POWER training in chronic stroke individuals: differences between responders and nonresponders

Lower limb revascularization leads to faster walking but with less efficient mechanics in claudicating patients

Peripheral artery disease (PAD) is characterized by reduced blood flow to the extremities due to atherosclerosis. Studies report impaired gait mechanics in patients with lower extremity PAD. We hypothesized that revascularization surgery would improve gait mechanics when quantified by net lower limb joint work across the stance phase of walking. We performed gait analyses in 35 patients with PAD and 35 healthy, older adults. Patients with PAD performed a walking protocol prior to and six months following revascularization surgery. Healthy adults only took part in a single walking session. Lower limb joint powers were calculated using inverse dynamics and were integrated across early, middle, and late stance phases to determine the work performed during each phase (J kg-1). The work mechanical ratio between positive-producing and negative-producing phases of stance was calculated for each lower-limb joint. Self-selected walking speed significantly increased from 1.13 ± 0.2 ms-1 to 1.26 ± 0.18 ms-1 in patients following revascularization (p < 0.001). We observed a significant decrease in positive late stance work (p < 0.001) in conjunction with more negative work during early stance (p < 0.001) in patients following revascularization. Revascularization surgery led to faster walking without an increase in the ankle joint's mechanical ratio. Our results suggest faster walking was achieved via work done at the hip rather than the ankle. These findings suggest that additional therapies that facilitate the restoration of muscle, tissue, and nervous system damage caused by years of having reduced blood flow to the limbs might still be beneficial following revascularization.

Comparing the contribution of each clinical indicator in predictive models trained on 980 subacute stroke patients: a retrospective study

Post-stroke disability affects patients' lifestyles after discharge, and it is essential to predict functional recovery early in hospitalization to allow time for appropriate decisions. Previous studies reported important clinical indicators, but only a few clinical indicators were analyzed due to insufficient numbers of cases. Although review articles can exhaustively identify many prognostic factors, it remains impossible to compare the contribution of each predictor. This study aimed to determine which clinical indicators contribute more to predicting the functional independence measure (FIM) at discharge by comparing standardized coefficients. In this study, 980 participants were enrolled to build predictive models with 32 clinical indicators, including the stroke impairment assessment set (SIAS). Trunk function had the most significant standardized coefficient of 0.221. The predictive models also identified easy FIM sub-items, SIAS, and grip strength on the unaffected side as having positive standardized coefficients. As for the predictive accuracy of this model, R² was 0.741. This is the first report that included FIM sub-items separately in post-stroke predictive models with other clinical indicators. Trunk function and easy FIM sub-items were included in the predictive model with larger positive standardized coefficients. This predictive model may predict prognosis with high accuracy, fewer clinical indicators, and less effort to predict.

Effect of power training on rate of torque development and spatiotemporal gait parameters post stroke

BACKGROUND

Maximizing independence and function post-stroke are two common therapy goals. Rate of torque development in lower-extremity muscles was recently reported to be associated with walking speed; however, trainability and subsequent effect on gait is unknown. This study aimed to determine effect of power training on paretic and non-paretic limb torque parameters, spatiotemporal gait parameters, and walking speed in chronic stroke survivors.

METHODS

Individuals with chronic stroke (n = 22; 7 females; 62.7 ± 8.8 yrs) completed 24 progressive power-training sessions over 8 weeks with pre and post assessments. Knee extensor strength was assessed via dynamometry with torque parameters measured from maximal voluntary isometric contractions. Gait speed and spatiotemporal gait parameters were assessed via an instrumented gait mat, and a 6-min walk test was performed.

FINDINGS

Rate of torque development at 200 ms and peak torque improved 58.6% and 14.1%, respectively, in the quadricep of the paretic limb (p < 0.05); conversely the non-paretic limb was unchanged. On average, self-selected walking speed, fastest-comfortable walking speed, and 6-min walk test improved 21.7%, 21.1%, and 19.5%, respectively (all p < 0.05). Change in torque development at 100 ms in the quadricep of the non-paretic limb was positively associated with improvements in self-selected and fastest-comfortable walking speeds (both r = 0.70, p < 0.05) and 6-min walk (r = 0.78, p < 0.001).

