Strength training for walking in neurologic rehabilitation is not task specific: a focused review

Corticospinal and spinal responses following a single session of lower limb motor skill and resistance training

Prior studies suggest resistance exercise as a potential form of motor learning due to task-specific corticospinal responses observed in single sessions of motor skill and resistance training. While existing literature primarily focuses on upper limb muscles, revealing a task-dependent nature in eliciting corticospinal responses, our aim was to investigate such responses after a single session of lower limb motor skill and resistance training. Twelve participants engaged in a visuomotor force tracking task, self-paced knee extensions, and a control task. Corticospinal, spinal, and neuromuscular responses were measured using transcranial magnetic stimulation (TMS) and peripheral nerve stimulation (PNS). Assessments occurred at baseline, immediately post, and at 30-min intervals over two hours. Force steadiness significantly improved in the visuomotor task (P < 0.001). Significant fixed-effects emerged between conditions for corticospinal excitability, corticospinal inhibition, and spinal excitability (all P < 0.001). Lower limb motor skill training resulted in a greater corticospinal excitability compared to resistance training (mean difference [MD] = 35%, P < 0.001) and control (MD; 37%, P < 0.001). Motor skill training resulted in a lower corticospinal inhibition compared to control (MD; - 10%, P < 0.001) and resistance training (MD; - 9%, P < 0.001). Spinal excitability was lower following motor skill training compared to control (MD; - 28%, P < 0.001). No significant fixed effect of Time or Time*Condition interactions were observed. Our findings highlight task-dependent corticospinal responses in lower limb motor skill training, offering insights for neurorehabilitation program design.

Lateral Centre of Mass Displacement can predict running in adults with traumatic brain injury

BACKGROUND

Running is an important skill that improves a person's ability to participate in community-based social, leisure and work activities, and therefore improve quality of life. Following traumatic brain injury, many ambulant people are unable to run. Whilst established for walking, the physical impairments that limit running following traumatic brain injury remain unknown. Therefore, the primary aim of this study was to identify which physical impairments contribute to a person's ability to run post traumatic brain injury.

METHODS

In this study, 88 adults with traumatic brain injury were included. Runners and non-runners were compared regarding their clinical assessment of physical impairments, including postural control, focal muscle spasticity, muscle strength, self-selected walking speed and ability to run. Participants also completed a three-dimensional quantitative gait analysis to assess motor skill using the Gait Profile Score. Logistic regression was applied to identify the most important predictors for the ability to run.

FINDINGS

Significant differences between runners and non-runners were found for postural control, motor control and strength. Dynamic postural control, measured by lateral center of mass displacement, was the best predictor of running, with every centimeter increase in lateral center of mass movement during walking associated with a 30% reduction in the chance of being able to run.

INTERPRETATION

Lateral center of mass displacement should be considered when selecting interventions for ambulant patients with the goal to run. Although postural control, motor control and muscle strength were all different between runners and non-runners, they did not contribute to a person's ability to run.

Functional Resistance Training Improves Thigh Muscle Strength after ACL Reconstruction: A Randomized Clinical Trial

PURPOSE

Quadriceps weakness is common after anterior cruciate ligament (ACL) reconstruction, resulting in prolonged disability and increased risk for reinjury and osteoarthritis. Functional resistance training (FRT) combines resistance training with task-specific training and may prove beneficial in restoring quadriceps strength. The primary purpose of this study was to determine if a walking-specific FRT program (e.g., resisted walking) improves knee strength in individuals after ACL reconstruction.

METHODS

Thirty participants were randomized into one of three groups: 1) FRT with a customized knee BRACE applied to the ACL leg, 2) FRT with elastic BAND tethered to the ankle of the ACL leg, or 3) a TARGET MATCH condition where no resistance was externally applied. Participants in all groups received training while walking on a treadmill 2-3 times per week for 8 wk. Isometric knee extension and flexion strength were measured before the start of the intervention, after the intervention (POST), and 8 wk after intervention completion (POST-2).

RESULTS

The BRACE group had greater knee extensor strength compared with the TARGET MATCH group at POST and POST-2 ( P < 0.05). The BRACE group had greater knee flexor strength than the TARGET MATCH group at POST and POST-2 ( P < 0.05) and the BAND group at POST ( P < 0.05).

CONCLUSIONS

FRT applied via a customized knee brace results in improvements in knee extensor and flexor strength after ACL reconstruction. FRT is a beneficial adjuvant to ACL rehabilitation and leads to better strength compared with standard of care.

Ballistic resistance training has a similar or better effect on mobility than non-ballistic exercise rehabilitation in people with a traumatic brain injury: a randomised trial

QUESTIONS

In people recovering from traumatic brain injury, is a 3-month ballistic resistance training program targeting three lower limb muscle groups more effective than non-ballistic exercise rehabilitation for improving mobility, strength and balance? Does improved mobility translate to better health-related quality of life?

DESIGN

A prospective, multicentre, randomised trial with concealed allocation, intention-to-treat analysis and blinded measurement.

PARTICIPANTS

A total of 144 people with a neurological movement disorder affecting mobility as a result of traumatic brain injury.

INTERVENTION

For 3 months, the experimental group had three 60-minute sessions of non-ballistic exercise rehabilitation per week replaced by ballistic resistance training. The control group had non-ballistic exercise rehabilitation of equivalent time. The non-ballistic exercise rehabilitation consisted of balance exercises, lower limb stretching, conventional strengthening exercises, cardiovascular fitness training and gait training.

OUTCOME MEASURES

The primary outcome was mobility measured using the High-Level Mobility Assessment Tool (HiMAT). Secondary outcomes were walking speed, strength, balance and quality of life. They were measured at baseline (0 months), after completion of the 3-month intervention (3 months) and 3 months after cessation of intervention (6 months).

RESULTS

After 3 months of ballistic resistance training, the experimental group scored 3 points (95% CI 0 to 6) higher on the 54-point HiMAT than the control group and remained 3 points (95% CI -1 to 6) higher at 6 months. Although there was a transient decrement in balance at 3 months in the experimental group, the interventions had similar effects on all secondary outcomes by 6 months. Participants with a baseline HiMAT < 27 gained greater benefit from ballistic training: 6 points (1 to 10) on the HiMAT.

