المؤلفون: Pimentel, Richard E., Feldman, Jordan N., Lewek, Michael D., Franz, Jason R.

المصدر: Frontiers in Sports and Active Living, 4

مصطلحات موضوعية: treadmill, energy expenditure, locomotion, gait, push-off, walking economy

الوصف: Walking speed is a useful surrogate for health status across the population. Walking speed appears to be governed in part by interlimb coordination between propulsive (FP) and braking (FB) forces generated during step-to-step transitions and is simultaneously optimized to minimize metabolic cost. Of those forces, FP generated during push-off has received significantly more attention as a contributor to walking performance. Our goal was to first establish empirical relations between FP and walking speed and then to quantify their effects on metabolic cost in young adults. To specifically address any link between FP and walking speed, we used a self-paced treadmill controller and real-time biofeedback to independently prescribe walking speed or FP across a range of condition intensities. Walking with larger and smaller FP led to instinctively faster and slower walking speeds, respectively, with ~80% of variance in walking speed explained by FP. We also found that comparable changes in either FP or walking speed elicited predictable and relatively uniform changes in metabolic cost, together explaining ~53% of the variance in net metabolic power and ~14% of the variance in cost of transport. These results provide empirical data in support of an interdependent relation between FP and walking speed, building confidence that interventions designed to increase FP will translate to improved walking speed. Repeating this protocol in other populations may identify other relations that could inform the time course of gait decline due to age and disease.

العلاقة: https://doi.org/10.17615/80wa-jw69Test; https://cdr.lib.unc.edu/downloads/v692tj07v?file=thumbnailTest; https://cdr.lib.unc.edu/downloads/v692tj07vTest

الإتاحة: https://doi.org/10.17615/80wa-jw69Test
https://cdr.lib.unc.edu/downloads/v692tj07v?file=thumbnailTest
https://cdr.lib.unc.edu/downloads/v692tj07vTest

المؤلفون: Feasel, Jeff, Whitton, Mary C., Kassler, Laura, Brooks, Frederick P., Lewek, Michael D.

المصدر: IEEE Transactions on Neural Systems and Rehabilitation Engineering, 19(3)

مصطلحات موضوعية: Visualization, gait analysis, interlimb asymmetry, feedback, ground reaction force data, patient rehabilitation, split-belt treadmill, gait speed, biomechanics, Virtual environment, Adaptive systems, Real time systems, handicapped aids, gait symmetry, Belts, Legged locomotion, medical disorder, medical disorders, locomotion rehabilitation, locomotor retraining, intuitive feedback, IVERT system, Force, Integrated Virtual Environment Rehabilitation Treadmill, Training

الوصف: Slow gait speed and interlimb asymmetry are prevalent in a variety of disorders. Current approaches to locomotor retraining emphasize the need for appropriate feedback during intensive, task-specific practice. This paper describes the design and feasibility testing of the integrated virtual environment rehabilitation treadmill (IVERT) system intended to provide real-time, intuitive feedback regarding gait speed and asymmetry during training. The IVERT system integrates an instrumented, split-belt treadmill with a front-projection, immersive virtual environment. The novel adaptive control system uses only ground reaction force data from the treadmill to continuously update the speeds of the two treadmill belts independently, as well as to control the speed and heading in the virtual environment in real time. Feedback regarding gait asymmetry is presented 1) visually as walking a curved trajectory through the virtual environment and 2) proprioceptively in the form of different belt speeds on the split-belt treadmill. A feasibility study involving five individuals with asymmetric gait found that these individuals could effectively control the speed of locomotion and perceive gait asymmetry during the training session. Although minimal changes in overground gait symmetry were observed immediately following a single training session, further studies should be done to determine the IVERT’s potential as a tool for rehabilitation of asymmetric gait by providing patients with congruent visual and proprioceptive feedback.

العلاقة: https://doi.org/10.17615/ja5b-5x81Test; https://cdr.lib.unc.edu/downloads/w0892j271?file=thumbnailTest; https://cdr.lib.unc.edu/downloads/w0892j271Test

الإتاحة: https://doi.org/10.17615/ja5b-5x81Test
https://cdr.lib.unc.edu/downloads/w0892j271?file=thumbnailTest
https://cdr.lib.unc.edu/downloads/w0892j271Test

المؤلفون: Carll, Alex P., Hazari, Mehdi S., Perez, Christina M., Krantz, Q. Todd, King, Charly J., Haykal-Coates, Najwa, Cascio, Wayne E., Costa, Daniel L., Farraj, Aimen K.