INTERPRETATIONS

These findings suggest power training may be an effective intervention for improving torque development in the quadricep of the paretic limb in individuals with chronic stroke. Further research to explore utility and mechanistic aspects of force development for gait function in chronic stroke survivors is warranted.

Hip Abductor Power and Velocity: Reliability and Association With Physical Function

ABSTRACT

Lanza, MB, Jin, KH, Karl, H, Myers, J, Ryan, E, and Gray, VL. Hip abductor power and velocity: reliability and association with physical function. J Strength Cond Res 37(2): 284-290, 2023-Muscle power, defined as the ability of the muscle to produce torque quickly, has received little attention and may be critical for understanding physical function and performance. Hip abductors' capacity to produce power through both torque and velocity is important for different human activities; hence, a reliable assessment of hip abduction is critical. The first aim of the study was to assess the intersession reliability of hip abductor muscles maximal torque and submaximal power and power during standing hip abduction in young adults using pneumatic resistance. A secondary aim was to investigate whether there was a relationship between hip abductor maximal torque and submaximal power and velocity with clinical assessments of strength and power in young adults. The subjects (n = 24; 26.0 ± 3.7 years) visited the laboratory 2 times. In the first visit, the subjects performed on a pneumatic resistance machine 1-repetition maximum (1RM) and submaximal tests (40, 60, and 70% of 1RM) of the hip abductors and clinical tests of lower-extremity strength and power (The 30-second chair stand test [30CST]; and stair climb power test). During the second visit, all tests were repeated except the clinical tests. One-repetition maximum torque and submaximal power and velocity (at all levels) had excellent reliability (intraclass correlation coefficient ≥ 0.943) with absolute reliability of 13.5% up to 28.3%. The agreement between days from Bland-Altman plots for power and velocity was near 0 for all levels. Hip abduction velocity had a significant positive correlation with 30CST at 60% (r = 0.416; p = 0.048) and 70% of 1RM (r = 0.442; p = 0.035). In conclusion, we showed an excellent intersession reliability of the hip abductor muscles 1RM torque and submaximal power and velocity using pneumatic resistance. Furthermore, we demonstrated that hip abduction velocity might be important for the performance of the 30CST.

Effects of Subtalar Joint Mobilization with Movement on Muscle Strength, Balance, Functional Performance, and Gait Parameters in Patients with Chronic Stroke: A Single-Blind Randomized Controlled Study

BACKGROUND

Losses in muscle strength, balance, and gait are common in patients with chronic stroke (CS). Ankle joint movements play a key role in this population to maintain a sufficient level of functional activity. The aim of this study was to investigate the effects of the subtalar joint (STJ) mobilization with movement (MWM) technique on muscle strength, balance, functional performance, and gait speed (GS) in patients with CS.

METHODS

Twenty-eight patients with CS were randomly divided into the control group (n = 14) and the STJ MWM group (n = 14). A 30-min neurodevelopmental treatment program and talocrural joint MWM were applied to both groups. Also, STJ MWM was applied to the STJ MWM group. The patients were treated 3 days a week for 4 weeks. Ankle dorsiflexion and plantarflexion muscle strength, Berg Balance Scale, Timed Up and Go test, and GS were evaluated before and after treatment.

RESULTS

Berg Balance Scale and Timed Up and Go test scores, dorsiflexion and plantarflexion muscle strength, and GS improved in both groups after the treatment sessions (P < .05), but the improvements were greater in the STJ MWM group compared with the control group (P < .05).

CONCLUSIONS

According to these results, STJ MWM together with neurodevelopmental treatment and talocrural joint MWM can increase ankle muscle strength, balance, functional performance, and GS on the affected leg in patients with CS.

Lessons Learned: The Difficulties of Incorporating Intensity Principles Into Inpatient Stroke Rehabilitation

Objective

The objective of this study was to determine the feasibility of a rehabilitation approach focusing on cardiovascular, strength, and gait training intensity in the inpatient rehabilitation setting after a new onset of stroke. We additionally aimed to determine the efficacy of this intensity-based program on rehabilitation outcomes compared with usual care.

