Low intensity strength training for ambulatory stroke patients

Functional Resistance Training With Viscous and Elastic Devices: Does Resistance Type Acutely Affect Knee Function?

OBJECTIVE

Functional resistance training (FRT) during walking is an emerging approach for rehabilitating individuals with neuromuscular or orthopedic injuries. During FRT, wearable exoskeleton/braces can target resistance to a weakened leg joint; however, the resistive properties of the training depend on the type of resistive elements used in the device. Hence, this study was designed to examine how the biomechanical and neural effects of functional resistance training differ with viscous and elastic resistances during both treadmill and overground walking.

METHODS

Fourteen able-bodied individuals were trained on two separate sessions with two devices that provided resistance to the knee (viscous and elastic) while walking on a treadmill. We measured gait biomechanics and muscle activation during training, as well as kinematic aftereffects and changes in peripheral fatigue and neural excitability after training.

RESULTS

We found the resistance type differentially altered gait kinetics during training-elastic resistance increased knee extension during stance while viscous resistance primarily affected swing. Also, viscous resistance increased power generation while elastic resistance could increase power absorption. Both devices resulted in significant kinematic and neural aftereffects. However, overground kinematic aftereffects and neural excitability did not differ between devices.

CONCLUSION

Different resistance types can be used to alter gait biomechanics during training. While there were no resistance-specific changes in acute neural adaptation following training, it is still possible that prolonged and repeated training could produce differential effects.

SIGNIFICANCE

Resistance type alters the kinetics of functional resistance training. Prolonged and repeated training sessions on patients will be needed to further measure the effects of these devices.

A Review of Rehabilitation Benefits of Exercise Training Combined with Nutrition Supplement for Improving Protein Synthesis and Skeletal Muscle Strength in Patients with Cerebral Stroke

Cerebral vascular accident (CVA) is one of the main causes of chronic disability, and it affects the function of daily life, so it is increasingly important to actively rehabilitate patients' physical functions. The research confirmed that the nutrition supplement strategy is helpful to improve the effect of sports rehabilitation adaptation and sports performance. The patients with chronic strokes (whose strokes occur for more than 6 months) have special nutritional needs while actively carrying out rehabilitation exercises, but there are still few studies to discuss at present. Therefore, this paper will take exercise rehabilitation to promote muscle strength and improve muscle protein synthesis as the main axis and, through integrating existing scientific evidence, discuss the special needs of chronic stroke patients in rehabilitation exercise intervention and nutrition supplement one by one. At the same time, we further evaluated the physiological mechanism of nutrition intervention to promote training adaptation and compared the effects of various nutrition supplement strategies on stroke rehabilitation. Literature review pointed out that immediately supplementing protein nutrition (such as whey protein or soybean protein) after resistance exercise or endurance exercise can promote the efficiency of muscle protein synthesis and produce additive benefits, thereby improving the quality of muscle tissue. Recent animal research results show that probiotics can prevent the risk factors of neural function degradation and promote the benefits of sports rehabilitation. At the same time, natural polyphenols (such as catechin or resveratrol) or vitamins can also reduce the oxidative stress injury caused by animal stroke and promote the proliferation of neural tissue. In view of the fact that animal research results still make up the majority of issues related to the role of nutrition supplements in promoting nerve repair and protection, and the true benefits still need to be confirmed by subsequent human studies. This paper suggests that the future research direction should be the supplement of natural antioxidants, probiotics, compound nutritional supplements, and integrated human clinical research.

Functional resistance training methods for targeting patient-specific gait deficits: A review of devices and their effects on muscle activation, neural control, and gait mechanics

BACKGROUND

Injuries to the neuromusculoskeletal system often result in weakness and gait impairments. Functional resistance training during walking-where patients walk while a device increases loading on the leg-is an emerging approach to combat these symptoms. However, there are many methods that can be used to resist the patient, which may alter the biomechanics of the training. Thus, all methods may not address patient-specific deficits.

METHODS

We performed a comprehensive electronic database search to identify articles that acutely (i.e., after a single training session) examined how functional resistance training during walking alters muscle activation, gait biomechanics, and neural plasticity. Only articles that examined these effects during training or following the removal of resistance (i.e., aftereffects) were included.

