Is there a relationship between balance, gait performance and muscular strength in 75-year-old women?

Test-retest reliability and concurrent validity of knee extensor strength measured by a novel device incorporated into a weight stack machine vs. handheld and isokinetic dynamometry

BACKGROUND

The current clinical gold standard for assessing isometric quadriceps muscle strength is an isokinetic dynamometer (IKD). However, in clinics without an IKD, clinicians default to using handheld dynamometers (HHD), which are less reliable and accurate than the IKD, particularly for large muscle groups. A novel device (ND) was developed that locks the weight stack of weight machines, and measures forces applied to the machine, turning this equipment into an isometric dynamometer. The objectives of this study were to characterize the test-retest reliability of the ND, determine the within-day and between-days inter-rater reliability and concurrent validity compared with that of the HHD, in healthy volunteers (HV) and individuals with knee osteoarthritis (OA) for measuring knee extensors isometric muscle force.

MATERIALS AND METHODS

29 healthy (age = 28.4 ± 7.4 years) and 15 knee OA (age = 37.6 ± 13.4 years) participants completed three maximum force isometric strength testing trials on dominant side knee extensor muscles on three devices (ND, HHD, and IKD) in two separate sessions by two raters. The maximum force (Fmax) produced, and the force-time series were recorded. Reliability and validity were assessed using Intraclass Correlation Coefficient (ICC), Bland-Altman Plots, Pearson's r, and cross-correlations.

RESULTS

The ND demonstrated excellent test-retest reliability (ICC2,3 = 0.97). The within-day (ICC2,3 = 0.88) and between-day inter-rater reliability (ICC2,3 = 0.87) was good for HHD. The ND showed excellent within-day (ICC2,3 = 0.93) and good between-day (ICC2,3 = 0.89) inter-rater reliability. The Bland-Altman analysis revealed HHD systematic bias and underestimation of force particularly with quadriceps force values exceeding 450 N. Mean differences were found in maximum force between HHD vs. IKD (MDabs = 58 N, p < .001) but not the HHD vs. ND (MDabs = 24 N, p = .267) or ND vs. IKD (MDabs = 34 N, p = .051). The concurrent validity of Fmax (r = 0.81) and force-time curve correlation (0.96 ± 0.05) were the highest between the ND and IKD.

CONCLUSIONS

The ND's test-retest reliability and concurrent validity make it a potential strength assessment tool with utility in physical therapy and fitness settings for large muscle groups such as the knee extensors.

Individual and environmental variables related to outdoor walking among older adults: Verifying a model to guide the design of interventions targeting outdoor walking

OBJECTIVE

To estimate the relationships between individual and environmental variables and outdoor walking (OW) in older adults with OW limitations through verifying a conceptual model.

METHODS

Baseline data from 205 older adults participating in a randomized trial of a park-based OW program were analyzed using structural equation modeling. We evaluated a three latent factor model: OW (accelerometry and self-report); individual factors (balance; leg strength; walking self-confidence, speed and endurance; mental health; education; income; car access); and environmental factors (neighbourhood walkability components).

RESULTS

Mean age was 75 years; 73% were women. Individual factors was significantly associated with OW (β = 0.39, p < .01). Environmental factors was not directly associated with OW but was indirectly linked to OW through its significant covariance with the individual factors (β = 0.22, p < .01). The standardized factor loadings from the individual factors on walking self-confidence and walking capacity measures exceeded 0.65.

CONCLUSIONS

Better walking capacity and more confidence in the ability to walk outdoors are associated with higher OW in older adults. Better neighbourhood walkability is indirectly associated with more OW. The conceptual model demonstrates an individual and environment association; if the capacity of the individual is increased (potentially through walking interventions), they may be able to better navigate environmental challenges.

Community ambulation in older adults and people with OA - a model verification using Canadian Longitudinal Study on Aging (CLSA) data

BACKGROUND

There are health and well-being benefits of community ambulation; however, many older adults do not regularly walk outside of their home. Objectives were to estimate the associations between latent constructs related to community ambulation in older adults aged 65-85 (65+), and in adults with osteoarthritis (OA) aged 45-85.

METHODS

Secondary data analysis of the comprehensive baseline and maintaining contact questionnaire data from the Canadian Longitudinal Study of Aging (CLSA) was completed. Based on a previous model of community ambulation post-stroke, structural equation modeling (SEM) was used to develop measurement and structural models for two groups: older adults 65+ and people with OA. Multi-group SEM was conducted to test measurement invariance across sex and age groups. Measurement models were developed for the following latent factors: ambulation (frequency of walking outside/week, hours walked/day, ability to walk without help, frequency and aids used in different settings); health perceptions (general health, pain frequency/intensity); timed functional mobility (gait speed, timed up-and-go, sit-to-stand, balance). Variables of depression, falls, age, sex, and fear of walking alone at night were covariates in the structural models.

RESULTS

Data were used from 11,619 individuals in the 65+ group (mean age 73 years ±6, 49% female) and 5546 individuals in the OA group (mean age 67 ± 10, 60% female). The final 65+ model had a close fit with RMSEA (90% CI) = 0.018 (0.017, 0.019), CFI = 0.91, SRMR = 0.09. For the OA group, RMSEA (90% CI) = 0.021 (0.020, 0.023), CFI = 0.92, SRMR = 0.07. Health perceptions and timed functional mobility had a positive association with ambulation. Depression was associated with ambulation through negative associations with health perceptions and timed functional mobility. Multi-group SEM results reveal the measurement model was retained for males and females in the 65+ group, for males and females and for age groups (65+, < 65) in the OA group.

CONCLUSIONS

The community ambulation model post-stroke was verified with adults aged 65+ and for those with OA. The models of community ambulation can be used to frame and conceptualize community ambulation research and clinical interventions.

Association between walking speed and calcaneus stiffness index in older adults

INTRODUCTION

The aim here is to examine the association between objectively measured usual walking speed (UWS) and bone status in community-dwelling older Chinese.

MATERIALS AND METHODS

This is a cross-sectional study of a population of 1528 adults (817 females, mean age 68.5 ± 5.3; 711 males, mean age 69.1 ± 5.2) aged 60-79, living in communities in Shanghai. Walking speed was assessed using a 4-m walk test at a usual-pace walking speed a walking speed at which the subject felt relaxed-and bone status measured by quantitative ultrasound (QUS). The health-related characteristics of participants include family background, physical activity level, chronic disease, smoking and alcohol consumption, frequency of falls, vitamin intake, and hormone therapy.

RESULTS

Multiple linear regression is used to analyses any association between UWS and bone status, adjusting for confounding factors showing a significant association between faster UWS and a higher calcaneal stiffness index (SI) (p < 0.01). Comparing the lowest quartile of the data set with the highest at UWS, a high SI is achieved with 5.34 (95% CI = 3.22, 7.46) (p < 0.01), after adjusting for confounders. An increase of 1 dm/s was associated with a 0.91 (95% CI = 0.53, 1.29) increase in SI. This relationship for most subgroups is consistent.

CONCLUSION

Our findings suggest that UWS can be a sensitive indicator of calcaneal bone loss among an older population.

Evaluation of clinical factors associated with early postoperative physical function and lower extremity functional impairment in patients with soft tissue sarcoma

PURPOSE

This study aimed to investigate the relationship between various clinical factors and physical function in the early postoperative period in patients with soft tissue sarcomas (STSs) by subjective and objective evaluations.