Design

Participants were pseudo-randomized to an intensity-based program focusing on gait, cardiovascular, and strength training or to usual care. Outcomes included FIM, 10-meter walk, 2-minute walk, timed Up and Go test, 5-time sit-to-stand test, and Tinetti balance assessment.

Intervention

The intervention consisted of 6 20-minute sessions per week dedicated to intensity of activity: 2 each for walking, cardiovascular training, and strength training.

Participants

Patients (N=49) with new onset stroke admitted to inpatient rehabilitation over the course of 1 year.

Setting

Four inpatient rehabilitation facilities with comprehensive neurologic rehabilitation teams.

Results

Thirty-five individuals (16 intervention, 19 controls) completed all testing. Subject compliance to the intensity intervention demonstrated completion of approximately half the prescribed sessions. All outcomes improved significantly from admission to discharge, and a significant interaction between treatment group and time was observed for the 2-minute walk and the Tinetti balance assessment. The 2-minute walk, Tinetti balance assessment, 10-meter walk, and FIM demonstrated between-group effect sizes greater than 0.60 in favor of the intervention group.

Conclusions

The intensity-based protocol was safe, and several measures demonstrated efficacy when compared with usual care. Results may have been limited by poor program compliance, showing a need to identify and ameliorate obstacles to integration of comprehensive intensity-based programs addressing endurance, strength, and gait training. Applying physiological principles of exercise to acute stroke rehabilitation demonstrates great promise for improving independent physical function.

An Orthotic Joint Design for Enhancing Ankle Mobility With Ankle Foot Orthoses Use

Articulated ankle foot orthoses (AFOs) are prescribed to treat drop-foot, a common neuromuscular weakness observed after a stroke. These assistive devices prevent the toe from dragging during swing (drop-foot) by providing a resistive moment at the ankle. However, existing ankle joint designs for articulated AFOs introduce additional gait pathologies as they also constrain ankle mobility during stance. A novel ankle joint for AFOs to prevent drop-foot during swing and improve ankle mobility during stance was developed, thereby reducing compensatory knee motion during stance. The design intent was to mimic the unconstrained kinematic response of a nonpathologic ankle at initial contact while preventing drop-foot during swing. The design incorporated two modes of operation: locked during swing for support and unlocked during stance for enhanced range of motion. Proof of concept testing with able-bodied subjects was conducted to test walking ability over level ground based on kinetic and kinematic parameters. The comparative tests confirmed the ability of the novel design to prevent drop-foot and its potential for enhanced ankle mobility during stance. Preliminary results indicate that the novel ankle joint should be refined to facilitate smooth and consistent unlocking but can be safely used in its current form with mobility impaired individuals.

Muscle Power is Related to Physical Function in Patients Surviving Acute Respiratory Failure: A Prospective Observational Study

BACKGROUND

Up to 66% of patients admitted to the intensive care unit (ICU) for acute respiratory failure (ARF) develop ICU-acquired weakness, which is diagnosed by muscle strength testing. Muscle power, different from strength, is an important determinant of function that is not a common focus in patients surviving critical illness. Therefore, the purpose of this study is to assess muscle power in survivors of ARF.

METHODS

A cross-sectional observational study performed with survivors of ARF. Muscle power, strength and physical function were assessed 4-8 weeks post-hospital discharge. Cross sectional area and echogenicity of rectus femoris and tibialis anterior muscles were assessed using ultrasonography. Healthy community-dwelling adults were included for comparison.

RESULTS

12 survivors of ARF mean age of 55.6 ± 17.1 (66% male) and 12 healthy adults mean age of 51.6.1 ± 10.3 (66% male) participated in this study. Patients in the post-ARF group had a mean muscle power of 9.9 ± 3.5 W and 63.7 ± 31.6 W for 2-lb and 10% of body-weight loads, respectively. Compared to matched controls, power in ARF group was reduced by 43%. Muscle power in post-ARF group had moderate correlations with 5-times sit-to-stand testing (r = -0.644, P = 0.024), 4-m habitual gait speed (-0.780, P = 0.002), and 6-min walk distance (r = 0.589, P = 0.044).

