PubMed HealthSearch

SEARCH · PubMed Health

Results for “cadence”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

A new technique for simultaneous monitoring of electrocardiogram and walking cadence.

A new technique for simultaneously recording continuous electrocardiographic (ECG) data and walking step rate (cadence) is described. The ECG and gait signals are recorded on 2 channels of an ambulatory Holter monitor. Footfall is detected using ultrathin, force-sensitive foot switches and is frequency modulated. The footfall signal provides an indication of the subject's activity (walking or standing), as well as the instantaneous walking rate. Twenty-three young and elderly subjects were studied to demonstrate the use of this ECG and gait recorder. High-quality gait signals were obtained in all subjects, and the effects of walking on the electrocardiogram were assessed. Initial investigation revealed the following findings: (1) Although walking rates were similar in young and elderly subjects, the elderly had both decreased heart rate (HR) variability (p < 0.005) and increased cadence variability (p < 0.0001). (2) Overall, there was an inverse relation between HR and cadence variability (r = -0.73). Three elderly subjects with no known cardiac disease had HR and cadence variability similar to those of the young, whereas elderly subjects with history of congestive heart failure were among those with the lowest HR variability and the highest cadence variability. (3) Low-frequency (approximately equal to 0.1 Hz) HR oscillations (frequently observed during standing) persisted during walking in all young subjects. (4) In some subjects, both step rate and HR oscillated at the same low frequency (approximately equal to 0.1 Hz) previously identified with autonomic control of the baroreflex.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Effect of cadence on the economy of uphill cycling.

Competitive cyclists generally climb hills at a low cadence despite the recognized advantage in level cycling of high cadences. To test whether a high cadence is more economical than a low cadence during uphill cycling, nine experienced cyclists performed steady-state bicycling exercise on a treadmill under three randomized trials. Subjects bicycled at 11.3 km.h-1 up a 10% grade while 1) pedalling at 84 rpm in a sitting position-84 Sit, 2) pedalling at 41 rpm in a standing position-41 Stand, and 3) pedalling at 41 rpm in a sitting position-41 Sit. Heart rate (HR), oxygen consumption (VO2), ventilation (VE), and respiratory exchange ratio were measured continuously during 5-min trials and averaged over the last 2 min. Additionally, rating of perceived exertion was recorded during the fifth minute of each trial, and blood lactate concentration was recorded immediately before and after each trial. Significantly lower values for HR, VO2 and VE were recorded during 84 Sit (164 +/- 3 bpm, 51.8 +/- 0.8 ml.min-1 x kg-1, 94 +/- 5 l.min-1) than for either the 41 Stand (171 +/- 2 bpm, 53.1 +/- 0.7 ml.min-1 x kg-1, 105 +/- 6 l.min-1) o 41 Sit (168 +/- 2 bpm, 53.1 +/- 0.8 ml.min-1 x kg-1, 101 +/- 6 l.min-1) trials. No other differences were noted between trials for any of the measured variables. We conclude that uphill cycling is more economical at a high versus a low cadence.

Adolescent

Alterations in Spatiotemporal Parameters in Patients With Lower-Limb Amputation: A Systematic Review With Meta-Analysis.

OBJECTIVES: To evaluate differences in spatiotemporal gait parameters in individuals with transfemoral (TFA) and transtibial amputation (TTA) compared with physically able individuals. METHODS: This systematic review with meta-analysis was conducted according to the MOOSE guidelines. Cross-sectional studies or clinical trials that assessed spatiotemporal gait parameters in adults with unilateral TFA or TTA were included. Searches were performed in Medline (via PubMed), CINAHL, Scopus, LILACS, Cochrane Library, and Embase using descriptors related to amputation and gait. Risk of bias was assessed using the Joanna Briggs Institute scale for cross-sectional studies, whereas the meta-analysis was performed using quantitative data for the following outcomes: walking speed, step length, stride length, step width, cadence, stance time, swing time, step time, or stride time. RESULTS: A total of 12 cross-sectional studies involving 150 individuals with amputation (86 TTA and 64 TFA) and 138 healthy controls were included. Meta-analysis demonstrated a significant reduction in walking speed (mean difference of -0.24; 95% CI -0.32 to -0.17; p&#xa0;<&#xa0;0.0001; I2&#xa0;=&#xa0;61%) and cadence (mean difference of -6.01; 95% CI -9.69 to -2.34; p&#xa0;=&#xa0;0.001; I2: 54%) in patients with amputation compared with healthy individuals. A reduction in stride length (mean difference of -11.71; 95% CI -23.37 to -0.04; p&#xa0;=&#xa0;0.05; I2: 85%) and an increase in step width (mean difference of 5.22; 95% CI 2.99 to 7.45; p&#xa0;<&#xa0;0.0001; I2: 71%) were also observed. Step time showed no significant difference between groups (mean difference of 0.06; 95% CI -0.01 to 0.14; p&#xa0;=&#xa0;0.11; I2: 93%). Patients with TFA amputation exhibited greater impairment in gait variables, particularly cadence, when compared with a healthy individual. CONCLUSIONS: Patients with lower limb amputation present with functionally compromised gait, characterized by reduced walking speed. Increased step width and reduced stride length are findings that may suggest compensatory strategies during gait and improved balance, which are important requirements for amputee patients. These findings reinforce the need for rehabilitation interventions focused on improving propulsion and postural safety. TRIAL REGISTRATION: PROSPERO: CRD42024620098.

