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Alterations in the rate of limb movement using a lower body positive pressure treadmill do not influence respiratory rate or phase III ventilation.
Buono, MJ, Burnsed-Torres, M, Hess, B, Lopez, K, Ortiz, C, Girodo, A, Lolli, K, Bloom, B, Bailey, D, Kolkhorst, FW
BioMed research international. 2015;:618291
Abstract
The purpose of this study was to determine the effect of alterations in rate of limb movement on Phase III ventilation during exercise, independent of metabolic rate, gait style, and treadmill incline. Subjects completed five submaximal exercise bouts on a lower body positive pressure treadmill (AlterG P 200). The percent body weight for the five exercise bouts was 100, 87, 75, 63, and 50% and each was matched for carbon dioxide production (V CO2 ). Naturally, to match the V CO2 while reducing the body weight up to 50% of normal required a significant increase in the treadmill speed from 3.0 ± 0.1 to 4.1 ± 0.2 mph, which resulted in a significant (P < 0.05) increase in the mean step frequency (steps per minute) from 118 ± 10 at 3 mph (i.e., 100% of body weight) to 133 ± 6 at 4.1 mph (i.e., 50% of body weight). The most important finding was that significant increases in step frequency did not significantly alter minute ventilation or respiratory rate. Such results do not support an important role for the rate of limb movement in Phase III ventilation during submaximal exercise, when metabolic rate, gait style, and treadmill incline are controlled.
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Electromyographic assessment of isometric and dynamic activation characteristics of the latissimus dorsi muscle.
Beaudette, SM, Unni, R, Brown, SH
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 2014;(3):430-6
Abstract
The aim of the current study was to analyze the activation characteristics and potential compartmentalization of the latissimus dorsi (LD) muscle during common maximal voluntary isometric contractions (MVICs) and functional dynamic tasks. Surface electromyography (sEMG) was used to measure activation magnitudes from four electrode sites (referenced to the T10, T12, L1 & L4 LD vertebral origins) across the fanning muscle belly of the LD. In addition, EMG waveforms were cross-correlated to study temporal activation timing between electrode sites (T10-T12, T12-L1, L1-L4 & T10-L4). The MVICs that were tested included a humeral adduction, humeral adduction with internal rotation, a chest-supported row and a humeral extension. Dynamic movements included sagittal lift/lowers from the floor to knee, knee to hip and hip to shoulder. No magnitude-based (p=0.6116) or temporal-based differences were observed between electrode sites during the MVIC trials. During dynamic movements no temporal-based, but some magnitude-based differences between electrode sites were observed to be present; these differences were small in magnitude and were observed for both the maximum (p=0.0002) and mean (p=0.0002) EMG magnitudes. No clear pattern of compartmentalization was uncovered in the contractions studied here. In addition to these findings, it was determined that the most effective MVIC technique for LD EMG normalization purposes was a chest-supported row MVIC, paired with a T12 electrode site.
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Effects of dynamic stepping training on nonlocomotor tasks in individuals poststroke.
Straube, DD, Holleran, CL, Kinnaird, CR, Leddy, AL, Hennessy, PW, Hornby, TG
Physical therapy. 2014;(7):921-33
Abstract
BACKGROUND During the physical rehabilitation of individuals poststroke, therapists are challenged to provide sufficient amounts of task-specific practice in order to maximize outcomes of multiple functional skills within limited visits. Basic and applied studies have suggested that training of one motor task may affect performance of biomechanically separate tasks that utilize overlapping neural circuits. However, few studies have explicitly investigated the impact of training one functional task on separate, nonpracticed tasks. OBJECTIVE The purpose of this preliminary study was to investigate the potential gains in specific nonlocomotor assessments in individuals poststroke following only stepping training of variable, challenging tasks at high aerobic intensities. METHODS Individuals with locomotor deficits following subacute and chronic stroke (n=22) completed a locomotor training paradigm using a repeated-measures design. Practice of multiple stepping tasks was provided in variable environments or contexts at high aerobic intensities for ≥40 sessions over 10 weeks. The primary outcome was timed Five-Times Sit-to-Stand Test (5XSTS) performance, with secondary measures of sit-to-stand kinematics and kinetics, clinical assessment of balance, and isometric lower limb strength. RESULTS Participants improved their timed 5XSTS performance following stepping training, with changes in selected biomechanical measures. Statistical and clinically meaningful improvements in balance were observed, with more modest changes in paretic leg strength. CONCLUSIONS The present data suggest that significant gains in selected nonlocomotor tasks can be achieved with high-intensity, variable stepping training. Improvements in nonpracticed tasks may minimize the need to practice multiple tasks within and across treatment sessions.
