Increase In Movement Velocity Research Articles

The Inclusion of a Complementary Running Progression Program in the Rehabilitation of Acute Hamstring Injuries: A Critically Appraised Topic

Introduction/Clinical Scenario: As many hamstring injuries occur when the hamstrings are in a lengthened state during the deceleration phase of running when the muscle is eccentrically contracting to slow the body down this functional aspect needs to be addressed. Thus, a rehabilitation program with a focus on progressive targeted eccentric hamstring exercises by gradually placing and exposing the muscle to eccentric force in a lengthened state supplemented with progressive running drills should be evaluated. Focused Clinical Question: Does the inclusion of a complementary running progression program for the rehabilitation of an acute hamstring injury reduce the time to safe return to sport with less hamstring reinjury occurrence for an athletic population? Summary of Key Findings: Three studies assessed the inclusion of a progressive running program with several types of running progression parameters addressed. Progressive running drills will load the hamstring in a functional manner, with a gradual increase in velocity of movement and lengthening of the muscle. Clinical Bottom Line: It appears that a complementary progressive running program within an acute hamstring rehabilitation program should be included as it caused no further harm and does not tend to increase hamstring reinjury occurrence. Strength of Recommendation: There is grade B evidence to include a complementary running progression program within an acute hamstring rehabilitation program.

The AudioMaze: An EEG and motion capture study of human spatial navigation in sparse augmented reality.

Spatial navigation is one of the fundamental cognitive functions central to survival in most animals. Studies in humans investigating the neural foundations of spatial navigation traditionally use stationary, desk-top protocols revealing the hippocampus, parahippocampal place area (PPA), and retrosplenial complex to be involved in navigation. However, brain dynamics, while freely navigating the real world remain poorly understood. To address this issue, we developed a novel paradigm, the AudioMaze, in which participants freely explore a room-sized virtual maze, while EEG is recorded synchronized to motion capture. Participants (n=16) were blindfolded and explored different mazes, each in three successive trials, using their right hand as a probe to "feel" for virtual maze walls. When their hand "neared" a virtual wall, they received directional noise feedback. Evidence for spatial learning include shortening of time spent and an increase of movement velocity as the same maze was repeatedly explored. Theta-band EEG power in or near the right lingual gyrus, the posterior portion of the PPA, decreased across trials, potentially reflecting the spatial learning. Effective connectivity analysis revealed directed information flow from the lingual gyrus to the midcingulate cortex, which may indicate an updating process that integrates spatial information with future action. To conclude, we found behavioral evidence of navigational learning in a sparse-AR environment, and a neural correlate of navigational learning was found near the lingual gyrus.

Immediate effects of cervical mobilisations on global perceived effect, movement associated pain and neck kinematics in patients with non-specific neck pain. A double blind placebo randomised controlled trial

BackgroundNeck pain is prevalent, costly and disabling. Cervical mobilisations are frequently used to treat it but their effectiveness has been questioned by several systematic reviews. Evidence suggests that better outcomes are achieved with mobilisations when they are applied to specific patient subgroups. A criteria for patients suitable for neck mobilisations has been proposed, but the effectiveness on this patient subgroup has not been tested. ObjectiveTo assess the effectiveness of cervical mobilisations applied to a subgroup of patients with neck pain who fulfil specific criteria. DesignRandomised controlled trial. Method40 patients with neck pain attending a Physiotherapy clinic were recruited and randomised to a single session of either cervical mobilisations or motionless manual contact placebo. The immediate effects on global perceived effect, range of movement (ROM), movement velocity and movement associated pain were assessed. Resultsmobilisation participants reported significantly better global perceived effect (p˂0.001) and improvements in movement associated pain (p = 0.041). Mobilisations produced a significant increase in ROM in side flexion (p = 0.006) and rotation (p = 0.044) when compared with placebo, but only in patients with pre-intervention ROM restriction. 29–47% of all movement associated pains were resolved following mobilisations and 11–27% following placebo. Patients in both groups showed a significant (p < 0.05) increase in movement velocity, but only in those who had a velocity restriction pre-intervention. ConclusionsCervical mobilisations are effective in improving movement-associated pain, increasing ROM and velocity, and patient perceived improvement when applied to patients with neck pain that fulfil a criteria. Their use should be advocated.

Effects of combining ergonomic interventions and motor control exercises on muscle activity and kinematics in people with work-related neck-shoulder pain.

