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PubMed1994

Physiological and perceptual responses to walking while swinging hand-held towels.

The intent of this investigation was to determine the intensity of cardiovascular exercise produced by walking while swinging hand-held towels and its potential as a training method. Sixteen healthy college students were the volunteer subjects in this experiment. Each subject performed five randomly ordered trials in which they walked with: (1) a normal arm swing (NAS); (2) a vigorous arm swing (VAS); (3) a vigorous arm swing with hand-held towels (VAST); (4) a vigorous arm swing at NAS heart rate (VNH); and (5) a vigorous arm swing with hand-held towels at NAS heart rate (VTNH). Treadmill speed was 89 m.min-1 for VTNH, 103 for VNH, and 119 for NAS, VAS, and VAST trials. Each trial lasted 6 min and was separated by a 2 min walking recovery. Statistical analysis revealed (p < 0.05) that oxygen consumption (VO2), heart rate (HR), and rating of perceived exertion (RPE) were significantly greater for the VAST (27.8 +/- 3.9 ml.kg-1.min-1, 152 +/- 13.8 bpm, 4.2 +/- 1.4 Borg) vs. NAS (21.0 +/- 3.4, 125 +/- 14.7, 2.6 +/- 1.0) and VAS (24.7 +/- 3.7, 139 +/- 14.1, 3.4 +/- 1.1) vs. NAS trials, but were similar for NAS, VNH, and VTNH. Although not statistically significantly different, VO2, HR, and RPE were physiologically greater for the VAST than VAS trial. These results suggest that walking while swinging hand-held towels is a way to: (1) increase oxygen consumption without altering walking speed and (2) slow walking speed yet maintain exercise intensity.

Adult↗
PubMedDate not supplied

The effects of a walking/talking program on communication, ambulation, and functional status in residents with Alzheimer disease.

The purpose of this study was to investigate the effects of a walking/talking program on residents' communication, ambulation, and level of function when there were two residents to one care provider (2:1). A randomized control trial design was used. Subjects were residents with Alzheimer disease in three geriatric long-term care facilities in Metropolitan Toronto. Residents who met the inclusion criteria were randomly assigned to one of three groups: walk-and-talk group (30 min, 5 times per week for 16 weeks, walking/talking in pairs), talk-only group (30 min, 5 times per week for 16 weeks, talk only in pairs), or no intervention. The outcome measures were the Functional Assessment of Communication Skills for Adults, the 2-min walk test, and London Psychogeriatric Rating Scale. Residents who received the walk-and-talk intervention did not demonstrate statistically significant differences in the outcome variables measured posttest when compared with residents who received the talk-only intervention or no intervention, even after controlling for individual differences. Variability in the outcomes measured posttest is explained by differences in the residents' level of cognitive impairment before the study rather than by study group membership. These findings are contradictory to those of previous studies.

Activities of Daily Living↗
PubMedDate not supplied

The impact of exercise training on blood lipids in older adults.

Increasing physical activity is often prescribed to improve blood lipids; however, the efficacy of exercise in improving blood lipids in older adults is not clear. The objective of this study was to examine the effects of different exercise modes on blood lipid levels in previously sedentary older adults engaging in a 16-week exercise intervention. One hundred thirty-one subjects (mean age 74.6+/-6 years) were randomly assigned to a resistance training group, aerobic walking group, combined exercise group, or nonexercising control group. Blood lipids were measured at baseline, 8 weeks, and postintervention. Exercise mode did not impact blood lipids. All groups had lower lipid levels over time. Total cholesterol, low- and high-density lipoprotein, and triglycerides were significantly lower. The decrease in all groups, including the controls, may be due to a seasonal effect in older adults that has been documented in younger individuals.

Age Factors↗
PubMed2006

[Is triple combination of different neurohormonal modulators recommended for treatment of mild-to-moderate congestive heart failure patients? (Results of SADKO-CHF study). Part 2].

