Isometric Muscle Function of Knee Extensors and the Relation With Functional Performance in Patients With Stroke

Reliability and validity of belt-stabilized and tension dynamometry for assessing hip strength and power in uninjured adults

OBJECTIVES

To investigate the intra-rater reliability and validity of belt-stabilized and tension dynamometry to assess hip muscle strength and power.

DESIGN

Repeated measures.

SETTING

Biomechanics laboratory.

PARTICIPANTS

Seventeen uninjured adults (age = 22.0 ± 2.3y; 13 females).

MAIN OUTCOMES MEASURES

Peak torque (strength) and rate of torque development (RTD; power) were measured for hip abduction, internal rotation, external rotation and extension using an isokinetic dynamometer, and belt-stabilized and tension dynamometry.

RESULTS

For peak torque assessment, belt-stabilized and tension dynamometry showed good (Intraclass Correlation Coefficient [ICC] = 0.848-0.899) and good-to-excellent (ICC = 0.848-0.942) reliability, respectively. For RTD, belt-stabilized dynamometry showed fair reliability for abduction (ICC = 0.524) and good reliability for hip internal rotation, external rotation, and extension (ICC = 0.702-0.899). Tension dynamometry showed good reliability for all motions when measuring RTD (ICC = 0.737-0.897). Compared to isokinetic dynamometry, belt-stabilized and tension dynamometry showed good-to-excellent correlations for peak torque assessment (r = 0.503-0.870), and fair-to-good correlations for RTD (r = 0.438-0.674). Bland-Altman analysis showed that measures from belt-stabilized and tension dynamometry had clinically meaningful disagreement with isokinetic dynamometry.

CONCLUSION

Tension dynamometry is reliable for assessing hip strength and power in all assessed motions. Belt-stabilized dynamometry is reliable for assessing internal rotation, external rotation, and extension. Validity of both methods is questionable, considering the lack of agreement with isokinetic dynamometry.

Stroke-induced excess in capillarization relative to oxidative capacity in rats is muscle specific

Stroke is not only associated with muscle weakness, but also associated with reduced muscle fatigue resistance and reduced desaturation during exercise that may be caused by a reduced oxidative capacity and/or microvasculature. Therefore, the objective of the present study was to determine the effects of stroke on muscle mass, fiber size and shape, capillarization and oxidative capacity of the rat m. extensor carpi radialis (ECR) and m. flexor carpi ulnaris (FCU) after a photothrombotic stroke in the forelimb region of the primary sensorimotor cortex. The main observation of the present study was that 4 weeks after induction of stroke there were no significant changes in muscle fiber size and shape. Although there was no significant capillary rarefaction, there was some evidence for remodeling of the capillary bed as reflected by a reduced heterogeneity of capillary spacing (p = 0.006) that may result in improved muscle oxygenation. In the ECR, but not in the FCU, this was accompanied by reduction in muscle fiber oxidative capacity as reflected by reduced optical density of sections stained for succinate dehydrogenase (p = 0.013). The reduced oxidative capacity and absence of significant capillary rarefaction resulted in a capillary to fiber ratio per unit of oxidative capacity that was higher after stroke in the ECR (p = 0.01), but not in the FCU. This suggests that at least during the early stages, stroke is not necessarily accompanied by muscle fiber atrophy, and that stroke-induced reductions in oxidative capacity resulting in relative excess of capillarization are muscle specific.

"Effects of threshold respiratory muscle training on respiratory muscle strength, pulmonary function and exercise endurance after stroke: a meta-analysis"

BACKGROUND

Most studies on improvements in respiratory muscle strength, activities of daily living (ADL) and quality of life (QoL) in stroke patients receiving threshold respiratory muscle training (TRMT) have small sample sizes, and some studies have contradictory results.

OBJECTIVES

To evaluate the effectiveness of TRMT on respiratory muscle strength, pulmonary function and exercise endurance in stroke patients.

MATERIALS AND METHODS

PubMed, Cochrane Library, Physical Therapy Evidence Database (PEDro), Embase (via OVID) and Web of Science databases were searched for randomized controlled trial (RCT) from inception to January 17, 2024. The primary outcome was maximum inspiratory pressure (MIP) or maximum expiratory pressure (MEP). Secondary outcomes included pulmonary function measured by forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and peak expiratory flow (PEF), and exercise endurance measured by 6-minute walk test (6MWT).

RESULTS

A total of eight randomized controlled trials(RCTs), including 305 persons, were included in this study. The training time ranged from 3 weeks to 10 weeks. Among them, the intervention group in 4 studies used inspiratory muscle training, and the other 4 studies used inspiratory muscle training and expiratory muscle training. For the primary outcome, TRMT significantly improved MIP (mean=14.68 cmH2O, 95 %CI=2.28 to 27.09 cmH2O, P=0.02) and MEP (mean=9.37 cmH2O, 95 %CI=2.89 to 15.84 cmH2O, P=0.005) in stroke patients. Regarding the secondary outcomes, TRMT improved FVC, FEV1 and 6MWT (P<0.05) but did not significantly improve PEF.

CONCLUSION

TRMT improved inspiratory muscle strength and expiratory muscle strength, improved exercise endurance, and improved FVC and FEV1 of pulmonary function but did not significantly improve PEF.

Short-term and long-term predictors of balance function in stroke patients: a 6-month follow-up study

We aimed to determine early predictors of balance function (Berg Balance Scale, BBS) at 3 and 6 months after stroke using clinical, neurophysiological, and neuroimaging variables. Seventy-nine patients with hemiparesis after a stroke were included. Demographics, stroke characteristics, and clinical variables [Mini-Mental State Examination, BBS, strength in the hemiparetic hip, knee, and ankle muscles, and Fugl-Meyer Assessment Lower Extremity (FMA-LE)] were evaluated 2 weeks post-stroke, on average. Somatosensory-evoked potentials (SEP) from both tibial nerves and diffusion tensor imaging data were collected respectively within 3 weeks and 4 weeks post-onset to calculate the SEP amplitude ratio and the laterality index of fractional anisotropy of the corticospinal tract. In multiple linear regression analysis, younger age, higher FMA-LE score, and stronger hemiparetic hip extensors were independent predictors of higher BBS at 3 months post-stroke (adjusted R2  = 0.563, P  < 0.001). At 6 months post-stroke, significant predictors of higher BBS were younger age, higher FMA-LE, stronger hemiparetic hip extensors, and larger SEP amplitude ratio (adjusted R2  = 0.552, P  < 0.001), although the incremental contribution of the latter was rather small ( R2  = 0.019). We conclude that age and the initial motor impairment of the affected lower limb can inform the state of balance function at 3 and 6 months after stroke.

The Relationship Between Strength of the Affected Leg and Walking Speed After Stroke Varies According to the Level of Walking Disability: A Systematic Review

OBJECTIVE

The objectives of this review were to determine the relationship between muscle strength of the affected leg and walking speed after stroke and whether this relationship varied according to muscle group or level of walking disability.

METHODS

This systematic review with meta-analysis focused on observational studies of adult survivors of stroke. Muscle strength had to be measured as maximum voluntary force production during an isometric contraction of the affected leg. Walking had to be measured as walking speed. Studies had to report correlations between muscle strength and walking speed.

RESULTS

Thirty studies involving 1001 participants were included. Pooled mean correlations between muscle strength of the affected leg and walking speed was 0.51 (95% CI = 0.45 to 0.57). Pooled correlations between the strength of individual muscle groups and walking speed ranged from 0.42 (for the hip abductors) to 0.57 (for the ankle dorsiflexors). The correlation between level of walking disability and the mean correlation between muscle strength and walking speed was -0.70 (95% CI = -0.42 to -0.86).

CONCLUSION

After stroke, there is a strong relationship between strength of the affected leg and walking speed, with little variability across individual muscle groups. However, the level of walking disability of people with stroke does make a difference such that the more disabled people are, the stronger the relationship is between strength of the affected leg and walking speed.

IMPACT

This study suggests that the strength of all muscles of the affected leg is important for walking after stroke. It appears that increasing strength in the affected leg could be most important in people who are more disabled.