CONCLUSION

This randomised trial shows that ballistic resistance training has a similar or better effect on mobility than non-ballistic training in people with traumatic brain injury. It may be better targeted towards those with more severe mobility limitations.

TRIAL REGISTRATION

ACTRN12611001098921.

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.

The safety and accuracy of home-based ballistic resistance training for people with neurological conditions

AIM

In the past 5-10 years, there has been a growing number of studies implementing ballistic (i.e. fast) resistance training to improve walking. The aim of this study was to determine whether people with neurological conditions could perform ballistic exercises safely and accurately in their home environment.

DESIGN

An observational study of 24 adults with a neurological condition (i.e. stroke, brain injury, multiple sclerosis, and neurosurgical) that limited mobility was carried out. Participants were supervised during seven ballistic exercises over six home-based sessions across three weeks. Safety was determined as the ability to perform the exercise independently. Accuracy was determined as the ability to perform the exercise on pre-determined criteria.

RESULTS

The majority of participants had sustained a traumatic brain injury (n = 13) or stroke (n = 9) with a mean age of 38.3 (SD 15.3, range 17-68) years. The mean walking speed was 1.11 (SD 0.29, range 0.53-1.56) m/s. In terms of safety, participants performed the exercises safely 88% of the time, and accurately 49% of the time. Safe completion of each individual exercise ranged initially from 46% to 100% for participants, but accuracy was lower ranging from 17% to 58%. Threshold self-selected walking speeds for optimal sensitivity and specificity for safety ranged from 0.86 to 1.17 m/s and for accuracy ranged from 0.97 to 1.23 m/s.

CONCLUSION

Most of the home-based ballistic resistance exercises were safe, but accuracy was low for several of the ballistic resistance exercises. Higher self-selected walking speeds were associated with more accurate performance.

Lower limb muscle performance during a closed chain single leg squat and a squat jump in people with leg weakness after stroke: A comparative study

Objective:

To determine if the intention to perform an exercise at speed leads to beneficial alterations in kinematic and kinetic components of the movement in people with post-stroke hemiplegia.

Design:

Comparative study.

Setting:

Subacute metropolitan rehabilitation hospital.

Participants:

Convenience sample of patients admitted as an inpatient or outpatient with a diagnosis of stroke with lower limb weakness, functional ambulation category score ≥3, and ability to walk ≥14metres.

Methods:

Participants performed a single leg squat exercise on their paretic and nonparetic legs on a leg sled under three conditions: 1) self-selected speed (SS), 2) fast speed (FS), 3) jump squat (JS). Measures of displacement, flight time, peak concentric velocity, and muscle excitation (via electromyography) were compared between legs and conditions.

Results:

Eleven participants (age: 56 ± 17 years; median time since stroke onset: 3.3 [IQR 3,41] months) were tested. All participants achieved a jump during the JS, as measured by displacement and flight time respectively, on both their paretic (0.25 ± 0.16 m and 0.42 ± 0.18 s) and nonparetic (0.49 ± 0.36 m and 0.73 ± 0.28 s) legs; however it was significantly lower on the non-paretic leg (p < 0.05). Peak concentric velocity increased concordantly with intended movement speed (JS-FS paretic: 0.96 m/s, non-paretic: 0.54 m/s; FS-SS paretic 0.69 m/s, nonparetic 0.38 m/s; JS-SS paretic 1.66 m/s, non-paretic 0.92 m/s). Similarly, muscle excitation increased significantly (p < 0.05) with faster speed for the paretic and nonparetic vastus lateralis. For gastrocnemius, the only significant difference was an increase during nonparetic JS vs. SS and FS.

Conclusions:

Speed affects the kinematic and kinetic components of the movement. Performing exercises ballistically may improve training outcomes for people post-stroke.

Lower limb muscle performance during a closed chain single leg squat and a squat jump in people with leg weakness after stroke: A comparative study

OBJECTIVE

To determine if the intention to perform an exercise at speed leads to beneficial alterations in kinematic and kinetic components of the movement in people with post-stroke hemiplegia.

DESIGN

Comparative study.

SETTING

Subacute metropolitan rehabilitation hospital.

PARTICIPANTS

Convenience sample of patients admitted as an inpatient or outpatient with a diagnosis of stroke with lower limb weakness, functional ambulation category score ≥3, and ability to walk ≥14metres.

METHODS

Participants performed a single leg squat exercise on their paretic and nonparetic legs on a leg sled under three conditions: 1) self-selected speed (SS), 2) fast speed (FS), 3) jump squat (JS). Measures of displacement, flight time, peak concentric velocity, and muscle excitation (via electromyography) were compared between legs and conditions.

RESULTS

Eleven participants (age: 56 ± 17 years; median time since stroke onset: 3.3 [IQR 3,41] months) were tested. All participants achieved a jump during the JS, as measured by displacement and flight time respectively, on both their paretic (0.25 ± 0.16 m and 0.42 ± 0.18 s) and nonparetic (0.49 ± 0.36 m and 0.73 ± 0.28 s) legs; however it was significantly lower on the non-paretic leg (p p Conclusions: Speed affects the kinematic and kinetic components of the movement. Performing exercises ballistically may improve training outcomes for people post-stroke.

The Effectiveness of Aquatic Plyometric Training in Improving Strength, Jumping, and Sprinting: A Systematic Review

CONTEXT

Aquatic plyometric training may provide benefits due to reduced joint loading compared with land plyometric training; however, the reduced loading may also limit performance gains.

OBJECTIVE

To systematically review the effect of aquatic plyometric training on strength, performance outcomes, soreness, and adverse events in healthy individuals.

EVIDENCE ACQUISITION

Five databases were searched from inception to June 2020. Quality assessment and data extraction were independently completed by 2 investigators. When similar outcome measures were used, standardized mean differences were calculated.