CONCLUSIONS

Muscle power is significantly reduced in survivors of critical illness and associated with deficits in physical function. These preliminary findings may support therapeutic interventions aimed at improving muscle power to potentially increase functional benefit.

Sarcopenia risk and diabetes mellitus are independent factors for lower limb muscle strength in older patients with acute stroke: A cross-sectional study

OBJECTIVES

Lower extremity (LE) muscle strength is an important factor for functional outcome in patients with stroke. However, to our knowledge, the factors influencing LE muscle strength in older patients with acute stroke have not been studied. The aim of this study was to investigate the relationships between prestroke sarcopenia risk and comorbidities with LE muscle strength in older patients with acute stroke.

METHODS

In this cross-sectional study, we assessed LE muscle strength using the Motricity IUndex (MI), and prestroke sarcopenia risk using SARC-F, a questionnaire for sarcopenia. Multivariate regression analysis was used to investigate the relationship of MI with sarcopenia risk, neurologic deficit assessed by the National Institutes of Health Stroke Scale (NIHSS), and comorbidities in these patients.

RESULTS

We enrolled 223 patients aged 65 and over with acute stroke (127 men and 96 women; mean age 76 y). Multivariate analyses for MI after adjusting for potential confounders, NIHSS score, diabetes mellitus, and the presence of sarcopenia risk were independently and negatively associated with MI in older patients with stroke (β = -0.775, P < 0.001; β = -0109, P = 0.010; β = -0.097, P = 0.030, respectively).

CONCLUSIONS

Prestroke sarcopenia and diabetes mellitus are associated with LE muscle strength in older patients with acute stroke, and these assessments would be useful for clinicians.

Recovery of mobility function and life-space mobility after ischemic stroke: the MOBITEC-Stroke study protocol

Background

Stroke is a major cause of disability and stroke incidence increases with age. Stroke frequently results in permanent limitations of mobility, and, consequently, the need for the help of others in activities of daily living. In order to optimize rehabilitative efforts and their functional outcomes, detailed knowledge of the functional recovery process, regarding mobility, is needed. Objectives of the MOBITEC-Stroke study are: 1.) To characterize mobility, including lower extremity physical function (LEPF) and life space (the geospatial extent of all of a person’s movements), and changes in mobility within the first year after stroke. 2.) To identify and characterize subgroups with different mobility trajectories. 3.) To evaluate whether changes in LEPF are associated with changes in life-space. 4.) To evaluate participants’ reasons for going outdoors, transportation use, and assistance needed for outdoor movement.

Methods

Patients with incident first stroke who live in their own homes (target N = 59, based on sample size calculation) will be included in this cohort study. At 3, 6, 9, and 12 months after stroke a battery of mobility tests will be performed at the study centre, including laboratory-based tests of balance and strength, and quantitative gait analysis. Life-space assessment (including 1-week GPS measurements) will be performed in participants’ real life. Semantic information on visited locations (reasons for going outdoors, transportation use, assistance needed) will be collected by using interactive digital maps. Linear mixed effects models will be used to model the trajectories of mobility measures for the total sample and for predefined subgroups. As an exploratory analysis, growth mixture models (GMMs) will be used to identify relevant subgroups with different trajectories. Linear mixed effect models will be used to test whether changes in LEPF parameters are associated with changes in life-space. Participants’ motivation for going outdoors, transportation use, and assistance needed for outdoor mobility will be analysed descriptively.

Discussion

A comprehensive and detailed knowledge of recovery patterns will enable the planning of targeted and adaptively tailored rehabilitation measures. Information about patients’ reasons for outdoor mobility will provide the opportunity to define individualized and patient-oriented rehabilitation goals.

Trial registration

ISRCTN85999967 (on 13 August 2020; retrospectively).