AIM: To assess different variants of neurohormonal (NH) modulation with angiotensin converting enzyme (ACE-I) quinapril (Q), angiotensin-receptor blocker (ARB) valsartan (V) and their combination in addition to beta-adrenergic blocker bisoprolol (B) on functional status, quality of life (QL), parameters of left ventricular (LP) remodeling, main indices of 24-h heart rate variability (HRV) and NH profile in patients with stable mild-to-moderate CHF. MATERIAL AND METHODS: 63 patients with CHF (NYHA class II-III) as a result of ischemic heart disease and dilated cardiomyopathy with LV EF < 40% were randomly assigned to one of the treatment variants on 1:1:1 basis: B+Q (n = 22; mean daily dose of B-5.5 mg; Q-15.4 mg), B+V (n = 23; mean daily dose of B = 4.8 mg; V = 128 mg) and combination of B+Q+V (n = 18; mean daily dose of B = 4.1 mg; Q = 12 mg; V = 82 mg). At baseline, all the patients in this study were on background B treatment and according to the study design Q or V were then added to B at randomization. NYHA FC, 6-min walking test (6MT), QL, 2D-echocardiography, plasma rennin activity (PRA), angiotensin II (AT-II), aldosterone (Ald), norepinephrine (NE), epinephrine (E), brain natriuretic peptide (BNP) concentrations and 24-hour HRV parameters were investigated at baseline, 3 and 6 months after randomization. RESULTS: During the study NYHA FC improvement was revealed in all 3 treatment groups with comparative significant changes in 6MT distance by 20.4%, 19.1% and 19.4% in B+Q, B+V and B+Q+V groups. QL maximally decreased in B+V combination (from 45 to 21 points). LV volumes significantly decreased and LV ejection fraction (EF) increased in all groups to the end of the study. Triple combination had no additional effect on LV volumes and LVEF changes compared to B+Q and B+V groups. Maximally plasma NE concentrations decreased in B+Q group (from 650 to 430 pg/ml, p = 0.007). A worse effect was observed in the combination of B+Q+V, with any NE changes in B+V group. The E concentration increased significantly (from 215 to 295 pg/ml, p = 0.024) in the B+Q+V group at the end of the study. Plasma A-H concentration did not differ from the baseline during the study in B+Q group, but significantly increased in B+V group and maximally in B+Q+V group (from 11.4 to 23.5 pg/ml, p = 0.009). To the end of the study plasma Ald concentrations remain reduced significantly only in B+V group. The level of BNP significantly decreased in all 3 treatment groups. Significant changes in HRV indices, both in time and frequency domain, were revealed in the B+Q group at 3-month follow-up and SDNN increased on month 24 (p = 0.039). These changes became insignificant at the end of the study. The lesser effect was revealed in B+Q+V group, with insignificant trend toward an increase of SDNN to the end of the study. HRV indices did not improve in the B+V group. CONCLUSION: During long-term treatment the triple combination of B+Q+V has no significant advantages over B+Q and B+V by the functional status, QL and parameters of LV remodeling in patients with mild-to-moderate CHF. The combination of B+Q has more potent effect on 24-hour HRV parameters, sympatho-adrenal activity and renal function compared to B+V and B+Q+V groups in CHF patients in our study. The combination B+Q+V may have a negative effect on NH profile (excessive activation of ATII and E) in CHF patients. The triple combination is not recommended for therapy of stable mild-to-moderate CHF patients.

Adrenergic beta-Antagonists↗
PubMed2006

[Is triple combination of different neurohormonal modulators recommended for treatment of mild-to-moderate congestive heart failure patients? (Results of Sadko-CHF study)].