EVIDENCE SYNTHESIS

A total of 19 randomized controlled trials with 633 participants (mean age, range 14-30 y) were included. Aquatic plyometric training was most commonly performed in waist to chest deep water (12/19 studies), 2 to 3 times per week for 6 to 12 weeks (18/19 studies), with final program foot contacts ranging from 120 to 550. Meta-analyses were not completed due to the clinical and statistical heterogeneity between studies. Compared with land plyometric training, aquatic plyometric training exercises and dosage were replicated (15/16 studies) and showed typically similar performance gains (3/4 knee extensor strength measures, 2/4 leg extensor strength measures, 3/4 knee flexor strength measures, 7/10 vertical jump measures, 3/3 sprint measures). In total, 2 of 3 studies monitoring muscle soreness reported significantly less soreness following training in water compared with on land. Compared with no active training (no exercise control group or passive stretching), most effect sizes demonstrated a mean improvement favoring aquatic plyometric training (23/32 measures). However, these were not significant for the majority of studies measuring isokinetic knee strength, vertical jump, and sprinting. The effect sizes for both studies assessing leg press strength indicated that aquatic plyometric training is significantly more effective than no training.

CONCLUSION

Aquatic plyometric training appears similarly effective to land plyometric exercise for improving strength, jumping, and sprinting and may be indicated when joint impact loading needs to be minimized. However, the low quality of studies limits the strength of the conclusions.

Paretic and Nonparetic Step Tests Are Noninterchangeable in Stroke: A Prospective Cohort Study

OBJECTIVE

The step test (ST) is a common clinical assessment of dynamic balance among survivors of stroke. The ST assesses a person's ability to place their paretic (paretic ST) or nonparetic (nonparetic ST) foot rapidly and repeatedly on and off a standardized block while standing. No study has formally explored if the 2 tests are interchangeable. Our study aimed to: (1) differentiate the correlates of paretic and nonparetic ST, and (2) compare their associations with physical function and falls.

METHODS

Eighty-one survivors of stroke were consecutively recruited from inpatient rehabilitation units (n = 4) and were assessed within 1 week prior to discharge. In addition to the ST, a handheld dynamometer and computerized posturography were used to measure lower limb muscle strength and standing balance, respectively. Self-selected gait speed and Timed Up and Go test were also assessed as measures of physical function. Falls data were monitored for 12 months post discharge using monthly calendars. Multivariable regression analyses were used to differentiate (1) the correlates of paretic and nonparetic STs, and (2) their associations with physical function and falls.

RESULTS

The median score for the paretic and nonparetic STs were 8 and 9 steps, respectively. Paretic ankle plantar-flexor and dorsiflexor strength were the strongest correlates of nonparetic ST, whereas both paretic ankle and knee extensor strength were the strongest correlates of paretic ST. In multivariable analyses adjusting for each other, both STs were independently associated with gait speed and Timed Up and Go scores. Paretic ST (odds ratio = 0.37; 95% CI = 0.22 to 0.62) was a stronger predictor than nonparetic ST (odds ratio = 0.51; 95% CI = 0.34 to 0.78) in predicting future falls.

CONCLUSION

This study confirmed that the paretic and nonparetic STs are noninterchangeable. ST scores should be assessed separately to achieve a more complete interpretation.

IMPACT

To our knowledge, this study is the first to objectively evaluate the similarities and differences between paretic and nonparetic STs. This information may refine the use and interpretation of the 2 STs for survivors of stroke.

Functional Resistance Training to Improve Knee Strength and Function After Acute Anterior Cruciate Ligament Reconstruction: A Case Study

BACKGROUND

Thigh muscle weakness after anterior cruciate ligament reconstruction (ACLR) can persist after returning to activity. While resistance training can improve muscle function, "nonfunctional" training methods are not optimal for inducing transfer of benefits to activities such as walking. Here, we tested the feasibility of a novel functional resistance training (FRT) approach to restore strength and function in an individual with ACLR.

HYPOTHESIS

FRT would improve knee strength and function after ACLR.

STUDY DESIGN

Case report.

LEVEL OF EVIDENCE

Level 5.

METHODS

A 15-year-old male patient volunteered for an 8-week intervention where he performed 30 minutes of treadmill walking, 3 times per week, while wearing a custom-designed knee brace that provided resistance to the thigh muscles of his ACLR leg. Thigh strength, gait mechanics, and corticospinal and spinal excitability were assessed before and immediately after the 8-week intervention. Voluntary muscle activation was evaluated immediately after the intervention.

RESULTS

Knee extensor and flexor strength increased in the ACLR leg from pre- to posttraining (130 to 225 N·m [+74%] and 44 to 88 N·m [+99%], respectively) and increases in between-limb extensor and flexor strength symmetry (45% to 92% [+74%] and 47% to 72% [+65%], respectively) were also noted. After the intervention, voluntary muscle activation in the ACLR leg was 72%, compared with the non-ACLR leg at 75%. Knee angle and moment during late stance phase decreased (ie, improved) in the ACLR leg and appeared more similar to the non-ACLR leg after FRT training (18° to 14° [-23.4] and 0.07 to -0.02 N·m·kg^-1·m^-1 [-122.8%], respectively). Corticospinal and spinal excitability in the ACLR leg decreased (3511 to 2511 [-28.5%] and 0.42 to 0.24 [-43.7%], respectively) from pre- to posttraining.

CONCLUSION

A full 8 weeks of FRT that targeted both quadriceps and hamstring muscles lead to improvements in strength and gait, suggesting that FRT may constitute a promising and practical alternative to traditional methods of resistance training.

CLINICAL RELEVANCE

FRT may serve as a viable approach to improve knee strength and function after ACL reconstruction.

