Effects of Low-Intensity Exercise on Patients with Peripheral Artery Disease

Abstract

Background: Peripheral artery disease (PAD) is one of the many unhealthy conditions that may get worse with age. Its most common symptom is intermittent claudication (IC). Intermittent claudication is the exercise-induced ischemic pain caused by the reduced blood flow to the lower extremities. Objectives: To investigate the effects of low intensity treadmill walking on the functional capacity of PAD patients with IC. Walking ability (time, rate, and distance), heart rate, and blood pressure responses were recorded before, during, and after each exercise session. Only the initial and final values recorded were used for data analysis. This 6-week program of low-intensity, pain-free endurance training was designed to keep the exercise level low enough to minimize ischemic leg pain. Methods: Thirteen PAD patients volunteered for twice weekly exercise sessions for 6 consecutive weeks. Each session consisted of a 10-minute warm-up consisting of routine, pain-free static and proprioceptive neuromuscular facilitation stretching. Each patient exercised for 10 to 20 minutes as tolerated on the treadmill. Proprioceptive neuromuscular facilitation was conducted following walking. Results: As a group the patients with PAD had an average 148% improvement in distance, 34% in rate, and 94% in duration of walking. Five of the 13 patients had over 100% improvement in distance, with the maximum being 525%. One of the 13 patients had a 100% improvement in rate. Four of the 13 patients had over 100% improvement in duration, with the maximum being 500%. Conclusions: This study introduces a new method of low-intensity treadmill walking exercise, which seems to be an effective nonpharmacologic treatment even within a 6-week period for patients with IC due to PAD. It also supports the benefits of walking exercise to increase the mobility of these patients, thus improving functional capacity of life.     

Correlation of Patient-reported Symptom Outcomes and Treadmill Test Outcomes after Treatment for Aortoiliac Claudication

PurposeTo examine the relationship between objective treadmill test outcomes and subjective symptom outcomes among patients with claudication treated with stent revascularization (ST) compared with supervised exercise (SE).Materials and MethodsFive scales of the Peripheral Artery Questionnaire and Walking Impairment Questionnaire were correlated with peak walking time and treadmill claudication onset time.ResultsThe correlation between change in disease-specific quality of life (QOL) and change in peak walking time differed according to treatment group, with statistically significant correlations for all five scales for the ST group and weaker trends for the SE group, only one of which was statistically significant. In contrast, improvements in disease-specific QOL correlated well with increases in claudication onset time, with no significant interaction with treatment group for any of the five scales.ConclusionsDisease-specific QOL results at 6 months in the Claudication: Exercise Vs. Endoluminal Revascularization (CLEVER) study show that improved maximal treadmill walking in patients with claudication treated with SE correlated poorly with self-reported symptom relief. Conversely, patients treated with ST showed good correlation between improved maximal treadmill walking and self-reported symptom improvement. The correlation between claudication onset time and self-reported symptom relief was good across treatment groups. This finding indicates that traditional objective treadmill test outcomes may not correlate well with symptom relief in patients with claudication. Future studies should investigate these data and improve understanding of patient relevance of traditional objective treadmill-based treatment outcomes.     

模拟失重对大鼠红细胞变形性的影响

In order to investigate the mechanism of space anemia, the erythrocyte deformability membrane fluidity and cell shape in 7, 15, 30 day tail-suspended rats were observed. The results were: (1) erythrocyte deformability (DImax and IDI) in suspended rats was significantly lower than that in the control on the 7th day (P<0.05), and had a further decrease on the 15th day (P<0.01), but a recovery was found on the 30th day (P<0.05). (2) membrane fluidity in suspended rats was markedly lower than that in the control group on the 15th and 30th day, degrees of fluorescence polarization was increased (P<0.01), but there was no change on the 7th day. (3) percentage of erythrocytes with abnormal shape in suspended rats was higher than that in the control group during the whole experimental period. The results indicate that the changes of rheological and morphological properties of red cell were induced by simulated weightlessness (SWL), which may be an important cause of space anemia.     