MATERIALS AND METHODS

The 90 patients enrolled in this study were classified into five groups according to tumor location: retroperitoneal, gluteal, groin, thigh, and lower leg. The Musculoskeletal Tumor Society (MSTS) score was evaluated at discharge; the timed up-and-go test (TUGT) was performed preoperatively and at discharge. Group comparisons by tumor location were performed. To identify significant factors associated with physical dysfunction, multivariate analysis was performed using an MSTS score of <80% and a change in pre and postoperative TUGT score.

RESULTS

There were no significant differences between the tumor location and physical function. The change in pre- and postoperative TUGT scores was significantly associated with an MSTS score of <80%. Quadriceps and tibialis anterior muscle resections were significantly associated with the change in pre- and post-operative TUGT scores.

CONCLUSIONS

The quadriceps and tibialis anterior muscles may affect physical dysfunction after surgery for STSs. Early postoperative rehabilitation should include the identification of resected muscles and functional improvement of residual muscles, possibly with orthotic support for knee extension and ankle dorsiflexion.

Acute effect of kinesiotaping on pain, balance and gait performance in patients with knee osteoarthritis: A randomized controlled study

BACKGROUND

Kinesiotape application is one of the non-pharmacological methods frequently used in patients with knee OA. Guidelines do not have a consensus on its use in knee osteoarthritis (OA).

OBJECTIVE

In this study, we aimed to investigate the acute effect of kinesiotape application on pain, balance, and gait performance in patients with knee OA.

METHODS

We included 164 patients with grade 1-3 knee OA according to the Kellgren-Lawrence staging system in the study. Patients were evaluated with visual analog scale (VAS), 10-meter walking test (10MeWT), timed-up and go test (TUG-T), single leg stance test (SLST), and functional reach test (FRT) before and after taping.

RESULTS

There was a significant improvement in the post-taping scores of all evaluation parameters in the kinesiotaping group compared with pre-taping scores. Statistically significant improvement was found in all scores of evaluated parameters except FRT scores in the placebo taping group. We found a significant superiority in the mean recovery scores of the kinesiotaping group compared to the placebo-taping group in all parameters except for 10MeWT.

CONCLUSIONS

We found significant improvements in both groups. The mean improvement levels in pain and balance scores were better in the KT group than in the PT group.

The Effects of High-Speed Resistance Training on Health Outcomes in Independent Older Adults: A Systematic Review and Meta-Analysis

Human ageing involves several physiological impairments—in particular, a decrease in sensorimotor function and changes in the nervous system reduce muscle strength, power, balance, and functional capacity performance. Preventive strategies are essential to ensure the quality of life of the elderly. High-speed resistance training (HSRT) may be an effective approach to muscle power development in this population, with significant short-term effects on neural adaptations and muscle power production. Therefore, the present study intends to analyze and systematize the studies focused on HSRT interventions and their effects on health outcomes in independent older adults. Four electronic databases (PubMed, Web of Science, EBSCO, and Scielo) were used for the purposes of searching randomized controlled trials that measured at least one key outcome measure focusing on velocity-based training and health outcomes in older adults on 7 March 2022 and identified 1950 studies. At the end of the process, fourteen studies were included in this systematic review and ten studies were included in the quantitative analysis. The main results showed that HSRT interventions would improve health measures, mostly cognitive function (large effects, p = 0.001, SMD = 0.94), neuromuscular function (moderate effects, p = 0.003, SMD = 0.70), and physical function (moderate effects, p = 0.04, SMD = 0.55 and p = 0.009, SMD = −0.59). Additionally, the results suggested that interventions with ten weeks or more, performed three times a week, provide significant improvements in neuromuscular function. In this sense, HSRT is effective for improving overall health outcomes in older adults. Future studies should include proper follow-ups (e.g., minimum six months) to assess the durability of HSRT intervention effects on all health-related variables.

Predictors of Future Walking Speed: A 12-Month Monitoring Program

The purpose of the current study was to identify significant predictors of walking speed (WS) among community-dwelling older adults, as it is one of the most representative measures of functioning in their daily lives. Seventy-seven (24 adult men, 26 adult women, and 27 older-adult women) community-dwelling older adults (73.7 ± 4.9 years) performed two assessments, over a 12-month period. Several physical, cognitive, and psychological tests were performed, as well as assessing the preferred WS. Multiple linear regression, stratified by gender, was used to identify significant predictors of future WS. For the adult men, walking and functional performances at the first assessment predicted 71.9%; for adult women, reaction time, walking, and balance performance predicted 64.4%; and, for the older-adult women, fast walking and reaction time predicted 48.2% of the variance of future WS. Clinicians should consider including different exercises for each group of older adults to evaluate and preserve functional abilities.

Prediction of Bone Mineral Density (BMD) Adaptation in Pelvis-Femur Model with Hip Arthroplasties

The prediction of bone remodeling behaviour is a challenging factor in encouraging the long-term stability of hip arthroplasties. The presence of femoral components modifies the biomechanical environment of the bone and alters the bone growth process. Issues of bone loss and gait instability on both limbs are associated with the remodeling process. In this study, finite element analysis with an adaptive bone remodeling algorithm was used to predict the changes in bone mineral density following total hip and resurfacing hip arthroplasty. A three-dimensional model of the pelvis–femur was constructed from computed tomography (CT-based) images of a 79-year-old female patient with hip osteoarthritis. The prosthesis stem of the total hip arthroplasty was modelled with a titanium alloy material, while the femoral head had alumina properties. Meanwhile, resurfacing of the hip implant was completed with a cobalt-chromium material. Contact between the components and bone was designed to be perfectly bonded at the interface. Results indicate that the bone mineral density was modified over five years on all models, including hip osteoarthritis. The changes of BMD were predicted as being high between year zero and year one, especially in the proximal region. Changes were observed to be minimal in the following years. The bone remodeling process was also predicted for the non-operated femur. However, the adaptation was lower compared to the operated limbs. The reduction in bone mineral density suggested the bone loss phenomenon after a few years.

Are Static and Dynamic Postural Balance Assessments Two Sides of the Same Coin? A Cross-Sectional Study in the Older Adults

The aim of this study was to investigate if the combination of static and dynamic postural balance assessments gives more accurate indications on balance performance among healthy older adults. We also aimed at studying the effect of a dual-task condition on static and dynamic postural balance control. Fifty-seven healthy older adults (age = 73.2 ± 5.0 year, height = 1.66 ± 0.08 m, and body mass = 72.8 ± 13.8 kg) completed the study. Static and dynamic balance were assessed both in single-task and dual-task conditions through a force plate and an oscillating platform. The dominant handgrip strength was also measured with a dynamometer. Pearson’s correlation revealed non-statistically significant correlations between static and dynamic balance performance. The dual-task worsened the balance performance more in the dynamic (+147.8%) than in the static (+25.10%, +43.45%, and +72.93% for ellipse area, sway path, and AP oscillations, respectively) condition (p < 0.001). A weak correlation was found between dynamic balance performance and handgrip strength both in the single (p < 0.05; r = −0.264) and dual (p < 0.05; r = −0.302) task condition. The absence of correlations between static and dynamic balance performance suggests including both static and dynamic balance tests in the assessment of postural balance alterations among older adults. Since cognitive-interference tasks exacerbated the degradation of the postural control performance, dual-task condition should also be considered in the postural balance assessment.