Strength training to improve walking after stroke: how physiotherapist, patient and workplace factors influence exercise prescription

Background:Muscle weakness is well established as the primary impairment that affects walking after stroke and strength training is an effective intervention to improve this muscle weakness. Observation of clinical practice however has highlighted an evidence-practice gap in the implementation of evidence-based strength training guidelines. Objective: To explore perceived barriers and facilitators that influence Australian physiotherapy practices when prescribing strength training with stroke survivors undergoing gait rehabilitation. Methods: Semi-structured interviews were conducted with a convenience sample of physiotherapists currently providing rehabilitation services to patients following stroke in Australia. Interviews were transcribed verbatim and line-by-line thematic analysis was undertaken to create themes and sub-themes. Results: Participants were 16 physiotherapists (12 females) with 3 months - 42 years experience working with people after stroke. Major themes identified were1) patient factors influence the approach to strength training; 2) interpretation and implementation of strength training principles is diverse; and 3) workplace context affects the treatment delivered. Physiotherapists displayed wide variation in their knowledge, interpretation and implementation of strength training principles and strength training exercise prescription was seldom evidence or guideline based. Workplace factors included the clinical preference of colleagues, and the need to modify practice to align with workforce resources. Conclusions: Implementation of strength training to improve walking after stroke was diverse. Therapist-related barriers to the implementation of effective strength training programs highlight the need for improved knowledge, training and research engagement. Limited resourcing demonstrates the need for organizational prioritization of stroke education and skill development. Narrowing the evidence-practice gap remains a challenge.

The cognitive augmented mobility program (CAMP): feasibility and preliminary efficacy

BACKGROUND

Best evidence suggests incorporating task-specific training, aerobics, and strengthening to improve mobility and gait in persons with stroke (PWS). Related research suggests incorporating cognitive problem-solving strategy training may lead to better skill maintenance and transfer. The present study examined the feasibility and preliminary outcomes of an evidence-based cognitive augmented mobility program (CAMP) for PWS.

METHODS

A single-arm pre-post and follow-up design was conducted, in two blocks (NCT03683160). Participants completed an exercise intervention with an integrated cognitive strategy component and had weekly 1:1 sessions with a physiotherapist trained in Cognitive Orientation to daily Occupational Performance (CO-OP), focusing on goal practice and cognitive strategy use. CAMP consisted of a pre-intervention education and goal-setting session and 16 90-minute sessions held in a group format, 2x/wk for 8 weeks. Assessments were conducted 1 week prior to beginning the intervention, 1 week post-intervention, and at a 4-5 week follow-up.

RESULTS

CAMP was found to be feasible with 96% session attendance and strong participant satisfaction. Pre to post-CAMP intervention, a large effect was found for endurance (r = 0.53), balance (r = 0.59), mobility (r = 0.63) and goal attainment (r = 0.63) indicators, and large effects were maintained at follow-up for balance, mobility, and goal attainment. A medium effect was found for functional independence (r = 0.38), gait speed (r = 0.39), and balance confidence (r = 0.38). A small effect was found for participation (r = 0.27) and overall stroke recovery (r = 0.25).

CONCLUSIONS

Preliminary results suggest CAMP is feasible; there may be a beneficial effect of combining best evidence for mobility and fitness with cognitive strategy training. The positive results for skill maintenance and transfer suggest further investigation is warranted.

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.

Trunk and pelvis movement compensation in people with multiple sclerosis: Relationships to muscle function and gait performance outcomes

BACKGROUND

Problems with gait are common in people with multiple sclerosis (MS), but little is known about pelvis and trunk kinematics, especially in the frontal plane.

RESEARCH QUESTION

Are pelvis and trunk kinematics in people with MS related to muscle function, spatiotemporal parameters, and gait performance?

METHODS

In this cross-sectional study, 20 people with MS (Expanded Disability Status Scale 1.5-5.5) and 10 people with comparable age and sex (CTL) underwent threedimensional gait analysis, muscle function assessments (hip and trunk strength and endurance), and gait performance measures (Timed 25-Foot Walk - T25FW, 2-Minute Walk Test - 2MWT). Frontal and sagittal plane pelvis and trunk excursion during the stance period of walking were compared between groups; and in the MS group, associations were determined between kinematic variables, muscle function, spatiotemporal parameters, and gait performance.

RESULTS

Compared to the CTL group, the MS group had significantly greater sagittal plane trunk and pelvis excursion for both the stronger (p = 0.031) and weaker (p = 0.042) sides; less frontal plane trunk and pelvis excursion for both the stronger (p = 0.008) and weaker (p = 0.024) sides; and more sagittal plane trunk excursion for the stronger side (p = 0.047) during stance phase. There were low-to-moderate correlations in the MS group for sagittal plane pelvis excursion with muscle function (p = 0.019 to 0.030), spatiotemporal parameters (p < 0.001 to 0.005), and gait performance (p = < 0.001 to 0.001). Using linear regression, frontal and sagittal plane pelvis excursion were significant predictors of both T25FW and 2MWT, explaining 34 % and 46 % of the variance of each gait performance measure, respectively.

SIGNIFICANCE

Rehabilitation interventions may consider addressing pelvis movement compensations in order to improve spatiotemporal parameters and gait performance in people with MS.

Five times sit-to-stand following stroke: Relationship with strength and balance

BACKGROUND

Rising from a chair is an important functional measure after stroke. Originally developed as a measure of lower-limb strength, the five times sit-to-stand test has shown associations with other measures of impairment, such as balance ability. We aimed to compare strength and balance in their relationship with the five times sit-to-stand test following stroke.

METHODS

Sixty-one participants following stroke were recruited from two hospitals in this cross-sectional observational study. Participants underwent assessment of the five times sit-to-stand (measured with a stopwatch), bilateral lower-limb muscle strength of seven individual muscle groups (hand-held dynamometry), and standing balance (computerised posturography). Partial correlations (controlling for body mass and height) were used to examine bivariate associations. Regression models with partial F-tests (including pertinent covariates) compared the contribution of strength (both limbs) and balance to five times sit-to-stand time.