A primary care walking exercise program for patients with intermittent claudication

PURPOSE: In a pilot study, the hypothesis was tested that a home-based walking exercise program with structured coaching would improve walking performance and adherence in patients with intermittent claudication (IC). METHODS: Thirty-one IC patients with a rest ankle-brachial pressure index < 0.90 started a 24-wk walking program in the home environment. They were coached according to the Health Counseling Model (HCM). Patients were instructed to walk at least 9 bouts.wk-1 and to walk through the pain. The main effect measures were pain-free (initial claudication distance (ICD)) and maximum walking distance (absolute claudication distance (ACD)) measured with a graded treadmill test, a corridor exercise test, a walking-diary, and the score on the Walking Impairment Questionnaire (WIQ). RESULTS: Twenty-four participants completed the program. The reported walking frequency was 7.4 times.wk-1. The average ICD improved from 289 m (95% CI, 209-369) to 347 m (95% CI, 244-449) (P < 0.05) and from 241 m (95% CI, 171-310) to 373 m (95% CI, 273-472) on the treadmill and the corridor test, respectively. The average ACD improved from 490 m (95% CI, 397-583) to 544 m (95% CI, 438-650) and from 564 m (95% CI, 412-717) to 726 m (95% CI, 546-906) (P < 0.01) on the treadmill and the corridor test, respectively. The average maximum distance reported in the walking-diary improved from 957 m (95% CI, 291-1623) to 1294 m (95% CI, 646-1941). The score of the walking distance on the WIQ improved from 57% (95% CI, 42-71%) to 60% (95% CI, 46-74%). CONCLUSION: IC patients improved their average ICD and ACD. The walking exercise program in the home environment with coaching according to the HCM seems a promising intervention to be tested in a randomized controlled trial.     

Quality of life and exercise performance after aortoiliac stent placement for claudication

PURPOSE: To determine the effect of aortoiliac stent placement on walking ability and health-related quality of life (QOL) for elderly individuals with moderate to severe intermittent claudication. MATERIALS AND METHODS: A prospective single-center study was performed in 35 consecutive patients (46 symptomatic limbs) with intermittent claudication and aortoiliac insufficiency (mean age+/-SD, 61.1 years+/-9.5). Baseline and follow-up data to 12 months included clinical status, ankle-brachial index (ABI), exercise performance according to a standardized treadmill exercise protocol, and self-reported health-related QOL according to the Walking Impairment Questionnaire (WIQ) and the Short Form 36 (SF-36). RESULTS: Comparing baseline with 12-month data, mean ABI significantly improved from 0.64+/-0.15 to 0.89+/-0.19 (P<.01). Similarly, mean initial claudication duration improved from 1.7 minutes+/-1.0 to 4.7 minutes+/-3.3 and maximum walking duration on the treadmill test improved from a mean of 3.3 minutes+/-1.8 to 8.7 minutes+/-4.4. All WIQ subscales showed significant improvement, and the SF-36 physical component scale as well as subscales of physical functioning, bodily pain, role physical, and vitality showed significant improvement. There was no 30-day mortality. Complications in the perioperative period that required treatment were observed in three patients (9%), but surgery was not required for any complications. Importantly, urgent or emergent surgery was not required for any complication and no permanent disability related to complications occurred. CONCLUSIONS: A high technical success rate (97%) and low complication rate were observed. Exercise performance and health-related QOL results improved significantly after stent placement. Revascularization with stent placement should be strongly considered in addition to conservative management for moderate to severe claudication with aortoiliac obstruction. A randomized clinical trial would be needed to gauge the relative effectiveness of stent implantation and conservative therapy.     

Effect of an 8-week endurance training program on markers of antioxidant capacity in women

AIM: The effects of endurance training and of exhaustive treadmill running on low density lipoprotein (LDL) oxidation in women are not clearly established. METHODS: Twenty training and 10 control persons, all not endurance trained, aged 26+/-4 and 23+/-3 years, were recruited for 8 weeks of running training 3x/week 30 min. The susceptibility of LDL to in vitro oxidation, conjugated dienes, malondialdehyde (MDA), nitric oxide (NO) and cholesterol, lipoproteins, triglycerides, apolipoprotein (apo) A-I, apo B and lipoprotein (a) were determined before and after training, at rest and after exhaustive spiroergometric exercise. The training was tailored individually at the speed of the 4 mmol/L lactate threshold. RESULTS: At rest and after treadmill running, training induced an increase in lag-time (P<0.05), a decrease in MDA (P<0.05), and lower values for cholesterol (P<0.001), LDL (P<0.01), triglycerides (P<0.05) and apo B (P<0.001), but no increase for high density lipoprotein (HDL) or apo A-I. Before training, treadmill running induced lower conjugated dienes and malondialdehyde, after training an increase for LDL and decrease for cholesterol and triglycerides, no increase for HDL or apo A-I. In the control group, all parameters remained unchanged, only NO lowered (P<0.01). CONCLUSION: Endurance training in women shows favorable effects on LDL oxidation, cholesterol, LDL-cholesterol, triglycerides and apo B.     