FINDINGS

We found 41 studies that matched these criteria. Most studies (24) used passive devices (e.g., weighted cuffs or resistance bands) while the remainder used robotic devices. Devices varied on if they were wearable (14) or externally tethered, and the type of resistance they applied (i.e., inertial [14], elastic [8], viscous [7], or customized [12]). Notably, these methods provided device-specific changes in muscle activation, biomechanics, and spatiotemporal and kinematic aftereffects. Some evidence suggests this training results in task-specific increases in neural excitability.

INTERPRETATION

These findings suggest that careful selection of resistive strategies could help target patient-specific strength deficits and gait impairments. Also, many approaches are low-cost and feasible for clinical or in-home use. The results provide new insights for clinicians on selecting an appropriate functional resistance training strategy to target patient-specific needs.

EMG-Triggered Pedaling Training on Muscle Activation, Gait, and Motor Function for Stroke Patients

This study aimed to determine the effects of electromyography (EMG)-triggered pedaling training to improve motor functions in the lower extremities, muscle activation, gait, postural balance, and activities of daily living in stroke patients. Subjects were randomly allocated to two groups: the EMG-triggered pedaling training group (EMG-PTG, n = 21) and the traditional pedaling training group (TPTG, n = 20). Both groups trained five times per week for four weeks, with 50 min per session. Lower extremity motor function was assessed using the Fugl–Meyer Assessment (FMA). Muscle activation of the four muscles of the lower extremities was assessed using eight-channel electromyography, while gait ability was assessed using GaitRite. Postural balance was assessed using the Berg balance scale (BBS), the timed up and go (TUG), and functional reach tests (FRT). Daily activities were assessed using the Modified Barthel Index (MBI). For lower extremity motor function, gait ability, balance ability, and activities of daily living, the EMG-PTG showed significant improvement compared to TPTG (p < 0.05). These results suggest that EMG-triggered pedaling training effectively improves lower extremity motor function, muscle activation, gait, postural balance, and activities of daily living in stroke patients.

Adaptive robot mediated upper limb training using electromyogram-based muscle fatigue indicators

Studies on improving the adaptability of upper limb rehabilitation training do not often consider the implications of muscle fatigue sufficiently. In this study, electromyogram features were used as fatigue indicators in the context of human-robot interaction. They were utilised for auto-adaptation of the task difficulty, which resulted in a prolonged training interaction. The electromyogram data was collected from three gross-muscles of the upper limb in 30 healthy participants. The experiment followed a protocol for increasing the muscle strength by progressive strength training, that was an implementation of a known method in sports science for muscle training, in a new domain of robotic adaptation in muscle training. The study also compared how the participants in three experimental conditions perceived the change in task difficulty levels. One task benefitted from robotic adaptation (Intervention group) where the robot adjusted the task difficulty. The other two tasks were control groups 1 and 2. There was no difficulty adjustment at all in Control 1 group and the difficulty was adjusted manually in Control 2 group. The results indicated that the participants could perform a prolonged progressive strength training exercise with more repetitions with the help of a fatigue-based robotic adaptation, compared to the training interactions, which were based on manual/no adaptation. This study showed that it is possible to alter the level of the challenge using fatigue indicators, and thus, increase the interaction time. The results of the study are expected to be extended to stroke patients in the future by utilising the potential for adapting the training difficulty according to the patient's muscular state, and also to have a large number repetitions in a robot-assisted training environment.

Quantitative data analysis of perceived barriers and motivators to physical activity in stroke survivors

BACKGROUND

Levels of physical activity after stroke are low, despite multiple health benefits. We explored stroke survivors' perceived barriers, motivators, self-efficacy and intention to physical activity.

METHODS

Fifty independently mobile stroke survivors were recruited prior to hospital discharge. Participants rated nine possible motivators and four possible barriers based on the Mutrie Scale, as having 'no influence', 'some influence' or 'a major influence' on physical activity. Participants also rated their self-efficacy and intention to increasing walking.

RESULTS

The most common motivator was 'physical activity is good for health' [34 (68%)]. The most common barrier was 'feeling too tired' [24 (48%)]. Intention and self-efficacy were high. Self-efficacy was graded as either 4 or 5 (highly confident) on a five-point scale by [34 (68%)] participants, while 42 (84%) 'strongly agreed' or 'agreed' that they intended to increase their walking.

CONCLUSION

Participants felt capable of increasing physical activity but fatigue was often perceived as a barrier to physical activity. This needs to be considered when encouraging stroke survivors to be more active.