RESULTS

The strength of the majority of lower-limb muscle groups (6/7) on the paretic side had a significant (P < 0.05) partial correlation with five times sit-to-stand time (r = -0.34 to -0.47) as did all balance measures (r = -0.27 to -0.56). In our regression models, knee extensor strength, total path length, and anteroposterior path velocity provided the largest contribution to five times sit-to-stand over covariates amongst strength and balance measures (R² = 16.6 to 17.9 %). Partial F-tests revealed that both lower-limb strength and balance contribute to five times sit-to-stand time independent of each other. A regression model containing knee extensor strength and anteroposterior path velocity accounted for 25.5 % of the variance in five times sit-to-stand time over covariates.

CONCLUSIONS

The strength of the knee extensor muscle group along with measures of standing balance ability (total path length and anteroposterior path velocity) both independently contribute to five times sit-to-stand time. Further research is required to examine how other important impairments post stroke impact five times sit-to-stand performance.

Gait Velocity and Joint Power Generation After Stroke: Contribution of Strength and Balance

OBJECTIVE

The aim of the study was to assess the degree to which isometric strength of multiple lower limb muscle groups and balance is associated with gait velocity and joint power generation during gait after stroke.

DESIGN

Sixty-three participants in a multisite, multinational, cross-sectional, observational study underwent assessment of gait velocity (10-m walk test), standing balance (computerized posturography), and isometric strength (hand-held dynamometry). Twenty-seven participants had joint power generation assessed (three-dimensional gait analysis). Bivariate associations were examined using Spearman's correlations. Regression models with partial F tests were used to compare the contribution to gait between measures.

RESULTS

Although all muscle groups demonstrated significant associations with gait velocity (ρ = 0.40-0.72), partial F tests identified that ankle plantar flexor and hip flexor strength made the largest contribution to gait velocity. Ankle plantar flexor strength also had strong associations with habitual and fast-paced ankle power generation (ρ = 0.65 and 0.75). Balance had significant associations with habitual and fast gait velocity (ρ = -0.57 and -0.53), with partial F tests showing that the contribution was independent of strength.

CONCLUSIONS

Ankle plantar flexor and hip flexor strength had the largest contribution to gait velocity. Future research may wish to refocus strength assessment and treatment to target the ankle plantar flexors and hip flexors.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Differentiate the contribution that lower limb strength of each muscle group has on gait velocity after stroke; (2) Appraise the relationship between isometric strength and joint power generation during gait; and (3) Interpret the contribution of both strength and balance to gait after stroke.

LEVEL

Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s). Physicians should only claim credit commensurate with the extent of their participation in the activity.

Functional resistance training during walking: Mode of application differentially affects gait biomechanics and muscle activation patterns

BACKGROUND

Task-specific loading of the limbs-termed as functional resistance training-is commonly used in gait rehabilitation; however, the biomechanical and neuromuscular effects of various forms of functional resistance training have not been studied systematically. This information is crucial for correctly selecting the appropriate mode of functional resistance training when treating individuals with gait disorders.

RESEARCH QUESTION

To comprehensively evaluate the biomechanical (i.e., joint moment and power) and muscle activation changes with different forms of functional resistance training that are commonly used in clinics and research using biomechanical simulation-based analyses.

METHODS

We developed simulations of functional resistance training during walking using OpenSim (Gait2354, 23 degrees of freedom and 54 muscles) and custom MATLAB scripts. We investigated five modes of functional resistance training that have been commonly used in clinics or in research: (1) a weight attached at the ankle, (2) an elastic band attached at the ankle, (3) a viscous device attached to the hip and knee, (4) a weight attached at the pelvis, and (5) a constant backwards pulling force at the pelvis. Lower-extremity joint moments and powers were computed using inverse dynamics and muscle activations were estimated using computed muscle control while walking with each device under multiple resistance levels: normal walking with no resistance, and walking with 30, 60, and 90 Newtons of resistance.

RESULTS

The results indicate that the way in which resistance is applied during gait training differentially affects the internal joint moments, powers, and muscle activations as well as the joints and phase of the gait cycle where the resistance was experienced.

SIGNIFICANCE

The results highlight the importance of understanding the joints and muscles that are targeted by various modes of functional resistance training and carefully choosing the best mode of training that meets the specific therapeutic needs of the patient.

Strength Training to Improve Gait in People with Multiple Sclerosis: A Critical Review of Exercise Parameters and Intervention Approaches

Background

There are mixed reports on the effectiveness of strength training to improve gait performance in people with multiple sclerosis (MS), yet the reasons for these inconsistent results are not clear. Therefore, a critical review was conducted to explore dosage, frequency, mode, position, and muscle targets of studies that have included strength training in people with MS.

Methods

An electronic search was conducted through July 2017. Randomized controlled trials involving people with MS were included that implemented strength training with or without other interventions and assessed 1) strength in the lower extremities and/or trunk and 2) gait speed and/or endurance. Strength and gait results were extracted, along with exercise frequency, intensity, duration, mode, position, and muscle targets.

Results

Thirteen trials met the inclusion criteria; nine used dosing consistent with recommended guidelines. Overall, six studies reported significant between-group strength improvements, and four reported within-group changes. Four studies reported significant between-group gait improvements for gait speed and/or endurance, and two reported within-group changes. Most exercises were performed on exercise machines while sitting, supine, or prone. The most common intervention target was knee extension.

Conclusions

Studies generally improved strength, yet only two studies reported potentially meaningful between-group changes in gait. Future strength intervention studies designed to improve gait might consider dosing beyond that of the minimum intensity to improve strength and explore muscles targets, positions, and modes that are task-specific to walking.

