Strength, power, and postural control in seniors: Considerations for functional adaptations and for fall prevention

The automatic activity of abdominal muscles during stable and unstable standing postural tasks in older adults with and without low back pain- A cross-sectional study

BACKGROUND

The postural control and abdominal muscles' automatic activity were found to be impaired in subjects with low back pain (LBP) during static activities. However, the studies are predominantly conducted on younger adults and a limited number of studies have evaluated abdominal muscles' automatic activity during dynamic standing activities in subjects with LBP. The present study investigated the automatic activity of abdominal muscles during stable and unstable standing postural tasks in older adults with and without LBP.

METHODS

Twenty subjects with and 20 subjects without LBP were included. The thickness of the transversus abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles was measured during rest (in supine), static, and dynamic standing postural tasks. To estimate automatic muscle activity, each muscle's thickness during a standing task was normalized to its thickness during the rest. Standing postural tasks were performed using the Biodex Balance System.

RESULTS

The mixed-model analysis of variance revealed that task dynamicity significantly affected thickness change only in the TrA muscle (P = 0.02), but the main effect for the group and the interaction were not significantly different (P > 0.05). There were no significant main effects of the group, task dynamicity, or their interaction for the IO and EO muscles (P > 0.05). During dynamic standing, only the TrA muscle in the control group showed greater thickness changes than during the static standing task (P < 0.05).

CONCLUSIONS

Standing on a dynamic level increased the automatic activity of the TrA muscle in participants without LBP compared to standing on a static level. Further research is required to investigate the effects of TrA muscle training during standing on dynamic surfaces for the treatment of older adults with LBP.

Neural Correlates of Balance Skill Learning in Young and Older Individuals: A Systematic Review and Meta-analysis

BACKGROUND

Despite the increasing number of research studies examining the effects of age on the control of posture, the number of annual fall-related injuries and deaths continues to increase. A better understanding of how old age affects the neural mechanisms of postural control and how countermeasures such as balance training could improve the neural control of posture to reduce falls in older individuals is therefore necessary. The aim of this review is to determine the effects of age on the neural correlates of balance skill learning measured during static (standing) and dynamic (walking) balance tasks in healthy individuals.

METHODS

We determined the effects of acute (1-3 sessions) and chronic (> 3 sessions) balance skill training on balance in the trained and in untrained, transfer balance tasks through a systematic review and quantified these effects by robust variance estimation meta-analysis in combination with meta-regression. We systematically searched PubMed, Web of Science, and Cochrane databases. Balance performance and neural plasticity outcomes were extracted and included in the systematic synthesis and meta-analysis.

RESULTS

Forty-two studies (n = 622 young, n = 699 older individuals) were included in the systematic synthesis. Seventeen studies with 508 in-analysis participants were eligible for a meta-analysis. The overall analysis revealed that acute and chronic balance training had a large effect on the neural correlates of balance skill learning in the two age groups combined (g = 0.79, p < 0.01). Both age groups similarly improved balance skill performance in 1-3 training sessions and showed little further improvements with additional sessions. Improvements in balance performance mainly occurred in the trained and less so in the non-trained (i.e., transfer) balance tasks. The systematic synthesis and meta-analysis suggested little correspondence between improved balance skills and changes in spinal, cortical, and corticospinal excitability measures in the two age groups and between the time courses of changes in balance skills and neural correlates.

CONCLUSIONS

Balance skill learning and the accompanying neural adaptations occur rapidly and independently of age with little to no training dose-dependence or correspondence between behavioral and neural adaptations. Of the five types of neural correlates examined, changes in only spinal excitability seemed to differ between age groups. However, age or training dose in terms of duration did not moderate the effects of balance training on the changes in any of the neural correlates. The behavioral and neural mechanisms of strong task-specificity and the time course of skill retention remain unclear and require further studies in young and older individuals.

REGISTRATION

PROSPERO registration number: CRD42022349573.

Effects of Resistance Training with Blood Flow Restriction on Explosive Power of Lower Limbs: A Systematic Review and Meta-Analysis

The purpose of this systematic review and meta-analysis was to compare changes in explosive power between blood flow restriction training and traditional resistance training protocols. Searches of PubMed, Scopus, Web of Science, and OVID Medline were conducted for studies. Inclusion criteria were: (a) healthy people; (b) randomized controlled or controlled trials; (c) outcome measures of explosive performance (peak power, rate of force development, jump performance, sprint performance, etc.); (d) involving a comparison between blood flow restriction training and traditional resistance training. Quality assessment was conducted using the Physiotherapy Evidence Database (PEDro) scale. A total of 12 studies (262 subjects) were finally included for analysis. The PEDro scale score had a median of 5 of 10 points (range: 3-6 points). Significant small to moderate improvements were observed in blood flow restriction training [jump: standard mean difference (SMD) of 0.36 (95% CI: 0.02; 0.69); sprint: SMD of 0.54 (95% CI: 0.00; 1.07); power: SMD of 0.72 (95% CI: 0.17; 1.27)] when compared to traditional resistance training. The findings indicate that blood flow restriction training is more effective in improving explosive power of lower limbs compared to traditional resistance training in healthy people. In addition, blood flow restriction with a wide cuff (≥ 10 cm) during training improved explosive power better than with a narrow cuff or during the rest interval. Blood flow restriction training is very suitable for athletes in short competitive seasons and those who are not able to tolerate high loads (i.e., rehabilitators and the elderly).

Spatiotemporal characteristics of lower back muscle fatigue during a ten minutes endurance test at 50% upper body weight in healthy inactive, endurance, and strength trained subjects

In modern developed societies, heavy physical demands are decreasing and getting replaced by longer periods of static, low-exertion activities such as sitting or standing. To counteract this lack of physical activity, more and more people are engaging in physical activity through exercise and training. Virtually opposite training modalities are endurance and strength. We asked if back muscle endurance capacity is influenced by training mode. 38 healthy male subjects (age range 19–31 years, mean age 22.6 years) were investigated: sedentary (Control, n = 12), endurance trained (ET, n = 13), and strength trained participants (ST, n = 13). They underwent a ten-minutes isometric extension task at 50% of their upper body weight. Surface EMG was measured in the low-back region utilizing quadratic 4*4 monopolar electrode montages per side. Relative amplitude and mean frequency changes were analysed with respect to electrode position and group during the endurance task. Eight ST subjects failed to complete the endurance task. Relative amplitude and frequency changes were largest in the ST group, followed by Control and ET groups (amplitude: F 6.389, p 0.004, frequency: F 11.741, p<0.001). Further, independent of group largest amplitude increase was observed for the most upper and laterally positioned electrodes. Mean frequency changes showed no systematic spatial distribution pattern. Although, in the light of an aging population, strength training has its merits our results question the functional suitability of frequent and isolated high-impact strength training for everyday endurance requirements like doing the dishes. Fatigue related amplitude elevations are systematically distributed in the back region, showing least fatigue signs for the most caudal and medial, i.e. the lumbar paravertebral region.

Norm Values of Muscular Strength Across the Life Span in a Healthy Swiss Population: The COmPLETE Study

BACKGROUND

Grip strength is used to estimate whole-body strength for health surveillance purposes. Explosive strength is considered important, yet economic measures able to detect early deterioration of neuromuscular capabilities are lacking. Whether handgrip maximum rate of force development (GRFD) or whole-body strength tests are better predictors of lower body power than handgrip maximum strength (GF_max) and their trajectories throughout the life span are unknown.

