High-intensity Locomotor Training Research Articles

A retrospective analysis of a clinician-initiated high-intensity locomotor training implementation project in an inpatient rehabilitation facility.

The Academy of Neurologic Physical Therapy's Intensity Matters campaign recommends the implementation of high-intensity locomotor training for all patients with neurologic dysfunction with goals to improve walking. Retrospectively determine the effectiveness of a clinician-initiated implementation project on the adoption, reach, and fidelity of high-intensity locomotor training for patients with stroke during inpatient rehabilitation and, determine whether the project led to changes in patient outcomes. Retrospective analysis of electronic medical records from 1 year before and after the project. Patients admitted with a stroke diagnosis were included. Demographic information, the number of high-intensity sessions, the percentage of time spent in the target heart rate zone, standardized assessment scores for motor function, functional mobility, balance, gait speed and endurance, and discharge destination were extracted for descriptive and linear mixed model analysis. Clinician reach was 75%, and adoption of high-intensity training varied between clinicians from 47.1% and 83.3%. Of eligible patients, 55% received the target intervention at least once, reflecting the patient reach. Implementation fidelity was 18.84%. Linear mixed effects modeling revealed a statistically significant effect of time (p < .001) but not group allocation or group × time interaction. Although statistically significant differences in patient outcomes compared to pre-implementation were not found, results highlight the limitations associated with adopting high-intensity locomotor training for patients post-stroke in this setting .It remains unclear whether the implementation fidelity achieved was sufficient to impact patient outcomes. Further research is needed to establish fidelity targets and identify barriers to successful implementation projects by clinicians.

Predicting Walking Capacity Outcomes After Moderate to High Intensity Locomotor Training in Chronic Stroke.

Moderate-to-high intensity locomotor training (M-HIT) is strongly recommended in stroke rehabilitation but outcomes are variable. This study aimed to identify baseline clinical characteristics that predict change in walking capacity following M-HIT in chronic stroke. This analysis used data from the HIT-Stroke Trial (N=55), which involved up to 36 sessions of either moderate or high intensity locomotor training. A prespecified model assessed how well baseline motor impairment (Fugl-Meyer lower limb motor scale [FM-LL]), comfortable gait speed (CGS), and balance confidence (Activities Balance Confidence scale [ABC]), independently explain changes in 6-minute walk distance (Δ6MWD), while controlling for treatment group. Exploratory analysis tested additional baseline covariates using the all-possible regressions procedure. The prognostic value of each potential covariate was assessed by its average contribution to the explained variance in Δ6MWD (Δ pseudo-R 2 ). With the prespecified model, 8-week Δ6MWD was significantly associated with baseline FM-LL (β=5.0 [95% CI: 1.4, 8.6]) and ABC (β=0.7 [0.0, 1.4]), but not CGS (β=-44.6 [-104.7, 15.6]). The exploratory analysis revealed the top 7 covariates with the highest mean Δ pseudo-R 2 were: FM-LL, pain-limited walking duration, ABC, the use of an assistive device, fatigue, depression, and recent walking exercise history >2 days per week. On average, participants with less motor impairment and higher balance confidence have greater walking capacity improvements after M-HIT in chronic stroke. Additional negative prognostic factors may include pain-limited walking duration, use of an assistive device, fatigue, depression, and recent walking exercise but these exploratory findings need to be confirmed in future studies.

Stimulation of the cuneiform nucleus enables training and boosts recovery after spinal cord injury.

Severe spinal cord injuries result in permanent paraparesis in spite of the frequent sparing of small portions of white matter. Spared fibre tracts are often incapable of maintaining and modulating the activity of lower spinal motor centres. Effects of rehabilitative training thus remain limited.Here, we activated spared descending brainstem fibres by electrical deep brain stimulation of the cuneiform nucleus of the mesencephalic locomotor region, the main control centre for locomotion in the brainstem, in adult female Lewis rats.We show that deep brain stimulation of the cuneiform nucleus enhances the weak remaining motor drive in highly paraparetic rats with severe, incomplete spinal cord injuries and enables high-intensity locomotor training. Stimulation of the cuneiform nucleus during rehabilitative aquatraining after subchronic (n = 8 stimulated versus n = 7 unstimulated versus n = 7 untrained rats) and chronic (n = 14 stimulated versus n = 9 unstimulated versus n = 9 untrained rats) spinal cord injury re-established substantial locomotion and improved long-term recovery of motor function. We additionally identified a safety window of stimulation parameters ensuring context-specific locomotor control in intact rats (n = 18) and illustrate the importance of timing of treatment initiation after spinal cord injury (n = 14).This study highlights stimulation of the cuneiform nucleus as a highly promising therapeutic strategy to enhance motor recovery after subchronic and chronic incomplete spinal cord injury with direct clinical applicability.