PoleStriding exercise and vitamin E for management of peripheral vascular disease

PURPOSE: The purpose of this investigation was to evaluate the efficacy of PoleStriding exercise (a form of walking that uses muscles of the upper and lower body in a continuous movement similar to cross-country skiing) and vitamin E (alpha-tocopherol) to improve walking ability and perceived quality of life (QOL) of patients with claudication pain secondary to peripheral arterial disease (PAD). METHODS: Fifty-two subjects were randomized into four groups: PoleStriding with vitamin E (N = 13), PoleStriding with placebo (N= 14), vitamin E without exercise (N= 13), and placebo without exercise (N = 12). The dose of vitamin E was 400 IU daily. Only the PoleStriding with vitamin E and PoleStriding with placebo groups received PoleStriding instruction and training. Assignment to vitamin E or placebo was double blind. Subjects trained three times weekly for 30-45 min (rest time excluded). Individuals in vitamin E and placebo groups came to the laboratory biweekly for ankle blood-pressure measurements. RESULTS: Results of this randomized clinical trial provide strong evidence that PoleStriding significantly (P< 0.001) improved exercise tolerance on the constant work-rate and incremental treadmill tests. Ratings of perceived claudication pain were significantly less after the PoleStriding training program (P= 0.02). In contrast, vitamin E did not have a statistically significant effect on the subjects' ratings of perceived leg pain (P= 0.35) or treadmill walking duration ( P= 0.36). Perceived distance and walking speed (Walking Impairment Questionnaire) and perceived physical function (Rand Short Form-36) improved in the PoleStriding trained group only (P< 0.001, 0.022 and 0.003, respectively). CONCLUSION: PoleStriding effectively improved the exercise tolerance and perceived QOL of patients with PAD. Little additional benefit to exercise capacity was realized from vitamin E supplementation.     

Beta-blockers, exercise, and the immune system in men with coronary artery disease

PURPOSE: The purpose of the present study was to examine the effect of aerobic exercise training on the immune system in coronary artery disease patients treated with beta-blockers. METHODS: Twenty-five patients (46.1 +/- 2 yr) treated with atenolol, a beta-blocker agent, for 3 months before exercising were divided randomly into two groups: 15 underwent an aerobic exercise training program for 12 wk at 65-70% of their work capacity, whereas the other 10 patients served as controls. RESULTS: After training, levels of CD4 and CD8 cells were significantly (P < 0.05) higher and concomitantly the CD4/CD8 ratio decreased significantly (P < 0.05) in the exercising group compared with the control group. CONCLUSIONS: Data suggest that coronary artery disease patients exercising aerobically at 65-70% of their work capacity gain a statistically significant higher lymphocyte T cell function as compared with their untrained counterparts.     

Effects of supervised treadmill-walking training on strength and endurance of the calf muscles of individuals with peripheral arterial disease.