Humans

Metabolic energy cost of unrestrained walking.

Physiologic factors of metabolic energy cost as well as selected mechanical characteristics of gait are described in a group of 40 presumably normal men and women between the ages of 20 and 60 years. Special emphasis was placed on unrestrained (free cadence) walking to provide a reliable baseline for comparison to persons with physical gait impairments. Velocity of walking was the most important factor in determining oxygen uptake and was independent of age or sex. An empirical equation was established relating oxygen uptake to the speed of walking. The average velocity for men in unrestrained walking trials was 89 meters per minute; for women 74 meters per minute. These differences were related to the greater stride length in men. The average cadence selected by both sexes was 116 steps per minute. None of these factors was age dependent. Of the physiologic measures only systolic blood pressure was age dependent predictably rising with age. The mean heart rate was 103 beats per minute and did not vary significantly between men and women. The mean respiratory rate was 19 per minute; the mean respiratory quotient, 0.85, neither being age or sex dependent. Oxygen uptake values averaged 12.95 ml/kg-min for the population studied and again were neither age nor sex dependent.

Adult

Cardiorespiratory responses of healthy subjects to calisthenics performed on land versus in water.

This study evaluated the oxygen consumption (VO2) and heart rate response curves for standardized upper- and lower-extremity exercise on land and in water. Forty healthy subjects performed one upper-extremity and one lower-extremity exercise at three selected cadences on land and in water. Steady-state heart rate was determined by electrocardiographic radiotelemetry and expressed as a percentage of age-predicted maximal heart rate (% APMHR). Percentage of age-predicted maximal heart rate was used as the criterion measure of relative exercise intensity. Oxygen consumption was determined by the open-circuit method. Results indicated systematic increases in VO2 from 2 to 9 metabolic equivalents (METs) (1 MET = 3.5 mL O2.kg-1.min-1) and % APMHR from 45% to 73% with increased cadence. The VO2 responses were highest during water exercise, whereas % APMHR was greater during land exercise. Based on the magnitude of the responses, water calisthenics appear to be of sufficient intensity to elicit training adaptations. Training studies are needed to document these changes.

Adult

Gait in relation to ageing and idiopathic parkinsonism.

Distance/time measures of gait in 105 sufferers from idiopathic Parkinsonism, who were able to walk unaided, and 144 healthy controls were examined systematically. Those sufferers with overt fluctuations in control were assessed during their "therapeutic window". Free walking speed was lower for a given cadence in the sufferers, but reached a plateau whilst cadence could still be increased. Age, cognitive function and the range of passive hip flexion were important determinants of gait in them. Even minor degrees of cognitive impairment were associated with reduced free walking speed in sufferers: it appears unwise that they were prescribed more sedatives than the controls. The potential benefit of physiotherapy in maintaining joint flexibility was noted. The deficits in speed of individual sufferers, and hence the estimated potential for prophylaxis and treatment, were unrelated to age at presentation. There was no evidence for a limited period of responsiveness to levodopa therapy in this cross-sectional study.

Adult

Effect of MHC class-I transfection on local tumor growth and metastasis in an H-2-negative clone derived from a chemically induced fibrosarcoma.

