subjects and patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Each subject stood on the floor, wore a head and a hip electromagnetic tracker. Sway amplitude and velocity were recorded and the mean direction difference (MDD) in the velocity vector between trackers was calculated as a flexibility index.

Results

Head and hip postural sway increased more in patients with CIDP than in healthy controls. MDD values reflecting hip strategies also increased more in patients than in controls. In the eyes closed condition MDD values in healthy subjects decreased but in patients remained unchanged.

Discussion

Sensori-motor impairment changes the balance between postural strategies that patients adopt to maintain upright quiet stance. Motor impairment leads to hip postural strategy overweight (eyes open), and prevents strategy re-balancing when the sensory context predominantly relies on proprioceptive input (eyes closed).

Mobility-Related Consequences of Reduced Lower-Extremity Peripheral Nerve Function with Age: A Systematic Review

The objective of this study is to systematically review the relationship between lower-extremity peripheral nerve function and mobility in older adults. The National Library of Medicine (PubMed) was searched on March 23, 2015 with no limits on publication dates. One reviewer selected original research studies of older adults (≥65 years) that assessed the relationship between lower-extremity peripheral nerve function and mobility-related outcomes. Participants, study design and methods of assessing peripheral nerve impairment were evaluated and results were reported and synthesized. Eight articles were identified, including 6 cross-sectional and 2 longitudinal studies. These articles investigated 6 elderly cohorts (4 from the U.S. and 2 from Italy): 3 community-dwelling (including 1 with only disabled women and 1 without mobility limitations at baseline), 1 with both community-dwelling and institutionalized residents, 1 from a range of residential locations, and 1 of patients with peripheral arterial disease. Mean ages ranged from 71-82 years. Nerve function was assessed by vibration threshold (n=2); sensory measures and clinical signs and symptoms of neuropathy (n=2); motor nerve conduction (n=1); and a combination of both sensory measures and motor nerve conduction (n=3). Each study found that worse peripheral nerve function was related to poor mobility, although relationships varied based on the nerve function measure and mobility domain assessed. Six studies found that the association between nerve function and mobility persisted despite adjustment for diabetes. Evidence suggests that peripheral nerve function impairment at various levels of severity is related to poor mobility independent of diabetes. Relationships varied depending on peripheral nerve measure, which may be particularly important when investigating specific biological mechanisms. Future research needs to identify risk factors for peripheral nerve decline beyond diabetes, especially those common in late-life and modifiable. Interventions to preserve nerve function should be investigated with regard to their effect on postponing or preventing disability in older adults.

Accuracy of Clinical Techniques for Evaluating Lower Limb Sensorimotor Functions Associated With Increased Fall Risk

BACKGROUND

In prior work, laboratory-based measures of hip motor function and ankle proprioceptive precision were critical to maintaining unipedal stance and fall/fall-related injury risk. However, the optimal clinical evaluation techniques for predicting these measures are unknown.

OBJECTIVE

To evaluate the diagnostic accuracy of common clinical maneuvers in predicting laboratory-based measures of frontal plane hip rate of torque development (Hip(RTD)) and ankle proprioceptive thresholds (AnkPRO) associated with increased fall risk.

DESIGN

Prospective, observational study.

SETTING

Biomechanical research laboratory.

PARTICIPANTS

A total of 41 older subjects (aged 69.1 ± 8.3 years), 25 with varying degrees of diabetic distal symmetric polyneuropathy and 16 without.

ASSESSMENTS

Clinical hip strength was evaluated by manual muscle testing (MMT) and lateral plank time, defined as the number of seconds that the laterally lying subject could lift the hips from the support surface. Foot/ankle evaluation included Achilles reflex and vibratory, proprioceptive, monofilament, and pinprick sensations at the great toe.

MAIN OUTCOME MEASURES

Hip(RTD), abduction and adduction, using a custom whole-body dynamometer. AnkPRO determined with subjects standing using a foot cradle system and a staircase series of 100 frontal plane rotational stimuli.