OBJECTIVE: Supervised treadmill-walking training is an effective treatment to improve walking capacity for individuals with peripheral arterial disease (PAD). The primary aim of this study was to examine whether a supervised treadmill-walking program would improve calf-muscle strength and endurance in individuals with PAD. DESIGN: The study included two stages. The first 12-week period was a nonexercise, within-subject control stage and the second 12-week period was an exercise training stage. SETTING: Southern Cross University, Australia. SUBJECTS: Twenty-two subjects with stable intermittent claudication were recruited. Their resting and postexercise ankle-to-brachial systolic blood pressure index (ABI) was 0.61 +/- 0.13 and 0.41 +/- 0.22, respectively. INTERVENTIONS: Subjects trained in the laboratory, 3 sessions per week for 12 weeks. OUTCOME MEASUREMENTS: Walking capacity, calf-muscle strength (peak torques in isokinetic plantar flexion at velocities of 30 degrees per second, 60 degrees per second, and 90 degree per second) and endurance (mean peak force, total work, and mean power in repeated maximal plantar flexions at 60 degrees per second), ABI, and peak oxygen uptake were measured at the baseline and the end of each stage. RESULTS: Analysis of variance (ANOVA) with repeated measures indicated that the supervised treadmill-walking program significantly increased calf-muscle strength and endurance. Walking capacity and peak oxygen uptake also showed significant improvements following the training program. Significant correlation was found between the improved calf-muscle endurance and walking capacity. CONCLUSION: Supervised treadmill exercise is highly effective in improving walking capacity. The improved walking capacity is accompanied by improved calf-muscle strength and endurance in individuals with PAD.     

The effects of treadmill or overground walking training program on gait in Parkinson's disease

BackgroundGait impairment in Parkinson's disease (PD) patients is characterized by the inability to generate appropriate stride length. Treadmill training has been proposed as a therapeutic tool for PD patients. However, it remains unknown whether treadmill training effects are different from overground walking training. Thus, our goal was to explore the effects of two training programs, walking on a treadmill and walking overground, in PD patients.Methods22 PD patients were randomly assigned to a treadmill or overground training group. The training program consisted of 5 weeks (3 sessions/week). Before and after the program we evaluated gait kinematics during walking at preferred and maximal speed; Timed Up and Go (TUG); static posturography and knee extensors strength. Gait parameters were reevaluated in the treadmill training group one month after the cessation of the training.ResultsPreferred speed walking improved in both groups after the training program. The treadmill training program, but not the overground, led to an improvement in the stride length at the preferred and maximal walking speed in the PD patients. In addition, the treadmill training group showed improvement of the TUG and static posturography tests. The improvement in gait parameters was maintained one month after the cessation of the treadmill training.ConclusionsThis study provides evidence of a specific therapeutic effect of treadmill training on Parkinsonian gait and balance. Walking on a treadmill may be used as an easy, effective and accessible way to improve the stride length and balance in PD patients.     

Does treadmill training improve lower-extremity tasks in Parkinson disease? A randomized controlled trial.

OBJECTIVE: To investigate whether gait training with treadmill improves functional tasks of lower extremities in patients with Parkinson disease (PD). DESIGN: Randomized controlled trial including two groups, the treadmill training group and the nonintervention group. SETTING: University hospital. PATIENTS: Thirty consecutive patients diagnosed with idiopathic PD, who were on stable regimens of antiparkinsonian medication, able to walk independently, and had not participated in a rehabilitation program in the previous 3 months. Patients with severe cognitive impairments or severe musculoskeletal, cardiopulmonary, neurologic, or other systemic disorders were excluded. Twenty-four patients completed the study. INTERVENTIONS: Group I attended a training program on a treadmill for 6 weeks, and group II served as the control group. Both groups were instructed in home mobility exercises. MAIN OUTCOME MEASUREMENTS: The primary study outcome measures were timed functional lower-extremity tasks (walking at a corridor, U-turn, turning around a chair, stairs, standing on one foot, standing from a chair), and secondary outcome measures were exercise test and patient's global assessment. Assessments were performed at baseline and at the end of the study. RESULTS: There were significant improvements in functional lower-extremity tests, exercise test parameters, and patients' global assessment in group I, whereas no significant improvements were observed in group II. CONCLUSIONS: Even though long-term effects remain unknown and the study sample was small, it was concluded that treadmill training in PD patients led to improvements in lower-extremity tasks, thus improving patients' physical well-being in daily life.     