GR9 is a chemically induced fibrosarcoma composed of clones with different H-2 class-I expression. These clones differ with respect to local growth and spontaneous metastasis. The B9 clone (H-2 negative) is highly tumorigenic (local growth) but of low metastatic potential (spontaneous metastasis assay). We have analyzed the effect that transfection of H-2Dd and H-2Kd genes on this clone have upon local growth, lung colonization after i.v. injection and ability to form spontaneous metastases. The results showed that the effect on local growth of transfection of the Kd-gene was stronger than that of the Dd gene. In addition, B9 co-transfected with H-2Kd and Dd genes showed the highest immunogenic properties in syngeneic BALB/c mice. Interestingly, the pSV2-neo transfected clone gave almost the same result as that obtained with Dd transfection. Lung colonization after i.v. injection of the different clones (experimental metastasis), paralleled the results obtained for local growth: the number of lung nodules followed the cadence KdDd less than Kd less than Dd less than pSV2. Survival of mice was always inversely correlated with local growth, e.g., all mice injected with 5 x 10(5) B9 H-2KdDd transfected cells survived. In contrast, no mice injected with the B9 control did. These differences were abrogated in irradiated and nude BALB/c mice. Finally, all transfected clones remained non-metastatic in a spontaneous metastasis assay, behaving as the control, non-transfected B9 cells.

Animals

Determining the variability of performance on Wingate anaerobic tests in children aged 6-12 years.

In two parts, this study investigated variability of performance in Wingate anaerobic tests (WAnTs) of normal, healthy, male children aged six, eight, ten and twelve years. The purpose of the first part of the study was to investigate the mean coefficient of variation (C.V. = [S.D./X].100) of children who performed four WAnTs over a period of four weeks. The results revealed age-related differences in the performance data of peak power (PP) and mean power (MP) but no differences between age groups in fatigue index (FI%) = [PP-Pend)/PP.100]. C.V. data from this group of children did not differ significantly between ages in any of the dependent variables. Coggan and Costill (5) measured the variability of male adults during 30 seconds of highly intense cycling and reported C.V.s in PP and MP performances of 6.7 and 6.5%, respectively. C.V.s of children in the first part of the present study were 7.3 and 6.8% for PP and MP, respectively. The C.V. in the FI% of the children (26.7%) however differed substantially from the previously studied adults (10.3%). The second part of the study was conducted to examine the C.V. in FI% performances of children in the WAnT. The purpose of this part of the study was to examine the extent to which a computerized onscreen game, which was linked to pedal cadence affected the variability of children performing WAnTs. A significant decrease was obtained in the C.V. of the FI% in the presence of the computerized feedback game (16.3 and 23.6, with and without the game, respectively). It is suggested that game-based testing procedures may ensure more consistent result in the assessment of pediatric populations.

Anaerobic Threshold

Effect of cane on variables of gait for patients with hip disorders.

The purposes of this study were to determine the effect of a cane, used in the hand contralateral to the involved hip, on patients' floor reaction forces and on selected time and distance measurements of gait. An instrumented cane, force plate, dynograph recorder and footswitch were among the equipment items used. When the patients walked with a cane the stride length and swing times were increased, while the cadence and the vertical component of the floor reaction force were decreased. The average peak axial loading on the can was 11.6 kg and the average anterior bending moment on the cane was 67.3 kgcm.

Arthroplasty

Evaluation of a clinical method of gait analysis.

Data on step and stride length, step width, foot angle, and cadence were collected from a sample of 30 normal women. The gait patterns were recorded on white paper by a method which involved the application of moleskin and ink to the soles of the subjects' shoes. The purpose of the investigation was to demonstrate the validity, technical reliability, and clinical feasibility of this method of gait analysis. The values obtained compared favorably with the results of a similarly designed laboratory study cited in the literature. In addition, the method was easy to apply, was not time consuming, and yielded data which were reproducible at greater than a 95% level of confidence.

Adult

Accelerographic, temporal, and distance gait factors in below-knee amputees.

Gait characteristics of 19 patients with a unilateral below-knee amputation were studied. The accelerographic and foot placement method used in this study allowed for simultaneous acquisition of data commonly obtained in the experimental laboratory (acceleration) and data easily gathered in the physical therapy clinic (temporal and distance factors). The following results may be of interest to the clinician: 1) measures of cadence, stride length, and velocity were highly related and the magnitude of these measures was below commonly accepted values for normal; 2) the below-knee amputees spent more time in stance phase on their uninvolved lower extremity than on their involved (prosthetic) extemity; 3) the step length from heel strike of the uninvolved lower extremity to heel strike of the involved (prosthetic) lower extremity was greater and accomplished in less time than the opposite step; and 4) smoothness of the gait pattern and any single temporal and distance factor exhibited low statistical relationships.