The Value of High Intensity Locomotor Training Applied to Patients With Acute-Onset Neurologic Injury

Long-standing research in animal models and humans with stroke or incomplete spinal cord injury (iSCI) indicate that specific physical training variables, such as the specificity and amount of practice, may influence neurologic recovery and locomotor function. More recent data highlight the contributions of exercise intensity, as estimated indirectly by cardiovascular exertion, as potentially more important than previously considered. The effects of exercise intensity are well described in neurologically intact individuals, although confusion regarding the definitions of intensity and safety concerns have limited its implementation during physical rehabilitation of patients with neurologic injury.The purpose of this review is to delineate some of the evidence regarding the effects of exercise intensity during locomotor training in patients with stroke and iSCI. We provide specific definitions of exercise intensity used within the literature, describe methods used to ensure appropriate levels of exertion, and discuss potential adverse events and safety concerns during its application. Further details on the effects of locomotor training intensity on clinical outcomes, and on neuromuscular and cardiovascular function will be addressed as available. Existing literature across multiple studies and meta-analyses reveals that exercise training intensity is likely a major factor that can influence locomotor function after neurologic injury. To extend these findings, we describe previous attempts to implement moderate to high intensity interventions during physical rehabilitation of patients with neurologic injury, including the utility of specific strategies to facilitate implementation, and to navigate potential barriers that may arise during implementation efforts.

Locomotor Kinematics and Kinetics Following High-Intensity Stepping Training in Variable Contexts Poststroke

Background and Purpose. Previous studies suggest that individuals poststroke can achieve substantial gains in walking function following high-intensity locomotor training (LT). Recent findings also indicate practice of variable stepping tasks targeting locomotor deficits can mitigate selected impairments underlying reduced walking speeds. The goal of this study was to investigate alterations in locomotor biomechanics following 3 different LT paradigms. Methods. This secondary analysis of a randomized trial recruited individuals 18 to 85 years old and >6 months poststroke. We compared changes in spatiotemporal, joint kinematics, and kinetics following up to 30 sessions of high-intensity (>70% heart rate reserve [HRR]) LT of variable tasks targeting paretic limb and balance impairments (high-variable, HV), high-intensity LT focused only on forward walking (high-forward, HF), or low-intensity LT (<40% HRR) of variable tasks (low-variable, LV). Sagittal spatiotemporal and joint kinematics, and concentric joint powers were compared between groups. Regressions and principal component analyses were conducted to evaluate relative contributions or importance of biomechanical changes to between and within groups. Results. Biomechanical data were available on 50 participants who could walk ≥0.1 m/s on a motorized treadmill. Significant differences in spatiotemporal parameters, kinematic consistency, and kinetics were observed between HV and HF versus LV. Resultant principal component analyses were characterized by paretic powers and kinematic consistency following HV, while HF and LV were characterized by nonparetic powers. Conclusion. High-intensity LT results in greater changes in kinematics and kinetics as compared with lower-intensity interventions. The results may suggest greater paretic-limb contributions with high-intensity variable stepping training that targets specific biomechanical deficits. Clinical Trial Registration. https://clinicaltrials.gov/ Unique Identifier: NCT02507466

Effects of Locomotor Exercise Intensity on Gait Performance in Individuals With Incomplete Spinal Cord Injury.

High-intensity stepping practice may be a critical component to improve gait following motor incomplete spinal cord injury (iSCI). However, such practice is discouraged by traditional theories of rehabilitation that suggest high-intensity locomotor exercise degrades gait performance. Accordingly, such training is thought to reinforce abnormal movement patterns, although evidence to support this notion is limited. The purposes of this study were: (1) to evaluate the effects of short-term manipulations in locomotor intensity on gait performance in people with iSCI and (2) to evaluate potential detrimental effects of high-intensity locomotor training on walking performance. A single-day, repeated-measures, pretraining-posttraining study design was used. Nineteen individuals with chronic iSCI performed a graded-intensity locomotor exercise task with simultaneous collection of lower extremity kinematic and electromyographic data. Measures of interest were compared across intensity levels of 33%, 67%, and 100% of peak gait speed. A subset of 9 individuals participated in 12 weeks of high-intensity locomotor training. Similar measurements were collected and compared between pretraining and posttraining evaluations. The results indicate that short-term increases in intensity led to significant improvements in muscle activity, spatiotemporal metrics, and joint excursions, with selected improvements in measures of locomotor coordination. High-intensity locomotor training led to significant increases in peak gait speed (0.64-0.80 m/s), and spatiotemporal and kinematic metrics indicate a trend for improved coordination. Measures of gait performance were assessed during treadmill ambulation and not compared with a control group. Generalizability of these results to overground ambulation is unknown. High-intensity locomotor exercise and training does not degrade, but rather improves, locomotor function and quality in individuals with iSCI, which contrasts with traditional theories of motor dysfunction following neurologic injury.