RESULTS

Pearson correlation coefficients (r) and receiver operator characteristic (ROC) curves revealed that LPT correlated more strongly with Hip(RTD) (r/P = 0.61/<.001 and 0.67/<.001, for abductor/adductor, respectively) than did hip abductor MMT (r/P = 0.31/.044). Subjects with greater vibratory and proprioceptive sensation, and intact Achilles reflexes, monofilament, and pin sensation had more precise AnkPRO. LPT of <12 seconds yielded a sensitivity/specificity of 91%/80% for identifying Hip(RTD) < 0.25 (body size in Newton-meters), and vibratory perception of <8 seconds yielded a sensitivity/specificity of 94%/80% for the identification of AnkPRO >1.0°.

CONCLUSIONS

LPT is a more effective measure of Hip(RTD) than MMT. Similarly, clinical vibratory sense and monofilament testing are effective measures of AnkPRO, whereas clinical proprioceptive sense is not.

Test-retest reliability and responsiveness of centre of pressure measurements in patients with hip osteoarthritis

OBJECTIVE

The aim of this study was to determine a set of measures for the evaluation of balance in patients suffering from hip osteoarthritis (OA) that were both reliable and responsive to change.

DESIGN

Three groups of subjects; Healthy, hip OA patients without surgery, and hip OA with surgery (pre and post-surgery) were included in this study. Subjects had to perform balance tests in two positions: standard and narrowed stance. CoP-based measures test-retest reliability was assessed in hip OA without surgery group, responsiveness were assessed between all groups and between pre and post-surgery.

RESULTS

Intraclass Correlation Coefficient (ICC) values from hip OA without surgery ranged from -0.03 to 0.9 for only five parameters (CoP path length, SD velocity, mean velocity, and antero-posterior Root Mean Square (RMS(AP)) having values over 0.7. SD velocity and RMS(AP) showed significant differences between healthy and surgery group in standard stance whereas narrowed stance revealed most differences between all groups. RMS(AP) showed the best responsiveness (Standardized Response Mean ∼0.5) between pre vs post-surgery in both conditions. RMS(AP) was also capable of discriminating between hip OA with surgery vs without surgery groups with good sensitivity and specificity.

CONCLUSIONS

Our results showed there to be reliability and responsiveness of five postural parameters in hip OA patients in two conditions of standing balance. More parameters were significantly different in narrowed stance whereas sensitivity was better in standard stance. SD velocity and RMS(AP) discriminate between degrees of OA severity and highlight potential balance deficits even after arthroplasty. Selected parameters during standing balance could be assessed to complete the set of quantitative measures to quantify hip OA patient deficiencies.

Reconceptualizing balance: attributes associated with balance performance

Balance tests are commonly used to screen for impairments that put older adults at risk for falls. The purpose of this study was to determine the attributes that were associated with balance performance as measured by the Frailty and Injuries: Cooperative Studies of Intervention Techniques (FICSIT) balance test. This study was a cross-sectional secondary analysis of baseline data from a longitudinal cohort study, the Boston Rehabilitative Impairment Study of the Elderly (Boston RISE). Boston RISE was performed in an outpatient rehabilitation research center and evaluated Boston area primary care patients aged 65 to 96 (N=364) with self-reported difficulty or task-modification climbing a flight of stairs or walking 1/2 of a mile. The outcome measure was standing balance as measured by the FICSIT-4 balance assessment. Other measures included: self-efficacy, pain, depression, executive function, vision, sensory loss, reaction time, kyphosis, leg range of motion, trunk extensor muscle endurance, leg strength and leg velocity at peak power. Participants were 67% female, had an average age of 76.5 (±7.0) years, an average of 4.1 (±2.0) chronic conditions, and an average FICSIT-4 score of 6.7 (±2.2) out of 9. After adjusting for age and gender, attributes significantly associated with balance performance were falls self-efficacy, trunk extensor muscle endurance, sensory loss, and leg velocity at peak power. FICSIT-4 balance performance is associated with a number of behavioral and physiologic attributes, many of which are amenable to rehabilitative treatment. Our findings support a consideration of balance as multidimensional activity as proposed by the current International Classification of Functioning, Disability, and Health (ICF) model.

Postural stability and ankle sprain history in athletes compared to uninjured controls

BACKGROUND

Diminished postural stability is a risk factor for ankle sprain occurrence and ankle sprains result in impaired postural stability. To date, ankle sprain history has not been taken into account as a determinant of postural stability, while it could possibly specify subgroups of interest.