Vibration Perception Threshold and Related Factors for Balance Assessment in Patients with Type 2 Diabetes Mellitus

Diabetic peripheral neuropathy (DPN) is a common complication of type 2 diabetes mellitus (DM). DPN causes a decrease in proprioception, which could reduce balance ability. We investigated the association of impaired vibration sense, based on vibration perception threshold (VPT), with assessments of balance and other factors affecting balance impairment and fear of falling in patients with type 2 DM. Sixty-three patients with DM aged >50 years were categorized as having normal vibration sense (NVS; n = 34) or impaired vibration sense (IVS; n = 29) according to a VPT value of 8.9 μm. The following parameters were evaluated for all patients: postural steadiness through the fall index using posturography, functional balance through the Berg Balance Scale (BBS), the Timed Up and Go test (TUG), and fear of falling through the Falls Efficacy Scale-International (FES-I). The IVS group showed a significantly greater balance impairment in fall index, BBS, and TUG, as well as greater fear of falling on the FES-I than the NVS group. The linear regression analysis showed that the fall index was associated only with the VPT, whereas BBS, TUG, and FES-I were associated with the VPT, age, and/or lower extremity muscle strength. VPT, age, and/or muscle strength were identified as predictors of balance and fear of falling in patients with type 2 DM. Therefore, along with age and lower extremity strength, the VPT can be useful for balance assessment in patients with type 2 DM.

Associations between functional fitness and walking speed in older adults

This cross-sectional study aimed to explore 1) the overall associations between functional fitness and walking speed in older adults and 2) the key functional fitness parameters affecting older adults' walking speeds. A total of 242 apparently healthy older adults finished a 6-m walking speed test at both usual walking speed (UWS) and maximum walking speed (MWS). Functional fitness was assessed using the Senior Fitness Test battery. The results revealed significantly moderate correlations of functional fitness with UWS (r = 0.380) and MWS (r = 0.436). Both age (UWS = -0.332, MWS = -0.324) and dynamic balance and agility (UWS = 0.329, MWS = 0.411) were key indicators of both UWS and MWS. In addition, gender (r = 0.090), aerobic endurance (r = 0.326), and lower body flexibility (r = 0.183) were key fitness indicators of MWS in older adults.

Body shape, fear of falling, physical performance, and falls among individuals aged 55 years and above

PURPOSE

To evaluate the relationship between waist-to-hip ratio (WHR) and fall-related outcomes in community-dwelling individuals aged 55 and above.

METHODS

Cross-sectional data obtained from the first wave of the Malaysian Elders Longitudinal Research (MELoR) study were utilized for this study. Participants aged 55 years and over were recruited using simple random sampling from the electoral rolls of three local parliamentary constituencies. Socio-demographics, falls history and medical history were obtained through home-based computer-assisted interviews while anthropometric measurements, including WHR, and physical performance were obtained during hospital-based health checks. WHR was categorized into three arbitrary categories stratified by gender.

RESULTS

Data on both falls and WHR were available for 1335 participants, mean age ± standard deviation (SD) = 68.4 ± 7.1 years. Logistic regression analyses using dummy variables revealed that individuals within the higher WHR group were significantly more likely to report a history of fall in the preceding 12 months {adjusted odds ratio (aOR) [95% confidence interval (CI)] = 1.78 (1.18-2.67)}, fear of falling [aOR (95% CI) = 1.58 (1.08-2.32)], impaired timed-up-and-go [2.14 (1.44-3.17)] and reduced functional reach [1.68 (1.18-2.38)] compared to those with lower WHR. A higher WHR remained independently associated with increased risk of falls compared to those with lower WHR after additional adjustment for fear of falling and functional performance.

CONCLUSION

Our finding suggests WHR as an independent risk factor for higher risk of fall which may indicate body shape as a potentially modifiable risk factor for falls in adults in aged 55 years and over.

Exercise training in older adults, what effects on muscle force control? A systematic review of randomized clinical trials

AIM

To determine the magnitude of the effects of different exercise training (ET) modalities on variables of muscle force control in older adults.

METHODS

Relevant articles were searched in PubMed, Web of Science, Science Direct and Scopus, using the keywords: Aged AND "Exercise Movement Techniques" AND ("Complexity of torque" OR "Complexity of force" OR "Variability of torque" OR "Variability of force" OR "Force Steadiness" OR "Force fluctuations"). To be included in the full analysis, the studies had to be randomized controlled trials in which older adults were submitted to ET programs and muscle force control assessment.

RESULTS

The searches resulted in 702 articles from which 6 met all the inclusion criteria. The trials involved 171 healthy and functionally limited older adults (71.64 ± 1.53 years). Studies included resistance, steadiness and functional training programs. Training sessions were 2-3 time per week, lasted 6-16 months with intensities determined as percentage of the one repetition maximum loads. There is a heterogeneity regarding experimental set-up and data analysis parameters between studies. The findings show an improved muscle force control in older adults after ET. Such response is better evidenced by the assessment of the coefficient of variation (CV) of the force signals. There is moderate evidence that resistance training programs are effective to decrease CV of knee extensor force signals at lower force targets.

CONCLUSIONS

The findings from this review suggest that ET programs are effective to improve muscle force control in older adults.

Reduced gait and postural stability under challenging conditions in fallers with upper limb fracture

BACKGROUND

While most fractures are caused by falls, not all falls result in fractures. Risk factors for falls are well established, but only weak associations have been demonstrated for risk factors for fractures. Conflicting results on the implication of bone mineral density (BMD) suggest that other risk factors should be studied, such as gait and balance disorders.

AIMS

Gait and postural stability in challenging conditions were, therefore, compared between fallers with and without fracture.

METHODS

We enrolled 80 adults aged 55 and older who fell in the previous year. We compared gait and posture after obstacle crossing between fallers with an upper-limb fracture (n = 38), and fallers without fracture (n = 42). Data on BMD, body mass index, handgrip strength, fear of falling, number of comorbidities, number of falls, global cognition, executive functioning and education level were collected.

RESULTS

Compared to fallers without fracture, fallers with fracture had significant lower gait velocity (Likelihood-Ratio = 4.93; P = 0.03) and lower postural stability during stabilization after obstacle crossing (Likelihood-Ratio = 10.99; P < 0.001). In addition, fallers with fracture had lower handgrip strength (Likelihood-Ratio = 9.92; P = 0.002), lower education level (Likelihood-Ratio = 8.32; P = 0.004), poorer executive functions (Likelihood-Ratio = 5.81; P = 0.02, higher fear of falling (Likelihood-Ratio = 5.55; P = 0.02) and were more likely women (Likelihood-Ratio = 17.55; P < 0.001), compared to fallers without fracture.

DISCUSSION

This study demonstrated that the main difference between fallers with upper-limb fracture and fallers without fracture is mobility in dynamic condition. Poor executive function and low muscular strength could also be involved.

CONCLUSIONS

These factors should be taken into account when assessing risk factors for fracture and implementing preventive programs.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov. NCT02292316.

Factors Affecting Walking Speed in Schizophrenia Patients

Objective

This study investigated the factors affecting walking speed in schizophrenia patients who were inpatients at a psychiatric hospital.

Methods

The study subjects were 37 patients with schizophrenia who were hospitalized in a psychiatric hospital. The measured assessment items included age, duration of hospitalization, duration of disease, muscle strength (30-s chair stand test), balance ability (one-leg standing time with eyes open/closed, Functional Reach Test, and Timed Up & Go Test), flexibility (long sitting position toe-touching distance), walking speed (10-m maximum walking speed), and the antipsychotic drug intake.