Sex differences in claudication pain in subjects with peripheral arterial disease

PURPOSES: To compare the claudication distances between men and women patients with peripheral arterial disease (PAD), and to determine whether sex differences in claudication pain persisted after controlling for potential confounders such as demographic, functional, and physiological measures. METHODS: A total of 488 men and 72 women functionally limited by intermittent claudication were evaluated. Patients were characterized on PAD-specific measures consisting of ankle/brachial index (ABI) and treadmill claudication distances, physical function measures consisting of ambulatory function, monitored physical activity, balance, and strength, and demographic measures obtained during a medical history. RESULTS: Initial claudication distance (ICD) was 33% shorter ( = 0.024) in women than in men (126 +/- 22 vs 189 +/- 13 m; mean +/- SEM), and absolute claudication distance (ACD) was 23% shorter ( = 0.022) in women (313 +/- 43 vs 407 +/- 18 m). These differences were present despite similar ( = 0.440) ABI values between women (0.63 +/- 0.02) and men (0.62 +/- 0.01). Peak oxygen uptake ( = 0.043) and self-perceived stair climbing ability ( = 0.020) were different between men and women, and were independently related to ICD (multiple R = 0.57, < 0.001) and to ACD (multiple R = 0.71, < 0.001). The sex differences in ICD ( = 0.524) and ACD ( = 0.722) were no longer present after controlling for peak oxygen uptake and self-perceived stair climbing ability. CONCLUSION: Shorter treadmill claudication distances in women with PAD were explained by their lower cardiopulmonary fitness and poorer self-perceived ability to climb stairs than compared with men. Therefore, women with intermittent claudication represent a subgroup of PAD patients who should receive high priority for exercise rehabilitation to improve physical function.     

Limb muscle dysfunction in COPD: effects of muscle wasting and exercise training

PURPOSE: Lower-limb muscle weakness has often been reported in COPD, and contributes to exercise intolerance. Controversial information is available regarding upper-limb muscle adaptations and the influence of muscle wasting on muscle weakness. We investigated leg and arm muscle function in 59 stable COPD patients (GOLD stage III) with preserved fat-free mass (FFM) and in 28 patients with reduced FFM relative to age- and sex-matched healthy control subjects and studied the effects of 8 wk of whole-body exercise training. METHODS: FFM was measured with bioelectrical impedance analysis. Isokinetic quadriceps (F-leg) and biceps strength (F-arm), as well as quadriceps (E-leg) and biceps endurance (E-arm) were determined with a Biodex dynamometer. Exercise training consisted of cycle ergometry, treadmill walking, weight training, and gymnastics during 5 d.wk. RESULTS: F-leg (76.2 +/- 3.6 vs 118.2 +/- 6.3 N.m, P < 0.001) and F-arm (25.6 +/- 1.3 vs 38.1 +/- 2.1 N.m, P < 0.001) were significantly and similarly reduced in the COPD patient group compared with controls. Also, E-leg (-2.13 +/- 0.12 vs -1.61 +/- 0.11, P < 0.01), but not E-arm (-2.72 +/- 0.11 and -2.47 +/- 0.13 NS), was decreased in patients. F-leg (62.4 +/- 4.3 vs 82.8 +/- 4.7 N.m, P < 0.01), but not F-arm or muscle endurance, was reduced in FFM-depleted compared with non-FFM-depleted patients. Whereas after training F-leg and E-leg significantly increased by 20% in the whole COPD group, biceps muscle function remained unchanged. CONCLUSION: Lower- and upper-limb muscle dysfunction was observed in COPD patients, irrespective of the presence of FFM depletion. Generalized muscle weakness suggests systemic muscular involvement, although the preserved arm endurance and the poor response of arm performance to exercise training is indicative for intrinsic differences in muscular adaptations between leg and arm muscles.     

强骨抗萎方对尾悬吊大鼠血液流变性影响的观察

目的研究中药复方强骨抗萎方对尾吊大鼠血液流变性的影响。方法用大鼠 5 1只尾吊 - 30° 2 1d模拟失重 ,观察强骨抗萎方对大鼠血沉、红细胞压积、纤维蛋白原、血液粘度及红细胞变形性、聚集性等指标的作用。结果与正常对照组相比 ,悬吊大鼠纤维蛋白原明显升高 (P <0 .0 1 ) ,全血还原粘度及全血粘度明显增加 (P <0 .0 1或P <0 .0 5 ) ,红细胞刚性指数升高 (P <0 .0 1 ) ,最大变形指数降低 (P <0 .0 1 ) ,最大聚集指数增加 (P <0 .0 1 )。该方不同剂量显示了不同的作用。低剂量组 ( 1 0 g/kg)可降低各个切变率下的全血还原粘度和全血粘度 (P <0 .0 1或P <0 .0 5 ) ,以及异常的红细胞刚性指数和最大聚集指数 (P <0 .0 1 ) ;中剂量组 ( 2 0 g/kg)可使纤维蛋白原含量减少 (P <0 .0 1 ) ;高剂量组 ( 30g/kg)可降低高切变率下的全血还原粘度和全血粘度 (P <0 .0 1或P <0 .0 5 ) ,降低红细胞刚性指数 (P <0 .0 1 ) ,并可升高红细胞最大变形指数 (P <0 .0 1 )。结论该方具有改善尾吊大鼠血液流变性的作用 ,但无明显的量效关系     