LAY SUMMARY

After stroke, the speed at which a person can walk is highly associated with the muscle strength of their affected leg. In people whose walking speed is severely affected, this association is stronger, and the physical therapist might focus on strengthening that leg so the individual can walk faster.

Respiratory muscle training improves exercise tolerance and respiratory muscle function/structure post-stroke at short term: A systematic review and meta-analysis

BACKGROUND

Previous reviews relating to the effects of respiratory muscle training (RMT) after stroke tend to focus on only one type of training (inspiratory or expiratory muscles) and most based the results on poor-quality studies (PEDro score ≤4).

OBJECTIVES

With this systematic review and meta-analysis, we aimed to determine the effects of RMT (inspiratory or expiratory muscle training, or mixed) on exercise tolerance, respiratory muscle function and pulmonary function and also the effects depending on the type of training performed at short- and medium-term in post-stroke.

METHODS

Databases searched were MEDLINE, PEDro, CINAHL, EMBASE and Web of Science up to the end of April 2020. The quality and risk of bias for each included study was examined by the PEDro scale (including only high-quality studies) and Cochrane Risk of Bias tool.

RESULTS

Nine studies (463 patients) were included. The meta-analysis showed a significant increase in exercise tolerance [4 studies; n = 111; standardized mean difference [SMD] = 0.65 (95% confidence interval 0.27-1.04)]; inspiratory muscle strength [9 studies; n = 344; SMD = 0.65 (0.17-1.13)]; inspiratory muscle endurance [3 studies; n = 81; SMD = 1.19 (0.71-1.66)]; diaphragm thickness [3 studies; n = 79; SMD = 0.9 (0.43-1.37)]; and peak expiratory flow [3 studies; n = 84; SMD = 0.55 (0.03-1.08)] in the short-term. There were no benefits on expiratory muscle strength and pulmonary function variables (forced expiratory volume in 1 s) in the short-term.

CONCLUSIONS

The meta-analysis provided moderate-quality evidence that RMT improves exercise tolerance, diaphragm thickness and pulmonary function (i.e., peak expiratory flow) and low-quality evidence for the effects on inspiratory muscle strength and endurance in stroke survivors in the short-term. None of these effects are retained in the medium-term. Combined inspiratory and expiratory muscle training seems to promote greater respiratory changes than inspiratory muscle training alone.

Effect of cycling and functional electrical stimulation with linear and interval patterns of timing on gait parameters in patients after stroke: a randomized clinical trial

OBJECTIVE

Patients in the chronic phase after a stroke are an underrepresented group in the literature. Therefore, the aim of this study was to compare the effects of cycling and functional electrical stimulation with linear versus interval patterns of timing on gait parameters in patients after stroke.

DESIGN

A double blinded, parallel, randomized clinical trial.

SETTING

Neuroscience Institute.

PARTICIPANTS

Patients with lower limb disability due to stroke (N = 30) with a stroke onset >6 months and <18 months.

INTERVENTIONS

Twenty-eight minutes of leg cycling with functional electrical stimulation with linear or interval patterns of timing applied to the peroneal and biceps femoris muscles, 3 times/week for 4 weeks.

MAIN MEASURES

Timed 10-Meter Walk Test and Functional Ambulation Classification were the primary outcome measures. The Modified Modified Ashworth scale, active range of motion, Timed Up and Go Test, and Single Leg Stance Test were the secondary outcome measures. Evaluation was performed at baseline, after 4, and after 8 weeks.

RESULTS

Thirty participants completed the 4-week intervention (interval group, n = 16; linear group, n = 14). The Functional Ambulation Classification, Timed 10-Meter Walk Test, and the Timed Up and Go Test improved significantly in both groups. The Modified Modified Ashworth scale scores for quadriceps and plantar flexion statistically decreased after 4-weeks in the interval group. Significant group-by-time interaction was shown for Timed Up and Go Test (p = 0.003, np²=0.228), knee flexion active range of motion (p < 0.001, np²=0.256) and dorsiflexion active range of motion (p < 0.001, np²=0.359). Modified Modified Ashworth scale and active range of motion in both the ankle and knee improved significantly in the interval group.

CONCLUSIONS

The functional electrical stimulation with cycling protocols improved the Functional Ambulation Classification, Timed 10-Meter Walk Test, active range of motion, Timed Up and Go Test, and Modified Modified Ashworth scale. An interval protocol of timing was more effective than the linear protocol in terms of spasticity and active range of motion.Implications for rehabilitationCycling + functional electrical stimulation training with an interval pattern of timing seems superior to cycling + functional electrical stimulation training with a linear pattern.Interval protocol has positive effects on spasticity and range of motion after 12 sessions in patients post stroke.Cycling + functional electrical stimulation improves functional mobility and speed in stroke survivors and the effects of this intervention lasted in follow-up assessment after one month.

Impaired Firing Behavior of Individually Tracked Paretic Motor Units During Fatiguing Contractions of the Dorsiflexors and Functional Implications Post Stroke

Introduction: This study quantified stroke-related changes in the following: (1) the averaged discharge rate of motor units (individually tracked and untracked) identified from high-density electromyography (HD-EMG) recordings, (2) global muscle EMG properties of the dorsiflexors during a fatiguing contraction, and the relationship between task endurance and measures of leg function.

Methods: Ten individuals with chronic stroke performed a sustained sub-maximal, isometric, fatiguing dorsiflexion contraction in paretic and non-paretic legs. Motor-unit firing behavior, task duration, maximal voluntary contraction strength (MVC), and clinical measures of leg function were obtained.

Results: Compared to the non-paretic leg, the paretic leg task duration was shorter, and there was a larger exercise-related reduction in motor unit global rates, individually tracked discharge rates, and overall magnitude of EMG. Task duration of the paretic leg was more predictive of walking speed and lower extremity Fugl-Meyer scores compared to the non-paretic leg.

Discussion: Paretic leg muscle fatigability is increased post stroke. It is characterized by impaired rate coding and recruitment and relates to measures of motor function.

Comparison of ground reaction force during gait between the nonparetic side in hemiparetic patients and the dominant side in healthy subjects

Considering the occurrence of gait impairment following stroke, walk-ing recovery is an important goal of rehabilitation. Ground reaction force (GRF) is used for gait assessment of rehabilitation progress during exercise in stroke patients. The aim of this study was to compare the GRF during gait of the nonparetic side in hemiparetic patients and the dominant side in healthy subjects. Twenty hemiparetic patients and 20 healthy subjects were enrolled in the study. Force plate was used to evaluate GRF during gait. Additionally, with the patients and subjects in supine position, we measured their range of motion (ROM) in ankle dor-siflexion using a digital goniometer. The force values of stance phase on the nonparetic side of hemiparetic patients were significantly less than on the dominant side of healthy subjects (P<0.05). The impulse values of stance phase on the paretic side and the nonparetic side of hemiparetic patients were significantly greater than on the dominant side of healthy subjects (P<0.05). The ankle ROM result was signifi-cantly correlated with the GRF values (P<0.05). It is important to assess and understand the nonparetic side as well as paretic side. These re-sults suggest that the analysis of GRF for exercise rehabilitation will be a valuable clinical evaluation in hemiparetic patients after a stroke.

Peripheral Electrical Stimulation Paired With Movement-Related Cortical Potentials Improves Isometric Muscle Strength and Voluntary Activation Following Stroke

Background

Endogenous paired associative stimulation (ePAS) is a neuromodulatory intervention that has potential to aid stroke recovery. ePAS involves pairing endogenous electroencephalography (EEG) signals known as movement-related cortical potentials (MRCPs), with peripheral electrical stimulation. Previous studies have used transcranial magnetic stimulation (TMS) to demonstrate changes in corticomotor excitability following ePAS. However, the use of TMS as a measure in stroke research is limited by safety precautions, intolerance, and difficulty generating a measurable response in more severely affected individuals. We were interested in evaluating the effect of ePAS using more feasible measures in people with stroke. This study asks whether ePAS produces immediate improvements in the primary outcomes of maximal voluntary isometric contraction (MVIC) and total neuromuscular fatigue of the dorsiflexor muscles, and in the secondary outcomes of muscle power, voluntary activation (VA), central fatigue, peripheral fatigue, and electromyography activity.