Results

The walking speed was found to be correlated with the results of the 30-s chair stand test, the one-leg standing time with eyes open, the one-leg standing time with eyes closed, and the Timed Up & Go Test. Stepwise multiple regression analysis revealed that only the Timed Up & Go Test results affected walking speed.

Conclusion

In schizophrenia patients, walking speed is influenced by balance and lower-limb muscle force, just as it is for patients without mental diseases. In schizophrenia patients, the dynamic balance ability has a strong influence on the walking speed.

Postural control is associated with muscle power in post-menopausal women with low bone mass

Older women with low bone mass are at higher risk of fracture and there is limited data on what is associated with risk of falls. We found explosive jumping to relate most strongly to postural control. It may be beneficial to include power or speed training into falls prevention programs.

INTRODUCTION

Post-menopausal women with low bone mass are at higher risk of bone fractures subsequent to falls. Understanding the correlates of postural control in this collective informs intervention design for falls prevention.

METHODS

We examined postural control in single-leg stance on stable and unstable surfaces in 63 community-dwelling post-menopausal women with osteopenia or osteoporosis but without diagnosed neuromuscular, vestibular or arthritic diseases. Postural measures were compared to countermovement jump performance (height, force and power), leg-press strength (10 repetition maximum), calf muscle area and density (via peripheral quantitative computed tomography), body mass, height and age.

RESULTS

On step-wise regression, peak countermovement jump power and jump height (p ≤ 0.014), but not jump force, leg-press strength or calf muscle size, were related to postural control in single-leg stance on, respectively, an unstable surface (eyes open) and standing on a stable surface (eyes open). None of the parameters measured were significantly related to the postural control parameters in single-leg stance on a stable surface with eyes closed. With testing on the stable surface, body mass was associated with slow mean centre of pressure movement speed (p ≤ 0.030).

CONCLUSIONS

Our findings show that, in post-menopausal women with low bone mass, neuromuscular power is a more important determinant of postural control than muscle strength or size. Our findings provide evidence to support the integration of power or speed training into falls prevention and balance training programs in post-menopausal women with osteopenia and osteoporosis.

Associations Between Types of Balance Performance in Healthy Individuals Across the Lifespan: A Systematic Review and Meta-Analysis

Background: The objective of this systematic review and meta-analysis was to quantify and statistically compare correlations between types of balance performance in healthy individuals across the lifespan. Methods: Literature search was performed in the electronic databases PubMed, Web of Science, and SPORTDiscus. Studies were included if they investigated healthy individuals aged ≥6 years and reported measures of static/dynamic steady-state, proactive, and/or reactive balance. The included studies were coded as follows: age group, gender, and balance type, test, parameter. Pearson's correlation coefficients were extracted, transformed (i.e., Fisher's z-transformed r _z -value), aggregated (i.e., weighted mean r _z -value), back-transformed to r-values, classified according to their magnitude, and statistically compared. The methodological quality of each study was assessed using the Appraisal tool for Cross-Sectional Studies. Results: We detected twenty-six studies that examined associations between types of balance and exclusively found small-sized correlations, irrespective of the age group considered. More specifically, the weighted mean r _z-values amounted to 0.61 (back-transformed r-value: 0.54) in old adults for the correlation of dynamic steady-state with proactive balance. For correlations between dynamic and static steady-state balance, the weighted mean r _z-values amounted to 0.09 in children (r-value: 0.09) and to 0.32 in old adults (r-value: 0.31). Further, correlations of proactive with static steady-state balance revealed weighted mean r _z-values of 0.24 (r-value: 0.24) in young adults and of 0.31 (r-value: 0.30) in old adults. Additionally, correlations between reactive and static steady-state balance yielded weighted mean r _z-values of 0.21 (r-value: 0.21) in young adults and of 0.19 (r-value: 0.19) in old adults. Moreover, significantly different correlation coefficients (z = 8.28, p < 0.001) were only found for the association between dynamic and static steady-state balance in children (r = 0.09) compared to old adults (r = 0.31). Lastly, we detected trivial to considerable heterogeneity (i.e., 0% ≤ I² ≤ 83%) between studies. Conclusions: Our systematic review and meta-analysis showed exclusively small-sized correlations between types of balance performance across the lifespan. This indicates that balance performance seems to be task-specific rather than a "general ability." Further, our results suggest that for assessment/training purposes a test battery/multiple exercises should be used that include static/dynamic steady-state, proactive, and reactive types of balance. Concerning the observed significant age differences, further research is needed to investigate whether they are truly existent or if they are caused by methodological inconsistencies.

Muscle plasticity of aged subjects in response to electrical stimulation training and inversion and/or limitation of the sarcopenic process

This review addresses the possible structural and functional adaptations of the muscle function to neuromuscular electrical stimulation (NMES) training in frail and/or aged (without advanced chronic disease) subjects. Evidence suggests that the sarcopenic process and its structural and functional effects would be limited and/or reversed through NMES training using excito-motor currents (or direct currents). From a structural viewpoint, NMES helps reduce muscle atrophy. From a functional viewpoint, NMES enables the improvement of motor output (i.e., muscle strength), gait, balance and activities of daily living which enhances the quality of life of aged subjects. Muscle plasticity of aged subjects in response to NMES training turns out to be undeniable, although many mechanisms are not yet explained and deserve to be explore further. Mechanistic explanations as well as conceptual models are proposed to explain how muscle plasticity operates in aged subjects through NMES training. NMES could be seen as a clinically applicable training technique, safe and efficient among aged subjects and could be used more often as part of prevention of sarcopenia. Therapists and physical conditioners/trainers could exploit this new knowledge in their professional practice to improve life conditions (including the risk of fall) of frail and/or aged subjects.

Validity of maximal isometric knee extension strength measurements obtained via belt-stabilized hand-held dynamometry in healthy adults

[Purpose] To determine the validity of knee extension muscle strength measurements using belt-stabilized hand-held dynamometry with and without body stabilization compared with the gold standard isokinetic dynamometry in healthy adults. [Subjects and Methods] Twenty-nine healthy adults (mean age, 21.3 years) were included. Study parameters involved right side measurements of maximal isometric knee extension strength obtained using belt-stabilized hand-held dynamometry with and without body stabilization and the gold standard. Measurements were performed in all subjects. [Results] A moderate correlation and fixed bias were found between measurements obtained using belt-stabilized hand-held dynamometry with body stabilization and the gold standard. No significant correlation and proportional bias were found between measurements obtained using belt-stabilized hand-held dynamometry without body stabilization and the gold standard. The strength identified using belt-stabilized hand-held dynamometry with body stabilization may not be commensurate with the maximum strength individuals can generate; however, it reflects such strength. In contrast, the strength identified using belt-stabilized hand-held dynamometry without body stabilization does not reflect the maximum strength. Therefore, a chair should be used to stabilize the body when performing measurements of maximal isometric knee extension strength using belt-stabilized hand-held dynamometry in healthy adults. [Conclusion] Belt-stabilized hand-held dynamometry with body stabilization is more convenient than the gold standard in clinical settings.

Are there different factors affecting walking speed and gait cycle variability between men and women in community-dwelling older adults?

BACKGROUND

Few studies have examined the relationships between walking speed and gait cycle variability, and muscle strength and postural stability, with a focus on gender differences.

AIM

The aim of this study was to examine whether there are different factors affecting walking speed and gait cycle variability between men and women in community-dwelling older adults.