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Analysis of the 5 iron golf swing when hitting for maximum distance.
Healy, A, Moran, KA, Dickson, J, Hurley, C, Smeaton, AF, O'Connor, NE, Kelly, P, Haahr, M, Chockalingam, N
Journal of sports sciences. 2011;(10):1079-88
Abstract
Most previous research on golf swing mechanics has focused on the driver club. The aim of this study was to identify the kinematic factors that contribute to greater hitting distance when using the 5 iron club. Three-dimensional marker coordinate data were collected (250 Hz) to calculate joint kinematics at eight key swing events, while a swing analyser measured club swing and ball launch characteristics. Thirty male participants were assigned to one of two groups, based on their ball launch speed (high: 52.9 ± 2.1 m · s(-1); low: 39.9 ± 5.2 m · s(-1)). Statistical analyses were used to identify variables that differed significantly between the two groups. Results showed significant differences were evident between the two groups for club face impact point and a number of joint angles and angular velocities, with greater shoulder flexion and less left shoulder internal rotation in the backswing, greater extension angular velocity in both shoulders at early downswing, greater left shoulder adduction angular velocity at ball contact, greater hip joint movement and X Factor angle during the downswing, and greater left elbow extension early in the downswing appearing to contribute to greater hitting distance with the 5 iron club.
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Apneic preterms and methylxanthines: arousal deficits, sleep fragmentation and suppressed spontaneous movements.
Hayes, MJ, Akilesh, MR, Fukumizu, M, Gilles, AA, Sallinen, BA, Troese, M, Paul, JA
Journal of perinatology : official journal of the California Perinatal Association. 2007;(12):782-9
Abstract
OBJECTIVE To determine if apneic preterm infants currently treated with methylxanthines develop evidence of sleep deprivation from cumulative arousal and motor activational effects. STUDY DESIGN Sleep, wake, arousal and actigraphic movements were monitored in extubated clinically stable premature infants (N=37). Neonates were free of other medications for >72 h and were grouped based on methylxanthine exposure: >5 days with caffeine (n=14), >5 days theophylline (n=13) or no prior exposure (n=10). RESULT Duration of methylxanthine treatment predicted increased arousals, wakefulness and actigraphic movements, and decreased active sleep. Recording from 1200 to 0500 hours, methylxanthine-treated groups showed reductions in all arousal parameters: waking state, number of wake epochs, brief arousals and composite arousal index, and shorter fast-burst, sleep-related motility than untreated controls. CONCLUSION In apneic preterms, chronic methylxanthine treatment appears to produce sleep deprivation secondary to the stimulatory action of methylxanthines on arousal and motor systems.
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A temporal comparison of BOLD, ASL, and NIRS hemodynamic responses to motor stimuli in adult humans.
