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Introduction: The aim of this study was to assess the effects of neuromuscular fatigue on stretch reflex-related torque and electromyographic activity of spastic knee extensor muscles in hemiplegic patients. The second aim was to characterize the time course of quadriceps muscle fatigue during repetitive concentric contractions., Methods: Eighteen patients performed passive, isometric and concentric isokinetic evaluations before and after a fatigue protocol using an isokinetic dynamometer. Voluntary strength and spasticity were evaluated following the simultaneous recording of torque and electromyographic activity of rectus femoris (RF), vastus lateralis (VL) and biceps femoris (BF)., Results: Isometric knee extension torque and the root mean square (RMS) value of VL decreased in the fatigued state. During the fatigue protocol, the normalized peak torque decreased whereas the RMS of RF and BF increased between the first five and last five contractions. There was a linear decrease in the neuromuscular efficiency-repetitions relationships for RF and VL. The peak resistive torque and the normalized RMS of RF and VL during passive stretching movements were not modified by the fatigue protocol for any stretch velocity., Discussion: This study showed that localized quadriceps muscle fatigue caused a decrease in voluntary strength which did not modify spasticity intensity. Changes in the distribution of muscle fiber type, with a greater number of slow fibers on the paretic side, may explain why the stretch reflex was not affected by fatigue., (Copyright © 2014. Published by Elsevier Ltd.)

Background and Objective: Individuals who survive a stroke often display considerable gait impairments that occur in part due to inadequate muscle force production. This study aimed to investigate lower limb muscle forces in poststroke patients during walking. Methods: Kinematics, kinetics, and electromyographic (EMG) measurements were performed on nine poststroke and healthy individuals walking at natural speed in a cross-sectional study. Recorded parameters were used in an EMG-driven model to estimate the forces exerted by the muscles around the knee and ankle joints during the stance (braking and propulsion) and swing phases. Results: For hemiparetic patients, in comparison to healthy controls, the paretic side exhibited (i) lower forces generated by plantar-flexors and quadriceps respectively during the braking and propulsion phases, but (ii) higher knee-flexors forces during the propulsion phase. Regarding the non-paretic side, it displayed (i) higher forces generated by knee-flexors and quadriceps (only for the propulsion phase) forces during the stance phase, and (iii) higher plantar-flexors forces during the swing phase, in comparison to controls. Conclusion: Reduced forces exerted by the plantar-flexors and the knee-extensors along with increased force generated by the knee-flexors on the paretic side give possible explanation for hemiparetic gait abnormalities. Increased muscle forces exerted by the non-paretic side might be a compensatory strategy to better support body weight and properly adjust the center of mass forward. [ABSTRACT FROM AUTHOR]

BACKGROUND: The Timed Up and Go (TUG) is a test of functional mobility which is routinely used in the assessment of hemiparetic patients. This easy and rapid to perform test includes motor tasks which occur frequently in daily life (stand up, walk, turn, sit down). Correlations between TUG performance and kinematic and kinetic gait parameters have never been studied. OBJECTIVE: The aim of this study was to determine whether kinematic and kinetic gait parameters would be more related to TUG performance than spatio-temporal parameters in stroke patients. METHODS: Sixty hemiparetic patients able to walk alone performed the TUG test and underwent 3D gait analysis and a clinical evaluation. A stepwise regression analysis was used to select the gait variables that best explained the variability in TUG performance. RESULTS: The percentage of the gait cycle spent in single support phase on the paretic limb was the factor which was the most predictive and correlated with TUG performance, explaining 67% of the variance. No kinematic or kinetic gait parameters explained TUG performance. The results also suggested that TUG performance is mainly related to paretic lower limb motor function. CONCLUSIONS: TUG performance in hemiparetic patients mainly depends on the motor ability of the paretic lower limb, particularly the single support phase on the paretic side. Kinematic and kinetic gait parameters do not predict the TUG performance in stroke patients. [ABSTRACT FROM AUTHOR]

Background: Timed Up and Go (TUG) performance is reduced following stroke. Gait training improves gait-related activities in hemiparetic patients. However, no study has compared the impact of a single overground training session with a treadmill training session on gait-related activities (assessed by TUG). Objective: To compare the immediate effect of a single overground training session versus a single treadmill training session on TUG performance in hemiparetic patients. Methods: In this randomized controlled clinical trial, 56 hemiparetic patients were randomized to 1 or 2 distinct groups: a single gait training session overground (O group) or on a treadmill (T group). Time taken to perform the TUG (in seconds) was assessed before and immediately after the completion of each session. Results: Time taken to perform the TUG decreased significantly, and to a similar extent, in both groups following the training session (O group, 5.9%; T group, 5.2%). Conclusions: An overground training session and a treadmill training session were equally effective in improving TUG performance in hemiparetic patients. Hemiparetic patients should be encouraged to walk regularly overground including turns for 20 minutes without stopping. This is an easy and inexpensive self-rehabilitation method to improve functional gait-related activities involved in the TUG test. [ABSTRACT FROM AUTHOR]

Background: Gait training for patients with hemiparesis is carried out independently overground or on a treadmill. Several studies have shown differences in hemiparetic gait parameters during overground versus treadmill walking. However, few studies have compared the effects of these 2 gait training conditions on gait parameters, and no study has compared the short-term effects of these techniques on all biomechanical gait parameters. Objective: To determine whether a gait training session performed overground or on a treadmill induces specific short-term effects on biomechanical gait parameters in patients with hemiparesis. Methods: Twenty-six subjects with hemiparesis were randomly assigned to a single session of either overground or treadmill gait training. The short-term effects on spatiotemporal, kinematic, and kinetic gait parameters were assessed using gait analysis before and immediately after the training and after a 20-minute rest. Results: Speed, cadence, percentage of single support phase, peak knee extension, peak propulsion, and braking on the paretic side were significantly increased after the gait training session. However, there were no specific changes dependent on the type of gait training performed (overground or on a treadmill). Conclusion: A gait training session performed by subjects with hemiparesis overground or on a treadmill did not induce specific short-term effects on biomechanical gait parameters. The increase in gait velocity that followed a gait training session seemed to reflect specific modifications of the paretic lower limb and adaptation of the nonparetic lower limb. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to analyze the effects of clearing and skirting obstacles during the gait on the energetic cost of walking (ECW) of patients with chronic hemiplegia. The hypothesis was that hemiplegia would have a greatest increase in the ECW than in the healthy group. Design: Fifteen healthy subjects and 17 patients with chronic hemiplegia completed two 6-min walking sessions: one with obstacles and the other without obstacles. During both sessions, the patients were equipped with a portable gas analyzer to measure oxygen uptake (...o2). Gait velocity and ECW were calculated. Results: In both groups, gait velocity was lower in the with-obstacles condition and the ECW was significantly higher. ...o2 was greater in the with-obstacles condition for the healthy group, whereas it remained unchanged for the group with hemiplegia. Conclusions: Results demonstrated that the addition of obstacles during gait increased the ECW and decreased mean walking speed in both the healthy subjects and the patients with hemiplegia. More interestingly, the authors found differences in adaptation strategies between the healthy subjects and the patients with hemiplegia. During the with-obstacles condition, the oxygen uptakes of the healthy subjects increased and mean walking speed decreased, whereas, in the subjects with hemiplegia, only mean walking speed decreased. [ABSTRACT FROM AUTHOR]