METHODS

The subjects comprised 712 community-dwelling older adults (252 men, 460 women, aged 68.7 ± 4.8 years). Walking speed and coefficient of variation (CV) of step time at a comfortable walking pace were measured. The maximal isometric strength of six lower limb muscles and postural stability were evaluated. Stepwise regression analysis was performed, using lower limb muscle strength and postural stability as independent variables, to investigate the association with walking speed or CV.

RESULTS

For older men, age, body mass index (BMI) and quadriceps setting (QS) strength were significant and independent determinants of walking speed. No variables were identified as significant determinants of CV. For older women, BMI and hip flexion, hip abduction, QS muscle strength were significant determinants of walking speed. Only hip abduction strength was a significant determinant of CV.

DISCUSSION

The results of this study suggest that QS strength is related to walking speed in both men and women, whereas hip flexion and abduction muscle strength are related to walking speed, and hip abduction muscle strength is related to gait cycle variability in older women.

CONCLUSION

Gender differences exist in factors affecting walking speed and gait cycle variability in community-dwelling older adults.

Physical Activity Protects Men but Not Women for Sarcopenia Development

Objective: Sarcopenia is among the most deleterious effects of aging. The objective of this study was to analyze the relationship between performance tests and muscular volume over the life span of male and female participants. Method: A correlation study was conducted with healthy individuals (50 males and 47 females) between the ages of 20 and 94; the study group included active older people, sedentary younger people, and young athletes. Muscular volume was determined by tomography and muscular performance (4-meter speed tests [4 MSTs], chair test, and handgrip test), and a correlation analysis between the groups was performed. Results: Sex-related differences were observed between the variables; in males, muscle volume and functional parameters were closely related with age and physical activity, whereas in females, they were not related at all. Conclusion: Male and female muscle volume and performance demonstrate strong differences, which should be considered during clinical evaluations of sarcopenia.

Associations Between Measures of Balance and Lower-Extremity Muscle Strength/Power in Healthy Individuals Across the Lifespan: A Systematic Review and Meta-Analysis

BACKGROUND

It has frequently been reported that balance and lower-extremity muscle strength/power are associated with sports-related and everyday activities. Knowledge about the relationship between balance, strength, and power are important for the identification of at-risk individuals because deficits in these neuromuscular components are associated with an increased risk of sustaining injuries and falls. In addition, this knowledge is of high relevance for the development of specifically tailored health and skill-related exercise programs.

OBJECTIVES

The objectives of this systematic literature review and meta-analysis were to characterize and, if possible, quantify associations between variables of balance and lower-extremity muscle strength/power in healthy individuals across the lifespan.

DATA SOURCES

A computerized systematic literature search was performed in the electronic databases PubMed, Web of Science, and SPORTDiscus up to March 2015 to capture all relevant articles.

STUDY ELIGIBILITY CRITERIA

A systematic approach was used to evaluate the 996 articles identified for initial review. Studies were included only if they investigated healthy individuals aged ≥6 years and tested at least one measure of static steady-state balance (e.g., center of pressure [CoP] displacement during one-legged stance), dynamic steady-state balance (e.g., gait speed), proactive balance (e.g., distance in the functional-reach-test), or reactive balance (e.g., CoP displacement during perturbed one-legged stance), and one measure of maximal strength (e.g., maximum voluntary contraction), explosive force (e.g., rate of force development), or muscle power (e.g., jump height). In total, 37 studies met the inclusionary criteria for review.

STUDY APPRAISAL AND SYNTHESIS METHODS

The included studies were coded for the following criteria: age (i.e., children: 6-12 years, adolescents: 13-18 years, young adults: 19-44 years, middle-aged adults: 45-64 years, old adults: ≥65 years), sex (i.e., female, male), and test modality/outcome (i.e., test for the assessment of balance, strength, and power). Studies with athletes, patients, and/or people with diseases were excluded. Pearson's correlation coefficients were extracted, transformed (i.e., Fisher's z-transformed r z value), aggregated (i.e., weighted mean r z value), back-transformed to r values, classified according to their magnitude (i.e., small: r ≤ 0.69, medium: r ≤ 0.89, large: r ≥ 0.90), and, if possible, statistically compared. Heterogeneity between studies was assessed using I2 and Chi-squared (χ2) statistics.

RESULTS

Three studies examined associations between balance and lower-extremity muscle strength/power in children, one study in adolescents, nine studies in young adults, three studies in middle-aged adults, and 23 studies in old adults. Overall, small-sized associations were found between variables of balance and lower-extremity muscle strength/power, irrespective of the age group considered. In addition, small-sized but significantly larger correlation coefficients were found between measures of dynamic steady-state balance and maximal strength in children (r = 0.57) compared with young (r = 0.09, z = 3.30, p = 0.001) and old adults (r = 0.35, z = 2.94, p = 0.002) as well as in old compared with young adults (z = 1.95, p = 0.03).

LIMITATIONS

Even though the reported results provided further insight into the associations between measures of balance and lower-extremity muscle strength/power, they did not allow us to deduce cause and effect relations. Further, the investigated associations could be biased by other variables such as joint flexibility, muscle mass, and/or auditory/visual acuity.

CONCLUSIONS

Our systematic review and meta-analysis showed predominately small-sized correlations between measures of balance and lower-extremity muscle strength/power in children, adolescents, and young, middle-aged, and old adults. This indicates that these neuromuscular components are independent of each other and should therefore be tested and trained complementarily across the lifespan. Significantly larger but still small-sized associations were found between measures of dynamic steady-state balance and maximal strength in children compared with young and old adults as well as in old compared with young adults. These findings imply that age/maturation may have an impact on the association of selected components of balance and lower-extremity muscle strength.

Gait characteristics, balance performance and falls in ambulant adults with cerebral palsy: An observational study

The relationship between spatiotemporal gait parameters, balance performance and falls history was investigated in ambulant adults with cerebral palsy (CP). Participants completed a single assessment of gait using an instrumented walkway at preferred and fast speeds, balance testing (Balance Evaluation Systems Test; BESTest), and reported falls history. Seventeen ambulatory adults with CP, mean age 37 years, participated. Gait speed was typically slow at both preferred and fast speeds (mean 0.97 and 1.21m/s, respectively), with short stride length and high cadence relative to speed. There was a significant, large positive relationship between preferred gait speed and BESTest total score (ρ=0.573; p<0.05) and fast gait speed and BESTest total score (ρ=0.647, p<0.01). The stride lengths of fallers at both preferred and fast speeds differed significantly from non-fallers (p=0.032 and p=0.025, respectively), with those with a prior history of falls taking shorter strides. Faster gait speed was associated with better performance on tests of anticipatory and postural response components of the BESTest, suggesting potential therapeutic training targets to address either gait speed or balance performance. Future exploration of the implications of slow walking speed and reduced stride length on falls and community engagement, and the potential prognostic value of stride length on identifying falls risk is recommended.

Relationship between performances of 10-time-repeated sit-to-stand and maximal walking tests in non-disabled older women

Aim

Sit-to-stand (STS) test is extensively used to assess the functionality of the lower body in elderly people. This study aimed to examine how the score of STS can be associated with that of maximal walking (MW) tests through a cross-sectional as well as longitudinal analysis for non-disabled older women.