Method

In this repeated-measures cross-over study, 15 participants with chronic stroke completed two interventions, ePAS and sham, in a randomized order. During ePAS, 50 repetitions of visually cued dorsiflexion were completed, while single pulses of electrical stimulation were delivered to the deep branch of the common peroneal nerve. Each somatosensory volley was timed to arrive in the primary motor cortex at the peak negativity of the MRCP. Univariate and multivariate linear mixed models were used to analyze the primary and secondary data, respectively.

Results

There was a statistically significant increase in dorsiflexor MVIC immediately following the ePAS intervention (mean increase 7 N), compared to the sham intervention (mean change 0 N) (univariate between-condition analysis p = 0.047). The multivariate analysis revealed a statistically significant effect of ePAS on VA of the tibialis anterior muscle, such that ePAS increased VA by 7 percentage units (95% confidence interval 1.3–12.7%). There was no statistically significant effect on total neuromuscular fatigue, muscle power, or other secondary measures.

Conclusion

A single session of ePAS can significantly increase isometric muscle strength and VA in people with chronic stroke. The findings confirm that ePAS has a central neuromodulatory mechanism and support further exploration of its potential as an adjunct to stroke rehabilitation. In addition, the findings offer alternative, feasible outcome measures for future research.

Clinical trial registration

Australia New Zealand Clinical Trials Registry ACTRN12617000838314 (www.anzctr.org.au), Universal Trial Number U111111953714.

Physical fitness training for stroke patients

BACKGROUND

Levels of physical activity and physical fitness are low after stroke. Interventions to increase physical fitness could reduce mortality and reduce disability through increased function.

OBJECTIVES

The primary objectives of this updated review were to determine whether fitness training after stroke reduces death, death or dependence, and disability. The secondary objectives were to determine the effects of training on adverse events, risk factors, physical fitness, mobility, physical function, health status and quality of life, mood, and cognitive function.

SEARCH METHODS

In July 2018 we searched the Cochrane Stroke Trials Register, CENTRAL, MEDLINE, Embase, CINAHL, SPORTDiscus, PsycINFO, and four additional databases. We also searched ongoing trials registers and conference proceedings, screened reference lists, and contacted experts in the field.

SELECTION CRITERIA

Randomised trials comparing either cardiorespiratory training or resistance training, or both (mixed training), with usual care, no intervention, or a non-exercise intervention in stroke survivors.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed quality and risk of bias, and extracted data. We analysed data using random-effects meta-analyses and assessed the quality of the evidence using the GRADE approach. Diverse outcome measures limited the intended analyses.

MAIN RESULTS

We included 75 studies, involving 3017 mostly ambulatory participants, which comprised cardiorespiratory (32 studies, 1631 participants), resistance (20 studies, 779 participants), and mixed training interventions (23 studies, 1207 participants). Death was not influenced by any intervention; risk differences were all 0.00 (low-certainty evidence). There were few deaths overall (19/3017 at end of intervention and 19/1469 at end of follow-up). None of the studies assessed death or dependence as a composite outcome. Disability scores were improved at end of intervention by cardiorespiratory training (standardised mean difference (SMD) 0.52, 95% CI 0.19 to 0.84; 8 studies, 462 participants; P = 0.002; moderate-certainty evidence) and mixed training (SMD 0.23, 95% CI 0.03 to 0.42; 9 studies, 604 participants; P = 0.02; low-certainty evidence). There were too few data to assess the effects of resistance training on disability. Secondary outcomes showed multiple benefits for physical fitness (VO2 peak and strength), mobility (walking speed) and physical function (balance). These physical effects tended to be intervention-specific with the evidence mostly low or moderate certainty. Risk factor data were limited or showed no effects apart from cardiorespiratory fitness (VO2 peak), which increased after cardiorespiratory training (mean difference (MD) 3.40 mL/kg/min, 95% CI 2.98 to 3.83; 9 studies, 438 participants; moderate-certainty evidence). There was no evidence of any serious adverse events. Lack of data prevents conclusions about effects of training on mood, quality of life, and cognition. Lack of data also meant benefits at follow-up (i.e. after training had stopped) were unclear but some mobility benefits did persist. Risk of bias varied across studies but imbalanced amounts of exposure in control and intervention groups was a common issue affecting many comparisons.

AUTHORS' CONCLUSIONS

Few deaths overall suggest exercise is a safe intervention but means we cannot determine whether exercise reduces mortality or the chance of death or dependency. Cardiorespiratory training and, to a lesser extent mixed training, reduce disability during or after usual stroke care; this could be mediated by improved mobility and balance. There is sufficient evidence to incorporate cardiorespiratory and mixed training, involving walking, within post-stroke rehabilitation programmes to improve fitness, balance and the speed and capacity of walking. The magnitude of VO2 peak increase after cardiorespiratory training has been suggested to reduce risk of stroke hospitalisation by ˜7%. Cognitive function is under-investigated despite being a key outcome of interest for patients. Further well-designed randomised trials are needed to determine the optimal exercise prescription, the range of benefits and any long-term benefits.

Hand strengthening exercises in chronic stroke patients: Dose-response evaluation using electromyography

STUDY DESIGN

Cross-sectional.

PURPOSE OF THE STUDY

This study evaluates finger flexion and extension strengthening exercises using elastic resistance in chronic stroke patients.

METHODS

Eighteen stroke patients (mean age: 56.8 ± 7.6 years) with hemiparesis performed 3 consecutive repetitions of finger flexion and extension, using 3 different elastic resistance levels (easy, moderate, and hard). Surface electromyography was recorded from the flexor digitorum superficialis (FDS) and extensor digitorum (ED) muscles and normalized to the maximal electromyography of the non-paretic arm.

RESULTS

Maximal grip strength was 39.2 (standard deviation: 12.5) and 7.8 kg (standard deviation: 9.4) in the nonparetic and paretic hand, respectively. For the paretic hand, muscle activity was higher during finger flexion exercise than during finger extension exercise for both ED (30% [95% confidence interval {CI}: 19-40] vs 15% [95% CI: 5-25] and FDS (37% [95% CI: 27-48] vs 24% [95% CI: 13-35]). For the musculature of both the FDS and ED, no dose-response association was observed for resistance and muscle activity during the flexion exercise (P > .05).

CONCLUSION

The finger flexion exercise showed higher muscle activity in both the flexor and extensor musculature of the forearm than the finger extension exercise. Furthermore, greater resistance did not result in higher muscle activity during the finger flexion exercise. The present results suggest that the finger flexion exercise should be the preferred strengthening exercise to achieve high levels of muscle activity in both flexor and extensor forearm muscles in chronic stroke patients. The finger extension exercise may be performed with emphasis on improving neuromuscular control.

LEVEL OF EVIDENCE

4b.

The Comparison between Isokinetic Knee Muscles Strength in the Ipsilateral and Contralateral Limbs and Correlating with Function of Patients with Stroke

Objective The aim of this study is to compare the isokinetic knee muscles peak torque measurements and proprioception between the affected and intact limbs of patients with stroke, in addition to finding the correlation between knee muscles strength and lower limb function. Methods Twelve patients with stroke (mean age 64.33 ± 6.140 years), with 3 to 7 months poststroke who can walk 25 feet independently without using or using assistive devices and full passive range of motion were included in the study. Biodex isokinetic dynamometer was used for measuring isokinetic strength at 90°/s, 120°/s, and 150°/s and isometric strength at 60°/s in both flexors and extensors of the knee, whereas proprioception was measured at 45°/s knee flexion, all for affected and intact limbs. Functional measurements were assessed using the Fugl-Meyer Assessment for Lower Limb scale and Barthel Index (BI). Results The differences shown were found to be statistically significant between affected and intact limbs in isokinetic 90°/s flexion ( p = 0.005), extension ( p = 0.0013), and isometric at 60°/s flexion ( p < 0.0001) knee muscle strengths and also the proprioception ( p = 0.05). Significant positive correlation was found between isokinetic affected side knee flexion at 90°/s ( r = 0.903) with BI ( r = 0.704). Conclusion There is a significant difference in peak torque measurements between affected and normal lower limbs of poststroke patients, as well as a significant correlation between the knee strength and lower limb functions. Furthermore, it can also be concluded that the differences in knee proprioception between the affected and intact limbs were shown to be significant.