Clinical education alone is sufficient to increase resistance training exercise prescription

A large body of evidence demonstrates that resistance training has been ineffective for improving walking outcomes in adults with neurological conditions. However, evidence suggests that previous studies have not aligned resistance exercise prescription to muscle function when walking. The main aim of this study was to determine whether a training seminar for clinicians could improve knowledge of gait and align resistance exercise prescription to the biomechanics of gait and muscle function for walking. A training seminar was conducted at 12 rehabilitation facilities with 178 clinicians. Current practice, knowledge and barriers to exercise were assessed by observation and questionnaire prior to and immediately after the seminar, and at three-month follow-up. Additionally, post-seminar support and mentoring was randomly provided to half of the rehabilitation facilities using a cluster randomised controlled trial (RCT) design. The seminar led to significant improvements in clinician knowledge of the biomechanics of gait and resistance training, the amount of ballistic (t = -2.38; p = .04) and conventional (t = -2.30; p = .04) resistance training being prescribed. However, ongoing post-seminar support and mentoring was not associated with any additional benefits F(1, 9) = .05, p = .83, partial eta squared = .01. Further, improved exercise prescription occurred in the absence of any change to perceived barriers. The training seminar led to significant improvements in the time spent in ballistic and conventional resistance training. There was no further benefit obtained from the additional post-seminar support. The seminar led to improved knowledge and significantly greater time spent prescribing task-specific resistance exercises.

Feasibility of a targeted strengthening program to improve gait in people with multiple sclerosis: a brief report

This study aims to determine feasibility of strengthening muscles that are important contributors to gait for people with multiple sclerosis, yet are not routinely targeted in the literature. An 8-week strengthening intervention targeted ankle plantarflexion, hip abduction, and trunk muscles using a repeated-measures design. Outcomes included satisfaction, adherence, muscle strength, gait speed (timed 25-foot walk), gait endurance (6-min walk test), and self-reported gait-related participation (Multiple Sclerosis Walking Scale-12). Ten participants (Expanded Disability Status Scale: 3.5-5.5) completed the intervention. All participants were at least 'satisfied'; adherence was 87% (supervised sessions) and 75% (home sessions). All quantitative measures improved: muscle strength (23.1-47.6%, P<0.001-0.039), timed 25-foot walk (-13.4%, P<0.001), 6-min walk test (41.56 m, P=0.019), and Multiple Sclerosis Walking Scale-12 (-10.5, P=0.007). Strengthening of ankle plantarflexion, hip abduction, and trunk muscles was feasible and associated with improvements in gait performance.

A wearable resistive robot facilitates locomotor adaptations during gait

BACKGROUND

Robotic-resisted treadmill walking is a form of task-specific training that has been used to improve gait function in individuals with neurological injury, such as stroke, spinal cord injury, or cerebral palsy. Traditionally, these devices use active elements (e.g., motors or actuators) to provide resistance during walking, making them bulky, expensive, and less suitable for overground or in-home rehabilitation. We recently developed a low-cost, wearable robotic brace that generates resistive torques across the knee joint using a simple magnetic brake. However, the possible effects of training with this device on gait function in a clinical population are currently unknown.

OBJECTIVE

The purpose of this study was to test the acute effects of resisted walking with this device on kinematics, muscle activation patterns, and gait velocity in chronic stroke survivors.

METHODS

Six stroke survivors wore the resistive brace and walked on a treadmill for 20 minutes (4×5 minutes) at their self-selected walking speed while simultaneously performing a foot trajectory-tracking task to minimize stiff-knee gait. Electromyography, sagittal plane gait kinematics, and overground gait velocity were collected to evaluate the acute effects of the device on gait function.

RESULTS

Robotic-resisted treadmill training resulted in a significant increase in quadriceps and hamstring EMG activity during walking. Significant aftereffects (i.e., improved joint excursions) were also observed on the hip and knee kinematics, which persisted for several steps after training. More importantly, training resulted in significant improvements in overground gait velocity. These results were consistent in all the subjects tested.

CONCLUSION

This study provides preliminary evidence indicating that robotic-resisted treadmill walking using our knee brace can result in meaningful biomechanical aftereffects that translate to overground walking.

Lower limb angular velocity during walking at various speeds

BACKGROUND

Although it is well established that lower limb joint angles adapt to walking at various speeds, limited research has examined the modifications in joint angular velocity. There is currently no normative dataset for joint angular velocity during walking, which would be useful to allow comparisons for patient cohorts. Additionally, understanding normal joint angular velocity may assist clinical assessment and treatment procedures to incorporate methods that replicate the movement speed of the lower limb joints during walking.

RESEARCH QUESTION

This study aimed to examine lower limb joint angles and angular velocities in a healthy population walking at various gait speeds.

METHODS

Thirty-six healthy adult participants underwent three-dimensional gait analysis while walking at various speeds during habitual and slowed walking. The peak joint angles and angular velocities during important phases of the gait cycle were examined for the hip, knee and ankle in the sagittal plane. Data were grouped in 0.2 m/s increments from a walking speed of 0.4 m/s to 1.6 m/s to represent the range of walking speeds reported in studies of people with gait impairments.

RESULTS

For joint angles and angular velocities, the shape of the gait traces were consistent regardless of the walking speed. However as walking speed increased, so did the peak joint angles and angular velocities for the hip, knee and ankle. The largest angular velocity occurred when the knee joint extended at the terminal swing phase of gait. For the ankle and hip joints, the largest angular velocity occurred during the push-off phase.

SIGNIFICANCE

This study examined how lower limb joint angular velocities change with various walking speeds. These data can be used as a comparator for data from clinical cohorts, and has the potential to be used to match clinical assessment and treatment methods to joint angular velocity during walking.

Contributions of Ankle, Knee, Hip, and Trunk Muscle Function to Gait Performance in People With Multiple Sclerosis: A Cross-Sectional Analysis

BACKGROUND

The relative importance of lower extremity and trunk muscle function to gait in people with multiple sclerosis (MS) is unknown.

OBJECTIVE

This study aimed to investigate the association of lower extremity and trunk muscle function with gait performance in people who have MS and mild-to-moderate disability.

DESIGN

This was a cross-sectional, observational study.

METHODS

Participants were people who had an Expanded Disability Status Scale score of ≤ 5.5. Eleven lower extremity and trunk muscles were assessed using handheld dynamometry or endurance tests. Gait performance was assessed with the Timed 25-Foot (7.62 m) Walk (T25FW) and 6-Minute Walk Test (6MWT). Regression analysis was used to quantify the association between gait outcomes and muscle variables.