HYPOTHESIS

GRFD should be more closely related to lower body power than GF_max, and its trajectories over the life span should more closely follow that of lower body power.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 2b.

METHODS

A total of 613 healthy participants aged 20 to 91 years were tested for countermovement jump peak power, GF_max, handgrip rate of force development, and midthigh pull peak force (MTP). Cubic splines and linear models were built for age trajectories, generalized additive models for quintile curves, and linear regression was used to assess predictive quality.

RESULTS

Peak power (P_max) declined linearly to 60% of young adult level, with GRFD, GF_max, and MTP remaining stable up to age 50 years and then declining more sharply to 52% to 71% of young adult levels. Trajectories were similar for male and female participants. GRFD (β = 0.17) and MTP (β = 0.08) were worse predictors of P_max than GF_max (β = 0.24) in models adjusted for age, sex, lean body mass, and vigorous physical activity levels.

CONCLUSION

GRFD was not superior to maximum strength in predicting lower body power. For health surveillance purposes, it therefore appears that GF_max tests are more economical and equally good predictors of lower body explosive strength at older age. The data provided can be used as norm values for healthy subjects.

CLINICAL RELEVANCE

Incorporating countermovement jump testing for early detection of declines in explosive capabilities might be advised.

Static Postural Control Deficits in Adults with Myotonic Dystrophy Type 1, Steinert Disease

BACKGROUND

Myotonic dystrophy type 1 (DM1) is characterized by progressive and predominantly distal muscle atrophy and myotonia. Gait and balance impairments, resulting in falls, are frequently reported in this population. However, the extent to which individuals with DM1 rely more on a specific sensory system for balance than asymptomatic individuals (AI) is unknown.

OBJECTIVE

Evaluate postural control performance in individuals with DM1 and its dependence on vision compared to AI.

METHODS

20 participants with DM1, divided into two groups based on their diagnosis, i.e. adult and congenital phenotype, and 12 AI participants were recruited. Quiet standing postural control was assessed in two visual conditions: eyes-open and eyes-closed. The outcomes measures were center of pressure (CoP) mean velocity, CoP range of displacement in anteroposterior and mediolateral axis, and the 95% confidence ellipse's surface. Friedman and Kruskal-Wallis analysis of variance were used to compare outcomes between conditions and groups, respectively.

RESULTS

Significant group effect and condition effect were observed on postural control performance. No significant difference was observed between the two DM1 groups. The significant differences observed between the AI group and the two DM1 groups in the eyes-open condition were also observed in the eyes-closed condition.

CONCLUSIONS

The result revealed poorer postural control performance in people with DM1 compared to AI. The DM1 group also showed similar decrease in performance than AI in eyes-closed condition, suggesting no excessive visual dependency.

Relationship of proprioception, cutaneous sensitivity, and muscle strength with the balance control among older adults

BACKGROUND

Balance impairment is one of the strongest risk factors for falls. Proprioception, cutaneous sensitivity, and muscle strength are 3 important contributors to balance control in older adults. The relationship that dynamic and static balance control has to proprioception, cutaneous sensitivity, and muscle strength is still unclear. This study was performed to investigate the relationship these contributors have to dynamic and static balance control.

METHODS

A total of 164 older adults (female = 89, left dominant = 15, age: 73.5 ± 7.8 years, height: 161.6 ± 7.1 cm, weight: 63.7 ± 8.9 kg, mean ± SD) participated in this study. It tested the proprioception of their knee flexion/extension and ankle dorsi/plantarflexion, along with cutaneous sensitivity at the great toe, first and fifth metatarsals, arch, and heel, and the muscle strength of their ankle dorsi/plantarflexion and hip abduction. The Berg Balance Scale (BBS) and the root mean square (RMS) of the center of pressure (CoP) were collected as indications of dynamic and static balance control. A partial correlation was used to determine the relationship between the measured outcomes variables (BBS and CoP-RMS) and the proprioception, cutaneous sensitivity, and muscle strength variables.

RESULTS

Proprioception of ankle plantarflexion (r = -0.306, p = 0.002) and dorsiflexion (r = -0.217, p = 0.030), and muscle strength of ankle plantarflexion (r = 0.275, p = 0.004), dorsiflexion (r = 0.369, p < 0.001), and hip abduction (r = 0.342, p < 0.001) were weakly to moderately correlated with BBS. Proprioception of ankle dorsiflexion (r = 0.218, p = 0.020) and cutaneous sensitivity at the great toe (r = 0.231, p = 0.041) and arch (r = 0.285, p = 0.002) were weakly correlated with CoP-RMS in the anteroposterior direction. Proprioception of ankle dorsiflexion (r = 0.220, p = 0.035), knee flexion (r = 0.308, p = 0.001) and extension (r = 0.193, p = 0.040), and cutaneous sensitivity at the arch (r = 0.206, p = 0.028) were weakly to moderately correlated with CoP-RMS in the mediolateral direction.

CONCLUSION

There is a weak-to-moderate relationship between proprioception and dynamic and static balance control, a weak relationship between cutaneous sensitivity and static balance control, and a weak-to-moderate relationship between muscle strength and dynamic balance control.

Delayed functional therapy after acute lateral ankle sprain increases subjective ankle instability - the later, the worse: a retrospective analysis

Background

The lateral ankle sprain (LAS) is one of the most common injuries in everyday and sports activities. Approximately 20–40 % of patients with LAS develop a chronic ankle instability (CAI). The underlying mechanisms for CAI have not yet been clearly clarified. An inadequate rehabilitation after LAS can be speculated, since the LAS is often handled as a minor injury demanding less treatment. Therefore, the aims of this retrospective study were to determine the CAI rate depending on age and sex and to identify possible determinants for developing CAI.

Methods

Between 2015 and 2018 we applied the diagnostic code “sprain of ankle” (ICD S93.4) to identify relevant cases from the database of the BG Klinikum Duisburg, Germany. Patients received a questionnaire containing the Tegner-Score, the Cumberland Ankle Instability Tool (CAIT) and the Foot and Ankle Disability Index. Additionally, there were questions about the modality and beginning of therapy following LAS and the number of recurrent sprains. There was a total of 647 completed datasets. These were divided into a CAI and non-CAI group according to a CAIT cut-off-score with CAI ≤ 24 and non-CAI > 24 points, representing one out of three criteria for having CAI based on international consensus.

Results

The overall CAI rate was 17.3 %. We identified a higher CAI rate in females and within the age segment of 41 to 55 years. A later start of therapy (> 4 weeks) after acute LAS significantly increases ankle instability in CAIT (p < .05). There was a significantly higher CAIT score in patients having no recurrent sprain compared to patients having 1–3 recurrent sprains or 4–5 recurrent sprains (p < .001).

Conclusions

Females over 41 years show a higher CAI rate which implies to perform specific prevention programs improving ankle function following acute LAS. A delayed start of therapy seems to be an important determinant associated with the development of CAI. Another contributing factor may be a frequent number of recurrent sprains that are also linked to greater levels of subjective ankle instability. Therefore, we would recommend an early start of functional therapy after acute LAS in the future to minimize the development of CAI.