This study compared the effects of "Ergomotor" intervention and conventional physiotherapy, on influencing the motor control in the neck-shoulder region in people with work-related neck-shoulder pain (WRNSP). 101 patients (age range 20-54years) diagnosed with chronic WRNSP were randomized into control (CO) group (n = 50) and Ergomotor (EM) group (n = 51). Each group received a 12-week intervention. Participants in CO group received treatment for pain relief and general exercises. EM group received individualized motor control training and advice of ergonomic modifications at their workplaces. At post-intervention, EM group showed significant reduction of bilateral upper trapezius muscle activity during active neck movements (left: 40-35%, right: 35-27%) and functional tasks such as lifting a weight forward-backward (left: 31-21%, right: 22-14%) and upward-downward (left: 26-23%, right: 20-13%). Cervical erector spinae also showed significant decrease in muscle activity during some phases of the functional tasks (left: 13-6%, right: 10-2%). In contrast, CO group did not show such changes in muscle activity at post-intervention. EM group also showed significant increase in movement velocity and acceleration during active neck movements in all directions (from 18 to 31%), while CO group only showed significant increase in movement velocity in some directions. Both groups reported significant but similar reduction in pain scores, at post-intervention and 1-year follow-up. The present results provided some evidence to support the positive and sustainable benefits of integrating motor control training into the workplace postures and motions.

Estimating changes in lichen mat volume through time and related effects on barren ground caribou (Rangifer tarandus groenlandicus) movement.

Lichens form a critical portion of barren ground caribou (Rangifer tarandus groenlandicus) diets, especially during winter months. Here, we assess lichen mat volume across five herd ranges in the Northwest Territories and Nunavut, Canada, using newly developed composite Landsat imagery. The lichen volume estimator (LVE) was adapted for use across 700 000 km2 of barren ground caribou habitat annually from 1984–2012. We subsequently assessed how LVE changed temporally throughout the time series for each pixel using Theil-Sen’s slopes, and spatially by assessing whether slope values were centered in local clusters of similar values. Additionally, we assessed how LVE estimates resulted in changes in barren ground caribou movement rates using an extensive telemetry data set from 2006–2011. The Ahiak/Beverly herd had the largest overall increase in LVE (median = 0.033), while the more western herds had the least (median slopes below zero in all cases). LVE slope pixels were arranged in significant clusters across the study area, with the Cape Bathurst, Bathurst, and Bluenose East herds having the most significant clusters of negative slopes (more than 20% of vegetated land in each case). The Ahiak/Beverly and Bluenose West had the most significant positive clusters (16.3% and 18.5% of vegetated land respectively). Barren ground caribou displayed complex reactions to changing lichen conditions depending on season; the majority of detected associations with movement data agreed with current understanding of barren ground caribou foraging behavior (the exception was an increase in movement velocity at high lichen volume estimates in Fall). The temporal assessment of LVE identified areas where shifts in ecological conditions may have resulted in changing lichen mat conditions, while assessing the slope estimates for clustering identified zones beyond the pixel scale where forage conditions may be changing. Lichen volume estimates associated with barren ground caribou movement metrics in an expected manner and, as such, show value for future habitat assessments.

Gait and Balance Performance Improvements Attributable to Ankle–Foot Orthosis in Subjects with Hemiparesis

To assess the change in the balance performance and the improvement in the gait performance of subjects with hemiparesis, as a result of their wearing an ankle-foot orthosis. This was a cross-sectional control trial. Fifty-eight subjects with hemiparesis of a duration of less than 6 mos participated in this study. Each subject was evaluated for the balance and gait performance with and without an ankle-foot orthosis on the affected side. The balance activities were evaluated by the Balance Master System, and the gait performance was measured using GAITRite. The increase in movement velocity and the change in maximal excursion toward the affected side during the balance testing were found to be correlated significantly with the change in walking speed as a result of wearing an ankle-foot orthosis (r=0.274, P=0.039; r=0.325, P=0.020; respectively). Only the change in maximal excursion toward the affected side was found to be significantly correlated with the change in nonaffected step length (r=0.381, P=0.010). The maximal excursion toward the affected side improved as a result of wearing an ankle-foot orthosis. This correlated with an increase in step length on the nonaffected side and, hence, an improvement in the walking speed of the subjects with hemiparesis.

Positive geotaxis in infant rats (Rattus norvegicus): a natural behavior and a historical correction.

Infant rats (Rattus norvegicus) placed on a shallow incline (2 degrees, 4 degrees, or 8 degrees) oriented and moved downhill within 1 min; that is, they displayed positive geotaxis. Their downhill translocation increased with angle of inclination. A variety of possible behavioral elements (e.g., initial orientation, rotational movements, ambulatory velocities) were eliminated as explanations of the geotaxis. Wall contact was recognized as a determinative event: Pups on the inclines showed no orientation with respect to the geogravitational stimulus before contacting a wall. The event of wall contact, however, evoked reliable downhill orientation and more linear movements. Positive geotaxis was created by pups' orientation against walls and an associated increase in movement velocity. This is a distinct perspective on a behavioral response that replaces a traditionally misinterpreted phenomenon. The authors discuss the ecological validity and historical context of these findings.