RESULTS

Seventy-two participants with MS and a mean Expanded Disability Status Scale score of 3.5 (SD = 1.14) were enrolled. Adjusted for age and sex, the multivariate model including hip abduction, ankle plantar flexion, trunk flexion, and knee flexion explained 57% of the adjusted variance in the T25FW; hip abduction, ankle plantar flexion, and trunk flexion explained 61% of the adjusted variance in the 6MWT. The strongest predictors were ankle plantar flexion endurance for the T25FW and hip abduction strength for the 6MWT: a 1-SD increase in ankle plantar flexion (15.2 heel-raise repetitions) was associated with a 0.33-second reduction in the T25WT (95% CI = - 0.71 to - 0.14 seconds); a 1-SD increase in normalized hip abduction strength (0.14 kg/body mass index) was associated with a 54.4-m increase in the 6MWT (28.99 to 79.81 m).

LIMITATIONS

Different measurement scales for independent variables were included because the muscle function assessment used either force or endurance.

CONCLUSIONS

For the major muscles in the lower extremity and trunk, hip abduction, ankle plantar flexion, trunk flexion, and knee flexion were the strongest predictors of gait performance.

Feasibility of Ballistic Strength Training in Subacute Stroke: A Randomized, Controlled, Assessor-Blinded Pilot Study

OBJECTIVE

To establish the feasibility and effectiveness of a 6-week ballistic strength training protocol in people with stroke.

DESIGN

Randomized, controlled, assessor-blinded study.

SETTING

Subacute inpatient rehabilitation.

PARTICIPANTS

Consecutively admitted inpatients with a primary diagnosis of first-ever stroke with lower limb weakness, functional ambulation category score of ≥3, and ability to walk ≥14 m were screened for eligibility to recruit 30 participants for randomization.

INTERVENTIONS

Participants were randomized to standard therapy or ballistic strength training 3 times per week for 6 weeks.

MAIN OUTCOME MEASURES

The primary aim was to evaluate feasibility and outcomes included recruitment rate, participant retention and attrition, feasibility of the exercise protocol, therapist burden, and participant safety. Secondary outcomes included measures of mobility, lower limb muscle strength, muscle power, and quality of life.

RESULTS

A total of 30 participants (11% of those screened) with mean age of 50 years (SD 18) were randomized. The median number of sessions attended was 15 of 18 and 17 of 18 for the ballistic and control groups, respectively. Earlier than expected discharge to home (n=4) and illness (n=7) were the most common reasons for nonattendance. Participants performed the exercises safely, with no study-related adverse events. There were significant (P<.05) between-group changes favoring the ballistic group for comfortable gait velocity (mean difference [MD] 0.31m/s, 95% confidence interval [CI]: 0.08-0.52), muscle power, as measured by peak jump height (MD 8cm, 95% CI: 3-13), and peak propulsive velocity (MD 64cm/s, 95% CI: 17-112).

CONCLUSIONS

Ballistic training was safe and feasible in select ambulant people with stroke. Similar rates of retention and attrition suggest that ballistic training was acceptable to patients. Secondary outcomes provide promising results that warrant further investigation in a larger trial.

A narrative review of gait training after stroke and a proposal for developing a novel gait training device that provides minimal assistance

BACKGROUND

Gait impairment is common in stroke survivors. Recovery of walking ability is one of the most pressing objectives in stroke rehabilitation.

OBJECTIVES

Of this report are to briefly review recent progress in gait training after stroke including the use of partial body weight-supported treadmill training (PBWSTT) and robot-assisted step training (RAST), and propose a minimal assistance strategy that may overcome some of limitations of current RAST.

METHODS

The literature review emphasizes a dilemma that recent randomized clinical trials did not support the use of RAST. The unsatisfactory results of current RAST clinical trials may be partially due to a lack of careful analysis of movement deficiencies and their relevance to gait training task specificity after stroke. Normal movement pattern is implied to be part of task specificity in the current RAST. Limitations of such task specificity are analyzed.

RESULTS

Based on the review, we redefine an alternative set of gait training task specificity that represents a minimal assistance strategy in terms of assisted body movements and amount of assistance. Specifically, assistances are applied only to hip flexion and ankle dorsiflexion of the affected lower limb during swing phase. Furthermore, we propose a conceptual design of a novel device that may overcome limitations of current RAST in gait training after stroke. The novel device uses a pulling cable, either manually operated by a therapist or automated by a servomotor, to provide assistive forces to help hip flexion and ankle dorsiflexion of the affected lower limb during gait training.

CONCLUSION

The proposed minimal assistance strategy may help to design better devices for gait or other motor training.

Resistance training using a novel robotic walker for over-ground gait rehabilitation: a preliminary study on healthy subjects

Strength training is an aspect of gait rehabilitation, which complements balance control and weight-bearing training. However, conventional strength training does not show positive gait outcomes, due to lack of task specificity. Therefore, the aims of this study were to investigate the effects of a resistance force applied at the center of mass (CoM) and to investigate whether this exercise can be used for effective task-specific gait training. Using a novel robotic walker, a consistent resistive force was applied to the CoM of subjects in the posterior direction. Eleven healthy subjects were instructed to walk under five walking conditions with increasing forces, based on each subject's body weight (BW), at 0, 2.5, 5, 7.5, and 10% BW. Joint kinematics and mean amplitude and frequency of electromyography signals from nine major muscles were measured. The application of resistance resulted in significantly increased flexion angles at ankle, knee, and hip joints. A large amount of motor unit activation with lower firing rates was found at knee and hip joints, indicating that this type of resistance training can improve muscular strength and endurance in a task-specific manner. The long-term effects of the resistance training on neurologically challenged patients will be investigated in the future.

The distribution of positive work and power generation amongst the lower-limb joints during walking normalises following recovery from traumatic brain injury

OBJECTIVE

To determine whether better walking performance following recovery from traumatic brain injury (TBI) is attributable to an accentuation of compensatory strategies or an improvement in the way positive work is done and power is generated by the lower-limb joints.

SETTING

A large metropolitan rehabilitation hospital.

PARTICIPANTS

Thirty-five ambulant people with extremely-severe TBI who were attending physiotherapy for mobility limitations, and a comparative sample of 25 healthy controls (HC).