Linking objective measures of physical activity and capability with brain structure in healthy community dwelling older adults

Maintaining high levels of daily activity and physical capability have been proposed as important constituents to promote healthy brain and cognitive aging. Studies investigating the associations between brain health and physical activity in late life have, however, mainly been based on self-reported data or measures designed for clinical populations. In the current study, we examined cross-sectional associations between physical activity, recorded by an ankle-positioned accelerometer for seven days, physical capability (grip strength, postural control, and walking speed), and neuroimaging based surrogate markers of brain health in 122 healthy older adults aged 65-88 years. We used a multimodal brain imaging approach offering complementary structural MRI based indicators of brain health: global white matter fractional anisotropy (FA) and mean diffusivity (MD) based on diffusion tensor imaging, and subcortical and global brain age based on brain morphology inferred from T1-weighted MRI data. In addition, based on the results from the main analysis, follow-up regression analysis was performed to test for association between the volume of key subcortical regions of interest (hippocampus, caudate, thalamus and cerebellum) and daily steps, and a follow-up voxelwise analysis to test for associations between walking speed and FA across the white matter Tract-Based Spatial Statistics (TBSS) skeleton. The analyses revealed a significant association between global FA and walking speed, indicating higher white matter integrity in people with higher pace. Voxelwise analysis supported widespread significant associations. We also found a significant interaction between sex and subcortical brain age on number of daily steps, indicating younger-appearing brains in more physically active women, with no significant associations among men. These results provide insight into the intricate associations between different measures of brain and physical health in old age, and corroborate established public health advice promoting physical activity.

Aging Affects Lower Limb Joint Moments and Muscle Responses to a Split-Belt Treadmill Perturbation

Age-related changes cause more fall-related injuries and impede the recoveries by older adults compared to younger adults. This study assessed the lower limb joint moments and muscle responses to split-belt treadmill perturbations in two groups (14 healthy young group [23.36 ± 2.90 years] and 14 healthy older group [70.93 ± 4.36 years]) who performed two trials of unexpected split-belt treadmill perturbations while walking on a programmable split-belt treadmill. A motion capture system quantified the lower limb joint moments, and a wireless electromyography system recorded the lower limb muscle responses. The compensatory limb's (i.e., the tripped limb's contralateral side) joint moments and muscle responses were computed during the pre-perturbation period (the five gait cycles before the onset of a split-belt treadmill perturbation) and the recovery period (from the split-belt treadmill perturbation to the baseline gait relying on the ground reaction forces' profile). Joint moments were assessed by maximum joint moments, and muscle responses were quantified by the normalization (%) and co-contraction index (CCI). Joint moments and muscle responses of the compensatory limb during the recovery period were significantly higher for the YG than the OG, and joint moments (e.g., knee flexion and extension and hip flexion moments) and muscle responses during the recovery period were higher compared to the pre-perturbation period for both groups. For CCI, the older group showed significantly higher co-contraction for biceps femoris/rectus femoris muscles than the young group during the recovery period. For both groups, co-contraction for biceps femoris/rectus femoris muscles was higher during the pre-perturbation period than the recovery period. The study confirmed that older adults compensated for muscle weakness by using lower joint moments and muscle activations and increasing muscle co-contractions to recover balance after split-belt treadmill perturbations. A better understanding of the recovery mechanisms of older adults who train on fall-inducing systems could improve therapeutic regimens.

Reliability and Validity of the Sit-to-Stand as a Muscular Power Measure in Older Adults

The study aims were to analyze the reliability and validity of the GymAware™ linear position transducer's velocity and power measures during the sit-to-stand, compared with the Dartfish 2D videography analysis, and to assess the relationship of age and handgrip strength with velocity and power in 48 older men and women (77.6 ± 11.1 years). The results showed excellent agreement between GymAware- and Dartfish-derived sit-to-stand velocity (intraclass correlation coefficient2-1 = .94 and power intraclass correlation coefficient2-1 = .98) measures. A moderate and negative relationship was found between age and velocity (r = -.62; p < .001) and age and power (r = -.63; p < .001). A moderate and positive relationship was found between handgrip strength and velocity (r = .43; p = .002) and handgrip strength and power (r = .54; p < .001). The results show the GymAware velocity and power measures during the sit-to-stand in older adults to be reliable and valid.

Gait Speed Characteristics and Their Spatiotemporal Determinants in Nursing Home Residents: A Cross-Sectional Study

BACKGROUND AND PURPOSE

Low and slowing gait speeds among nursing home residents are linked to a higher risk of disability, cognitive impairment, falls, and mortality. A better understanding of the spatiotemporal parameters of gait that influence declining mobility could lead to effective rehabilitation and preventative intervention. The aims of this study were to objectively quantify the spatiotemporal characteristics of gait in the nursing home setting and define the relationship between these parameters and gait speed.

METHODS

One hundred nursing home residents were enrolled into the study and completed 3 habitual gait speed trials over a distance of 3.66 m. Trials were performed using an instrumented gait analysis. The manner in which the spatiotemporal parameters predicted gait speed was examined by univariate and multivariable regression modeling.

RESULTS

The nursing home residents had a habitual mean (SD) gait speed of 0.63 (0.19) m/s, a stride length of 0.83 (0.15) m, a support base of 0.15 (0.06) m, and step time of 0.66 (0.12) seconds. Multivariable linear regression revealed stride length, support base, and step time predicted gait speed (R = 0.89, P < .05). Step time had the greatest influence on gait speed, with each 0.1-second decrease in step time resulting in a 0.09 m/s (95% confidence interval, 0.08-0.10) increase in habitual gait speed.

CONCLUSIONS

This study revealed step time, stride length, and support base are the strongest predictors of gait speed among nursing home residents. Future research should concentrate on developing and evaluating intervention programs that were specifically designed to focus on the strong predictors of gait speed in nursing home residents. We would also suggest that routine assessments of gait speed, and if possible their spatiotemporal characteristics, be done on all nursing home residents in an attempt to identify residents with low or slowing gait speed.

Association between trunk muscle strength and static balance in older women

The aim of this study was to determine the relationship between trunk muscle strength and balance ability in both simple and dual-task conditions in older women. Sixty-seven older women (age: 67.2 ± 1.1 years) volunteered in this study. Each participant performed isometric trunk muscle strength testing in standing position (extension, flexion, and lateral flexion) and balance testing in semitandem stance for 30 seconds in two conditions: with and without an additional cognitive task (counting down by 3 from 300). Balance was quantified via force plate as a mean velocity of center of pressure (CoP) displacement over 30 seconds. We found a statistically significant correlation between the trunk extensor strength and mean velocity of CoP displacement, both without (r = 0.5, p < .05) and with an additional cognitive task (r = 0.4, p < .05). There were no statistically significant correlations between trunk flexor and lateral flexors strength and balance measures (r < 0.2; p > .05). These results indicate that trunk extensor muscle strength is related to balance ability of healthy older women. Although additional studies are needed, our findings suggest that trunk strength training could be of importance in prevention of falls and fall-related injuries in seniors.