Strength training protocols in hemiparetic individuals post stroke: a systematic review

Abstract Introduction: Hemiparesis is one of the main sequels of stroke. Evidence suggests that muscle strength exercises are important in rehabilitation programs for hemiparetic patients, but wide variation in previously studied protocols makes the most suitable choice difficult in clinical practice. Objective: The aim of this study was to investigate strength training protocols for people with hemiparesis after stroke. Methods: A systematic review of literature was performed in the PubMed, PEDro (Physiotherapy Evidence Database), SciELO (Scientific Electronic Library Online), and LILACS (Latin American and Caribbean Literature in Health Science) databases. Only controlled clinical studies that contained strength training protocols for hemiparesis after stroke were selected. Results: In total, 562 articles were found. Of them, 12 were accepted for the systematic review. Although strength training protocols are effective in hemiparetic patients, we did not found a standard method for strength training. Conclusion: This systematic revision highlights the lack of a standard protocol for strength training, considering the following training parameters: volume, intensity, frequency, series, and repetitions. Isotonic exercises are most commonly used.

Classifying physical activity research following stroke using the behavioral epidemiologic framework

BACKGROUND

Stroke is a significant public health issue in the USA and a need emerges to better understand how to reduce an individual's co-morbidity risk. Physical activity is one approach to improving the health of individuals and comprehensive literature supports increased activity as a means to reduce risk of morbidity and mortality. One approach to examining whether research in a field is addressing a public health issue is through application of the behavioral epidemiological framework.

OBJECTIVE

To classify physical activity research for individuals following stroke into distinct phases so that efforts can be made to systematically address gaps and disseminate evidence-based practice.

METHODS

Specific key words were identified and then searched through EBSCO host, PubMed, and Google Scholar. Physical activity and stroke literature from 2000-2014 was categorized into one of five discrete phases. Research in Phase 1 identified associations between activity and health; Phase 2 established valid measures of activity; Phase 3 examined determinants of behavior; Phase 4 evaluated activity interventions; and Phase 5 disseminated evidence-based practice.

RESULTS

A comprehensive review of literature identified 202 articles with 70% categorized in Phase 1 (n = 141), 11% in Phase 2 (n = 23), 10% in Phase 3 (n = 20), 8% in Phase 4 (n = 15), and 1% in Phase 5 (n = 3).

CONCLUSION

Findings suggest that physical activity research for individuals following stroke is in the early stages of development with less than 10% of research evaluating or disseminating interventions.

Factors that influence muscle weakness following stroke and their clinical implications: a critical review

PURPOSE

To provide a comprehensive review of changes that occur in the muscle after stroke and how these changes influence the force-generating capacity of the muscle.

METHODS

A literature search of PubMed, CINAHL, MEDLINE, and Embase was conducted using the search terms stroke, hemiparesis, muscle structure, cross sectional area, atrophy, force, velocity, and torque. There were 27 articles included in this review.

RESULTS

Three changes occur in the muscle after stroke: a decrease in muscle mass, a decrease in fibre length, and a smaller pennation angle. In addition, the tendon is stretched and becomes more compliant. All of these factors reduce the affected muscle's ability to generate forces similar to controls or to non-paretic muscles. The result is a leftward shift in the length-tension curve, a downward shift in the torque-angle curve, and a downward shift in the force-velocity curve.

CONCLUSION

Changes in muscle architecture contributing to weakness, such as muscle-fibre length, pennation angle, muscle atrophy, and tendon compliance, should be prevented or reversed by means of an appropriate rehabilitation programme.

The importance of psychological and social factors in influencing the uptake and maintenance of physical activity after stroke: a structured review of the empirical literature

Background. People with stroke are not maintaining adequate engagement in physical activity (PA) for health and functional benefit. This paper sought to describe any psychological and social factors that may influence physical activity engagement after stroke. Methods. A structured literature review of studies indexed in MEDLINE, CinAHL, P&BSC, and PsycINFO using search terms relevant to stroke, physical disabilities, and PA. Publications reporting empirical findings (quantitative or qualitative) regarding psychological and/or social factors were included. Results. Twenty studies from 19 publications (9 surveys, 1 RCT, and 10 qualitative studies) were included. Seventeen studies reported findings pertinent to psychological factors and fourteen findings pertinent to social factors. Conclusion. Self-efficacy, physical activity beliefs, and social support appear particularly relevant to physical activity behaviour after stroke and should be included in theoretically based physical interventions. The Transtheoretical Model and the Theory of Planned Behaviour are candidate behavioural models that may support intervention development.