AIM: To assess effects of different variants of neurohormonal (NH) modulation with angiotensin converting enzyme (ACE-I) quinapril (Q), angiotensin-receptor blocker (ARB) valsartan (V) and their combination in addition to beta-adrenergic blocker bisoprolol (B) on functional status, quality of life (QOL), parameters of left ventricular (LV) remodeling, main indices of 24-h heart rate variability (HRV) and NH profile in patients with stable mild-to-moderate congestive heart failure (CHF). MATERIAL AND METHODS: Sixty three patients with CHF (NYHA class II-III) as a result of ischemic heart disease and dilated cardiomyopathy with LV EF < 40% were randomly assigned to one of the treatment variants on 1:1:1 basis: B+Q (n = 22), B+V (n = 23) and combination of B+Q + V (n = 18). At baseline, all the patients in this study were on background B treatment and according to the study design Q or V were then added to B at randomization. NYHA FC, 6-min walking test (6MT), QOL, 2D-echocardiography, plasma renin activity (PRA), angiotensin II (AT-II), aldosterone (Ald), norepinephrine (NE), epinephrine (E), brain natriuretic peptide (BNP) concentrations and 24-hour HRV parameters were investigated at baseline, 3 and 6 months after randomization. RESULTS: During the study NYHA FC improvement was revealed in all three treatment groups with comparative significant changes in 6MT distance by 20.4%, 19.1% and 19.4% in B+Q, B+V and B+Q+V groups, respectively. QOL maximally decreased in B+V combination (from 45 to 21 points). LV volumes significantly decreased and LV ejection fraction (EF) increased in all groups to the end of the study. Triple combination had no additional effect on LV volumes and LVEF changes compared to B+Q and B+V groups. Plasma NE concentrations decreased maximally in B+Q group (from 650 to 430 pg/ml, p = 0.007). The lesser effect was observed in the combination of B+Q+V, with any NE changes in B+ V group. The E concentration increased significantly (from 215 to 295 pg/ml, p = 0.024) in the B+Q+V group at the end of the study. Plasma A-II concentration did not differ from the baseline during the study in B+Q group, but significantly increased in B+V group and maximally in B+Q+V group (from 11.4 to 23.5 pg/ml, p = 0.009). To the end of the study plasma Ald concentrations remain reduced significantly only in B+V group. The level of BNP significantly decreased in all 3 treatment groups. Significant changes in HRV indices, both in time and frequency domain, were revealed in the B+Q group at 3-month follow-up and SDNN increased on month 24 (p = 0.039). These changes became insignificant at the end of the study. The lesser effect was revealed in B+Q+V group, with insignificant trend toward an increase of SDNN to the end of the study. HRV indices did not improve in the B+V group. CONCLUSION: During long-term treatment the triple combination of B+Q+ V has no significant advantages over B+Q and B+V by the functional status, QOL and parameters of LV remodeling in patients with mild-to-moderate CHF. The combination of B+Q has more potent effect on 24-hour HRV parameters, sympatho-adrenal activity and renal function compared to B+V and B+Q+V groups in CHF patients in our study. The combination B+Q+V may have a negative effect on NH profile (excessive activation of ATII and E) in CHF patients. The triple combination is not recommended for therapy of stable mild-to-moderate CHF patients.

Adrenergic beta-Antagonists↗
PubMed2000

Effects of walking training on weight maintenance after a very-low-energy diet in premenopausal obese women: a randomized controlled trial.

BACKGROUND: Maintenance of weight loss is a core problem in the treatment of obesity. Physical activity may improve maintenance and metabolic risk factors associated with obesity. HYPOTHESES: (1) A walking training program of moderate intensity, started after weight reduction by a very-low-energy diet, improves maintenance of weight loss and obesity-related metabolic disorders; and (2) the effect of the training program is related to the prescribed amount of physical activity, ie, a higher amount (energy expenditure) leads to more favorable results. METHODS: The participants were premenopausal women with a mean body mass index of 34.0 kg/m(2). Eighty-two participants were randomized to this study; 74 participated in the follow-up assessment. A 12-week weight reduction by mostly a very-low-energy diet was followed by a 40-week maintenance program randomized in 3 groups: a control group with no increase in habitual exercise and with counseling on diet and relapse prevention; a walk-1 group, with a walking program targeted to expend 4.2 MJ/wk and diet counseling; and a walk-2 group, with a walking program of 8. 4 MJ/wk and diet counseling. Random permuted blocks within strata were used, with weight loss (in 3 classes) as the stratifying factor. After the intervention, the subjects were followed up for 2 years. MAIN OUTCOME MEASURES: Primary outcomes were body weight, fat mass, and waist circumference at the 2-year follow-up. Secondary outcomes were the levels of serum lipoproteins and lipids, plasma glucose, insulin, and blood pressure. RESULTS: The mean weight loss after weight reduction was 13.1 kg. The main outcome variables remained stable during the maintenance program, but increased during the follow-up period. Compared with the end of weight reduction, weight regain at the 2-year follow-up was 3.5 kg less (95% confidence interval, 0.2-6.8) and waist circumference regain 3.8 cm less (95% confidence interval, 0.3-7.3) in the walk-1 group vs controls. The secondary outcomes showed a partial relapse during the maintenance program, and a further regain during the follow-up period. CONCLUSIONS: Inclusion of a walking program of moderate training regimen into a weight maintenance program improved maintenance of losses in weight and waist circumference.