Walking meditation promotes ankle proprioception and balance performance among elderly women

BACKGROUND

Age-related change of proprioception affects body balance among the elderly. Walking meditation (WM)-a mindfulness practice-involves focusing on leg movements while walking slowly, possibly improving brain processes for perception and balance adjustments. This study investigates the WM's effects on ankle proprioception and balance among the elderly.

METHODS

Fifty-eight women aged 69.25 ± 6.06 were randomized into control (n = 29) and WM (n = 29) groups. The WM group engaged in 8 weeks of WM practice (30 min/day, 3 days/week). The absolute angular error of the ankle reposition test (AAE) was measured by an electrogoniometer. The balance performance was evaluated using the Berg Balance Scale (BBS), Functional Reach Test (FRT), and Timed Up and Go test (TUG). Data were analyzed using two-way ANOVA and Bonferroni post hoc test and BBS with nonparametric statistics.

RESULTS

At baseline, the WM group's AAE, BBS, FRT, and TUG were 4.2 ± 1.6°, 51.3 ± 4.1 points, 21.7 ± 5.7 cm, and 11.1 ± 2.5 s, respectively, whereas those of the control group were 3.6 ± 2.0°, 51.0 ± 5.0 points, 21.6 ± 5.2 cm, and 10.2 ± 3.1 s, respectively. Post-training, WM group showed significant decrease in AAE (2.4 ± 0.9°) and displayed improvements in BBS, FRT, and TUG (55.4 ± 0.9 points, 29.1 ± 5.8 cm, and 8.1 ± 1.1 s, respectively) (p < 0.01). Conversely, the control group presented no change in AAE, significant decreases in BBS and FRT, and slower TUG (p < 0.01). No difference was found between WM and control groups at the baseline. However, post-training, WM group demonstrated significant improvements in AAE, BBS, FRT, and TUG as compared to the control group (p < 0.001).

CONCLUSIONS

WM practice improved the balance and ankle reposition sense among the elderly. It can be used as an alternative form of training to promote balance and ankle proprioception. The results supported that balance performance worsens among the elders who do not engage in physical training.

Eccentric Overload Flywheel Training in Older Adults

Age-related reductions in muscle strength and muscle power can have significant adverse effects on functional performance in older adults. Exercise training has been shown to be a potent stimulus for improvements in strength and power. However, investigation into how to best optimize training-related adaptations, as well as the accessibility of training methods, is needed. Traditional (TR) methods using gravity-dependent free-weights or weight machines can improve and maintain strength and power but are limited in their ability to provide constant muscle tension and high levels of muscle activation throughout the lowering (eccentric) phase of lifting. Eccentric overload (EO) training may overcome these limitations and has been shown to result in potent adaptations in both young and older adults. Methods of producing EO are significantly limited from a practical perspective. The addition of whole-body flywheel training equipment provides a practical method of producing EO and may be appropriate for older adults wanting to optimize training outcomes. Our review provides limited evidence of the use of eccentric overload flywheel training as a novel training method in seniors. Through the review of literature, EO training overcame some of the limitations set forth by traditional resistance training and demonstrated to have key benefits when combating age-related changes affecting muscle strength and muscle power. It can be concluded that EO training is an important addition to the training arsenal for older adults. Flywheel training provides a practical method of achieving EO, increasing strength and power, combating age-related adaptations, and overall improving quality of life in older adults.

Bench stepping with incremental heights improves muscle volume, strength and functional performance in older women

AIM

Task-specific exercises such as bench stepping can improve functional ability and reduce falling incidents in older adults. However, such exercises are often not optimized to improve muscle volume and force-velocity characteristics. This study determined the effects of a 12-week stepping program using incremental step heights (STEEP), on muscle volume, strength, power, functional ability and balance performance in older women.

METHODS

Forty-five community-dwelling women (69y ± 4) were randomly assigned to the STEEP group or a non-training CONTROL group. Training intensity was primarily determined by step height, while training volume remained equal. Thigh muscle volume (CT-scan), force-velocity characteristics of the knee extensors (Biodex dynamometer) and functional ability (Short Physical Performance Battery, timed stair ascent, 10-m walk test and countermovement jump height) were determined pre- and post-intervention. In addition, 3D trunk accelerations were recorded at the lower back to assess balance during the Short Physical Performance Battery balance tests.

RESULTS

Two-way ANOVA showed that the STEEP program increased thigh muscle volume, knee extensor isometric peak torque, dynamic peak power, unloaded rate of velocity development and improved performance on all functional tests to a greater extent than CONTROL (p < .05), except the countermovement jump. No improvements were found for peak velocity and balance performance (p > .05).

CONCLUSION

Our results indicate that bench step training with incremental step heights simultaneously improves functional ability, thigh muscle volume and force-velocity characteristics of the knee extensors in older women.

The effects of a multicomponent intervention program on clinical outcomes associated with falls in healthy older adults

BACKGROUND

Multicomponent intervention programs have been shown to be effective in reducing risk factors associated with falls, but the primary target population of these interventions is often low-functioning older adults.

AIMS

The purpose of this study was to investigate the effectiveness of a multicomponent intervention program focusing on balance and muscle strength for independently functioning community-dwelling older adults.

METHODS

Fifty-three independently functioning older adults, aged 80.09 ± 6.62 years, participated in a group exercise class (conducted 2 times/week for 8 weeks) emphasizing balance. Outcome measures were balance performance using the Fullerton Advanced Balance (FAB) scale and muscle strength using the Senior Fitness Test (SFT).

RESULTS

The intervention improved balance (P < 0.001), and older adults who were classified as having high fall risks based on the FAB scores at pre-testing improved more than older adults who were classified as having low fall risks (P = 0.017). As a result, 22 participants transitioned from a high fall risk group at pre-testing to a low fall risk group at post-testing (P < 0.001). The intervention also enhanced both upper and lower muscle extremity strength based on SFT results (P < 0.001) regardless of participants' classification of fall risk status.

CONCLUSIONS AND DISCUSSION

The multicomponent intervention conducted two times per week for 8 weeks was effective in improving balance and enhancing muscle strength of independently functioning older adults. The results underscore the importance of providing fall prevention interventions to healthy older adults, a population often not a target of balance interventions.

Muscles of the trunk and pelvis are responsive to testosterone administration: data from testosterone dose-response study in young healthy men

Testosterone dose-dependently increases appendicular muscle mass. However, the effects of testosterone administration on the core muscles of the trunk and the pelvis have not been evaluated. The present study evaluated the effects of testosterone administration on truncal and pelvic muscles in a dose-response trial. Participants were young healthy men aged 18-50 years participating in the 5α-Reductase (5aR) Trial. All participants received monthly injections of 7.5 mg leuprolide acetate to suppress endogenous testosterone production and weekly injections of 50, 125, 300, or 600 mg of testosterone enanthate and were randomized to receive either 2.5 mg dutasteride (5aR inhibitor) or placebo daily for 20 weeks. Muscles of the trunk and the pelvis were measured at baseline and the end of treatment using 1.5-Tesla magnetic resonance imaging. The dose effect of testosterone on changes in the psoas major muscle area was the primary outcome; secondary outcomes included changes in paraspinal, abdominal, pelvic floor, ischiocavernosus, and obturator internus muscles. The association between changes in testosterone levels and muscle area was also assessed. Testosterone dose-dependently increased areas of all truncal and pelvic muscles. The estimated change (95% confidence interval) of muscle area increase per 100 mg of testosterone enanthate dosage increase was 0.622 cm² (0.394, 0.850) for psoas; 1.789 cm² (1.317, 2.261) for paraspinal muscles, 2.530 cm² (1.627, 3.434) for total abdominal muscles, 0.455 cm² (0.233, 0.678) for obturator internus, and 0.082 cm² (0.003, 0.045) for ischiocavernosus; the increase in these volumes was significantly associated with the changes in on-treatment total and free serum testosterone concentrations. In conclusion, core muscles of the trunk and pelvis are responsive to testosterone administration. Future trials should evaluate the potential role of testosterone administration in frail men who are predisposed to falls and men with pelvic floor dysfunction.