METHODS

Postural stability was compared between 18 field hockey athletes who had recovered from an ankle sprain (mean (SD); 3.6 (1.5) months post-injury), and 16 uninjured controls. Force plate and kinematics parameters were calculated during single-leg standing: mean center of pressure speed, mean absolute horizontal ground reaction force, mean absolute ankle angular velocity, and mean absolute hip angular velocity. Additionally, cluster analysis was applied to the 'injured' participants, and the cluster with diminished postural stability was compared to the other participants with respect to ankle sprain history.

FINDINGS

MANCOVA showed no significant difference between groups in postural stability (P = 0.68). A self-reported history of an (partial) ankle ligament rupture was typically present in the cluster with diminished postural stability. Subsequently, a 'preceding rupture' was added as a factor in the MANCOVA, which showed a significant association between diminished postural stability and a 'preceding rupture' (P = 0.01), for all four individual parameters (P: 0.001-0.029; Cohen's d: 0.96-2.23).

INTERPRETATION

Diminished postural stability is not apparent in all previously injured athletes. However, our analysis suggests that an (mild) ankle sprain with a preceding severe ankle sprain is associated with impaired balance ability. Therefore, sensorimotor training may be emphasized in this particular group and caution is warranted in return to play decisions.

Hip strength: ankle proprioceptive threshold ratio predicts falls and injury in diabetic neuropathy

INTRODUCTION

We determined lower limb neuromuscular capacities associated with falls and fall-related injuries in older people with declining peripheral nerve function.

METHODS

Thirty-two subjects (67.4 ± 13.4 years; 19 with type 2 diabetes), representing a spectrum of peripheral neurologic function, were evaluated with frontal plane proprioceptive thresholds at the ankle, frontal plane motor function at the ankle and hip, and prospective follow-up for 1 year.

RESULTS

Falls and fall-related injuries were reported by 20 (62.5%) and 14 (43.8%) subjects, respectively. The ratio of hip adductor rate of torque development to ankle proprioceptive threshold (Hip(STR) /AnkPRO ) predicted falls (pseudo-R(2)  = .726) and injury (pseudo-R(2)  = .382). No other variable maintained significance in the presence of Hip(STR) /AnkPRO .

CONCLUSIONS

Fall and injury risk in the population studied is related inversely to Hip(STR) /AnkPRO . Increasing rapidly available hip strength in patients with neuropathic ankle sensory impairment may decrease risk of falls and related injuries.

Step length after discrete perturbation predicts accidental falls and fall-related injury in elderly people with a range of peripheral neuropathy

AIMS

Distal symmetric polyneuropathy increases fall risk due to inability to cope with perturbations. We aimed to 1) identify the frontal plane lower limb sensorimotor functions which are necessary for robustness to a discrete, underfoot perturbation during gait; and 2) determine whether changes in the post-perturbed step parameters could distinguish between fallers and non fallers.

METHODS

Forty-two subjects (16 healthy old and 26 with diabetic PN) participated. Frontal plane lower limb sensorimotor functions were determined using established laboratory-based techniques. The subjects' most extreme alterations in step width or step length in response to a perturbation were measured. In addition, falls and fall-related injuries were prospectively recorded.

RESULTS

Ankle proprioceptive threshold (APrT; p=.025) and hip abduction rate of torque generation (RTG; p=.041) independently predicted extreme step length after medial perturbation, with precise APrT and greater hip RTG allowing maintenance of step length. Injured subjects demonstrated greater extreme step length changes after medial perturbation than non-injured subjects (percent change = 18.5 ± 9.2 vs. 11.3 ± 4.57; p = .01).

CONCLUSIONS

The ability to rapidly generate frontal plane hip strength and/or precisely perceive motion at the ankle is needed to maintain a normal step length after perturbation, a parameter which distinguishes between subjects sustaining a fall-related injury and those who did not.

Level of competitive success achieved by elite athletes and multi-joint proprioceptive ability

OBJECTIVES

Proprioceptive ability has been suggested to underpin elite sports performance. Accordingly, this study examined the relationship between an athlete's proprioceptive ability, competition level achieved, and years of sport-specific training.

DESIGN

Cross-sectional study.