Adult↗
PubMed2001

Energy consumption during level walking with arm and knee immobilized.

OBJECTIVE: To determine whether there is an increase in energy use for able-bodied subjects with their arm and/or knee immobilized, while walking on a level surface at comfortable walking speed (CWS). DESIGN: Prospective, quantitative, with randomly sequenced experimental trials. SETTING: Rehabilitation center. PARTICIPANTS: Ten healthy subjects, none of whom had gait abnormality. INTERVENTION: Subjects walked on a treadmill at CWS under 4 conditions: (1) without an arm or knee immobilized (N); (2) with an arm immobilized (AI); (3) with a knee immobilized (KI); and (4) with both arm and ipsilateral knee immobilized (KAI). MAIN OUTCOME MEASURES: Breath-by-breath oxygen cost; differences in energy consumption in trials during which constraints were used were compared with energy consumed under the N condition and the percentage of change was calculated. RESULTS: Mean oxygen cost increased by 22.7% with a knee immobilized compared with N values (mean difference,.044 mL x kg(-1) x m(-1), p <.0001), and increased by 24.7% with a knee and arm immobilized (mean difference,.048 mL x kg(-1) x m(-1), p <.0001). However, no significant differences existed in oxygen cost with AI compared with N, or with KAI compared with KI. The differences in CWS between the stages followed a similar pattern. CONCLUSIONS: Arm immobilization does not increase energy expenditure during level walking at CWS, and does not further increase energy expenditure when the ipsilateral knee also is immobilized.

Adult↗
PubMedDate not supplied

Measures of complexity in neural spike-trains of the slowly adapting stretch receptor organs.

Discrete sequence analysis methods were applied to study spike-trains generated by the isolated neuron of the slowly adapting stretch receptor organ. Calculation of the algorithmic complexity and block entropies of digitized individual spike-train forms allowed us to distinguish different classes of neural behavior. While some spike-trains exhibited significant structure, others displayed diverse degrees of randomness. The sequences recorded during the stimulated portions of the intermittent and walk-through forms, differed considerably from their randomly shuffled surrogates. Informational and grammar complexity measures (in two, four and eight-letter alphabets), tell us things about the structure of spike-trains that are not obtained with conventional spike analysis. Comparison of the conditional entropies for the digitized signals showed that the method distinguishes between different stimulated conditions. Additionally, comparison of the different stimulated conditions with their corresponding surrogates showed that, both, conditional entropies and complexities were significantly different for the two groups. Although the original and the randomly shuffled sequences had the same distribution and average firing rate, their complexity values were different. The results obtained with both measures of sequence structure were quite consistent.

Action Potentials↗
PubMed2007

Surgical or nonoperative treatment for lumbar spinal stenosis? A randomized controlled trial.

STUDY DESIGN: A randomized controlled trial. OBJECTIVES: To assess the effectiveness of decompressive surgery as compared with nonoperative measures in the treatment of patients with lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: No previous randomized trial has assessed the effectiveness of surgery in comparison with conservative treatment for spinal stenosis. METHODS: Four university hospitals agreed on the classification of the disease, inclusion and exclusion criteria, radiographic routines, surgical principles, nonoperative treatment options, and follow-up protocols. A total of 94 patients were randomized into a surgical or nonoperative treatment group: 50 and 44 patients, respectively. Surgery comprised undercutting laminectomy of the stenotic segments in 10 patients augmented with transpedicular fusion. The primary outcome was based on assessment of functional disability using the Oswestry Disability Index (scale, 0-100). Data on the intensity of leg and back pain (scales, 0-10), as well as self-reported and measured walking ability were compiled at randomization and at follow-up examinations at 6, 12, and 24 months. RESULTS: Both treatment groups showed improvement during follow-up. At 1 year, the mean difference in favor of surgery was 11.3 in disability (95% confidence interval [CI], 4.3-18.4), 1.7 in leg pain (95% CI, 0.4-3.0), and 2.3(95% CI, 1.1-3.6) in back pain. At the 2-year follow-up, the mean differences were slightly less: 7.8 in disability (95% CI, 0.8-14.9) 1.5 in leg pain (95% CI, 0.3-2.8), and 2.1 in back pain (95% CI, 1.0-3.3). Walking ability, either reported or measured, did not differ between the two treatment groups. CONCLUSIONS: Although patients improved over the 2-year follow-up regardless of initial treatment, those undergoing decompressive surgery reported greater improvement regarding leg pain, back pain, and overall disability. The relative benefit of initial surgical treatment diminished over time, but outcomes of surgery remained favorable at 2 years. Longer follow-up is needed to determine if these differences persist.