A mathematical model of neuromuscular adaptation to resistance training and its application in a computer simulation of accommodating loads

A large corpus of data obtained by means of empirical study of neuromuscular adaptation is currently of limited use to athletes and their coaches. One of the reasons lies in the unclear direct practical utility of many individual trials. This paper introduces a mathematical model of adaptation to resistance training, which derives its elements from physiological fundamentals on the one side, and empirical findings on the other. The key element of the proposed model is what is here termed the athlete's capability profile. This is a generalization of length and velocity dependent force production characteristics of individual muscles, to an exercise with arbitrary biomechanics. The capability profile, a two-dimensional function over the capability plane, plays the central role in the proposed model of the training-adaptation feedback loop. Together with a dynamic model of resistance the capability profile is used in the model's predictive stage when exercise performance is simulated using a numerical approximation of differential equations of motion. Simulation results are used to infer the adaptational stimulus, which manifests itself through a fed back modification of the capability profile. It is shown how empirical evidence of exercise specificity can be formulated mathematically and integrated in this framework. A detailed description of the proposed model is followed by examples of its application-new insights into the effects of accommodating loading for powerlifting are demonstrated. This is followed by a discussion of the limitations of the proposed model and an overview of avenues for future work.

Intensive training of subjects with chronic hemiparesis on a motorized cycle combined with functional electrical stimulation (FES): a feasibility and safety study

BACKGROUND AND PURPOSE

This study tested the safety and ability of subjects with chronic hemiplegia to tolerate intensive training using a motorized cycle combined with functional electrical stimulation (FES) system.

METHODS

A case series of 10 subjects with chronic stroke participated in 30-minute three times per week cycling on a stationary motorized cycling system combined with FES (RT300(TM) ). The stimulation activated the dorsal and plantar flexors, the quadriceps and the hamstrings using four channels and a stimulation pattern that assisted cycling motion of the paretic lower limb. Patients were instructed to cycle as close as possible to 60 rpm and the resistance to cycling was gradually increased using a computer-based algorithm. The training lasted eight weeks.

RESULTS

All 10 participants completed the training without adverse reactions to the training or the FES. The kcal utilized during the training increased significantly (p = 0.0003) between session 1 (2.2 ± 0.47), session 12 (4.3 ± 1.2) and session 24 (7.5 ± 1.8). Peak pedaling power increased from 6.5 ± 0.5 W pre-training to 18.0 ± 5.4 W post-training. Locomotion variables that improved significantly were time to complete the get up and go test (45.4 ± 54.9 seconds vs. 34.0 ± 31.8 seconds) a 24.6% improvement (p = 0.03) and gait velocity, which increased 25.0% from 0.4 ± 0.3 m/sec to 0.5 ± 0.4 m/sec (p = 0.01).

CONCLUSION

Using a motorized cycle combined with FES intensive training appears safe and can be tolerated by patients with chronic stroke of wide age range, diverse severity of cardio-pulmonary deconditioning, motor loss and locomotor deficits.

Effectiveness of a community-based low intensity exercise programme for ambulatory stroke survivors

PURPOSE

To establish the feasibility and effectiveness of a community-based exercise programme for ambulatory patients with stroke discharged from rehabilitation.

METHOD

Eighteen participants were recruited 3-12 months after onset of first stroke. Using a time series experimental design, the group completed a baseline period of 4 weeks (A1), a group exercise programme of low-intensity progressive resistive exercise and functional tasks for lower limb muscles (B) and repeat assessment after cessation of exercise (A2). Fitness instructors delivered sessions at Leisure Centres twice weekly for 14 weeks with physiotherapy support and the minimum attendance requirement was 16 sessions. Measures included muscle strength, gait velocity, Berg Balance Scale and Nottingham Extended Activities of Daily Living.

RESULTS

Lower limb muscle strength improved after training (ANOVA, p < 0.02). Paretic knee extension strength increased from 43.4 + or - 5.9 to 60.4 + or - 6.8 Nm after 16 exercise sessions. Walking velocity increased significantly (ANOVA, p < 0.001), from 0.54 + or - 0.07 to 0.75 + or - 0.08 m/s (t = -3.31, p < 0.01). Balance and everyday function were also significantly improved (p < 0.003). There were marked individual variation in the response to training, and those who completed additional training did not show benefit.