Cryotherapy reduces muscle hypertonia, but does not affect lower limb strength or gait kinematics post-stroke: a randomized controlled crossover study

BACKGROUND

Based on the premise that spasticity might affect gait post-stroke, cryotherapy is among the techniques used to temporarily reduce spasticity in neurological patients. This effective technique would enhance muscle performance, and ultimately, functional training, such as walking. However, understanding whether a decrease in spasticity level, if any, would lead to improving muscle performance and gait parameters is not based on evidence and needs to be clarified.

OBJECTIVES

to investigate the immediate effects of cryotherapy, applied to spastic plantarflexor muscles of subjects post-stroke, on tonus level, torque generation capacity of plantarflexors and dorsiflexors, and angular/spatiotemporal gait parameters.

METHODS

Sixteen chronic hemiparetic subjects participated in this randomized controlled crossover study. Cryotherapy (ice pack) or Control (room temperature sand pack) were applied to the calf muscles of the paretic limb. The measurements taken (before and immediately after intervention) were: 1) Tonus according to the Modified Ashworth Scale; 2) Torque assessments were performed using an isokinetic dynamometer; and 3) Spatiotemporal and angular kinematics of the hip, knee, and ankle (flexion/extension), obtained using a tridimensional movement analysis system (Qualisys).

RESULTS

Cryotherapy decreased plantarflexor tonus but did not change muscle torque generation capacity and did not affect spatiotemporal or angular parameters during gait compared to control application. These findings contribute to the evidence-based approach to clinical rehabilitation post-stroke.

CONCLUSIONS

The findings of this study suggest that cryotherapy applied to the calf muscles of subjects with chronic hemiparesis reduces muscle hypertonia but does not improve dorsiflexors and plantarflexors performance and gait parameters.

Muscle power, contraction velocity and functional performance after stroke

OBJECTIVE

The goal of this study was to describe muscle function deficit in patients after stroke as well as to define the relationship between maximal muscle power (P_max ) and optimal shortening velocity (υ_opt ) with functional efficiency in stroke survivors.

MATERIAL AND METHODS

A total of 134 participants were enrolled in the study, including 67 patients after a stroke and 67 volunteers, matched for age and sex (controls). Functional performance was measured with the timed Up and Go test (TUG) and additionally with Rivermead Motor Assessment (RMA) and Barthel Index (BI) in stroke survivors. To assess P_max and υ_opt of the knee extensor muscles, a specially equipped Monark cycle ergometer was used.

RESULTS

The power generated by stroke survivors was 49.6% that of their peers and muscle contraction velocity was 65.5%. P_max /kg and υ_opt were associated with TUG outcomes in both groups. P_max /kg and υ_opt were associated with age in the control group, but not in patients after stroke. In multivariate analysis in patients after stroke, TUG was better predicted by P_max /kg or υ_opt than by the age. In stroke survivors, both P_max /kg and υ_opt were related to the BI and to the RMA total results. Both BI and RMA total were not determined by age.

CONCLUSIONS

Muscle power and muscle contraction velocity in patients who have had a stroke within three months have reduced markedly. These factors significantly affect functional performance. Muscle power and optimal shortening velocity are more important determinants of functional status than age in these stroke survivors.

Different Error Size During Locomotor Adaptation Affects Transfer to Overground Walking Poststroke

BACKGROUND

Studies in neurologically intact subjects suggest that the gradual presentation of small perturbations (errors) during learning results in better transfer of a newly learned walking pattern to overground walking. Whether the same result would be true after stroke is not known.

OBJECTIVE

To determine whether introducing gradual perturbations, during locomotor learning using a split-belt treadmill influences learning the novel walking pattern or transfer to overground walking poststroke.

METHODS

Twenty-six chronic stroke survivors participated and completed the following walking testing paradigm: baseline overground walking; baseline treadmill walking; split-belt treadmill/adaptation period (belts moving at different speeds); catch trial (belts at same speed); post overground walking. Subjects were randomly assigned to the Gradual group (gradual changes in treadmill belts speed during adaptation) or the Abrupt group (a single, large, abrupt change during adaptation). Step length asymmetry adaptation response on the treadmill and transfer of learning to overground walking was assessed.

RESULTS

Step length asymmetry during the catch trial was the same between groups ( P = .195) confirming that both groups learned a similar amount. The magnitude of transfer to overground walking was greater in the Gradual than in the Abrupt group ( P = .041).

CONCLUSIONS

The introduction of gradual perturbations (small errors), compared with abrupt (larger errors), during a locomotor adaptation task seems to improve transfer of the newly learned walking pattern to overground walking poststroke. However, given the limited magnitude of transfer, future studies should examine other factors that could impact locomotor learning and transfer poststroke.

Effect of bilateral lower limb strengthening exercise on balance and walking in hemiparetic patients after stroke: a randomized controlled trial

[Purpose] To evaluate the effect of bilateral lower limb strengthening designed to improve balance and walking in stroke patients. [Subjects and Methods] Twenty hemiparetic stroke patients were divided into two groups: a unilateral therapy group (UTG) (n=10) and a bilateral therapy group (BTG) (n=10). The UTG completed strength training only in the paretic lower limb. The BTG completed strength training in the paretic and non-paretic lower limbs. Assessment tools included the functional reach test (FRT), the Berg balance scale (BBS), the timed up and go (TUG) test, and a 10-meter walk test (10MWT). [Results] In both groups, the lower limb strengthening exercise for balance and walking significantly improved the FRT, BBS, TUG, and 10MWT scores. Compared with UTG, the BTG attained significantly improved FRT and BBS scores. [Conclusion] Bilateral therapy using this lower limb strengthening exercise effectively promotes balance in hemiparetic stroke patients.

A structural equation model of the relationship between muscle strength, balance performance, walking endurance and community integration in stroke survivors

Purpose

To use structural equation modelling (SEM) to determine (1) the direct and indirect associations of strength of paretic lower limb muscles with the level of community integration, and (2) the direct association of walking endurance and balance performance with the level of community integration in community-dwelling stroke survivors.

Materials and methods

In this cross-sectional study of 105 stroke survivors, the Subjective Index of Physical and Social Outcome (SIPSO) was used to measure the level of community integration. Lower-limb strength measures included isometric paretic ankle strength and isokinetic paretic knee peak torque. The Berg Balance Scale (BBS) and the 6-minute walk test (6MWT) were used to evaluate balance performance and walking endurance, respectively.

Results

SEM revealed that the distance walked on the 6MWT had the strongest direct association with the SIPSO score (β = 0.41, p <0.001). An increase of one standard deviation in the 6MWT distance resulted in an increase of 0.41 standard deviations in the SIPSO score. Moreover, dorsiflexion strength (β = 0.18, p = 0.044) and the BBS score (β = 0.21, p = 0.021) had direct associations with the SIPSO score.

Conclusions

The results of the proposed model suggest that rehabilitation training of community-dwelling stroke survivors could focus on walking endurance, balance performance and dorsiflexor muscle strengthening if the aim is to augment the level of community integration.

Functioning Without Cartilage: Older People With Radiographic Knee Osteoarthritis Who Self-Report No Functional Limitations Do Score Lower on a Performance Battery

The majority of the older population shows signs of radiographic knee osteoarthritis. However, many remain without functional complaints for a long period. This study aims to find early functional changes associated with stages of radiographic knee osteoarthritis. A group of older people without self-reported complaints was divided in two groups: knee osteoarthritis (K&L = 2-4, N = 29) and control (K&L = 0-1, N = 31). Muscle function was assessed with voluntary and electrically-stimulated isometric knee contractions, including a fatigue test. Physical functioning was assessed with a 6-min walk test (6MWT), a stair climb test (SCT), and a short performance battery. There were no differences in muscle function parameters, 6MWT, and SCT between groups. A clinically relevant lower score on the performance battery was found in participants with knee osteoarthritis. In conclusion, even when older people indicate to have no functional limitations, a decline in functional outcome can be measured with a physical performance battery.