Movement velocity in the chair squat is associated with measures of functional capacity and cognition in elderly people at low risk of fall

Background

The purpose of this study was to analyze the relationships between muscular performance consisting of a single repetition on the chair squat exercise (CSQ) and different measures of functional capacity, balance, quality of life and cognitive status in older adults.

Methods

A total of 40 participants (22 women, 18 men; age = 72.2 ± 4.9 years) joined the investigation. Muscular performance was assessed by measuring movement velocity in the CSQ with no external load using a validated smartphone application (PowerLift for iOS). Functional capacity, balance, quality of life and cognitive status were evaluated using the hand-grip strength (HGS) test, the Berg-scale, the EuroQol 5D (EQ-5D) and the Mini mental state examination questionnaire (MMSE). Finally, participants were divided into two subgroups (N = 20) according to their velocity in the CSQ exercise.

Results

Positive correlations were obtained between movement velocity in the CSQ and HGS (r = 0.76, p < 0.001), the Berg-scale (r = 0.65, p < 0.001), the EQ-5D (r = 0.34, p = 0.03) and the MMSE (r = 0.36, p = 0.02). Participants in the fastest subgroup showed very likely higher scores in the Berg-scale (ES = 1.15) and the HGS (ES = 1.79), as well as likely higher scores in the MMSE scale (ES = 0.69).

Discussion

These results could have potential clinical relevance as they support the use of a time-efficient, non-fatiguing test of muscular performance (i.e., the CSQ) to evaluate functional capacity and mental cognition in older adults.

No Overt Effects of a 6-Week Exergame Training on Sensorimotor and Cognitive Function in Older Adults. A Preliminary Investigation

Several studies investigating the relationship between physical activity and cognition showed that exercise interventions might have beneficial effects on working memory, executive functions as well as motor fitness in old adults. Recently, movement based video games (exergames) have been introduced to have the capability to improve cognitive function in older adults. Healthy aging is associated with a loss of cognitive, as well as sensorimotor functions. During exergaming, participants are required to perform physical activities while being simultaneously surrounded by a cognitively challenging environment. However, only little is known about the impact of exergame training interventions on a broad range of motor, sensory, and cognitive skills. Therefore, the present study aims at investigating the effects of an exergame training over 6 weeks on cognitive, motor, and sensory functions in healthy old participants. For this purpose, 30 neurologically healthy older adults were randomly assigned to either an experimental (ETG, n = 15, 1 h training, twice a week) or a control group (NTG, n = 15, no training). Several cognitive tests were performed before and after exergaming in order to capture potential training-induced effects on processing speed as well as on executive functions. To measure the impact of exergaming on sensorimotor performance, a test battery consisting of pinch and grip force of the hand, tactile acuity, eye-hand coordination, flexibility, reaction time, coordination, and static balance were additionally performed. While we observed significant improvements in the trained exergame (mainly in tasks that required a high load of coordinative abilities), these gains did not result in differential performance improvements when comparing ETG and NTG. The only exergaming-induced difference was a superior behavioral gain in fine motor skills of the left hand in ETG compared to NTG. In an exploratory analysis, within-group comparison revealed improvements in sensorimotor and cognitive tasks (ETG) while NTG only showed an improvement in a static balance test. Taken together, the present study indicates that even though exergames might improve gaming performance, our behavioral assessment was probably not sensitive enough to capture exergaming-induced improvements. Hence, we suggest to use more tailored outcome measures in future studies to assess potential exergaming-induced changes.

Intradialytic exercise and postural control in patients with chronic kidney disease undergoing hemodialysis

Abstract Introduction: Exercise promotes physiological improvements that reflect better quality of life and survival among chronic kidney disease patients. However, little is known about the effect of exercise on postural control of hemodialysis patients. Objective: To evaluate the effect of intradialytic aerobic exercise on postural balance in patients on hemodialysis. Methods: a pilot study with seven individuals was conducted at the Hemodialysis Center of Bauru State Hospital. The Berg Balance Scale evaluated balance and postural balance was evaluated by the force platform Advance Mechanical Technology Inc. (AMTI - AccuGait). Trunk mean sway amplitude in the anterior-posterior (AP) and medial-lateral (ML) directions and mean velocity in the AP and ML directions were assessed. Secondary outcomes about functional capacity and body composition (DEXA) were evaluated. The aerobic exercise was performed with a ergometric bicycle during the first two hours of hemodialysis session for 50-60 minutes (BORG >12), three times a week for 12-weeks. Results: Four men and three women, 52.86 ± 11.08 years, participated in the study. There was no difference between pre and post-test of postural balance outcomes. Although the results were not statistically significant, except for the lean body mass and leg lean mass, the presented pilot study suggests improved functional balance and lower limb strength. Conclusion: The 12-weeks of aerobic exercise protocol during hemodialysis despite inducing gains in lean body mass and leg lean mass, was not able to promote improvements in postural control of chronic renal failure patients on hemodialysis.

Anodal Transcranial Direct Current Stimulation Does Not Facilitate Dynamic Balance Task Learning in Healthy Old Adults

Older adults frequently experience a decrease in balance control that leads to increased numbers of falls, injuries and hospitalization. Therefore, evaluating older adults’ ability to maintain balance and examining new approaches to counteract age-related decline in balance control is of great importance for fall prevention and healthy aging. Non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) have been shown to beneficially influence motor behavior and motor learning. In the present study, we investigated the influence of tDCS applied over the leg area of the primary motor cortex (M1) on balance task learning of healthy elderly in a dynamic balance task (DBT). In total, 30 older adults were enrolled in a cross-sectional, randomized design including two consecutive DBT training sessions. Only during the first DBT session, either 20 min of anodal tDCS (a-tDCS) or sham tDCS (s-tDCS) were applied and learning improvement was compared between the two groups. Our data showed that both groups successfully learned to perform the DBT on both training sessions. Interestingly, between-group analyses revealed no difference between the a-tDCS and the s-tDCS group regarding their level of task learning. These results indicate that the concurrent application of tDCS over M1 leg area did not elicit DBT learning enhancement in our study cohort. However, a regression analysis revealed that DBT performance can be predicted by the kinematic profile of the movement, a finding that may provide new insights for individualized approaches of treating balance and gait disorders.

Home-Based Exercise Supported by General Practitioner Practices: Ineffective in a Sample of Chronically Ill, Mobility-Limited Older Adults (the HOMEfit Randomized Controlled Trial)

OBJECTIVES

To evaluate the effects a home-based exercise program delivered to ill and mobility-limited elderly individuals on physical function, physical activity, quality of life, fall-related self-efficacy, and exercise self-efficacy.

