Concurrent neuromechanical and functional gains following upper-extremity power training post-stroke

Abstract

BackgroundRepetitive task practice is argued to drive neural plasticity following stroke. However, current evidence reveals that hemiparetic weakness impairs the capacity to perform, and practice, movements appropriately. Here we investigated how power training (i.e., high-intensity, dynamic resistance training) affects recovery of upper-extremity motor function post-stroke. We hypothesized that power training, as a component of upper-extremity rehabilitation, would promote greater functional gains than functional task practice without deleterious consequences.MethodNineteen chronic hemiparetic individuals were studied using a crossover design. All participants received both functional task practice (FTP) and HYBRID (combined FTP and power training) in random order. Blinded evaluations performed at baseline, following each intervention block and 6-months post-intervention included: Wolf Motor Function Test (WMFT-FAS, Primary Outcome), upper-extremity Fugl-Meyer Motor Assessment, Ashworth Scale, and Functional Independence Measure. Neuromechanical function was evaluated using isometric and dynamic joint torques and concurrent agonist EMG. Biceps stretch reflex responses were evaluated using passive elbow stretches ranging from 60 to 180º/s and determining: EMG onset position threshold, burst duration, burst intensity and passive torque at each speed.ResultsPrimary outcome: Improvements in WMFT-FAS were significantly greater following HYBRID vs. FTP (p = .049), regardless of treatment order. These functional improvements were retained 6-months post-intervention (p = .03).Secondary outcomes: A greater proportion of participants achieved minimally important differences (MID) following HYBRID vs. FTP (p = .03). MIDs were retained 6-months post-intervention. Ashworth scores were unchanged (p > .05).Increased maximal isometric joint torque, agonist EMG and peak power were significantly greater following HYBRID vs. FTP (p < .05) and effects were retained 6-months post-intervention (p’s < .05). EMG position threshold and burst duration were significantly reduced at fast speeds (≥120º/s) (p’s < 0.05) and passive torque was reduced post-washout (p < .05) following HYBRID.ConclusionsFunctional and neuromechanical gains were greater following HYBRID vs. FPT. Improved stretch reflex modulation and increased neuromuscular activation indicate potent neural adaptations. Importantly, no deleterious consequences, including exacerbation of spasticity or musculoskeletal complaints, were associated with HYBRID. These results contribute to an evolving body of contemporary evidence regarding the efficacy of high-intensity training in neurorehabilitation and the physiological mechanisms that mediate neural recovery.

Estimating Orientation Using Magnetic and Inertial Sensors and Different Sensor Fusion Approaches: Accuracy Assessment in Manual and Locomotion Tasks

“…In other studies, the orientation of a lower trunk mounted inertial sensor during treadmill walking was obtained by using an ad hoc developed Kalman filter [34] or a Weighted Fourier Linear Combiner adaptive filter [36]. Participants walked at natural, slow and fast speeds and trial duration was about 40 s [34] and 80 s [36]. RMS differences between reference and estimated attitude angles were lower than 1° in both studies.…”

Activation deficit correlates with weakness in chronic stroke: Evidence from evoked and voluntary EMG recordings

“…There is growing evidence that patients after stroke receive more neuromechanical and functional gains after high-intensity training (Patten et al, 2013) or even maximal strengthening (Hill et al, 2012) of the impaired side in chronic stroke survivors. In a recent study (Dragert and Zehr, 2013), it is also reported that unilateral dorsiflexor high-intensity resistance training in the non-impaired side of chronic stroke survivors results in significant increase in voluntary strength of bilateral dorsiflexors.…”

Non-Invasive Brain Stimulation Improves Paretic Limb Force Production: A Systematic Review and Meta-Analysis

“…Conventional rehabilitation protocols (e.g., bimanual movement training, robotic training, or power training) focusing on the recovery of affected muscles reveal evidence of robust force production improvements [1,[11][12][13][14][15]. These rehabilitation protocols facilitate improved muscle properties and motor control [16,17].…”