Impaired muscle strength may contribute to fatigue in patients with aneurysmal subarachnoid hemorrhage

Patients with aneurysmal subarachnoid hemorrhage (a-SAH) show long-term fatigue and face difficulties in resuming daily physical activities. Impaired muscle strength, especially of the lower extremity, impacts the performance of daily activities and may trigger the onset of fatigue complaints. The present study evaluated knee muscle strength and fatigue in patients with a-SAH. This study included 33 patients, 6 months after a-SAH, and 33 sex-matched and age-matched healthy controls. Isokinetic muscle strength of the knee extensors and flexors was measured at 60 and 180°/s. Maximal voluntary muscle strength was defined as peak torque and measured in Newton-meter. Fatigue was examined using the Fatigue Severity Scale. In patients with a-SAH, the maximal knee extension was 22% (60°/s) and 25% (180°/s) lower and maximal knee flexion was 33% (60°/s) and 36% (180°/s) lower compared with that of matched controls (P≤0.001). The Fatigue Severity Scale score was related to maximal knee extension (60°/s: r=-0.426, P=0.015; 180°/s: r=-0.376, P=0.034) and flexion (60°/s: r=-0.482, P=0.005; 180°/s: r=-0.344, P=0.083). The knee muscle strength was 28-47% lower in fatigued (n=13) and 11-32% lower in nonfatigued (n=20) patients; deficits were larger in fatigued patients (P<0.05), particularly when the muscle strength (peak torque) was measured at 60°/s. The present results indicate that patients with a-SAH have considerably impaired knee muscle strength, which is related to more severe fatigue. The present findings are exploratory, but showed that knee muscle strength may play a role in the severity of fatigue complaints, or vice versa. Interventions targeting fatigue after a-SAH seem necessary and may consider strengthening exercise training in order to treat a debilitating condition.

Strength of knee flexors of the paretic limb as an important determinant of functional status in post-stroke rehabilitation

OBJECTIVE

The purpose of the study was to assess the effectiveness of the multi-modal exercise program (MMEP) in patients after stroke, and to identify muscles that are the best predictors of functional performance and changes in functional status in a 3-week rehabilitation program.

METHODS

Thirty-one post-stroke patients (60.6±12.7 years) participating in a 3-week MMEP took part in the study. Measurements of extensor and flexor strength of the knee (F_ext, F_flex) were done. Functional performance was measured using Timed Up & Go test (TUG), 6-Minute Walk Test (6-MWT) and Tinetti Test.

RESULTS

The rehabilitation program improved all the results of functional tests, as well as the values of strength in the patients. Both baseline and post-rehabilitation functional status was associated with knee flexor and extensor muscle strength of paretic but not of non-paretic limbs. At baseline examination muscle strength difference between both F_flexkg^-1 and F_extkg^-1 had an influence on functional status. After rehabilitation the effect of muscle strength difference on functional status was not evident for F_extkg^-1 and, interestingly, even more prominent for F_flexkg^-1.

CONCLUSIONS

MMEP can effectively increase muscle strength and functional capacity in post-stroke patients. Knee flexor muscle strength of the paretic limb and the knee flexor difference between the limbs is the best predictor of functional performance in stroke survivors.

The effect of isolating the paretic limb on weight-bearing distribution and EMG activity during squats in hemiplegic and healthy individuals

BACKGROUND

Neural reorganization for movement therapy after a stroke is thought to be an important mechanism that facilitates motor recovery. However, there is a lack of evidence for the effectiveness of exercise programs in improving the lower limbs.

OBJECTIVE

We investigated the immediate effect of isolating the paretic limb using different foot positions ((i) foot parallel; both feet parallel, (ii) foot asymmetry; paretic foot backward by 10 cm, and (iii) foot lifting; nonparetic foot lifting by normalization to 25% of knee height) on weight-bearing distribution and electromyography (EMG) of the thigh muscle during squats.

METHODS

In total, 20 patients with hemiplegia and 16 healthy subjects randomly performed three squat conditions in which the knee joint was flexed to 30°. Weight distribution was measured using the BioRescue system. Muscle activity was measured using a surface EMG system.

RESULTS

Patients with hemiplegia exhibited significantly decreased weight bearing on the paretic foot at 0° and 30° knee flexion compared with the nondominant foot of a healthy subject. The muscle activity of the quadriceps was significantly lower in patients with hemiplegia compared to healthy subjects. Weight bearing and EMG activity of the quadriceps femoris on the paretic or nondominant side significantly increased during a knee flexion of 30° with under the foot asymmetry and foot lifting positions compared with the parallel foot position.

CONCLUSION

Isolating the paretic limb using the asymmetric foot positions and lifting of the foot during squats might help patients with hemiplegia to improve weight-bearing and achieve greater activation of the quadriceps muscle in the paretic limb.

The correlation between muscle activity of the quadriceps and balance and gait in stroke patients

[Purpose] The purpose of this study was to examine the correlation between quadriceps muscle activity and balance and gait in stroke patients. [Subjects and Methods] Fifty-five stroke patients (30 males 25 females; mean age 58.7 years; stroke duration 4.82 months; Korean mini-mental state examination score 26.4) participated in this study. MP100 surface electromyography, BioRescue, and LUKOtronic were used to measure the quadriceps muscle activity, balance, and gait, respectively. [Results] There was a significant correlation between quadriceps muscle activity (vastus lateralis % reference voluntary contraction, vastus medialis % reference voluntary contraction) and balance (limits of stability) and gait (gait velocity) but there was none between vastus lateralis % reference voluntary contraction, vastus medialis % reference voluntary contraction. [Conclusion] An increase in quadriceps muscle activity will improve balance and gait ability. To improve function in stroke patients, training is needed to strengthen the quadriceps muscles.

Physical fitness training for stroke patients

BACKGROUND

Levels of physical fitness are low after stroke. It is unknown whether improving physical fitness after stroke reduces disability.

OBJECTIVES

To determine whether fitness training after stroke reduces death, dependence, and disability and to assess the effects of training with regard to adverse events, risk factors, physical fitness, mobility, physical function, quality of life, mood, and cognitive function. Interventions to improve cognitive function have attracted increased attention after being identified as the highest rated research priority for life after stroke. Therefore we have added this class of outcomes to this updated review.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched February 2015), the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 1: searched February 2015), MEDLINE (1966 to February 2015), EMBASE (1980 to February 2015), CINAHL (1982 to February 2015), SPORTDiscus (1949 to February 2015), and five additional databases (February 2015). We also searched ongoing trials registers, handsearched relevant journals and conference proceedings, screened reference lists, and contacted experts in the field.

SELECTION CRITERIA

Randomised trials comparing either cardiorespiratory training or resistance training, or both (mixed training), with usual care, no intervention, or a non-exercise intervention in stroke survivors.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality and risk of bias, and extracted data. We analysed data using random-effects meta-analyses. Diverse outcome measures limited the intended analyses.