DESIGN

Randomized controlled trial (ISRCTN Registry, Reg.-No. ISRCTN17727272).

SETTING

Fifteen general practitioner (GP) practices and participants' homes.

PARTICIPANTS

Chronically ill and mobility-limited individuals aged 70 and older (N = 209).

INTERVENTIONS

An exercise therapist delivered the experimental intervention-a 12-week multidimensional home-based exercise program integrating behavioral strategies-in individual counseling sessions at the GPs' practices and over the telephone. The control intervention focused on promoting light-intensity activities of daily living. Interventions took place between February 2012 and March 2013.

MEASUREMENTS

The primary outcome was functional lower body strength (chair-rise test). Secondary outcomes were physical function (battery of motor tests), physical activity (step count), health-related quality of life (Medical Outcomes Study 8-item Short-Form Survey), fall-related (Falls Efficacy Scale-International Version), and exercise self-efficacy (Selbstwirksamkeit zur sportlichen Aktivitaet (SSA) scale). Postintervention differences between the groups were tested using analysis of covariance (intention to treat; adjusted for baseline value and GP practice; significance level P ≤ .05).

RESULTS

Participants had a mean age ± standard deviation of 80 ± 5, 74% were female, 87% had three or more chronic diseases, and 54% used a walking aid. The difference (intention to treat; experimental minus control) between adjusted postintervention chair-rise times was -0.1 (95% confidence interval = -1.8-1.7). Differences for all secondary outcomes were also nonsignificant.

CONCLUSION

The program was ineffective in the target population. Possibilities for improving the concept will have to be evaluated.

Down with Retirement: Implications of Embodied Cognition for Healthy Aging

Cognitive and neurocognitive approaches to human healthy aging attribute age-related decline to the biologically caused loss of cognitive-control functions. However, an embodied-cognition approach to aging implies a more interactive view according to which cognitive control emerges from, and relies on a person’s active encounters with his or her physical and social environment. We argue that the availability of cognitive-control resources does not only rely on biological processes but also on the degree of active maintenance, that is, on the systematic use of the available control resources. Unfortunately, there is evidence that the degree of actual use might systematically underestimate resource availability, which implies that elderly individuals do not fully exploit their cognitive potential. We discuss evidence for this possibility from three aging-related issues: the reduction of dopaminergic supply, loneliness, and the loss of body strength. All three phenomena point to a downward spiral, in which losses of cognitive-control resources do not only directly impair performance but also more indirectly discourage individuals from making use of them, which in turn suggests underuse and a lack of maintenance—leading to further loss. On the positive side, the possibility of underuse points to not yet fully exploited reservoirs of cognitive control, which calls for more systematic theorizing and experimentation on how cognitive control can be enhanced, as well as for reconsiderations of societal practices that are likely to undermine the active maintenance of control resources—such as retirement laws.

Review of safety and mobility issues among older pedestrians

Although old people make up an extremely vulnerable road-user group, older pedestrians' difficulties have been studied less extensively than those of older drivers, and more knowledge of this issue is still required. The present paper reviews current knowledge of older-adult problems with the main components of pedestrian activity, i.e., walking and obstacle negotiation, wayfinding, and road crossing. Compared to younger ones, old pedestrians exhibit declining walking skills, with a walking speed decrease, less stable balance, less efficient wayfinding strategies, and a greater number of unsafe road crossing behaviors. These difficulties are linked to age-related changes in sensorial, cognitive, physical, and self-perception abilities. It is now known that visual impairment, physical frailty, and attention deficits have a major negative impact on older pedestrians' safety and mobility, whereas the roles of self-evaluation and self-regulation are still poorly understood. All these elements must be taken into consideration, not only in developing effective safety interventions targeting older pedestrians, but also in designing roads and cars. Recent initiatives are presented here and some recommendations are proposed.

Rationale for Strengthening Muscle to Prevent Falls and Fractures: A Review of the Evidence

Falls represent a major public health problem in older people, predominantly due to the resulting injuries which lead to progressive disability, immobilization and resulting comorbidities, dependency, institutionalization, and death. Reduced muscle strength and power have been consistently identified as risk factors for falls and related injuries, and it is likely these associations result from the central role played by reduced muscle strength and power in poor balance recovery. In addition, muscle strength and power are involved with protective responses that reduce the risk of an injury if a fall occurs. Progressive resistance training (PRT) is the standard way to increase muscle strength and power, and this training forms one of the main components of fall prevention exercise interventions. However, PRT has rarely been implemented in routine practice due to multiple challenges inherent to frail older people. The ongoing development of drugs expected to increase muscle power offers a new opportunity to reduce the risk of falls and fall-related injuries. The intent here is not to replace exercise training with drugs but rather to offer a pharmacologic alternative when exercise is not possible or contraindicated. The target population would be those most likely to benefit from this mechanism of action, i.e., weak older people without major causes for falls independent of muscle weakness. Provided such a tailored strategy was followed, a muscle anabolic may address this major unmet need.

Does vibration training reduce the fall risk profile of frail older people admitted to a rehabilitation facility? A randomised controlled trial

PURPOSE

To determine the effect of Vibration Training (VT) on functional ability and falls risk among a group of frail older people admitted to an inpatient rehabilitation unit in a regional hospital in New Zealand.

METHOD

A randomized controlled trial of 56 participants (mean 82.01 years in the intervention group and 81.76 years in the control group). VT targeting lower limb muscles with a frequency 30-50 Hz occurred three times per week until discharge. Amplitude progressively increased from 2 to 5 mm to allow the programme to be individually tailored to the participant. The control group received usual care physiotherapy sessions. Outcome measures were: Physiological profile assessment (PPA); and Functional Independence measure (FIM) and Modified Falls Efficacy Scale (MFES).

RESULTS

There was a statistically significant difference observed between the two groups in terms of FIM score (F = 5.09, p = 0.03) and MFES (F = 3.52, p = 0.007) but no difference was observed in terms of PPA scores (F = 0.96, p = 0.36).

CONCLUSIONS

Among older people admitted to an inpatient rehabilitation facility there may be some beneficial effect to the use of VT in conjunction with usual care physiotherapy in terms of improved functional ability. The study design and the small dosage of VT provided may have precluded any change in falls risk among participants.

IMPLICATIONS FOR REHABILITATION

Vibration training (VT) may assist in reducing the risk of falling among at risk older people. Current pressures on health systems (ageing population, reduced hospital length of stay) necessitate the development of innovative strategies to maximise the rehabilitation potential of older people. Among older people admitted to an inpatient rehabilitation facility there may be some beneficial effect to the use of vibration training in conjunction with usual care physiotherapy in terms of improved functional ability.

Effects of a Supervised versus an Unsupervised Combined Balance and Strength Training Program on Balance and Muscle Power in Healthy Older Adults: A Randomized Controlled Trial

BACKGROUND

Losses in lower extremity muscle strength/power, muscle mass and deficits in static and particularly dynamic balance due to aging are associated with impaired functional performance and an increased fall risk. It has been shown that the combination of balance and strength training (BST) mitigates these age-related deficits. However, it is unresolved whether supervised versus unsupervised BST is equally effective in improving muscle power and balance in older adults.