Discharge pattern of human motor units during dynamic concentric and eccentric contractions

Objectives: A total of 45 motor units (MUs) from the human biceps brachii muscle were investigated during isovelocity concentric and eccentric movements performed by means of a device implementing an external torque in the direction of the extension proportionally to the elbow angle changes. The effects of movement velocity on the recruitment and decruitment thresholds (RT and DT) and the corresponding discharge patterns were determined. Methods: A wire branched electrode placed subcutaneously was used to discriminate the potentials from a single MV. Results: The majority of MUs (91%) were recruited at lower torque values with the increase of movement velocity. The decrease of RT was statistically significant for 47% of the investigated MUs. A typical discharge pattern of short first interspike interval (ISI) followed by a longer one was observed for 93% of all MUs. After the first 2–3 spikes the rate of the MU discharge was approximately constant regardless of the fact that the muscle force gradually increased until the end of the concentric movement. Conclusions: There are differences in the muscle force control during shortening and lengthening contractions. For 82% of the investigated MUs DT was smaller at faster movements and for 21 MUs (47%) the decrease of DT was significant. The gradually declined MU discharge rate throughout the entire movement with a very long last ISI was demonstrated for 93% of the investigated MUs.

Acute effects of levodopa on wrist movement in Parkinson's disease. Kinematics, volitional EMG modulation and reflex amplitude modulation.

Acute changes in motor performance due to levodopa were evaluated by a series of four motor tests unified by their focus on wrist flexion-extension movements. Subjects with idiopathic Parkinson's disease were evaluated with this battery of tests before (OFF) and after their usual morning dose of levodopa (ON). The test battery consisted of (i) repetitive self-paced movement in which velocity was to be maximized; (ii) visually guided tracking of a sinusoid and a square wave; and (iii) an assay of stretch reflex modulation during volitional sinusoidal tracking. The maximal wrist joint velocity of self-paced reciprocating flexion and extension movements increased after levodopa (ON), without significant changes in the movement period or amplitude. In the two tracking tasks, some subjects improved as evident by a lower root mean square (rms) error, but in similar numbers of subjects the rms error increased. Overall, the rms error, peak velocity or peak movement amplitude did not change after levodopa in either tracking task. Significant and consistent changes did occur after levodopa in an assay of reflex modulation during error-constrained tracking (Johnson et al., Brain 1991; 114: 443-60). The amplitude of volitional EMG increased after levodopa, with a concurrent reduction in reflex EMG. These changes are consistent with the noted increase in movement velocity. These results show that the effects of levodopa on movement velocity were not consistently translated into increased accuracy. The changes in the long latency reflex gain argue for a central control of this reflex, mediated by structures sensitive to levodopa. Finally, the results show that the quantitative evaluation of levodopa therapy cannot be unidimensional, but requires a battery of motor tests as undertaken in this study.

Response amendment latencies during discrete arm movements.

Examinations of the ability to rapidly modify ongoing movements have found that amendment latencies are shorter when a visual stimulus specifies an increase in movement velocity as compared to when a movement reversal is required. Our present study examined the hypothesis that amendment latencies for both continue and reverse instructions are dependent on the muscle activation state when the amendment is produced. Visual stimuli representing continue and reverse instructions wer represented at four different phases of a discrete arm movement, with amendment latencies measured to modified electromyographic (EMG) patterns. Amendment latencies for the continue instruction were shortest when the stimulus was presented early in the movement and increased when the stimulus was presented later in the response. The opposite trend was true for the reversal condition with long latencies occurring when the stimulus was presented early in the movement. Our findings support the notion that amendment latencies are directly related to the active state of the motor system when the modification is required, and the nature of the amendment to be generated.

Corrosion Testing of Aluminum (Part 1 — High Velocity Test Method in Aqueous Solutions)

Abstract A technique of corrosion testing, involving spinning of aluminum disks in aqueous solutions at high velocities, was used to investigate the effect of various natural waters and antifreezes on aluminum corrosion. Type of aluminum used was No. 100 aluminum brazing sheet, having zinc-aluminum cladding on one side, and silicon-aluminum cladding on the other. It was established that an increase in velocity of movement up to a maximum peripheral velocity of 4700 feet per minute (12,000 rpm) is accompanied by a systematic increase in corrosion rate reaching very high values in some waters. Type of corrosion occurring at higher velocities is similar to that occurring at low velocities and in service. Aqueous solutions particularly corrosive were those combining high chloride ion concentration and high alkalinity (as OH− or CO3= ion), such as Royal Oak, Michigan, tap water. High alkalinity (up to pH 11) appears to cause severe attack of aluminum even in the absence of chloride ion. In permanent antifreeze...