MAIN RESULTS

We included 58 trials, involving 2797 participants, which comprised cardiorespiratory interventions (28 trials, 1408 participants), resistance interventions (13 trials, 432 participants), and mixed training interventions (17 trials, 957 participants). Thirteen deaths occurred before the end of the intervention and a further nine before the end of follow-up. No dependence data were reported. Diverse outcome measures restricted pooling of data. Global indices of disability show moderate improvement after cardiorespiratory training (standardised mean difference (SMD) 0.52, 95% confidence interval (CI) 0.19 to 0.84; P value = 0.002) and by a small amount after mixed training (SMD 0.26, 95% CI 0.04 to 0.49; P value = 0.02); benefits at follow-up (i.e. after training had stopped) were unclear. There were too few data to assess the effects of resistance training.Cardiorespiratory training involving walking improved maximum walking speed (mean difference (MD) 6.71 metres per minute, 95% CI 2.73 to 10.69), preferred gait speed (MD 4.28 metres per minute, 95% CI 1.71 to 6.84), and walking capacity (MD 30.29 metres in six minutes, 95% CI 16.19 to 44.39) at the end of the intervention. Mixed training, involving walking, increased preferred walking speed (MD 4.54 metres per minute, 95% CI 0.95 to 8.14), and walking capacity (MD 41.60 metres per six minutes, 95% CI 25.25 to 57.95). Balance scores improved slightly after mixed training (SMD 0.27, 95% CI 0.07 to 0.47). Some mobility benefits also persisted at the end of follow-up. The variability, quality of the included trials, and lack of data prevents conclusions about other outcomes and limits generalisability of the observed results.

AUTHORS' CONCLUSIONS

Cardiorespiratory training and, to a lesser extent, mixed training reduce disability during or after usual stroke care; this could be mediated by improved mobility and balance. There is sufficient evidence to incorporate cardiorespiratory and mixed training, involving walking, within post-stroke rehabilitation programmes to improve the speed and tolerance of walking; some improvement in balance could also occur. There is insufficient evidence to support the use of resistance training. The effects of training on death and dependence after stroke are still unclear but these outcomes are rarely observed in physical fitness training trials. Cognitive function is under-investigated despite being a key outcome of interest for patients. Further well-designed randomised trials are needed to determine the optimal exercise prescription and identify long-term benefits.

Body, Person and Environment: Why Promoting Physical Activity (PA) with Stroke Survivors Requires Holistic Thinking

The role of physical activity (PA) after stroke is increasingly recognised as important for function, fitness and wellbeing. Current evidence shows that targeted PA after stroke improves cardiovascular fitness, walking ability and muscle strength and may ameliorate depression and improve quality of life. Secondary stroke prevention and management of cardiovascular risk factors are further health benefits. Despite increasing emphasis on organised exercise classes for stroke, PA levels remain low and effects of organised exercise interventions are not maintained once programmes have finished. Barriers to PA after stroke are complex and innovative approaches to maintaining and promoting long-term engagement in activity are required. This commentary proposes that using the International Classification of Disability and Functioning (ICF) to guide thinking about PA after stroke may help us develop and apply comprehensive solutions that increase PA levels. This approach considers stroke survivors’ PA engagement in terms of Body – the physical impairments imposed by stroke; Person – the role of identity, and psychological factors on PA; and Environment – the physical and social environments that influence PA engagement. The commentary discusses how innovative solutions addressing these issues may enable stroke survivors to be better supported to lead active lifestyles.

Assessment of Lower Limb Muscle Strength and Power Using Hand-Held and Fixed Dynamometry: A Reliability and Validity Study

Introduction

Hand-held dynamometry (HHD) has never previously been used to examine isometric muscle power. Rate of force development (RFD) is often used for muscle power assessment, however no consensus currently exists on the most appropriate method of calculation. The aim of this study was to examine the reliability of different algorithms for RFD calculation and to examine the intra-rater, inter-rater, and inter-device reliability of HHD as well as the concurrent validity of HHD for the assessment of isometric lower limb muscle strength and power.

Methods

30 healthy young adults (age: 23±5yrs, male: 15) were assessed on two sessions. Isometric muscle strength and power were measured using peak force and RFD respectively using two HHDs (Lafayette Model-01165 and Hoggan microFET2) and a criterion-reference KinCom dynamometer. Statistical analysis of reliability and validity comprised intraclass correlation coefficients (ICC), Pearson correlations, concordance correlations, standard error of measurement, and minimal detectable change.

Results

Comparison of RFD methods revealed that a peak 200ms moving window algorithm provided optimal reliability results. Intra-rater, inter-rater, and inter-device reliability analysis of peak force and RFD revealed mostly good to excellent reliability (coefficients ≥ 0.70) for all muscle groups. Concurrent validity analysis showed moderate to excellent relationships between HHD and fixed dynamometry for the hip and knee (ICCs ≥ 0.70) for both peak force and RFD, with mostly poor to good results shown for the ankle muscles (ICCs = 0.31–0.79).

Conclusions

Hand-held dynamometry has good to excellent reliability and validity for most measures of isometric lower limb strength and power in a healthy population, particularly for proximal muscle groups. To aid implementation we have created freely available software to extract these variables from data stored on the Lafayette device. Future research should examine the reliability and validity of these variables in clinical populations.

Hemiparetic Knee Extensor Strength and Balance Function Are Predictors of Ambulatory Function in Subacute Stroke Patients

Objective

To identify the potential predictors of ambulatory function in subacute stroke patients, and to determine the contributing factors according to gait severity.

Methods

Fifty-three subacute stroke patents were enrolled. Ambulatory function was assessed by gait speed and endurance. Balance function was evaluated by the Berg Balance Scale score (BBS) and the Timed Up and Go test (TUG). The isometric muscular strengths of bilateral knee extensors and flexors were measured using an isokinetic dynamometer. Cardiovascular fitness was evaluated using an expired gas analyzer. Participants were assigned into the household ambulator group (<0.4 m/s) or the community ambulator group (≥0.4 m/s) based on gait severity.

Results

In the linear regression analyses of all patients, paretic knee isometric extensor strength (p=0.007) and BBS (p<0.001) were independent predictors of gait endurance (R²=0.668). TUG (p<0.001) and BBS (p=0.037) were independent predictors of gait speed (R²=0.671). Paretic isometric extensor strength was a predictor of gait endurance (R²=0.340, p=0.008). TUG was a predictor of gait speed (R²=0.404, p<0.001) in the household ambulator group, whereas BBS was a predictive factor of gait endurance (R²=0.598, p=0.008) and speed (R²=0.713, p=0.006). TUG was a predictor of gait speed (R²=0.713, p=0.004) in the community ambulator group.

Conclusion

Our results reveal that balance function and knee extensor isometric strength were strong predictors of ambulatory function in subacute stroke patients. However, they work differently according to gait severity. Therefore, a comprehensive functional assessment and a different therapeutic approach should be provided depending on gait severity in subacute stroke patients.

Gait training in subacute non-ambulatory stroke patients using a full weight-bearing gait-assistance robot: A prospective, randomized, open, blinded-endpoint trial

BACKGROUND

This study was a prospective, randomized, open, blinded-endpoint trial with the aim of examining whether gait training with a gait-assistance robot (GAR) improves gait disturbances in subacute non-ambulatory hemiplegic stroke patients more than overground conventional gait training. The GAR adopts a robot arm control system with full weight bearing and foot pressure visual biofeedback.

METHODS

Twenty-six hemiplegic patients were randomly assigned to either the GAR-assisted gait training (GAGT) group or the overground conventional gait training (OCGT) group. Both groups underwent 60 min of standard physical therapy and 20 min of GAGT or OCGT 5 days a week for 4 weeks. The primary outcome measure was the Functional Ambulation Classification (FAC). The secondary outcome measures were the peak torque of the extensor muscles in the lower extremities and a 10-m walking test. The lower extremity function was evaluated using the Fugl-Meyer Assessment, and activities of daily living were assessed using the Functional Independence Measure.

RESULTS

The GAGT group demonstrated significantly greater improvements in FAC and peak torque on the unaffected side (p=0.02) than the OCGT group. Additionally, gait speed tended to be faster (p=0.07) in the GAGT group.

CONCLUSIONS

GAGT combined with standard physical therapy in subacute non-ambulatory hemiplegic patients led to significant improvements in gait and peak torque on the unaffected side compared to OCGT.