Method

Times taken for a 10-time-repeated STS (STS time) and 5-m MW (MW time) were determined before (pre) and after (post) a 3-month body mass-based exercise program in 154 non-disabled women aged 60 to 79 years. In addition to the time scores, STS and MW power indexes (STS-PI and MW-PI, respectively) were calculated using the following equations: STS-PI = (body height − 0.4) × body mass × 10/STS time and MW-PI = body mass × 5/MW time.

Results

At pre- and post-intervention, STS-PI was significantly correlated to MW-PI, with higher correlation coefficients (r = 0.545–0.567, P < 0.0001) than those between the two time scores (r = 0.271–0.309, P < 0.001). The intervention significantly improved STS-time (13.6 ± 3.2 s at pre to 9.4 ± 1.8 s at post, P < 0.0001), MW time (2.4 ± 0.3 s to 2.2 ± 0.3 s, P < 0.0001), STS-PI (46.5 ± 12.5 to 65.7 ± 12.7, P < 0.0001), and MW-PI (112.1 ± 20.2 to 124.2 ± 24.4, P < 0.0001). There were significant correlations between the changes of STS and MW times (r = 0.281, P < 0.001) and between those of STS-PI and MW-PI (r = 0.366, P < 0.0001).

Conclusion

In elderly women, the performance of sit-to-stand task and its training-induced gain are associated with those of the maximal walking task. In addition, the current results indicated that translation of the performance scores of the sit-to-stand and maximal walking tasks to power indexes may be a useful approach for examining the association between the two tasks.

Age- and Parkinson's disease-related evaluation of gait by General Tau Theory

The degeneration of postural control in the elderly and patients with Parkinson's disease (PD) can be debilitating and may lead to increased fall risk. This study evaluated the changes in postural control during gait affected by PD and aging using a new method based on the General Tau Theory. Fifteen patients with PD, 11 healthy old adults (HOs), and 15 healthy young adults (HYs) were recruited. Foot trajectories of each participant were monitored during walking by a three-camera Optotrak Certus(®) motion capture system. The anteroposterior direction of foot movement during stepping was analyzed by tau-G and tau-J guidance strategies. Two linear regression analyses suggested that the tau of the step-gap was strongly coupled onto the tau-J guidance during walking. The regression slope K could estimate the coupling ratio in the tau-coupling equation which reflects the performance of postural control during gait. The mean K value for the PD group, which was highest among the three groups, was approximately 0.5. Therefore, participants in the PD group walked with the poorest postural control and exhibited a relatively hard contact with the endpoint during stepping when compared with those in the HO and HY groups. The HY and HO groups obtained mean K values significantly lower than 0.5, which indicated that the gait was well controlled and ended at low speed with low deceleration. However, the HO group showed a decreased tendency for postural control, in which the mean K value was significantly higher than that of the HY group. The K value was moderately positively correlated with the double support time and negatively correlated with the stride length and walking speed. The tau-J coupling ratio can provide additional insight into gait disturbances and may serve as a reliable, objective, and quantitative tool to evaluate dynamic postural control during walking.

Determinants of Slow Walking Speed in Ambulatory Patients Undergoing Maintenance Hemodialysis

Walking ability is significantly lower in hemodialysis patients compared to healthy people. Decreased walking ability characterized by slow walking speed is associated with adverse clinical events, but determinants of decreased walking speed in hemodialysis patients are unknown. The purpose of this study was to identify factors associated with slow walking speed in ambulatory hemodialysis patients. Subjects were 122 outpatients (64 men, 58 women; mean age, 68 years) undergoing hemodialysis. Clinical characteristics including comorbidities, motor function (strength, flexibility, and balance), and maximum walking speed (MWS) were measured and compared across sex-specific tertiles of MWS. Univariate and multivariate logistic regression analyses were performed to examine whether clinical characteristics and motor function could discriminate between the lowest, middle, and highest tertiles of MWS. Significant and common factors that discriminated the lowest and highest tertiles of MWS from other categories were presence of cardiac disease (lowest: odds ratio [OR] = 3.33, 95% confidence interval [CI] = 1.26–8.83, P<0.05; highest: OR = 2.84, 95% CI = 1.18–6.84, P<0.05), leg strength (OR = 0.62, 95% CI = 0.40–0.95, P<0.05; OR = 0.57, 95% CI = 0.39–0.82, P<0.01), and standing balance (OR = 0.76, 95% CI = 0.63–0.92, P<0.01; OR = 0.81, 95% CI = 0.68–0.97, P<0.05). History of fracture (OR = 3.35, 95% CI = 1.08–10.38; P<0.05) was a significant factor only in the lowest tertile. Cardiac disease, history of fracture, decreased leg strength, and poor standing balance were independently associated with slow walking speed in ambulatory hemodialysis patients. These findings provide useful data for planning effective therapeutic regimens to prevent decreases in walking ability in ambulatory hemodialysis patients.

Physiology in Medicine: neuromuscular consequences of diabetic neuropathy

Diabetic polyneuropathy (DPN) refers to peripheral nerve dysfunction as a complication of diabetes mellitus. This condition is relatively common and is likely a result of vascular and/or metabolic disturbances related to diabetes. In the early or less severe stages of DPN it typically results in sensory impairments but can eventually lead to major dysfunction of the neuromuscular system. Some of these impairments may include muscle atrophy and weakness, slowing of muscle contraction, and loss of power and endurance. Combined with sensory deficits these changes in the motor system can contribute to decreased functional capacity, impaired mobility, altered gait, and increased fall risk. There is no pharmacological disease-modifying therapy available for DPN and the mainstay of treatment is linked to treating the diabetes itself and revolves around strict glycemic control. Exercise therapy (including aerobic, strength, or balance training-based exercise) appears to be a promising preventative and treatment strategy for patients with DPN and those at risk. The goal of this Physiology in Medicine article is to highlight important and overlooked dysfunction of the neuromuscular system as a result of DPN with an emphasis on the physiologic basis for that dysfunction. Additionally, we sought to provide information that clinicians can use when following patients with diabetes or DPN including support for the inclusion of exercise-based therapy as an effective, accessible, and inexpensive form of treatment.

The effects of dance training program on the postural stability of middle aged women

AIM

The aim of the study was to determine the effects of Greek folk dancing on postural stability in middle age women.

METHODS

Sixty-three women aged from 47-53 participated in this study. All participants were randomly divided into the experimental group - 33 participants (mean ± SD; body height=160.13 ± 12.07 cm, body mass=63.81 ± 10.56 kg), and the control group - 30 participants (mean ± SD; body height=160.63 ± 6.22 cm, body mass=64.79 ± 8.19 kg). The following tests were used to evaluate the motor balance and posture stability of participants; the double-leg stance along the length of a balance beam (eyes open), the double-leg stance along the width of a balance beam (eyes open), the single-leg stance (eyes open) and the double-leg stance on one's toes (eyes closed). The Functional Reach Test for balance and the Star Excursion Balance Test were used to evaluate dynamic balance.

RESULTS

The multivariate analysis of covariance of static and dynamic balance between participants of the experimental and control group at the final measuring, with neutralized differences at the initial measuring (Wilks' λ=0.45), revealed a significant difference (p<0.05). The intergroup difference at the final measuring was also found to be significant (p<0.05) for the following variables; the double-leg stance on one's toes, the Functional Reach Test, balance of the right anterolateral, balance of the right posterolateral and balance of the left posteromedial.

CONCLUSION

An organized dance activity programme does lead to the improvement of static and dynamic balance in middle aged women.