Paretic Propulsion and Trailing Limb Angle Are Key Determinants of Long-Distance Walking Function After Stroke

Background. Elucidation of the relative importance of commonly targeted biomechanical variables to poststroke long-distance walking function would facilitate optimal intervention design. Objectives. To determine the relative contribution of variables from 3 biomechanical constructs to poststroke long-distance walking function and identify the biomechanical changes underlying posttraining improvements in long-distance walking function. Methods. Forty-four individuals >6 months after stroke participated in this study. A subset of these subjects (n = 31) underwent 12 weeks of high-intensity locomotor training. Cross-sectional (pretraining) and longitudinal (posttraining change) regression quantified the relationships between poststroke long-distance walking function, as measured via the 6-Minute Walk Test (6MWT), and walking biomechanics. Biomechanical variables were organized into stance phase (paretic propulsion and trailing limb angle), swing phase (paretic ankle dorsiflexion and knee flexion), and symmetry (step length and swing time) constructs. Results. Pretraining, all variables correlated with 6MWT distance (rs = .39 to .75, Ps < .05); however, only propulsion (Prop) and trailing limb angle (TLA) independently predicted 6MWT distance, R2 = .655, F(6, 36) = 11.38, P < .001. Interestingly, only ΔProp predicted Δ6MWT; however, pretraining Prop, pretraining TLA, and ΔTLA moderated this relationship (moderation model R2s = .383, .468, .289, respectively). Conclusions. The paretic limb’s ability to generate propulsion during walking is a critical determinant of long-distance walking function after stroke. This finding supports the development of poststroke interventions that target deficits in propulsion and trailing limb angle.

Effects of training and weight support on muscle activation in Parkinson’s disease

The aim of this study was to investigate the effect of high-intensity locomotor training on knee extensor and flexor muscle activation and adaptability to increased body-weight (BW) support during walking in patients with Parkinson’s disease (PD). Thirteen male patients with idiopathic PD and eight healthy participants were included. The PD patients completed an 8-week training program on a lower-body, positive-pressure treadmill. Knee extensor and flexor muscles activation during steady treadmill walking (3km/h) were measured before, at the mid-point, and after training. Increasing BW support decreased knee extensor muscle activation (normalization) and increased knee flexor muscle activation (abnormal) in PD patients when compared to healthy participants. Training improved flexor peak muscle activation adaptability to increased (BW) support during walking in PD patients. During walking without BW support shorter knee extensor muscle off-activation time and increased relative peak muscle activation was observed in PD patients and did not improve with 8weeks of training. In conclusion, patients with PD walked with excessive activation of the knee extensor and flexor muscles when compared to healthy participants. Specialized locomotor training may facilitate adaptive processes related to motor control of walking in PD patients.

Improved Clinical Status, Quality of Life, and Walking Capacity in Parkinson's Disease After Body Weight-Supported High-Intensity Locomotor Training

ObjectiveTo evaluate the effect of body weight-supported progressive high-intensity locomotor training in Parkinson's disease (PD) on (1) clinical status; (2) quality of life; and (3) gait capacity. DesignOpen-label, fixed sequence crossover study. SettingUniversity motor control laboratory. ParticipantsPatients (N=13) with idiopathic PD (Hoehn and Yahr stage 2 or 3) and stable medication use. InterventionsPatients completed an 8-week (3 × 1h/wk) training program on a lower-body positive-pressure treadmill. Body weight support was used to facilitate increased intensity and motor challenges during treadmill training. The training program contained combinations of (1) running and walking intervals, (2) the use of sudden changes (eg, in body weight support and speed), (3) different types of locomotion (eg, chassé, skipping, and jumps), and (4) sprints at 50 percent body weight. Main Outcome MeasuresThe Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Parkinson's Disease Questionnaire-39 items (PDQ-39), and the six-minute walk test were conducted 8 weeks before and pre- and posttraining. ResultsAt the end of training, statistically significant improvements were found in all outcome measures compared with the control period. Total MDS-UPDRS score changed from (mean ± 1SD) 58±18 to 47±18, MDS-UPDRS motor part score changed from 35±10 to 29±12, PDQ-39 summary index score changed from 22±13 to 13±12, and the six-minute walking distance changed from 576±93 to 637±90m. ConclusionsBody weight-supported progressive high-intensity locomotor training is feasible and well tolerated by patients with PD. The training improved clinical status, quality of life, and gait capacity significantly.

Importance of Specificity, Amount, and Intensity of Locomotor Training to Improve Ambulatory Function in Patients Poststroke

The majority of individuals poststroke recover the ability to walk overground, although residual impairments contribute to reduced walking speed, spatiotemporal asymmetries, inefficient gait, and limited walking activity in the home and community. A substantial number of studies have investigated the effects of various interventions on locomotor function in individuals poststroke; these studies vary widely in types of tasks practiced, the amount of practiced activities, and the intensity or workload during the intervention. In contrast, basic and applied studies have identified specific parameters of training that could be applied towards treatment of patients poststroke. More directly, the specificity, amount, and intensity of walking practice are thought to be critical variables of rehabilitation interventions that can facilitate plasticity of neuromuscular and cardiopulmonary systems and result in improved locomotor function. In the present commentary, we delineate the evidence and physiological rationale for providing large amounts of high-intensity locomotor training to improve ambulatory function in individuals poststroke. Additional evidence is presented to indicate that improvements in non-walking tasks, such as static balance and performance of transfers, may also occur following locomotor training. We further evaluate previous and more recent studies in the context of these parameters and provide suggestions for providing locomotor training for patients with stroke in the clinical setting.