Huppert, TJ, Hoge, RD, Diamond, SG, Franceschini, MA, Boas, DA
NeuroImage. 2006;(2):368-82
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Abstract
In this study, we have preformed simultaneous near-infrared spectroscopy (NIRS) along with BOLD (blood oxygen level dependent) and ASL (arterial spin labeling)-based fMRI during an event-related motor activity in human subjects in order to compare the temporal dynamics of the hemodynamic responses recorded in each method. These measurements have allowed us to examine the validity of the biophysical models underlying each modality and, as a result, gain greater insight into the hemodynamic responses to neuronal activation. Although prior studies have examined the relationships between these two methodologies through similar experiments, they have produced conflicting results in the literature for a variety of reasons. Here, by employing a short-duration, event-related motor task, we have been able to emphasize the subtle temporal differences between the hemodynamic parameters with a high contrast-to-noise ratio. As a result of this improved experimental design, we are able to report that the fMRI measured BOLD response is more correlated with the NIRS measure of deoxy-hemoglobin (R = 0.98; P < 10(-20)) than with oxy-hemoglobin (R = 0.71), or total hemoglobin (R = 0.53). This result was predicted from the theoretical grounds of the BOLD response and is in agreement with several previous works [Toronov, V.A.W., Choi, J.H., Wolf, M., Michalos, A., Gratton, E., Hueber, D., 2001. "Investigation of human brain hemodynamics by simultaneous near-infrared spectroscopy and functional magnetic resonance imaging." Med. Phys. 28 (4) 521-527.; MacIntosh, B.J., Klassen, L.M., Menon, R.S., 2003. "Transient hemodynamics during a breath hold challenge in a two part functional imaging study with simultaneous near-infrared spectroscopy in adult humans". NeuroImage 20 1246-1252.; Toronov, V.A.W., Walker, S., Gupta, R., Choi, J.H., Gratton, E., Hueber, D., Webb, A., 2003. "The roles of changes in deoxyhemoglobin concentration and regional cerebral blood volume in the fMRI BOLD signal" Neuroimage 19 (4) 1521-1531]. These data have also allowed us to examine more detailed measurement models of the fMRI signal and comment on the roles of the oxygen saturation and blood volume contributions to the BOLD response. In addition, we found high correlation between the NIRS measured total hemoglobin and ASL measured cerebral blood flow (R = 0.91; P < 10(-10)) and oxy-hemoglobin with flow (R = 0.83; P < 10(-05)) as predicted by the biophysical models. Finally, we note a significant amount of cross-modality, correlated, inter-subject variability in amplitude change and time-to-peak of the hemodynamic response. The observed co-variance in these parameters between subjects is in agreement with hemodynamic models and provides further support that fMRI and NIRS have similar vascular sensitivity.
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Repeated maximal eccentric actions causes long-lasting disturbances in movement control.
Bottas, R, Linnamo, V, Nicol, C, Komi, PV
European journal of applied physiology. 2005;(1-2):62-9
Abstract
This study examined acute and long-lasting effects of fatigue and muscle damage on fast and accurate elbow flexion and extension target movements (TM) with eight male students. An isokinetic machine was used to perform 100 maximal eccentric and concentric elbow flexions at 4-week intervals. Movement range was 40-170 degrees in eccentric exercise (ECCE) and 170-40 degrees in concentric exercise (CONE), with an angular velocity of 2 rad s(-1). TM was performed in sitting position with the right forearm fixed to lever arm above protractor. Subjects performed TM in horizontal plane (amplitude 60 degrees ) by visual feedback of movement from a television monitor. Surface EMG was recorded from the biceps brachii and triceps brachii muscles. TM measurements and serum creatine kinase (CK) determinations were conducted before, after, 0.5 h, 2 days, and 7 days after both exercises. Blood lactate was taken before, after, and 0.5 h after the exercises. Both ECCE and CONE led to a large decline in maximal voluntary contractions, but the recovery was slower after ECCE when it remained incomplete even until day 7 post-exercise. Lactate increased (P < 0.001) similarly after both exercises. Delayed-onset muscle soreness peaked on day 2 and CK peaked on day 7 after ECCE. Exhaustive eccentric exercise of agonistic muscles impaired the flexion TM performance, and had a long-duration modulation effect on the triphasic EMG activity pattern of flexion and extension TM. In the acute phase, the observed changes in performance and in the EMG patterns are suggested to be related to metabolic changes via III and IV muscle afferents. The delayed recovery, on the other hand, may be related to problems in the proprioceptive feedback caused by muscle damage.
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Physical training in institutionalized elderly people with multiple diagnoses--a controlled pilot study.