METHODS

One hundred elite athletes, at competition levels ranging from regional to international, in aerobic gymnastics, swimming, sports dancing, badminton and soccer, were assessed for proprioceptive acuity at the ankle, knee, spine, shoulder, and finger joints. An active movement extent discrimination test was conducted at each joint, to measure ability to discriminate small differences in movements made to physical stops.

RESULTS

Multiple regression analysis showed that 30% of the variance in the sport competition level an athlete achieved could be accounted for by an equation that included: ankle movement discrimination score, years of sport-specific training, and shoulder and spinal movement discrimination scores (p<0.001). Mean proprioceptive acuity score over these three predictor joints was significantly correlated with sport competition level achieved (r=0.48, p<0.001), highlighting the importance of proprioceptive ability in underpinning elite sports performance. Years of sport-specific training correlated with an athlete's sport competition level achieved (r=0.29, p=0.004), however, proprioceptive acuity was not correlated with years of sport-specific training, whether averaged over joints or considered singly for each joint tested (all r≤0.13, p≥0.217).

CONCLUSIONS

Proprioceptive acuity is significantly associated with the performance level achieved by sports elites. The amount of improvement in proprioceptive acuity associated with sport-specific training may be constrained by biologically determined factors.

Fibular motor nerve conduction studies and ankle sensorimotor capacities

INTRODUCTION

Nerve conduction studies provide information regarding the status of peripheral nerves, but relationships with sensorimotor capacities that influence mobility have not been defined.

METHODS

A secondary analysis was conducted on data from 41 older subjects (20 women and 21 men, age 69.1 ± 8.3 years), including 25 with diabetic neuropathy of varying severity and 16 without diabetes or neuropathy. Measurements included routine fibular motor nerve conduction studies and laboratory-based determination of ankle inversion/eversion proprioceptive thresholds and ankle inversion/eversion motor function.

RESULTS

Independent of age, fibular amplitude correlated robustly with ankle inversion/eversion proprioceptive thresholds (R(2) = 0.591, P < 0.001), moderately with ankle inversion and eversion rates of torque generation (R(2) = 0.216; P = 0.004 and R(2) = 0.200; P = 0.006, respectively), and more strongly when fibular motor amplitude was normalized for body mass index (R(2) = 0.350; P < 0.001 and R(2) = 0.275; P = 0.001).

CONCLUSIONS

Fibular motor amplitude was strongly associated with ankle sensorimotor capacities that influence lateral balance and recovery from perturbations during gait. The results suggest that nerve conduction study measures have potential for an expanded clinical role in evaluating mobility function in the population studied.

Which lower limb frontal plane sensory and motor functions predict gait speed and efficiency on uneven surfaces in older persons with diabetic neuropathy?

OBJECTIVE

To identify which frontal plane lower limb sensorimotor functions predict gait speed and efficiency (step-width-to-step-length ratio) on an uneven surface.

DESIGN

Cross-sectional observational study.

SETTING

A biomechanics research laboratory.

PARTICIPANTS

Thirty-three subjects (14 women [42.4%]; 21 with diabetic distal symmetric peripheral neuropathy [63.6%]), with a spectrum of lower limb sensorimotor functions that ranged from normal to marked diabetic neuropathy.

METHODS

Independent variables included ankle inversion-eversion proprioceptive thresholds, and normalized measures of maximum voluntary strength and maximum rate of torque development (RTD) of hip abduction-adduction and ankle inversion-eversion. Kinematic data were obtained by using an optoelectronic system as subjects walked over an uneven 10-m surface.

MAIN OUTCOME MEASURES

Dependent variables included gait speed and efficiency (determined by step-width-to-step-length ratio) on an uneven surface.

RESULTS

Hip adduction RTD and ankle inversion RTD predicted 54% of gait speed, with the former predicting the majority (44%). Ankle inversion RTD was the only significant predictor of gait efficiency, which accounted for 46% of its variability. Age did not predict gait speed or efficiency.

CONCLUSIONS

The rapid generation of strength in the frontal plane at the hip and ankle is responsible for the successful negotiation of irregular surfaces in older persons. Age demonstrated no independent influence. Training regimens in older persons should include maneuvers that rapidly develop strength in hip adductors and ankle invertors if navigation of uneven surfaces is a functional goal.