Aged↗
PubMed2001

Walking and resting blood pressure in adults: a meta-analysis.

BACKGROUND: The purpose of this study was to examine the effects of walking on resting systolic and diastolic blood pressure in adults. METHODS: A total of 24 primary outcomes from 16 studies and 650 subjects (410 exercise, 240 control) met the criteria for inclusion: (1) randomized and nonrandomized controlled trials, (2) walking as the only intervention, (3) subjects apparently sedentary, (4) adult humans > or =18 years of age, (5) English-language studies published between January 1966 and December 1998, (6) resting blood pressure assessed, (7) training studies > or =4 weeks. RESULTS: Using a random effects model, statistically significant decreases of approximately 2% were found for both resting systolic and diastolic blood pressure (systolic, mean +/- SEM = -3 +/- 1 mm Hg, 95% confidence interval: -5 to -2 mm Hg; diastolic, mean +/- SEM = -2 +/- 1 mm Hg, 95% confidence interval: -3 to -1 mm Hg). CONCLUSION: Walking exercise programs reduce resting blood pressure in adults.

Adult↗
PubMed2002

The effect of noninvasive intermittent positive-pressure ventilation during exercise in severe scoliosis.

STUDY OBJECTIVES: Noninvasive intermittent positive-pressure ventilation (NIPPV) may improve exercise performance in COPD patients. It is not known whether this also applies to other patient groups such as those with restrictive respiratory diseases. DESIGN: Randomized controlled trial. SETTING: Regional center for assisted ventilation. SUBJECTS: Eight patients with severe congenital scoliosis. INTERVENTIONS: A submaximal treadmill test was performed with NIPPV applied via a mouthpiece. Each subject performed three walks breathing with three different ventilators and one walk breathing through the mouthpiece alone in random order. In addition, four unencumbered walks breathing normally and without monitoring were performed. MEASUREMENTS AND RESULTS: The four unencumbered walks did not show a significant learning effect. The mean (SD) distance walked was 204 m (134.9 m). Using the mouthpiece alone, the walking distance fell to 140 m (75.8 m), and with the addition of the ventilators it fell further to 109 m (59.3 m). Grouped-effects analysis of variance showed this to be a significant difference in walking distance according to the type of walk (p = 0.048). There was no difference shown among the three brands of ventilator. At the breakpoint of exercise, significant increases were seen in tidal volume and minute volume (Mv) in the ventilator-assisted walks (p < 0.05) compared to walks performed breathing with the mouthpiece alone. CONCLUSIONS: Breathing via a mouthpiece impaired exercise performance, and there was no improvement when breathing with a ventilator, despite the observed increase in Mv. NIPPV has no beneficial effect on exercise endurance in patients with severe scoliosis.

Analysis of Variance↗
PubMed1999

Establishing the reliability and validity of measurements of walking time using the Emory Functional Ambulation Profile.

BACKGROUND AND PURPOSE: The Emory Functional Ambulation Profile (E-FAP) measures time to walk in different environments and accounts for use of assistive devices. This study assessed the reliability and validity of walking time measurements using these components. SUBJECTS: Twenty-eight subjects who had strokes and 28 subjects without impairment were recruited. METHODS: The E-FAP, Berg Balance Test, Functional Reach Test, and Timed 10-Meter Walk Test were administered in random order during a single data collection session. RESULTS: Interrater reliability for the total E-FAP was > or = .997. Subjects without impairment performed better on all 4 tests than did subjects who had strokes. Increased times on the E-FAP correlated with poor performance on the Berg Balance Test and slow gait speeds on the Timed 10-Meter Walk Test in the subjects who had strokes. The E-FAP scores and the Functional Reach Test scores were not correlated. CONCLUSION AND DISCUSSION: The E-FAP can be administered easily and inexpensively. Because the E-FAP scores differentiated subject groups and correlated with known measures of function, the E-FAP may be a clinically useful measure of ambulation.