DESIGN

Cross-sectional cohort study with six month follow-up.

MAIN MEASURES

Positive work done and average power (i.e. over time) generation by the hip, knee and ankle during stance as well as self-selected gait velocity.

RESULTS

In comparison to HCs, TBI participants walked at baseline with a significantly (p<.01) reduced contribution from the ankle to total lower-limb average power generation (and positive work done) during stance, and a significantly (p=.03) greater contribution from the hip. However, this compensatory strategy resolved over time such that at six month follow-up no significant differences in the relative contributions from the ankle and hip were identified for the TBI participants when compared to HCs.

CONCLUSION

Better walking performance following recovery from TBI is attributable to an improvement in the way positive work is done and power is generated by the lower-limb joints rather than an accentuation of compensatory strategies.

FAST CP: protocol of a randomised controlled trial of the efficacy of a 12-week combined Functional Anaerobic and Strength Training programme on muscle properties and mechanical gait deficiencies in adolescents and young adults with spastic-type cerebral palsy

INTRODUCTION

Individuals with cerebral palsy (CP) have muscles that are smaller, weaker and more resistant to stretch compared to typically developing people. Progressive resistance training leads to increases in muscle size and strength. In CP, the benefits of resistance training alone may not transfer to improve other activities such as walking; however, the transfer of strength improvements to improved mobility may be enhanced by performing training that involves specific functional tasks or motor skills. This study aims to determine the efficacy of combined functional anaerobic and strength training in (1) influencing muscle strength, structure and function and (2) to determine if any changes in muscle strength and structure following training impact on walking ability and gross motor functional capacity and performance in the short (following 3 months of training) and medium terms (a further 3 months post-training).

METHODS AND ANALYSIS

40 adolescents and young adults with CP will be recruited to undertake a 12-week training programme. The training programme will consist of 3 × 75 min sessions per week, made up of 5 lower limb resistance exercises and 2-3 functional anaerobic exercises per session. The calf muscles will be specifically targeted, as they are the most commonly impacted muscles in CP and are a key muscle group involved in walking. If, as we believe, muscle properties change following combined strength and functional training, there may be long-term benefits of this type of training in slowing the deterioration of muscle function in people with spastic-type CP.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the ethics committees at The University of Queensland (2014000066) and Children's Health Queensland (HREC/15/QRCH/30). The findings will be disseminated by publications in peer-reviewed journals, conferences and local research organisations' media.

TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trials Registry (ACTRN12614001217695).

Clinical tests of ankle plantarflexor strength do not predict ankle power generation during walking

OBJECTIVE

The aim of this study was to investigate the relationship between a clinical test of ankle plantarflexor strength and ankle power generation (APG) at push-off during walking.

DESIGN

This is a prospective cross-sectional study of 102 patients with traumatic brain injury.

OUTCOME MEASURES

Handheld dynamometry was used to measure ankle plantarflexor strength. Three-dimensional gait analysis was performed to quantify ankle power generation at push-off during walking.

RESULTS

Ankle plantarflexor strength was only moderately correlated with ankle power generation at push-off (r = 0.43, P < 0.001; 95% confidence interval, 0.26-0.58). There was also a moderate correlation between ankle plantarflexor strength and self-selected walking velocity (r = 0.32, P = 0.002; 95% confidence interval, 0.13-0.48).

CONCLUSIONS

Handheld dynamometry measures of ankle plantarflexor strength are only moderately correlated with ankle power generation during walking. This clinical test of ankle plantarflexor strength is a poor predictor of calf muscle function during gait in people with traumatic brain injury.

Lower-limb muscular strategies for increasing running speed

This clinical commentary discusses the mechanisms used by the lower-limb musculature to achieve faster running speeds. A variety of methodological approaches have been taken to evaluate lower-limb muscle function during running, including direct recordings of muscle electromyographic signal, inverse dynamics-based analyses, and computational musculoskeletal modeling. Progressing running speed from jogging to sprinting is mostly dependent on ankle and hip muscle performance. For speeds up to approximately 7.0 m/s, the dominant strategy is to push on the ground forcefully to increase stride length, and the major ankle plantar flexors (soleus and gastrocnemius) have a particularly important role in this regard. At speeds beyond approximately 7.0 m/s, the force-generating capacity of these muscles becomes less effective. Therefore, as running speed is progressed toward sprinting, the dominant strategy shifts toward the goal of increasing stride frequency and pushing on the ground more frequently. This strategy is achieved by generating substantially more power at the hip joint, thereby increasing the biomechanical demand on proximal lower-limb muscles such as the iliopsoas, gluteus maximus, rectus femoris, and hamstrings. Basic science knowledge regarding lower-limb muscle function during running has implications for understanding why sprinting performance declines with age. It is also of great value to the clinician for designing rehabilitation programs to restore running ability in young, previously active adults who have sustained a traumatic brain injury and have severe impairments of muscle function (eg, weakness, spasticity, poor motor control) that limit their capacity to run at any speed.

The effects of poststroke aerobic exercise on neuroplasticity: a systematic review of animal and clinical studies

Aerobic exercise may be a catalyst to promote neuroplasticity and recovery following stroke; however, the optimal methods to measure neuroplasticity and the effects of training parameters have not been fully elucidated. We conducted a systematic review and synthesis of clinical trials and studies in animal models to determine (1) the extent to which aerobic exercise influences poststroke markers of neuroplasticity, (2) the optimal parameters of exercise required to induce beneficial effects, and (3) consistent outcomes in animal models that could help inform the design of future trials. Synthesized findings show that forced exercise at moderate to high intensity increases brain-derived neurotrophic factor (BDNF), insulin-like growth factor-I (IGF-I), nerve growth factor (NGF), and synaptogenesis in multiple brain regions. Dendritic branching was most responsive to moderate rather than intense training. Disparity between clinical stroke and stroke models (timing of initiation of exercise, age, gender) and clinically viable methods to measure neuroplasticity are some of the areas that should be addressed in future research.