Evoking the Withdrawal Reflex via Successive Needle-Pricking on the Plantar and Dorsal Aspect of the Foot Increases the FMA of the Lower Limb for Poststroke Patients in Brunnstrom Stage III: A Preliminary Study

The withdrawal reflex is a defensive reaction to nociceptive stimuli and can be used to regulate locomotor gait during rehabilitation. We investigated the effect of successive needle-pricking of the plantar and dorsal foot surfaces on poststroke lower limb function. Thirty-five hemiplegic patients, within one month after primary stroke, with an affected lower limb (Brunnstrom stage III) were randomly divided into intervention and control groups. Both groups received routine drug treatment, rehabilitation training, and upper limb acupuncture treatment on the hemiplegic side. The control group also received routine acupuncture on the hemiplegic side of the lower limb, while the intervention group received successive needle-pricking on the sole and instep of both the unaffected and affected side feet. Outcomes were assessed before inception (D0) and after three (D3) and six (D6) treatment days, using Brunnstrom stage (Ueda assessment), total Fugl–Meyer lower extremity assessment (FMA-LE) and its subscores (FMA-LE-ss), active lower limb range of motion (AROM-LL), Modified Ashworth Scale Score (MAS-LL), and manual muscle testing (MMT-LL). The Brunnstrom stage was better in the intervention group than in the control group at both D3 and D6 (P < 0.01). The total FMA-LE score and sections B, C, D, and G FMA-LE-ss were significantly better in the intervention group than in the control group at D3 and D6 (P < 0.05). The AROM-LL hip and knee flexion and hip extension improved more in the intervention group than in the control group (P < 0.05). In the intervention group, MAS-LL hip flexion significantly improved at D6 (P < 0.01). Improvement in lower limb joints on the MMT-LL in the intervention group exceeded that in the control group at D6 (P < 0.01). Successive needle-pricking on the plantar and dorsal foot aspects of Brunnstrom stage III in poststroke patients contributed to rapid lower limb motor function improvement via the withdrawal reflex. This trial is registered with ChiCTR1900020633.

Ballistic Resistance Training: Feasibility, Safety, and Effectiveness for Improving Mobility in Adults With Neurologic Conditions: A Systematic Review

OBJECTIVES

To determine whether ballistic resistance training is feasible, safe, and effective in improving muscle strength, power generation, and mobility in adults with neurologic conditions.

DATA SOURCES

Nine electronic databases were searched from inception to March 2019 in addition to the reference lists of included articles.

STUDY SELECTION

Articles were independently screened by 2 authors and were included if they were full-text; English-language articles published in a peer-reviewed journal; investigated ballistic resistance training for adults with a neurologic condition; and reported on feasibility, safety, strength, power, or mobility.

DATA EXTRACTION

Two authors independently extracted data. Study quality was assessed using the McMaster critical review form and the Physiotherapy Evidence Database scale.

DATA SYNTHESIS

The search identified 1540 articles, with 13 articles describing 9 studies meeting the criteria for inclusion. Five studies were randomized controlled trials and 4 were cohort studies. Ballistic resistance training was feasible and safe with only 1 intervention-related adverse event reported. Findings indicated improvements in strength for hip abduction, leg press, knee flexion, and ankle dorsiflexion, but not for hip flexion, hip extension, knee extension, or ankle plantarflexion. Muscle power generation improved for hip flexion, hip abduction, leg press, knee extension, and knee flexion, but not for ankle plantarflexion. Treatment effect was positive for self-selected walking speed, with a standardized mean difference (SMD) of 0.69 (95% confidence interval [CI], 0.01-1.38) from 3 studies. However, fastest comfortable walking speed results were inconclusive with a SMD from 4 studies of 0.45 (95% CI, -0.01 to 0.91).

CONCLUSIONS

Ballistic training is safe and feasible for people with a neurologic condition. The effects on muscle strength, power generation, and mobility were found to be positive but not conclusive.