Protocol variations and six-minute walk test performance in stroke survivors: a systematic review with meta-analysis

Objective. To investigate the use of the six-minute walk test (6MWT) for stroke survivors, including adherence to 6MWT protocol guidelines and distances achieved. Methods. A systematic search was conducted from inception to March 2014. Included studies reported a baseline (intervention studies) or first instance (observational studies) measure for the 6MWT performed by stroke survivors regardless of time after stroke.  Results. Of 127 studies (participants n = 6,012) that met the inclusion criteria, 64 were also suitable for meta-analysis. Only 25 studies made reference to the American Thoracic Society (ATS) standards for the 6MWT, and 28 reported using the protocol standard 30 m walkway. Thirty-nine studies modified the protocol walkway, while 60 studies did not specify the walkway used. On average, stroke survivors walked 284 ± 107 m during the 6MWT, which is substantially less than healthy age-matched individuals. The meta-analysis identified that changes to the ATS protocol walkway are associated with reductions in walking distances achieved. Conclusion. The 6MWT is now widely used in stroke studies. The distances achieved by stroke patients indicate substantially compromised walking ability. Variations to the standard 30 m walkway for the 6MWT are common and caution should be used when comparing the values achieved from studies using different walkway lengths.

Relationship between Depression and Strength Training in Survivors of the Ischemic Stroke

The Cerebral Vascular Accident is responsible for a significant increase in the mortality rate in individuals who have suffered this condition, regardless of the level of subsequent disability. This study aimed to analyze the influence of a strength training program on indicators of depression in survivors of the ischemic stroke. The study sample included subjects from both genders who were divided into two groups: an experimental group (EG) consisting of 11 subjects aged 51.7 8.0 years, and a control group (CG) consisting of 13 subjects aged 52.5 7.7 years. The EG underwent 12 weeks of strength training. Assessment was made in the pre-test before training and at the re-test after 12 weeks of training. We used the Beck Depression Inventory and evaluated 1RM. Significant differences in depression were found between post-test and pretest measurements (Δ% = -21.47%, p = 0,021) in the EG; furthermore, there were significant differences in all indicators of depression between the EG and CG after completing 12 weeks of training. There were significant gains in strength of the EG in relation to the CG. There was a negative correlation between the strength gains as determined with the 1RM test and the levels of depression, especially in lower-limb exercises. The results of this study suggest that improvements in strength are negatively correlated with levels of depression. Improvements in strength are therefore associated with a reduction in levels of depression.

Effects of dynamic stepping training on nonlocomotor tasks in individuals poststroke

BACKGROUND

During the physical rehabilitation of individuals poststroke, therapists are challenged to provide sufficient amounts of task-specific practice in order to maximize outcomes of multiple functional skills within limited visits. Basic and applied studies have suggested that training of one motor task may affect performance of biomechanically separate tasks that utilize overlapping neural circuits. However, few studies have explicitly investigated the impact of training one functional task on separate, nonpracticed tasks.

OBJECTIVE

The purpose of this preliminary study was to investigate the potential gains in specific nonlocomotor assessments in individuals poststroke following only stepping training of variable, challenging tasks at high aerobic intensities.

METHODS

Individuals with locomotor deficits following subacute and chronic stroke (n=22) completed a locomotor training paradigm using a repeated-measures design. Practice of multiple stepping tasks was provided in variable environments or contexts at high aerobic intensities for ≥40 sessions over 10 weeks. The primary outcome was timed Five-Times Sit-to-Stand Test (5XSTS) performance, with secondary measures of sit-to-stand kinematics and kinetics, clinical assessment of balance, and isometric lower limb strength.

RESULTS

Participants improved their timed 5XSTS performance following stepping training, with changes in selected biomechanical measures. Statistical and clinically meaningful improvements in balance were observed, with more modest changes in paretic leg strength.

CONCLUSIONS

The present data suggest that significant gains in selected nonlocomotor tasks can be achieved with high-intensity, variable stepping training. Improvements in nonpracticed tasks may minimize the need to practice multiple tasks within and across treatment sessions.

The stroke-related effects of hip flexion fatigue on over ground walking

Individuals post stroke often rely more on hip flexors for limb advancement during walking due to distal weakness but the effects of muscle fatigue in this group is not known. The purpose of this study was to quantify how stroke affects the influence of hip flexor fatigue on over ground walking kinematics and performance and muscle activation. Ten individuals with chronic stroke and 10 without stroke (controls) participated in the study. Maximal walking speed, walking distance, muscle electromyograms (EMG), and lower extremity joint kinematics were compared before and after dynamic, submaximal fatiguing contractions of the hip flexors (30% maximal load) performed until failure of the task. Task duration and decline in hip flexion maximal voluntary contraction (MVC) and power were used to assess fatigue. The stroke and control groups had similar task durations and percent reductions in MVC force following fatiguing contractions. Compared with controls, individuals with stroke had larger percent reductions in maximal walking speed, greater decrements in hip range of motion and peak velocity during swing, greater decrements in ankle velocity and lack of modulation of hip flexor EMG following fatiguing dynamic hip flexion contractions. For a given level of fatigue, the impact on walking function was more profound in individuals with stroke than neurologically intact individuals, and a decreased ability to up regulate hip flexor muscle activity may contribute. These data highlight the importance of monitoring the effect of hip flexor muscle activity during exercise or performance of activities of daily living on walking function post stroke.

Preoperative strength training for elderly patients awaiting total knee arthroplasty

Objective. To investigate the feasibility and effects of additional preoperative high intensity strength training for patients awaiting total knee arthroplasty (TKA). Design. Clinical controlled trial. Patients. Twenty-two patients awaiting TKA. Methods. Patients were allocated to a standard training group or a group receiving standard training with additional progressive strength training for 6 weeks. Isometric knee extensor strength, voluntary activation, chair stand, 6-minute walk test (6MWT), and stair climbing were assessed before and after 6 weeks of training and 6 and 12 weeks after TKA. Results. For 3 of the 11 patients in the intensive strength group, training load had to be adjusted because of pain. For both groups combined, improvements in chair stand and 6MWT were observed before surgery, but intensive strength training was not more effective than standard training. Voluntary activation did not change before and after surgery, and postoperative recovery was not different between groups (P > 0.05). Knee extensor strength of the affected leg before surgery was significantly associated with 6-minute walk (r = 0.50) and the stair climb (r - = 0.58, P < 0.05). Conclusion. Intensive strength training was feasible for the majority of patients, but there were no indications that it is more effective than standard training to increase preoperative physical performance. This trial was registered with NTR2278.

Physical fitness training for stroke patients

BACKGROUND

Levels of physical fitness are low after stroke. It is unknown whether improving physical fitness after stroke reduces disability.

OBJECTIVES

To determine whether fitness training after stroke reduces death, dependence, and disability. The secondary aims were to determine the effects of training on physical fitness, mobility, physical function, quality of life, mood, and incidence of adverse events.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched January 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 12: searched January 2013), MEDLINE (1966 to January 2013), EMBASE (1980 to January 2013), CINAHL (1982 to January 2013), SPORTDiscus (1949 to January 2013), and five additional databases (January 2013). We also searched ongoing trials registers, handsearched relevant journals and conference proceedings, screened reference lists, and contacted experts in the field.

SELECTION CRITERIA

Randomised trials comparing either cardiorespiratory training or resistance training, or both, with no intervention, a non-exercise intervention, or usual care in stroke survivors.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality, and extracted data. We analysed data using random-effects meta-analyses. Diverse outcome measures limited the intended analyses.

MAIN RESULTS

We included 45 trials, involving 2188 participants, which comprised cardiorespiratory (22 trials, 995 participants), resistance (eight trials, 275 participants), and mixed training interventions (15 trials, 918 participants). Nine deaths occurred before the end of the intervention and a further seven at the end of follow-up. No dependence data were reported. Diverse outcome measures made data pooling difficult. Global indices of disability show a tendency to improve after cardiorespiratory training (standardised mean difference (SMD) 0.37, 95% confidence interval (CI) 0.10 to 0.64; P = 0.007); benefits at follow-up and after mixed training were unclear. There were insufficient data to assess the effects of resistance training.Cardiorespiratory training involving walking improved maximum walking speed (mean difference (MD) 7.37 metres per minute, 95% CI 3.70 to 11.03), preferred gait speed (MD 4.63 metres per minute, 95% CI 1.84 to 7.43), walking capacity (MD 26.99 metres per six minutes, 95% CI 9.13 to 44.84), and Berg Balance scores (MD 3.14, 95% CI 0.56 to 5.73) at the end of the intervention. Mixed training, involving walking, increased preferred walking speed (MD 4.54 metres per minute, 95% CI 0.95 to 8.14), walking capacity (MD 41.60 metres per six minutes, 95% CI 25.25 to 57.95), and also pooled balance scores but the evidence is weaker (SMD 0.26 95% CI 0.04 to, 0.49). Some mobility benefits also persisted at the end of follow-up. The variability and trial quality hampered the assessment of the reliability and generalisability of the observed results.