المصدر: Toxicological Sciences, 135(2)

مصطلحات موضوعية: Inhalation, Disease Progression, Body Temperature, Ventricular Pressure, Dobutamine, Vagotomy, Heart, Atenolol, rats, Parasympathetic Nervous System, Rattus norvegicus, Exercise, Heart Rate, Heart Failure, Blood Pressure, autonomic nervous system, Atropine Derivatives, diesel exhaust, Air, Air Pollutants, treadmill, Vehicle Emissions, Particulate Matter

الوصف: Cardiac disease exacerbation is associated with short-term exposure to vehicular emissions. Diesel exhaust (DE) might impair cardiac performance in part through perturbing efferent sympathetic and parasympathetic autonomic nervous system (ANS) input to the heart. We hypothesized that acute changes in ANS balance mediate decreased cardiac performance upon DE inhalation. Young adult heart failure–prone rats were implanted with radiotelemeters to measure heart rate (HR), HR variability (HRV), blood pressure (BP), core body temperature, and pre-ejection period (PEP, a contractility index). Animals pretreated with sympathetic antagonist (atenolol), parasympathetic antagonist (atropine), or saline were exposed to DE (500 µg/m3 fine particulate matter, 4h) or filtered air and then treadmill exercise challenged. At 1 day postexposure, separate rats were catheterized for left ventricular pressure (LVP), contractility, and lusitropy and assessed for autonomic influence using the sympathoagonist dobutamine and surgical vagotomy. During DE exposure, atenolol inhibited increases in HR, BP, and contractility, but not body temperature, suggesting a role for sympathetic dominance. During treadmill recovery at 4h post-DE exposure, HR and HRV indicated parasympathetic dominance in saline- and atenolol-pretreated groups that atropine inhibited. Conversely, at treadmill recovery 21h post-DE exposure, HRV and PEP indicated sympathetic dominance and subsequently diminished contractility that only atenolol inhibited. LVP at 1 day postexposure indicated that DE impaired contractility and lusitropy while abolishing parasympathetic-regulated cardiac responses to dobutamine. This is the first evidence that air pollutant inhalation both causes time-dependent oscillations between sympathetic and parasympathetic dominance and decreases cardiac performance via aberrant sympathetic dominance.

العلاقة: https://doi.org/10.17615/7fe1-qg51Test; https://cdr.lib.unc.edu/downloads/sj1399790?file=thumbnailTest; https://cdr.lib.unc.edu/downloads/sj1399790Test

الإتاحة: https://doi.org/10.17615/7fe1-qg51Test
https://cdr.lib.unc.edu/downloads/sj1399790?file=thumbnailTest
https://cdr.lib.unc.edu/downloads/sj1399790Test

المصدر: Biology of Sport / Institute of Sport, 25(4)

مصطلحات موضوعية: Erythrocyte, Article, Treadmill exercise, CRI, Training status, Immune adherence

الوصف: The aims of this study were to investigate the effects of training status, different intensities, durations and modes of exercises on the activity of complement receptor type 1 (CR1) of erythrocytes. Fifteen sedentary male adults and 15 male adult endurance athletes performed five separate treadmill exercise trials: max VO2 test (T1), exercise at 40% max VO2 for 30 min (T2), 80% max VO2 for 30 min (T3) and for 60 min (T4) and downhill running (-10% gradient) at 60% max VO2 for 30 min (T5). Blood samples were taken before exercise, immediately, one h, two h and 24 h after each exercise trial to assay the activity of erythrocyte CR1. The results showed that there was no significant difference between trained and untrained participants in erythrocyte-tumor cell rosette (ETCR) formations at rest (p>0.05). ETCR was significantly decreased after five exercise trials (p<0.05). Changes in ETCR were more obvious after T1, T3 and T4. ETCR 24 h after T5 was significantly lower than that after uphill running. Greater reductions and slower recoveries in ETCR were found in the untrained group than in the trained group. The results indicated that erythrocyte CR1 activity at rest was not affected by training status, but was significantly inhibited by acute exercise. Exercise at higher intensities and longer durations resulted in a greater suppression in the activity of erythrocyte CR1. The suppression was more marked in the untrained participants than in the trained participants. Downhill running induced a longer delay in recovery in erythrocyte CR1 activity compared to uphill running.

العلاقة: https://doi.org/10.17615/xzyf-aa48Test; https://cdr.lib.unc.edu/downloads/mg74qw04z?file=thumbnailTest; https://cdr.lib.unc.edu/downloads/mg74qw04zTest

الإتاحة: https://doi.org/10.17615/xzyf-aa48Test
https://cdr.lib.unc.edu/downloads/mg74qw04z?file=thumbnailTest
https://cdr.lib.unc.edu/downloads/mg74qw04zTest