Treadmill versus shuttle walk tests of walking ability in intermittent claudication

PURPOSE: To compare treadmill and shuttle walk tests for assessing functional capacity in patients with intermittent claudication, with respect to test-retest reliability, cardiovascular responses, and patient preferences. METHODS: Patients with stable intermittent claudication (N = 55, ages 52-85 yr, median age 68 yr) were recruited from the Sheffield Vascular Institute at the Northern General Hospital, Sheffield, UK. Each patient performed an incremental shuttle walk test, a constant-pace shuttle walk test, and a standardized treadmill test (3.2 km x h(-1), 12% gradient), each on three occasions. The incremental shuttle walk began at 3 km x h(-1) and increased by 0.5 km x h(-1) every minute, whereas the constant-pace shuttle walk was performed at the fixed pace of 4 km x h(-1). Claudication distance (CD), maximum walking distance (MWD), heart rate (HR), and blood pressure were assessed in each testing session. The patients also completed a test preference questionnaire. RESULTS: CD and MWD for both shuttle walks were greater than the corresponding walking distances achieved in the treadmill test (P < 0.001). Average coefficients of variation for repeated incremental shuttle walk, constant-pace shuttle walk, and treadmill tests were 15.9%, 21.1%, and 18.7%, respectively, for MWD, corresponding to average intraclass correlation coefficients of 0.87, 0.82, and 0.87. Treadmill walking evoked greater increases in HR and blood pressure (P < 0.001), and fewer patients expressed a preference for it (24 vs 43% for shuttle walking). CONCLUSION: These findings indicated that shuttle walk testing exhibits similar test-retest reliability as treadmill testing, but that it evoked a lower level of cardiovascular stress and is preferred to treadmill testing by a large proportion of patients.     

Randomized,Double-Blind,Placebo-Controlled Trial to Evaluate Safety and Therapeutic Efficacy of Angiogenesis Induced by Intraarterial Autologous Bone Marrow–Derived Stem Cells in Patients with Severe Peripheral Arterial Disease

PurposeTo evaluate safety and efficacy of angiogenesis induced by intraarterial autologous bone marrow–derived stem cell (BMSC) injection in patients with severe peripheral arterial disease (PAD).Materials and MethodsEighty-one patients with severe PAD (77 men), including 56 with critical limb ischemia (CLI) and 25 with severe claudication, were randomized to receive sham injection (group A) or intraarterial BMSC injection at the site of occlusion (group B). Primary endpoints included improvement in ankle–brachial index (ABI) of > 0.1 and transcutaneous pressure of oxygen (TcPO₂) of > 15% at mid- and lower foot at 6 mo. Secondary endpoints included relief from rest pain, > 30% reduction in ulcer size, and reduction in major amputation in patients with CLI and > 50% improvement in pain-free walking distance in patients with severe claudication.ResultsTechnical success was achieved in all patients, without complications. At 6 mo, group B showed more improvements in ABI of > 0.1 (35 of 41 [85.37%] vs 13 of 40 [32.50%]; P < .0001) and TcPO₂ of > 15% at the midfoot (35 of 41 [85.37%] vs 17 of 40 [42.50%]; P = .0001] and lower foot (37 of 41 [90.24%] vs 19 of 40 [47.50%]; P < .0001). No patients with CLI underwent major amputation in group B, compared with 4 in group A (P = .0390). No significant difference was observed in relief from rest pain or > 30% reduction in ulcer size among patients with CLI or in > 50% improvement in pain-free walking distance among patients with severe claudication.ConclusionsIntraarterial delivery of autologous BMSCs is safe and effective in the management of severe PAD.     