Interactive balance training integrating sensor-based visual feedback of movement performance: a pilot study in older adults

Background

Wearable sensor technology can accurately measure body motion and provide incentive feedback during exercising. The aim of this pilot study was to evaluate the effectiveness and user experience of a balance training program in older adults integrating data from wearable sensors into a human-computer interface designed for interactive training.

Methods

Senior living community residents (mean age 84.6) with confirmed fall risk were randomized to an intervention (IG, n = 17) or control group (CG, n = 16). The IG underwent 4 weeks (twice a week) of balance training including weight shifting and virtual obstacle crossing tasks with visual/auditory real-time joint movement feedback using wearable sensors. The CG received no intervention. Outcome measures included changes in center of mass (CoM) sway, ankle and hip joint sway measured during eyes open (EO) and eyes closed (EC) balance test at baseline and post-intervention. Ankle-hip postural coordination was quantified by a reciprocal compensatory index (RCI). Physical performance was quantified by the Alternate-Step-Test (AST), Timed-up-and-go (TUG), and gait assessment. User experience was measured by a standardized questionnaire.

Results

After the intervention sway of CoM, hip, and ankle were reduced in the IG compared to the CG during both EO and EC condition (p = .007-.042). Improvement was obtained for AST (p = .037), TUG (p = .024), fast gait speed (p = . 010), but not normal gait speed (p = .264). Effect sizes were moderate for all outcomes. RCI did not change significantly. Users expressed a positive training experience including fun, safety, and helpfulness of sensor-feedback.

Conclusions

Results of this proof-of-concept study suggest that older adults at risk of falling can benefit from the balance training program. Study findings may help to inform future exercise interventions integrating wearable sensors for guided game-based training in home- and community environments. Future studies should evaluate the added value of the proposed sensor-based training paradigm compared to traditional balance training programs and commercial exergames.

Trial registration

http://www.clinicaltrials.govNCT02043834.

Electronic supplementary material

The online version of this article (doi:10.1186/1743-0003-11-164) contains supplementary material, which is available to authorized users.

Measures of static postural control moderate the association of strength and power with functional dynamic balance

BACKGROUND AND AIMS

Age-related reductions in strength and power are considered to negatively impact balance control, but the existence of a direct association is still an issue of debate. This is possibly due to the fact that balance assessment is complex, reflects different underlying physiologic mechanisms and involves quantitative measurements of postural sway or timing of performance during balance tasks. The present study evaluated the moderator effect of static postural control on the association of power and strength with dynamic balance tasks.

METHODS

Fifty-seven healthy 65-75 year old individuals performed tests of dynamic functional balance (walking speed under different conditions) and of strength, power and static postural control.

RESULTS AND CONCLUSIONS

Dynamic balance performance (walking speed) was associated with lower limb strength and power, as well as postural control under conditions requiring postural adjustments (narrow surface walking r(2) = 0.31, p < 0.001). An interaction effect between strength and static postural control was found with narrow surface walking and talking while walking (change of β 0.980, p < 0.001 in strength for 1 SD improvements in static postural control for narrow walking, and [Formula: see text] -0.730, p < 0.01 in talking while walking). These results indicate that good static postural control facilitates the utilisation of lower limb strength to better perform complex, dynamic functional balance tasks. Practical implications for assessment and training are discussed.

Muscle strength rather than muscle mass is associated with standing balance in elderly outpatients

OBJECTIVES

Assessment of the association of muscle characteristics with standing balance is of special interest, as muscles are a target for potential intervention (ie, by strength training).

DESIGN

Cross-sectional study.

SETTING

Geriatric outpatient clinic.

PARTICIPANTS

The study included 197 community-dwelling elderly outpatients (78 men, 119 women; mean age 82 years).

MEASUREMENTS

Muscle characteristics included handgrip and knee extension strength, appendicular lean mass divided by height squared (ALM/height(2)), and lean mass as percentage of body mass. Two aspects of standing balance were assessed: the ability to maintain balance, and the quality of balance measured by Center of Pressure (CoP) movement during 10 seconds of side-by-side, semitandem, and tandem stance, with both eyes open and eyes closed. Logistic and linear regression models were adjusted for age, and additionally for height, body mass, cognitive function, and multimorbidity.

RESULTS

Handgrip and knee extension strength, adjusted for age, were positively related to the ability to maintain balance with eyes open in side-by-side (P = .011; P = .043), semitandem (P = .005; P = .021), and tandem stance (P = .012; P = .014), and with eyes closed in side-by-side (P = .004; P = .004) and semitandem stance (not significant; P = .046). Additional adjustments affected the results only slightly. ALM/height(2) and lean mass percentage were not associated with the ability to maintain standing balance, except for an association between ALM/height(2) and tandem stance with eyes open (P = .033) that disappeared after additional adjustments. Muscle characteristics were not associated with CoP movement.

CONCLUSION

Muscle strength rather than muscle mass was positively associated with the ability to maintain standing balance in elderly outpatients. Assessment of CoP movement was not of additional value.

Promoção da saúde e prevenção de incapacidades funcionais dos idosos na estratégia de saúde da família: a contribuição da fisioterapia

A procura de idosos por serviços de saúde costuma ocorrer quando estes são acometidos por limitações importantes e/ou necessitam de assistência devido à redução da força muscular e a incapacidades funcionais. Tal momento é fundamental para que profissionais da saúde, particularmente fisioterapeutas, amenizem o enfraquecimento muscular e reduzam as incapacidades e dependências. O presente artigo expõe ações de promoção da saúde e prevenção das incapacidades funcionais na terceira idade para que as equipes de saúde da família possam estimular os idosos a mudarem seus hábitos e viverem suas vidas com melhor qualidade. Espera contribuir para a incorporação das práticas fisioterapêuticas entre as equipes de saúde.

Pilot Randomized Controlled Trial: Elastic-Resistance-Training and Lifestyle-Activity Intervention for Sedentary Older Adults

The aim of this study was to determine the efficacy and feasibility of a resistancetraining (RT) and lifestyle-activity program for sedentary older adults. Eligible participants (N= 44) were randomized to an 8-wk intervention or a control group. The primary outcome was lower body muscle strength, and participants completed a range of secondary outcomes. There was a significant group-by-time interaction for lower body muscle strength (difference = 3.9 repetitions [reps], 95% CI = 2.0–5.8 reps;p< .001;d= 1.0). Changes in secondary outcomes were generally small and not statistically significant. Attendance and program satisfaction were both high. A combined elastic-tubing RT and lifestyle-activity program delivered in the community setting is an efficacious and feasible approach to improve health in sedentary older adults.

Effects of Multicomponent Exercise Training on Physical Functioning among Institutionalized Elderly

This quasiexperimental study aimed to measure the effects of 12-week multicomponent exercise training on physical functioning among institutionalized elderly. Forty-three participants (age = 70.88 ± 7.82 years) were self-assigned to an intervention (n=23) or control (n=20) group. Before and after training, cardiorespiratory endurance, arm curl strength, grip strength, lower limb strength, upper and lower limb flexibility, balance, and mobility were assessed. The training included aerobic, resistance, balance and flexibility exercises, performed 3 times per week. Significant increases (P<0.05) were observed in the exercise group on cardiorespiratory endurance (41.79%), right arm curl strength (25%), left arm curl strength (30.79%), right hand grip strength (13.65%), left hand grip strength (9.93%), lower limb strength (46.19%), balance (49.58%), and mobility (26.37%). Measures of flexibility in the exercise group also showed improvement (right lower limb (63.57%), left lower limb (44.17%), right upper limb (36.67%), and left upper limb (63.1%)) but were not statistically significant (all, P>0.05). The control group did not show any significant changes (P>0.05) in any variables. The data suggested that 12-week multicomponent exercise training may improve physical functioning among institutionalized elderly.