OBJECTIVE

This study examined the impact of a 12-week BST program followed by 12 weeks of detraining on measures of balance and muscle power in healthy older adults enrolled in supervised (SUP) or unsupervised (UNSUP) training.

METHODS

Sixty-six older adults (men: 25, women: 41; age 73 ± 4 years) were randomly assigned to a SUP group (2/week supervised training, 1/week unsupervised training; n = 22), an UNSUP group (3/week unsupervised training; n = 22) or a passive control group (CON; n = 22). Static (i.e., Romberg Test) and dynamic (i.e., 10-meter walk test) steady-state, proactive (i.e., Timed Up and Go Test, Functional Reach Test), and reactive balance (e.g., Push and Release Test), as well as lower extremity muscle power (i.e., Chair Stand Test; Stair Ascent and Descent Test) were tested before and after the active training phase as well as after detraining.

RESULTS

Adherence rates to training were 92% for SUP and 97% for UNSUP. BST resulted in significant group × time interactions. Post hoc analyses showed, among others, significant training-related improvements for the Romberg Test, stride velocity, Timed Up and Go Test, and Chair Stand Test in favor of the SUP group. Following detraining, significantly enhanced performances (compared to baseline) were still present in 13 variables for the SUP group and in 10 variables for the UNSUP group.

CONCLUSION

Twelve weeks of BST proved to be safe (no training-related injuries) and feasible (high attendance rates of >90%). Deficits of balance and lower extremity muscle power can be mitigated by BST in healthy older adults. Additionally, supervised as compared to unsupervised BST was more effective. Thus, it is recommended to counteract intrinsic fall risk factors by applying supervised BST programs for older adults.

The effect of caffeine ingestion on functional performance in older adults

Caffeine is a widely used nutritional supplement which has been shown to enhance both physical and cognitive performance in younger adults. However, few studies have assessed the effect of caffeine ingestion on performance, particularly functional performance in older adults. The present study aims to assess the effect of acute caffeine ingestion on functional performance, manual dexterity and readiness to invest effort in older adults.

METHODS

19 apparently healthy, volunteers (10 females and 9 males aged 61-79; 66 ± 2 years) performed tests of functional fitness and manual dexterity post ingestion of caffeine (3mg*kg-1) or placebo in a randomised order. Pre and 60 minutes post ingestion, participants also completed measures of readiness to invest physical (RTIPE) and mental (RTIME) effort.

RESULTS

A series of repeated measures ANOVAS indicated enhanced performance in the following functional fitness tests; arm curls (P = .04), 8 foot up and go (P = .007), six minute walk (P = .016). Manual dexterity was also improved in the presence of caffeine (P = .001). RTIME increased (P = .015) pre to post ingestion in the caffeine condition but not in the placebo condition. There were no significant main effects or interactions for RTIPE or gender in any analysis (all P > .05).

CONCLUSIONS

The results of this study suggest that acute caffeine ingestion positively enhances functional performance, manual dexterity and readiness to invest effort in apparently healthy older adults.

Impact of exercise-induced fatigue on the strength, postural control, and gait of children with a neuromuscular disease

OBJECTIVE

Children with a neuromuscular disease are prone to early muscular fatigue. The objective of the present study was to evaluate the effects of fatigue induced by a walking exercise on the strength, postural control, and gait of children with a neuromuscular disease.

DESIGN

Maximal isometric knee strength (extension and flexion), quiet standing postural control, and gait were evaluated in 12 children (8.8 [1.4] yrs) with a neuromuscular disease before and after a walking exercise. The participants were asked to stop walking when they considered themselves "very fatigued."

RESULTS

After the exercise-induced fatigue, a significant increase in range of motion in pelvis obliquity, hip abduction and adduction, and ankle flexion and extension during gait was reported along with an increase in stride length variability. Fatigue also reduced the knee flexor strength and had a detrimental effect on postural control.

CONCLUSIONS

Fatigue affects the strength, postural control, and gait of children with a neuromuscular disease and could notably increase the risks of falling and the occurrence of serious injuries.

Scottish Country Dance: Benefits to Functional Ability in Older Women

The effects of long-term participation in Scottish country dance on body composition, functional ability, and balance in healthy older females were examined. Participants were grouped into dancers and physically active nondancers (ages 60–70 and 70–80 for both groups). Physical activity, body composition (body-mass index, skinfold thickness, waist-to-hip ratio), functional ability (6-min walk distance, 6-m walk time, 8-ft up-and-go time, lower body flexibility, shoulder flexibility), and static balance were measured. Younger dancers and physically active nondancers had similar 6-min walk distance, 6-m walk time, and 8-ft up-and-go time results; however, while older dancers performed similarly to younger dancers, older physically active nondancers performed poorer than their younger counterparts (p< .05). Body composition and static balance were the same for all groups. Regular physical activity can maintain body composition and postural stability with advancing age; however, Scottish country dance can delay the effects of aging on locomotion-related functional abilities.

Effects of core instability strength training on trunk muscle strength, spinal mobility, dynamic balance and functional mobility in older adults

BACKGROUND

Age-related postural misalignment, balance deficits and strength/power losses are associated with impaired functional mobility and an increased risk of falling in seniors. Core instability strength training (CIT) involves exercises that are challenging for both trunk muscles and postural control and may thus have the potential to induce benefits in trunk muscle strength, spinal mobility and balance performance.

OBJECTIVE

The objective was to investigate the effects of CIT on measures of trunk muscle strength, spinal mobility, dynamic balance and functional mobility in seniors.

METHODS

Thirty-two older adults were randomly assigned to an intervention group (INT; n = 16, aged 70.8 ± 4.1 years) that conducted a 9-week progressive CIT or to a control group (n = 16, aged 70.2 ± 4.5 years). Maximal isometric strength of the trunk flexors/extensors/lateral flexors (right, left)/rotators (right, left) as well as of spinal mobility in the sagittal and the coronal plane was measured before and after the intervention program. Dynamic balance (i.e. walking 10 m on an optoelectric walkway, the Functional Reach test) and functional mobility (Timed Up and Go test) were additionally tested.

RESULTS

Program compliance was excellent with participants of the INT group completing 92% of the training sessions. Significant group × test interactions were found for the maximal isometric strength of the trunk flexors (34%, p < 0.001), extensors (21%, p < 0.001), lateral flexors (right: 48%, p < 0.001; left: 53%, p < 0.001) and left rotators (42%, p < 0.001) in favor of the INT group. Further, training-related improvements were found for spinal mobility in the sagittal (11%, p < 0.001) and coronal plane (11%, p = 0.06) directions, for stride velocity (9%, p < 0.05), the coefficient of variation in stride velocity (31%, p < 0.05), the Functional Reach test (20%, p < 0.05) and the Timed Up and Go test (4%, p < 0.05) in favor of the INT group.

CONCLUSION

CIT proved to be a feasible exercise program for seniors with a high adherence rate. Age-related deficits in measures of trunk muscle strength, spinal mobility, dynamic balance and functional mobility can be mitigated by CIT. This training regimen could be used as an adjunct or even alternative to traditional balance and/or resistance training.