Rydwik, E, Frändin, K, Akner, G
Archives of gerontology and geriatrics. 2005;(1):29-44
Abstract
Reduction in muscle mass and physical function depends on a variety of interacting factors: age, physical activity level, nutritional state and the type and impact of disease. The aim of this study was to investigate the effect of an individualized moderate intensity physical training program on muscle strength, balance, mobility, ambulation and activities of daily living (ADL) in institutionalized elderly people aged 65 and over with multiple diagnoses. Baseline assessments consisted of strength, balance, mobility/ambulation, and ADL. Twenty-one subjects were included in the intervention program. A control group (21 subjects) was first matched in pairs according to gender, age, ADL and mobility, and then by balance, ambulation and strength. The intervention program was individualized and included strength, mobility, balance and endurance training. Follow-up measures were conducted directly after the intervention and 10 weeks later. After drop-out, 20 subjects in the intervention group and 15 subjects in the control group remained for analyses. Balance and mobility improved significantly in the intervention group while declining in the control group. This pilot study indicates that a physical training program may improve functional capacity for institutionalized elderly persons with multiple diagnoses.
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Fractal analysis of acceleration signals from patients with CPPD, rheumatoid arthritis, and spondyloarthroparthy of the finger joint.
Shah, EN, Reddy, NP, Rothschild, BM
Computer methods and programs in biomedicine. 2005;(3):233-9
Abstract
Arthritis is one of the leading causes of disability and affects a major segment of the population. Consequently, accurate diagnosis of arthritis is important. Arthritis due to calcium pyrophosphate deposition disease (CPPD), rheumatoid arthritis, and spondyloarthropathy, induce complex changes in the cartilage and the articular surface. The fractal dimension provides a measure of the complexity of a signal. Recently, we have developed non-invasive acceleration measurements to characterize the arthritic patients. The question remains if the fractal dimension of the acceleration signal is different for different arthritis conditions. The purpose of this study was to distinguish between different types of arthritis of the finger joint using the fractal dimension of the acceleration signal obtained from the finger joint of the arthritic patients. Acceleration signals were obtained from the finger joint of arthritis patients with rheumatoid arthritis, spondyloarthropathy, and calcium pyrophosphate deposition disease of the finger joint. ANOVA results showed that there were significant differences between the fractal dimension of acceleration signals from patients having calcium pyrophosphate deposition disease and rheumatoid arthritis and spondyloarthropathy. Fractal dimension of acceleration signals, in concert with other clinical symptoms, can be used to classify different types of arthritis.
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Exercise, self-efficacy, and mobility performance in overweight and obese older adults with knee osteoarthritis.
Focht, BC, Rejeski, WJ, Ambrosius, WT, Katula, JA, Messier, SP
Arthritis and rheumatism. 2005;(5):659-65
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Abstract
OBJECTIVE To examine changes in mobility-related self efficacy following exercise and dietary weight loss interventions in overweight and obese older adults with knee osteoarthritis (OA), and to determine if self efficacy and pain mediate the effects of the interventions on mobility task performance. METHODS The Arthritis, Diet, and Activity Promotion Trial was an 18-month, single-blind, randomized, controlled trial comparing the effects of exercise alone, dietary weight loss alone, a combination of exercise plus dietary weight loss, and a healthy lifestyle control intervention in the treatment of 316 overweight or obese older adults with symptomatic knee OA. Participants completed measures of stair-climb time and 6-minute walk distance, self efficacy for completing each mobility task, and self-reported pain at baseline, 6 months, and 18 months during the trial. RESULTS Mixed model analyses of covariance of baseline adjusted change in the outcomes demonstrated that the exercise + dietary weight loss intervention produced greater improvements in mobility-related self efficacy (P = 0.0035), stair climb (P = 0.0249) and 6-minute walk performance (P = 0.00031), and pain (P = 0.09) when compared with the healthy lifestyle control intervention. Mediation analyses revealed that self efficacy and pain served as partial mediators of the beneficial effect of exercise + dietary weight loss on stair-climb time. CONCLUSION Exercise + dietary weight loss results in improved mobility-related self efficacy; changes in these task-specific control beliefs and self-reported pain serve as independent partial mediators of the beneficial effect of exercise + dietary weight loss on stair-climb performance.