The effect of growth hormone treatment or physical training on motor performance in Prader-Willi syndrome: a systematic review

Although motor problems in Prader-Willi syndrome (PWS) are prominent in infants, and continue into childhood and adulthood, there is little insight into the factors important for clinical management. The literature was reviewed to: (1) provide an overview of the characteristics and prevalence of motor problems and (2) evaluate the effects of growth hormone (GH) treatment and physical training on motor performance. A systematic search revealed 34 papers: 13 on motor performance; 12 on GH treatment; and nine on physical training. In infants, motor development is 30-57% of the normal reference values, and children and adults also have significant problems in skill acquisition, muscle force, cardiovascular fitness, and activity level. GH treatment positively influenced motor performance in infants, children, and adults, although not all studies demonstrated an effect. All studies on physical training demonstrated beneficial effects in PWS patients. We suggest a combination of GH treatment and physical training to be started as soon as possible, especially in infants, to improve motor development as this will positively influence general development.

A qualitative review of balance and strength performance in healthy older adults: impact for testing and training

A continuously greying society is confronted with specific age-related health problems (e.g., increased fall incidence/injury rate) that threaten both the quality of life of fall-prone individuals as well as the long-term sustainability of the public health care system due to high treatment costs of fall-related injuries (e.g., femoral neck fracture). Thus, intense research efforts are needed from interdisciplinary fields (e.g., geriatrics, neurology, and exercise science) to (a) elucidate neuromuscular fall-risk factors, (b) develop and apply adequate fall-risk assessment tools that can be administered in clinical practice, and (c) develop and design effective intervention programs that have the potential to counteract a large number of fall-risk factors by ultimately reducing the number of falls in the healthy elderly. This paper makes an effort to present the above-raised research topics in order to provide clinicians, therapists, and practitioners with the current state-of-the-art information.

Factors associated with maximal walking speed among older community-living adults

BACKGROUND AND AIMS

The relative contribution of different domains on walking speed is largely unknown. This study investigated the central factors associated with maximal walking speed among older people.

METHODS

Cross-sectional analyses of baseline data from the SCAMOB study (ISRCTN 07330512) involving 605 community-living ambulatory adults aged 75-81 years. Maximal walking speed, leg extensor power, standing balance and body mass index were measured at the research center. Physical activity, smoking, use of alcohol, chronic diseases and depressive symptoms were self-reported by standard questionnaires.

RESULTS

The mean maximal walking speed was 1.4 m/s (range 0.3-2.9). In linear regression analysis, age, gender and body mass index explained 11% of the variation in maximal walking speed. Adding leg extensor power and standing balance into the model increased the variation explained to 38%. Further adjusting for physical activity, smoking status and use of alcohol increased the variation explained by an additional 7%. A minor further increase in variability explained was gained by adding chronic diseases and depressive symptoms to the model. In the final model, the single most important factors associated with walking speed were leg extensor power, standing balance and physical activity, and these associations were similar in men and women and in different body mass index categories.

CONCLUSIONS

Lower extremity impairment and physical inactivity were the central factors associated with slow walking speed among older people, probably because these factors capture the influences of health changes and other life-style factors, potentially leading to walking limitations.

Is leg muscle strength correlated with functional balance and mobility among inpatients in geriatric rehabilitation?

Determinants of functional balance and mobility have rarely been investigated in geriatric wards. This study examined if leg muscle strength correlates to functional balance and mobility among geriatric inpatients. Fifty inpatients, 29 women and 21 men (mean age 79.6 years) were included. Functional balance was assessed with the Berg Balance Scale (BBS) and mobility was assessed with the Physiotherapy Clinical Outcome Variable Scale (COVS). Strength in the leg extension muscles was measured as 1 Repetition Maximum (1RM) in a leg press and strength in the ankle muscles was measured with Medical Research Council grades (MRC, 0-5). The sum scores, and most of the single items, of the BBS and the COVS significantly correlated to 1RM/body weight, ankle dorsiflexion, and plantar flexion. In a stepwise multiple regression, ankle dorsiflexion and 1RM/body weight together accounted for 39% of the variance of the BBS and 41% of the variance of the COVS. Estimated values of the BBS and the COVS can be calculated from the equation. In clinical work, the knowledge about how leg muscle strength associates with balance and mobility may be useful in analyzing underlying causes of reduced balance and mobility function, and in planning rehabilitation programs.

Hand-grip strength cut points to screen older persons at risk for mobility limitation

OBJECTIVES

To determine optimal hand-grip strength cut points for likelihood of mobility limitation in older people and to study whether these cut points differ according to body mass index (BMI).

DESIGN

Cross-sectional analysis of data.

SETTING

Data collected in the Finnish population-based Health 2000 Survey.

PARTICIPANTS

One thousand eighty-four men and 1,562 women aged 55 and older with complete data on anthropometry, hand-grip strength and self-reported mobility.

MEASUREMENTS

Mobility limitation was defined as difficulty walking 0.5 km or climbing stairs. Receiver operating characteristic analysis was used to estimate hand-grip strength cut points for likelihood of mobility limitation.

RESULTS

The overall hand-grip strength cut points for likelihood of mobility limitation were 37 kg (sensitivity 62%; specificity 76%) for men and 21 kg (sensitivity 67%; specificity 73%) for women. The effect of the interaction between hand-grip strength and BMI on mobility limitation was significant in men (P=.02), but no such interaction was observed in women (P=.16). In men, the most-optimal cutoff points were 33 kg (sensitivity 73%; specificity 79%) for normal-weight men, 39 kg (sensitivity 67%; specificity 71%) for overweight men, and 40 kg (sensitivity 57%; specificity 68%) for obese men. In women, BMI-specific hand-grip strength cutoff values was not markedly more accurate than the overall cutoff value.

CONCLUSION

The hand-grip strength test is a useful tool to identify persons at risk of mobility limitation. In men, hand-grip strength cut points for mobility increased with BMI, whereas in women, only one hand-grip strength threshold was identified.

Force production capacity and functional reflex activity in young and elderly men

BACKGROUND AND AIMS

There is growing evidence that biological aging results in impaired force production of the lower extremities and deficits in reflex activity. This study therefore investigated maximal and explosive force production capacity, functional reflex activity (FRA) during gait perturbations, and the relationship between variables of force production capacity and FRA in young and elderly men.

METHODS

Twenty-eight young (age 27±3 yrs, n=14) and old (age 67±4 yrs, n=14) healthy active men were tested for decelerating impulses on a treadmill and for their maximal isometric leg extension force (MIF) and rate of force development (RFD) on a leg-press.

RESULTS

MIF and RFD were significantly lower in the elderly than in younger participants (MIF ~45%, p<0.01; RFD ~50%, p<0.01). Elderly subjects showed significant decreases in FRA in the prime mover which compensated for the decelerating impulse (FRA ~29%, p<0.05). No significant correlations were found between FRA, MIF or RFD.

CONCLUSIONS

Lower MIF, RFD and impaired FRA were found in old compared with young men. The absence of significant correlations between measures of strength performance and FRA may indicate that different mechanisms within the neuromuscular system are responsible for these capacities. This result may imply that force production and functional reflex activity are independent of each other and may have to be trained complementarily.