CONCLUSIONS

This community-based exercise programme was feasible and delivered positive improvements in physical function for participants. Further issues raised for investigation include the individual response to training and the benefits of extended training.

Progressive resistance strength training for improving physical function in older adults

BACKGROUND

Muscle weakness in old age is associated with physical function decline. Progressive resistance strength training (PRT) exercises are designed to increase strength.

OBJECTIVES

To assess the effects of PRT on older people and identify adverse events.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialized Register (to March 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 2), MEDLINE (1966 to May 01, 2008), EMBASE (1980 to February 06 2007), CINAHL (1982 to July 01 2007) and two other electronic databases. We also searched reference lists of articles, reviewed conference abstracts and contacted authors.

SELECTION CRITERIA

Randomised controlled trials reporting physical outcomes of PRT for older people were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data. Data were pooled where appropriate.

MAIN RESULTS

One hundred and twenty one trials with 6700 participants were included. In most trials, PRT was performed two to three times per week and at a high intensity. PRT resulted in a small but significant improvement in physical ability (33 trials, 2172 participants; SMD 0.14, 95% CI 0.05 to 0.22). Functional limitation measures also showed improvements: e.g. there was a modest improvement in gait speed (24 trials, 1179 participants, MD 0.08 m/s, 95% CI 0.04 to 0.12); and a moderate to large effect for getting out of a chair (11 trials, 384 participants, SMD -0.94, 95% CI -1.49 to -0.38). PRT had a large positive effect on muscle strength (73 trials, 3059 participants, SMD 0.84, 95% CI 0.67 to 1.00). Participants with osteoarthritis reported a reduction in pain following PRT(6 trials, 503 participants, SMD -0.30, 95% CI -0.48 to -0.13). There was no evidence from 10 other trials (587 participants) that PRT had an effect on bodily pain. Adverse events were poorly recorded but adverse events related to musculoskeletal complaints, such as joint pain and muscle soreness, were reported in many of the studies that prospectively defined and monitored these events. Serious adverse events were rare, and no serious events were reported to be directly related to the exercise programme.

AUTHORS' CONCLUSIONS

This review provides evidence that PRT is an effective intervention for improving physical functioning in older people, including improving strength and the performance of some simple and complex activities. However, some caution is needed with transferring these exercises for use with clinical populations because adverse events are not adequately reported.

Standardized voluntary force measurement in a lower extremity rehabilitation robot

BACKGROUND

Isometric force measurements in the lower extremity are widely used in rehabilitation of subjects with neurological movement disorders (NMD) because walking ability has been shown to be related to muscle strength. Therefore muscle strength measurements can be used to monitor and control the effects of training programs. A new method to assess isometric muscle force was implemented in the driven gait orthosis (DGO) Lokomat. To evaluate the capabilities of this new measurement method, inter- and intra-rater reliability were assessed.

METHODS

Reliability was assessed in subjects with and without NMD. Subjects were tested twice on the same day by two different therapists to test inter-rater reliability and on two separate days by the same therapist to test intra-rater reliability.

RESULTS

Results showed fair to good reliability for the new measurement method to assess isometric muscle force of lower extremities. In subjects without NMD, intraclass correlation coefficients (ICC) for inter-rater reliability ranged from 0.72 to 0.97 and intra-rater reliability from 0.71 to 0.90. In subjects with NMD, ICC ranged from 0.66 to 0.97 for inter-rater and from 0.50 to 0.96 for intra-rater reliability.

CONCLUSION

Inter- and intra- rater reliability of an assessment method for measuring maximal voluntary isometric muscle force of lower extremities was demonstrated. We suggest that this method is a valuable tool for documentation and controlling of the rehabilitation process in patients using a DGO.

Improvement in Functional Ambulation as a Therapeutic Effect of Peroneal Nerve Stimulation in Hemiplegia: Two Case Reports

Two chronic stroke survivors who utilized an ankle foot orthosis (AFO) prior to study entry were evaluated at baseline and after 4 weeks of daily use of a surface peroneal nerve stimulator. Participants were assessed without their dorsiflexor assistive device, using the modified Emory Functional Ambulation Profile (mEFAP). The participants demonstrated improvement in all 5 components of the mEFAP relative to baseline. These case reports indicate that enhanced functional ambulation may be an important therapeutic effect of peroneal nerve stimulation. Potential mechanisms are discussed. Controlled trials are needed to demonstrate a cause-and-effect relationship.