Adult↗
PubMed1986

A randomized exercise trial in older women: increased activity over two years and the factors associated with compliance.

The health effects of increased physical activity in the prevention or treatment of any disease can only be meaningfully assessed if compliance to the exercise regimen is maintained. The current research examined compliance in a clinical trial investigating the effect of walking on bone loss in 229 postmenopausal women, randomized into either a walking or a control group. Although at baseline there was no difference in physical activity between the two groups, after a period of 2 yr, the walking group reported significantly greater physical activity as measured by reported mean blocks walked daily and objective activity monitor day readings. Closer examination of the walking group revealed that compliers (average 7+ miles walked/wk over the 2 yr), when compared to non-compliers, tended at baseline to be more active, lighter weight, and non-smokers. However, the variable that best differentiated between the two compliance groups was the frequency of reported illness over the 2-yr period, with compliers claiming significantly less illness.

Aged↗
PubMed2006

[Self-reported walking, balance testing and risk of fall among the elderly].

BACKGROUND: Falls represent an important health problem among the elderly. Balance testing as well as registration of self-reported balance problems may be appropriate in order to predict the risk of future falls. MATERIALS AND METHODS: Self-reported walking was assessed in 307 randomly selected women 75 years or older living at home. The women underwent testing of gait and balance and were followed up for one year with respect to falls and fall-related injuries. RESULTS: 155 of the women fell during the observation period; 308 falls were reported. 13% of the falls resulted in a fracture. Factor analysis identified five anamnestic questions measuring the same latent construct. The sum score of this self-reported walking index correlated highly with simple balance tests. A poor result on the walking index indicated a high risk of falling (odds ratio (OR) 1.83, 95% confidence interval 1.41-2.30) and of fall-related fractures (OR 2.65, 95 % CI 1.27-5.05) the subsequent year. The areas under the ROC curves (receiver-operating characteristics) were, however, only .57 for falls and .61 for fractures. INTERPRETATION: Simple questions give useful information on the risk of falls and fall-related fractures among elderly women.

Accidental Falls↗
PubMed1995

Propionyl-L-carnitine in intermittent claudication: double-blind, placebo-controlled, dose titration, multicenter study.

OBJECTIVES: The aim of this double-blind, placebo-controlled, dose titration, multicenter trial was to assess the efficacy and safety of propionyl-carnitine in intermittent claudication. BACKGROUND: Human and animal studies indicate that propionyl-L-carnitine increases carnitine content and improves energy metabolism in the ischemic skeletal muscle. METHODS: After a 2-week preliminary period to assess maximal walking distance, 245 patients were randomly assigned to receive propionyl-L-carnitine (n = 118) or placebo (n = 127). The initial oral dose of 500 mg twice daily was increased at 2-month intervals to 2 g/day and then to 3 g/day in patients showing improvement in treadmill performance < 30% over baseline. Efficacy analysis was conducted for the 214 patients who completed the 24 weeks of treatment by comparing the effect of placebo and propionyl-L-carnitine on day 180. RESULTS: Analysis of variance showed a significant improvement of 73 +/- 9% (mean +/- SE) in maximal walking distance with propionyl-L-carnitine (n = 99) compared with 46 +/- 6% for placebo (n = 115, p = 0.03). For distance walked at onset of claudication, propionyl-L-carnitine showed about double the improvement of placebo; however, the difference was not statistically significant. There were no changes in electrocardiographic and routine biochemical and hematologic tests that would indicate an adverse effect of propionyl-L-carnitine. Adverse events requiring drug discontinuation (11 in the propionyl-L-carnitine group, 3 in the placebo group) were unrelated to study medication. The dose titration design of the study also provided information on the dose-response relation. Slightly less than 67% of patients were expected to improve their maximal walking distance by at least 30%, assuming 2 g/day of propionyl-L-carnitine (95% confidence interval 0.51 to 0.70). The response rate during the entire titration course was significantly in favor of propionyl-L-carnitine compared with placebo. CONCLUSIONS: Although the precise mode of therapeutic action requires clarification, propionyl-L-carnitine, at a dose of 1 to 2 g/day, appears to be effective and well tolerated, with minimal adverse effects.