Progressive vs single-stage treadmill tests for evaluation of claudication

The reliability of claudication pain and the metabolic and hemodynamic measurements of the lower limbs of patients with stable peripheral vascular occlusive disease (PVOD) were compared during and following single-stage (S) and progressive (P) treadmill tests. Ten patients (69.8 +/- 1.8 yr; X +/- SE) walked to maximal claudication pain twice a month for 4 months. Patients walked at 1.5 mph up a 7.5% grade (S test) and at 2 mph on a 0% grade, increasing by 2% every 2 min (P test). Distance walked to the onset of claudication pain (CPD) and maximal walking distance (MWD) were recorded. Foot transcutaneous oxygen tension (TcPO2) was measured before, during, and after exercise, while ankle systolic blood pressure (SBP) and the ankle-to-brachial SBP index (ABI) were measured before and after exercise. Intraclass correlation coefficients (R) of CPD and MWD during S tests were R = 0.53 and R = 0.55, respectively. In contrast, the respective R values during P tests were R = 0.89 and R = 0.93. Higher R values of foot TcPO2 were also obtained during and following P tests, while ankle SBP and ABI were highly reliable following both tests. It is concluded that the severity of PVOD is better assessed by P treadmill tests because clinical measurements are more reliable during exercise and recovery.     

Postural stability after treadmill and overground walking in young and elderly

BackgroundAgeing commonly disrupts the balance control and compensatory postural responses that contribute to maintaining balance and preventing falls during perturbation of posture. Improvement of compensatory postural responses during walking is one of the main goals in fall prevention programs which often include treadmill walking training. However, during treadmill walking, there is a sensory (visualsomatosensory and vestibular-somatosensory) conflict that can evoke aftereffects of self-motion sensation and could alter postural stability after training.Research questionThe aim of this study was to compare the effect of overground and treadmill walking on postural stability in healthy young and elderly subjects. Methods: Postural responses of 31 Young and 19 healthy Elderly before and after overground and treadmill walking were assessed by a force platform in four stance conditions: firm and foam surface with eyes open and eyes closed.ResultsIn Elderly group, velocity parameters significantly increased after treadmill walking but not after overground walking. This increase was found particularly in the conditions with eyes open in both types of surfaces (firm, foam). The velocity parameters values (expect Vx) were significantly increased in Elderly compared to Young almost in all four conditions after treadmill and overground walking. Significance: Our study suggests that Elderly become more unstable after treadmill walking and have greater difficulties to adapt to new balance circumstances caused by sensory conflict associated with treadmill walking. It seems that during treadmill walking and subsequent stance, vision is the major factor contributing to posture stabilization. Thus, the suitability of treadmill walking as a part of training programs for elderly adults with higher fall risk should be seriously considered.     

Continuous vs interval training on glycemic control and macro‐ and microvascular reactivity in type 2 diabetic patients

To determine the effects of continuous aerobic exercise training (CON) vs interval aerobic exercise training (INT) on glycemic control and endothelium‐dependent vasodilatation, 43 participants with type 2 diabetes were randomly allocated to the sedentary, CON, and INT groups. The CON and INT exercise training programs were designed to yield the same energy expenditure/exercise session and included walking on treadmill for 30 and 40 min/day, 3 times/week for 12 weeks. Body fatness and heart rate at rest decreased and leg muscle strength increased (all P < 0.05) in both the CON and INT groups. Fasting blood glucose levels decreased (P < 0.05) in both exercise groups but glycosylated hemoglobin levels decreased (P < 0.05) only in the INT group. Maximal aerobic capacity, flow‐mediated dilation, and cutaneous reactive hyperemia increased significantly in both exercise groups; however, the magnitude of improvements was greater in the INT group. Only the INT group experienced reductions in erythrocyte malondialdehyde and serum von Willebrand factor and increases in plasma glutathione peroxidase and nitric oxide (all P < 0.05). We concluded that both continuous and interval training were effective in improving glycemic control, aerobic fitness, and endothelium‐dependent vasodilation, but the interval training program appears to confer greater improvements than the continuous training program.