AUTHORS' CONCLUSIONS

The effects of training on death and dependence after stroke are unclear. Cardiorespiratory training reduces disability after stroke and this may be mediated by improved mobility and balance. There is sufficient evidence to incorporate cardiorespiratory and mixed training, involving walking, within post-stroke rehabilitation programs to improve the speed and tolerance of walking; improvement in balance may also occur. There is insufficient evidence to support the use of resistance training. Further well-designed trials are needed to determine the optimal content of the exercise prescription and identify long-term benefits.

Motor unit rate coding is severely impaired during forceful and fast muscular contractions in individuals post stroke

Information regarding how motor units are controlled to produce forces in individuals with stroke and the mechanisms behind muscle weakness and movement slowness can potentially inform rehabilitation strategies. The purpose of this study was to describe the rate coding mechanism in individuals poststroke during both constant (n = 8) and rapid (n = 4) force production tasks. Isometric ankle dorsiflexion force, motor unit action potentials, and surface electromyography were recorded from the paretic and nonparetic tibialis anterior. In the paretic limb, strength was 38% less and the rate of force development was 63% slower. Linear regression was used to describe and compare the relationships between motor unit and electromyogram (EMG) measures and force. During constant force contractions up to 80% maximal voluntary contraction (MVC), rate coding was compressed and discharge rates were lower in the paretic limb. During rapid muscle contractions up to 90% MVC, the first interspike interval was prolonged and the rate of EMG rise was less in the paretic limb. Future rehabilitation strategies for individuals with stroke could focus on regaining these specific aspects of motor unit rate coding and neuromuscular activation.

Towards more effective robotic gait training for stroke rehabilitation: a review

Background

Stroke is the most common cause of disability in the developed world and can severely degrade walking function. Robot-driven gait therapy can provide assistance to patients during training and offers a number of advantages over other forms of therapy. These potential benefits do not, however, seem to have been fully realised as of yet in clinical practice.

Objectives

This review determines ways in which robot-driven gait technology could be improved in order to achieve better outcomes in gait rehabilitation.

Methods

The literature on gait impairments caused by stroke is reviewed, followed by research detailing the different pathways to recovery. The outcomes of clinical trials investigating robot-driven gait therapy are then examined. Finally, an analysis of the literature focused on the technical features of the robot-based devices is presented. This review thus combines both clinical and technical aspects in order to determine the routes by which robot-driven gait therapy could be further developed.

Conclusions

Active subject participation in robot-driven gait therapy is vital to many of the potential recovery pathways and is therefore an important feature of gait training. Higher levels of subject participation and challenge could be promoted through designs with a high emphasis on robotic transparency and sufficient degrees of freedom to allow other aspects of gait such as balance to be incorporated.

Physical fitness training for stroke patients

BACKGROUND

Levels of physical fitness are low after stroke. It is unknown whether improving physical fitness after stroke reduces disability.

OBJECTIVES

To determine whether fitness training after stroke reduces death, dependence, and disability. The secondary aims were to determine the effects of training on physical fitness, mobility, physical function, quality of life, mood, and incidence of adverse events.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched April 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, July 2010), MEDLINE (1966 to March 2010), EMBASE (1980 to March 2010), CINAHL (1982 to March 2010), SPORTDiscus (1949 to March 2010), and five additional databases (March 2010). We also searched ongoing trials registers, handsearched relevant journals and conference proceedings, screened reference lists, and contacted experts in the field.

SELECTION CRITERIA

Randomised trials comparing either cardiorespiratory training or resistance training, or both, with no intervention, a non-exercise intervention, or usual care in stroke survivors.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed quality, and extracted data. We analysed data using random-effects meta-analyses. Diverse outcome measures limited the intended analyses.

MAIN RESULTS

We included 32 trials, involving 1414 participants, which comprised cardiorespiratory (14 trials, 651 participants), resistance (seven trials, 246 participants), and mixed training interventions (11 trials, 517 participants). Five deaths were reported at the end of the intervention and nine at the end of follow-up. No dependence data were reported. Diverse outcome measures made data pooling difficult. The majority of the estimates of effect were not significant. Cardiorespiratory training involving walking improved maximum walking speed (mean difference (MD) 8.66 metres per minute, 95% confidence interval (CI) 2.98 to 14.34), preferred gait speed (MD 4.68 metres per minute, 95% CI 1.40 to 7.96) and walking capacity (MD 47.13 metres per six minutes, 95% CI 19.39 to 74.88) at the end of the intervention. These training effects were retained at the end of follow-up. Mixed training, involving walking, increased preferred walking speed (MD 2.93 metres per minute, 95% CI 0.02 to 5.84) and walking capacity (MD 30.59 metres per six minutes, 95% CI 8.90 to 52.28) but effects were smaller and there was heterogeneity amongst the trial results. There were insufficient data to assess the effects of resistance training. The variability in the quality of included trials hampered the reliability and generalizability of the observed results.

AUTHORS' CONCLUSIONS

The effects of training on death, dependence, and disability after stroke are unclear. There is sufficient evidence to incorporate cardiorespiratory training involving walking within post-stroke rehabilitation programmes to improve speed, tolerance, and independence during walking. Further well-designed trials are needed to determine the optimal exercise prescription and identify long-term benefits.

The loss of dexterity in the bilateral lower extremities in patients with stroke

The aim of this study was to examine the dexterity of both lower extremities in patients with stroke. Twenty patients with stroke and 20 age-matched control subjects participated in this study. To determine the dexterity of the lower extremities, we examined the ability to control muscle force during submaximal contractions in the knee extensor muscles using a force tracking task. The root mean square errors were calculated from the difference between the target and response force. The root mean square error was significantly greater in the affected limb of patients with stroke compared with those of the unaffected limb and the control subjects, and in the unaffected limb compared with that of the control subjects. Furthermore, the root mean square error of the affected limb was related significantly to motor function as determined by Fugl-Myer assessment. These results demonstrate impairment of the dexterity of both the affected and the unaffected lower extremities in patients with stroke.

Corticospinal tract integrity correlates with knee extensor weakness in chronic stroke survivors

OBJECTIVE

Muscle weakness develops rapidly after stroke, adversely affecting motor performance, and contributing to reduced functional ability. While the contributions of structural and functional alterations in skeletal muscle to post-stroke weakness have been well described, the relationship between motor pathway integrity, measured using both radiological and electrophysiological techniques, and post-stroke muscle weakness is not clear. This study sought to determine the role of corticospinal tract (CST) integrity on knee extensor weakness in chronic stroke survivors.

METHODS

Knee extensor strength and activation testing were performed at 90° of knee flexion using an interpolated triplet technique. CST integrity was evaluated using data obtained from Diffusion Tensor Imaging and transcranial magnetic stimulation.

RESULTS

Recordings in nine stroke subjects indicated substantial knee extensor weakness and activation deficits in the paretic legs of the stroke survivors. Regression analysis revealed that asymmetry in CST integrity was strongly related to between-leg differences in knee strength.

CONCLUSIONS

The results of this study suggest a strong link between CST integrity and lower extremity strength, and add to the growing evidence of substantial knee extensor weakness and activation impairments in stroke survivors.

SIGNIFICANCE

The findings from this study further our understanding of the anatomical and neurophysiological contributions to motor impairments after stroke, which may benefit clinicians and researchers in the field of stroke rehabilitation.