Administration, Oral↗
PubMed2002

Posthatching locomotor experience alters locomotor development in chicks.

We have previously demonstrated that, even though chicks are very precocial and can locomote within hours of hatching, they require a period of time to develop a mature stable walk. As an example, 1- to 2-day-old animals move with disproportionately small stride lengths compared with 10- to 14-day-old animals. The purpose of this study was to determine whether the maturation of walking, including the development of a mature stride length, depends on locomotor experience. We also investigated the development and experience-dependence nature of head bobbing, an optokinetic behavior that occurs during walking in birds. Chicks were randomly assigned to one of three groups receiving either increased locomotor experience (i.e., treadmill exercise), decreased locomotor experience (i.e., decreased housing space), or no alteration in locomotor experience. To assess the dependence of locomotor maturation on N-methyl-D-aspartate (NMDA)-type glutamate receptors, animals in each group were either given an NMDA antagonist (MK-801, 1 mg/kg intramuscularly daily) or saline control. Locomotor characteristics (stride length, leg support durations, horizontal head excursions) were quantified from videotaped recordings of chicks walking overground unrestrained on posthatching days 1, 2, 4, 6, 8, and 10. Animals subject to exercise restriction for at least 6 days moved with shortened stride lengths compared with age-matched treadmill-exercised or control animals, a change that was maintained for the duration of the study. NMDA antagonism also resulted in shortened stride lengths. Head bobbing behavior matured during the same posthatching time period. The rate of this maturation was also decreased by exercise restriction. Thus locomotor experience is required for normal development of locomotor behavior, even in very precocial animals. These results are discussed in terms of the possible neuroanatomical and neurophysiological mechanisms underlying experience- and activity-dependent changes during motor development.

Animals↗
PubMed2005

Stride cycle influences on goal-directed head movements made during walking.

Horizontal head movements were studied in six subjects as they made rapid horizontal gaze adjustments while walking. The aim of the present research was to determine if gait cycle events alter the head movement response to a visual target acquisition task. Gaze shifts of approximately 40 degrees were elicited by a step change in the position of a visual target from a central location to a second location in the left or right horizontal periphery. The timing of the target position change was constrained to occur at 25%, 50%, 75% and 100% of the stride cycle. The trials were randomly presented as the subjects walked on a treadmill at their preferred speed (range: 1.25-1.48 m/s, mean: 1.39+/-0.09 m/s). Analyses focused on the movement onset latencies of the head and eyes and on the peak velocity and saccade amplitude of the head movement response. The head and eye movement onset latencies were not affected by either the direction of the target change or the point in the gait cycle during which the target relocation occurred. However, the presence of an interaction between the gait cycle events and the direction of the visual target shift for both the amplitude and peak velocity of the head movement response indicates that the head movement responses to visual target changes can be influenced by the phase of the gait cycle during which the target relocation takes place.

Adult↗
PubMed1985

Effects of a large carbohydrate load on walking performance in chronic air-flow obstruction.

The purpose of this study was to determine whether a single large liquid carbohydrate (CHO) load (920 calories) affects walking performance in patients with chronic air-flow obstruction (CAO). Walking performance was measured using the 12-min walking test. Fifteen patients with stable CAO (FEV1, 1.30 +/- 0.41 L; FVC, 3.26 +/- 0.46 L) underwent 12-min walking tests 40 min after ingestion of either CHO or placebo on consecutive days in randomized double-blind fashion. Three practice walks were performed on a preliminary day in order to eliminate learning effects. Resting measurements of ventilation (VE) and carbon dioxide output (VCO2) were obtained prior to each walking test. Carbohydrate significantly increased both VCO2 (from 0.288 +/- 0.060 to 0.372 +/- 0.057 L/min, p less than 0.001) and VE (from 15.2 +/- 3.5 to 18.5 +/- 3.1 L/min, p less than 0.001) at rest. The total 12-minute walking distance decreased from 894 +/- 199 to 847 +/- 191 m following CHO (p less than 0.005). This distance decreased in 14 of the 15 study patients. The decrease in walking distance ranged from 1.5 to 168 m (0.2 to 15.2%). From this study we conclude that a large liquid carbohydrate load adversely affects walking performance in patients with CAO. This potential impairment of functional capacity should be considered when caloric intake is increased in attempts to improve nutritional status in this patient population.

Aged↗