Acceleration

Energy cost of walking of below-knee amputees having no vascular disease.

Fifteen unilateral below-knee amputees with no preexisting vascular disease were studied during free velocity walking to determine energy expenditure with and without a prosthesis. Expired air was collected, and heart rate and respiratory rate data were telemetered. Mean velocity for the unrestrained walking was 71 m/min, both during ambulation with a prosthesis and during crutch walking (without a prosthesis). Heart rates were within normal ranges during prosthetic walking (106 beats/min), but rose significantly to 135 beats/min for crutch walking. Energy cost also rose significantly from a mean of 15.5 ml O2/kg/min with a prosthesis of 22.3 ml O2/kg/min with crutches. The oxygen uptake measured in units of ml O2/kg/m increased when the subjects walked faster or slower than their free cadence. We concluded that the use of the prosthesis should be encouraged and that the amputee should be allowed to choose his natural velocity of walking.

Adult

A clinical trial of strengthening and aerobic exercise to improve gait and balance in elderly male nursing home residents.

The purpose of this study was to determine whether a moderate to high intensity strengthening and aerobic exercise program can improve the strength, exercise capacity, gait and balance of deconditioned male nursing home residents. Ambulatory subjects who scored 30 or less on the modified Tinetti gait and balance assessment scale, who demonstrated less than 80% of age-matched lower extremity strength on isokinetic muscle testing and who gave informed consent were enrolled. Subjects were randomized to either an exercise (n = 8) or a control (n = 6) group. All participants underwent an exercise test to determine maximal oxygen uptake (VO2max) and received quantitative gait and balance measurements. The subjects assigned to the exercise group than completed a 12-wk program of weight training for the lower extremities and stationary cycling. Both the exercise and control groups were then retested. Ten outcome variables were assessed: Tinetti mobility scores, VO2max, isokinetic-tested lower extremity strength and endurance, stride length, gait velocity, stance time, gait duration, cadence and balance. The exercise group, after completion of the program, demonstrated significant improvements in Tinetti mobility scores (P < 0.05), combined right and left quadricep muscle strength (P < 0.01), right and left lower extremity muscular endurance (P < 0.01), left stride length and gait velocity (P < 0.05), although other outcome variables changed insignificantly. The control group revealed no changes of significance with the exception of improvement of the combined right and left hamstring muscle strength (P < 0.05). Nevertheless, for those outcome variables that had improved significantly in the exercise group, the changes amounted to only a 5 to 10% increase over the baseline measurements. These findings showed that an appropriately designed high intensity exercise program can result in significant although limited improvements for clinical mobility scores, strength, muscular endurance and certain gait parameters.

Aged

Gait electromyography in normal and spastic children, with special reference to quadriceps femoris and hamstring muscles.

Telemetered gait electromyography was used to investigate gait patterns and the phasic behavior of the quadriceps femoris and medial hamstring muscles in 26 normal children and 32 children with spastic cerebral palsy. The average child with spastic cerebral palsy was found to have a shorter stance phase than the normal, but the cadence, while more variable, was nearly the same as normal. The spastic muscles typically exhibited prolonged phasic activity or a dysphasic pattern. Most of the patients with spastic hamstrings also had spastic quadriceps, suggesting that over-weakening the hamstrings may produce an unwanted genu recurvatum or hyperextended knee gait. Care must be taken to balance hamstring spasticity with quadriceps spasticity. A final result with slight knee flexion is preferable to hyperextension.

Adolescent

Acute and chronic cycle length dependent increase in ventricular pacing threshold.

Several factors have been shown to influence ventricular pacing threshold in humans, including pacing lead location (endocardial vs epicardial), lead maturation, and antiarrhythmic agents. To determine whether ventricular pacing rate has a significant influence on acute and chronic pacing thresholds, we measured pacing thresholds in 16 patients receiving an implantable antitachycardia pacemaker cardioverter defibrillator (Cadence). Ventricular pacing thresholds were determined using the device programmer at cycle lengths of 600, 400 and 300 msec at the time of implantation; prior to hospital discharge at 3-14 days; and during follow-up outpatient visits at 6-8 weeks, 3 months, and 6 months to 1 year. Eleven patients had an epicardial lead system and five an endocardial lead system. Eleven patients were being treated with antiarrhythmic drug therapy. Device output ranged from 1-10 V and was adjustable in 1-V increments (pulse width was held constant at 1 msec). A cycle length dependent increase in pacing threshold (defined as a > or = 1-V increase in threshold at 400 or 300 msec relative to 600 msec) was observed in 10/16 patients during 12/72 pacing trials at 400 msec, and in 15/16 patients during 31/67 trials at 300 msec. In trials in which an increase in pacing threshold occurred, the magnitude of the increase at 400 msec relative to 600 msec was only 1 V in all 12 trials, but at 300 msec the increase ranged from 4-9 V in 7/31 (23%) trials.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Arrhythmia Agents