Effects of an exercise programme for chronically ill and mobility-restricted elderly with structured support by the general practitioner's practice (HOMEfit) - study protocol of a randomised controlled trial

BACKGROUND

Exercise programmes can be administered successfully as therapeutic agents to patients with a number of chronic diseases and help to improve physical functioning in older adults. Usually, such programmes target either healthy and mobile community-dwelling seniors or elderly individuals living in nursing institutions or special residences. Chronically ill or mobility-restricted individuals, however, are difficult to reach when they live in their own homes.A pilot study has shown good feasibility of a home-based exercise programme that is delivered to this target group through cooperation between general practitioners and exercise therapists. A logical next step involves evaluation of the effects of the programme.

METHODS/DESIGN

The study is designed as a randomised controlled trial. We plan to recruit 210 patients (≥ 70 years) in about 15 general practices.The experimental intervention (duration 12 weeks)-a multidimensional home-based exercise programme-is delivered to the participant by an exercise therapist in counselling sessions at the general practitioner's practice and on the telephone. It is based on methods and strategies for facilitating behaviour change according to the Health Action Process Approach (HAPA). The control intervention-baseline physical activities-differs from the experimental intervention with regard to content of the counselling sessions as well as to content and frequency of the promoted activities.Primary outcome is functional lower body strength measured by the "chair-rise" test. Secondary outcomes are: physical function (battery of motor tests), physical activity (step count), health-related quality of life (SF-8), fall-related self-efficacy (FES-I), and exercise self-efficacy (SSA-Scale).The hypothesis that there will be differences between the two groups (experimental/control) with respect to post-interventional chair-rise time will be tested using an ANCOVA with chair-rise time at baseline, treatment group, and study centre effects as explanatory variables. Analysis of the data will be undertaken using the principle of intention-to-treat.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN17727272.

Effects of muscle fatigue on gait characteristics under single and dual-task conditions in young and older adults

BACKGROUND

Muscle fatigue and dual-task walking (e.g., concurrent performance of a cognitive interference (CI) while walking) represent major fall risk factors in young and older adults. Thus, the objectives of this study were to examine the effects of muscle fatigue on gait characteristics under single and dual-task conditions in young and older adults and to determine the impact of muscle fatigue on dual-task costs while walking.

METHODS

Thirty-two young (24.3 ± 1.4 yrs, n = 16) and old (71.9 ± 5.5 yrs, n = 16) healthy active adults participated in this study. Fatigue of the knee extensors/flexors was induced by isokinetic contractions. Subjects were tested pre and post fatigue, as well as after a 5 min rest. Tests included the assessment of gait velocity, stride length, and stride length variability during single (walking), and dual (CI+walking) task walking on an instrumented walkway. Dual-task costs while walking were additionally computed.

RESULTS

Fatigue resulted in significant decreases in single-task gait velocity and stride length in young adults, and in significant increases in dual-task gait velocity and stride length in older adults. Further, muscle fatigue did not affect dual-task costs during walking in young and older adults. Performance in the CI-task was improved in both age groups post-fatigue.

CONCLUSIONS

Strategic and/or physiologic rationale may account for the observed differences in young and older adults. In terms of strategic rationale, older adults may walk faster with longer strides in order to overcome the feeling of fatigue-induced physical discomfort as quickly as possible. Alternatively, older adults may have learned how to compensate for age-related and/or fatigue-induced muscle deficits during walking by increasing muscle power of synergistic muscle groups (e.g., hip flexors). Further, a practice and/or learning effect may have occurred from pre to post testing. Physiologic rationale may comprise motor unit remodeling in old age resulting in larger proportions of type I fibres and thus higher fatigue-resistance and/or increased muscle spindle sensitivity following fatigue leading to improved forward propulsion of the body. These findings are preliminary and have to be confirmed by future studies.

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.

Effects of ankle fatigue on functional reflex activity during gait perturbations in young and elderly men

There is growing evidence that aging and muscle fatigue result in impaired postural reflexes in humans. Therefore, the objective of this study was to examine the effects of ankle fatigue on functional reflex activity (FRA) during gait perturbations in young and elderly men. Twenty-eight young (27.0+/-3.1 years, n=14) and old (67.2+/-3.7 years, n=14) healthy active men participated in this study. Fatigue of the plantarflexors and dorsiflexors was induced by isokinetic contractions. Pre and post-fatigue, subjects were tested for their ability to compensate for decelerating gait perturbations while walking on a treadmill. Latency, FRA of lower extremity muscles and angular velocity of the ankle joint complex were analysed by means of surface electromyography and goniometry. After the fatigue protocol, no significant main and interaction effects were detected for the parameter latency in m. tibialis anterior (TA). For both groups, a significant pre to post-test decrease in FRA in TA (p<.001) was observed coming along with increases in antagonist coactivity (p=.013) and maximal angular velocity of the ankle joint (p=.007). However, no significant groupxtest interactions were found for the three parameters. Ankle fatigue has an impact on the ability to compensate for gait perturbations in young and elderly adults. However, no significant differences in all analysed parameters were detected between young and elderly subjects. These results may imply that age-related deteriorations in the postural control system do not specifically affect the ability to compensate for gait perturbations under fatigued condition.

Feasibility of a multidimensional home-based exercise programme for the elderly with structured support given by the general practitioner's surgery: study protocol of a single arm trial preparing an RCT [ISRCTN58562962]

Background

Physical activity programmes can help to prevent functional decline in the elderly. Until now, such programmes use to target either on healthy community-dwelling seniors or on elderly living in special residences or care institutions. Sedentary or frail people, however, are difficult to reach when they live in their own homes. The general practitioner's (GP) practice offers a unique opportunity to acquire these people for participation in activity programmes. We conceptualised a multidimensional home-based exercise programme that shall be delivered to the target group through cooperation between GPs and exercise therapists. In order to prepare a randomised controlled trial (RCT), a feasibility study is being conducted.

Methods

The study is designed as a single arm interventional trial. We plan to recruit 90 patients aged 70 years and above through their GPs. The intervention lasts 12 weeks and consists of physical activity counselling, a home-exercise programme, and exercise consultations provided by an exercise therapist in the GP's practice and via telephone. The exercise programme consists of two main components: 1. a combination of home-exercises to improve strength, flexibility and balance, 2. walking for exercise to improve aerobic capacity. Primary outcome measures are: appraisal by GP, undesirable events, drop-outs, adherence. Secondary outcome measures are: effects (a. motor tests: timed-up-and-go, chair rising, grip strength, tandem stand, tandem walk, sit-and-reach; b. telephone interview: PRISCUS-Physical Activity Questionnaire, Short Form-8 Health Survey, three month recall of frequency of falls, Falls Efficacy Scale), appraisal by participant, exercise performance, focus group discussion. Data analyses will focus on: 1. decision-making concerning the conduction of a RCT, 2. estimation of the effects of the programme, detection of shortcomings and identification of subgroups with contrary results, 3. feedback to participants and to GPs.

Conclusion

A new cooperation between GPs and exercise therapists to approach community-dwelling seniors and to deliver a home-exercise programme is object of research with regard to feasibility and acceptance. In case of success, an RCT should examine the effects of the programme. A future implementation within primary medical care may take advantage from the flexibility of the programme.

Trial registration

Current Controlled Trials ISRCTN58562962.