Serious game for locomotor rehabilitation of hemiparetic stroke patients

Abstract Introduction: Hemiparesis post-stroke usually results in locomotor limitations. As conventional rehabilitation is monotonous, the Serious Games (SG) represents an excellent treatment strategy, allowing to perform physical training in an interesting and enjoyable way. Objective: To evaluate the effects of an exercise program using the SG developed for hemiparetic stroke patients’ locomotor rehabilitation. Method: Non-Randomized Controlled Clinical Trial. Twenty-four hemiparetic stroke patients with subacute or chronic stroke (twelve men), mean age of 57.8 ± 10.4 years (injury time of 16.8 ± 19.6 months) participated in the study. The experimental group (n = 16) participated in an exercise program with the SG for lower limb rehabilitation. The control group (n = 8) received conventional treatment (kinesiotherapy). The intervention consisted of sessions twice a week for ten weeks. The following parameters were assessed: muscle strength (dynamometry), spasticity (Modified Ashworth Scale), functional mobility (Timed Up and Go Test - TUGT), and the gait speed (GS). Results: Both groups showed improvements, but the experimental group was better in all the studied variables, the muscular strength of the lower limb paresis and of the quadriceps femoris (p = 0.002; d = 0.7); and for the hamstrings (p < 0.001; d = 1.3), TUGT (p < 0.001; d = 0.4), and GS (p = 0.001; d = 0.4). Conclusion: The exercise program with the SG was useful for the patients treated in this study. The results showed a superiority of the SG regarding the conventional treatment in all the controlled variables. This was probably because of the greater repeatability of the exercises and the increased attention and motivation.

Cross-sectional study of quadriceps properties and postural stability in patients with chronic stroke and limited vs. non-limited community ambulation

Background: Changes in the paretic-side metabolism post-stroke and quadriceps muscle mechanical properties favour muscle wasting, affecting postural instability and walking impairment. Further clarification is needed in subjects post-stroke who show limited or non-limited community ambulation. Objectives: To analyze between-limb differences in quadriceps muscle thickness, strength and thigh cutaneous temperature, as well as investigate postural stability in subjects with chronic stroke and limited vs. non-limited community ambulation and compared against healthy controls. Methods: In this controlled cross-sectional study, 26 participants with chronic hemiparesis post-stroke (divided in a slow gait group (SG<0.8 m/s) (n = 13) and a fast gait group with full community ambulation speed (FG≥0.8 m/s)) and 18 healthy people were recruited. Thigh surface temperature, rectus femoris (RF) and vastus intermedius (VI) muscles thickness, quadriceps' isometric maximal voluntary contraction and postural stability were measured. Results: The SG presented significantly lower RF (P = .019) and VI (P = .006) muscle thickness, less peak force (P < .001) and lower temperature (P = .002) in the paretic vs the non-paretic limb. The FG showed significantly lower VI thickness (P = .036) and peak force (P < .001) in the paretic vs the non-paretic limb. Regarding balance, all indices were worse in the SG versus the FG and CG. Conclusions: Subjects of the FG, despite showing full community ambulation speed, had less quadriceps strength and VI muscle thickness but not RF muscle wasting in the paretic limb. The paretic VI muscle wasting may be an important factor to reach normal walking. The SG showed between-limb differences in all the studied variables and the worst postural stability.

The effectiveness of group exercise for improving activity and participation in adult stroke survivors: a systematic review

BACKGROUND

Following post stroke rehabilitation, group exercise interventions can be used to continue improving cardiovascular fitness, activity levels, balance, gait, movement efficiency, and strengthening. However, little is known of the effectiveness of group exercise for improving activity and participation in stroke survivors.

OBJECTIVES

This review aims to assess the effectiveness of group exercise for improving activity and participation in adult stroke survivors.

DATA SOURCES

Databases searched were MEDLINE, Web of Science (Core collection), CINAHL, and the Cochrane Library.

STUDY ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) of group exercise using validated outcome measures of activity and participation for post stroke rehabilitation. Two independent reviewers assessed all abstracts, extracted data, conducted a narrative synthesis and assessed the quality of all included articles. The Cochrane Risk of Bias Tool assessed methodological quality and included outcome measure quality was assessed.

RESULTS

14 RCTs were included (n=624 chronic stroke survivors collectively). Studies ranged between 12 and 243 stroke participants with an average of left:right hemisphere lesions of 32:39 and average age was 66.7 years. Although intervention and control groups improved, no significant difference between group differences were evident.

CONCLUSION

and implications of key findings: The review found improvements are short-term and less evident at long-term follow up with little improvements in participation after 6months. However, this review was limited to the standard of intervention reporting. Further research should consider consistency in measuring underpinning mechanisms of group exercise interventions, which may explain the lack of activity changes in long-term follow-up.

SYSTEMATIC REVIEW REGISTRATION NUMBER PROSPERO

CRD42017078917.