Electrocardiographically documented unnecessary, spontaneous shocks in 241 patients with implantable cardioverter defibrillators.

The incidence and cause of electrocardiographically documented spontaneous implantable cardioverter defibrillator (ICD) discharges for a rhythm other than ventricular tachycardia (VT) or fibrillation (VF) (unnecessary shocks) were determined in 241 patients who underwent ICD implantation between March 1983 and November 1991. During follow-up of 24 +/- 20 months, 54 of 241 patients (22%) received a total of 132 unnecessary ICD shocks confirmed by Holter or telemetry monitoring or stored electrograms (Egs) from the ICD. The rhythm preceding these unnecessary ICD shocks was atrial fibrillation in 30 patients, sinus or supraventricular tachycardia (SVT) in 11 patients, antitachycardia pacing triggered by atrial fibrillation or SVT resulting in VT in 5 patients, nonsustained VT in 3 patients, and normal sinus or pacemaker rhythm in 10 patients. Unnecessary ICD discharges occurred most frequently during the first week after implantation or generator replacement (18 of 54 patients [33%]). Unnecessary ICD discharges could be documented more often by stored Egs in patients with devices with Eg storage capability (Ventritex Cadence, 19 of 54 patients [35%]) than by Holter or telemetry monitoring in patients with devices without Egs storage capabilities (34 of 193 patients [18%], P < 0.01), despite a shorter mean follow-up duration of 14 +/- 9 months versus 26 +/- 21 months, respectively. Only six of 54 patients (11%) in whom unnecessary ICD discharges occurred had recurrent unnecessary shocks during 22 +/- 20 months of follow-up after treatment directed at the cause of the first episode or device reprogramming to preclude non-VT rhythm detection.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Fibrillation

The cochlear implant; basic principles.

In recent years the cochlear implant has been a subject of much discussion and controversy. The clinician has often been confused by the conflicting reports of success and failure. In this paper the development of the cochlear implant is reviewed and its present status summarized. It is hoped that the clinician may thereby gain an understanding of this device so that he can better evaluate its present and future status. Selection of Patients for Cochlear Implantation. The cochlear implant will benefit only those patients with hair cell loss who have remaining viable auditory neurons. In order to determine whether viable neurons remain, an electric current is passed through a small needle which is place into the promontory through the tympanic membrane. If patients experience an auditory sensation as a result of this electrical stimulation, it is felt that they are suitable candidates for a cochlear implant. Feasibility of Long-Term VIIIth Nerve Stimulation. Many questions have been raised regarding the feasibility of long-term stimulation of the auditory nerve. The first question raised was whether the auditory nerve would survive severe hair cell degeneration. Studies have shown that in most cases at least a few auditory neurons remain. The next question was whether the cochlear implant itself would destroy the remaining auditory neurons. Preliminary studies have shown that the nerve will survive the placement of electrodes both into the modiolus and the scala tympani. Several electrode materials and insulation have been found to be well tolerated, and there has been minimal damage from thermal or electrolytic processes; therefore, it appears feasible to stimulate the auditory nerve over a long period. Information Transfer by Electrical Stimulation. Single-channel stimulation produces only periodicity pitch, and information transfer is insufficient for speech discrimination. Experience to date indicates that it will be possible to produce both place and volley pitch by electrical stimulation with multiple electrodes in the scala tympani. These findings give promise for the feasibility of producing a device which will transfer sufficient information to produce speech discrimination. Present Status of the Cochlear Implant. To the present time 15 patients have been implanted with a unipolar electrode under the direction of the Ear Research Institute. These patients have all benefited from their devices. They are able to perceive background sounds and receive a cadence or rhythm to speech which makes the device helpful in lipreading. None of the patients have developed significant speech discrimination.

Auditory Cortex