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Background: Patients with peripheral artery disease with intermittent claudication (PAD-IC) have altered gait variability from the first step they take, well before the onset of claudication pain. The mechanisms underlying these gait alterations are poorly understood., Aims: To determine the effect of reduced blood flow on gait variability by comparing healthy older controls and patients with PAD-IC. We also determined the diagnostic value of gait variability parameters to identify the presence of PAD., Methods: A cross-sectional cohort design was used. Thirty healthy older controls and thirty patients with PAD-IC walked on a treadmill at their self-selected speed in pain free walking (normal walking for healthy older controls; prior to claudication onset for PAD) and reduced blood flow (post vascular occlusion with thigh tourniquet for healthy older controls; pain for PAD) conditions. Gait variability was assessed using the largest Lyapunov exponent, approximate entropy, standard deviation, and coefficient of variation of ankle, knee, and hip joints range of motion. Receiver operating characteristics curve analyses of the pain free walking condition were performed to determine the optimal cut-off values for separating individuals with PAD-IC from those without PAD-IC., Results and Discussion: Patients with PAD-IC have increased amount of variability for knee and hip ranges of motion compared with the healthy older control group. Regarding the main effect of condition, reduced blood flow demonstrated increased amount of variability compared with pain free walking. Significant interactions between group and condition at the ankle show increased values for temporal structure of variability, but a similar amount of variability in the reduced blood flow condition. This demonstrates subtle interactions in the movement patterns remain distinct between PAD-IC versus healthy older controls during the reduced blood flow condition. A combination of gait variability parameters correctly identifies PAD-IC disease 70% of the time or more., Conclusions: Gait variability is affected both by PAD and by the mechanical induction of reduced blood flow. Gait variability parameters have potential diagnostic ability, as some measures had 90.0% probability of correctly identifying patients with PAD-IC., Competing Interests: The authors would like to declare that ankle-foot orthoses were donated to the University of Nebraska at Omaha by Ottobock, for a related project (NIH study R01HD090333). No data from those studies were included in this work. We confirm that the donation of ankle-foot orthoses does not alter our adherence to PLOS ONE policies on sharing data and materials.

Objective: In patients with peripheral artery disease (PAD), supervised exercise therapy is a first line of treatment because it increases maximum walking distances comparable with surgical revascularization therapy. Little is known regarding gait biomechanics after supervised exercise therapy. This study characterized the effects of supervised exercise therapy on gait biomechanics and walking distances in claudicating patients with PAD., Methods: Forty-seven claudicating patients with PAD underwent gait analysis before and immediately after 6 months of supervised exercise therapy. Exercise sessions consisted of a 5-minute warmup of mild walking and stretching of upper and lower leg muscles, 50 minutes of intermittent treadmill walking, and 5 minutes of cooldown (similar to warmup) three times per week. Measurements included self-perceived ambulatory limitations measured by questionnaire, the ankle-brachial index (ABI), walking distance measures, maximal plantar flexor strength measured by isometric dynamometry, and overground gait biomechanics trials performed before and after the onset of claudication pain. Paired t-tests were used to test for differences in quality of life, walking distances, ABI, and maximal strength. A two-factor repeated measures analysis of variance determined differences for intervention and condition for gait biomechanics dependent variables., Results: After supervised exercise therapy, quality of life, walking distances, and maximal plantar flexor strength improved, although the ABI did not significantly change. Several gait biomechanics parameters improved after the intervention, including torque and power generation at the ankle and hip. Similar to previous studies, the onset of claudication pain led to a worsening gait or a gait that was less like healthy individuals with a pain-free gait., Conclusions: Six months of supervised exercise therapy produced increases in walking distances and quality of life that are consistent with concurrent improvements in muscle strength and gait biomechanics. These improvements occurred even though the ABI did not improve. Future work should examine the benefits of supervised exercise therapy used in combination with other available treatments for PAD., (Copyright © 2019 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: Previous studies have indicated that patients with peripheral artery disease (PAD), display significant differences in their kinetic and kinematic gait characteristics when compared to healthy, aged-matched controls. The ability of patients with chronic obstructive pulmonary disease (COPD) to ambulate is also limited. These limitations are likely due to pathology-driven muscle morphology and physiology alterations establish in PAD and COP, respectively. Gait changes in PAD were compared to gait changes due to COPD to further understand how altered limb muscle due to disease can alter walking patterns. Both groups were independently compared to healthy controls. It was hypothesized that both patients with PAD and COPD would demonstrate similar differences in gait when compared to healthy controls., Methods: Patients with PAD (n=25), patients with COPD (n=16), and healthy older control subjects (n=25) performed five walking trials at self-selected speeds. Sagittal plane joint kinematic and kinetic group means were compared., Results: Peak values for hip flexion angle, braking impulse, and propulsive impulse were significantly reduced in patients with symptomatic PAD compared to patients with COPD. After adjusting for walking velocity, significant reductions (p<0.05) in the peak values for hip flexion angle, dorsiflexor moment, ankle power generation, propulsion force, braking impulse, and propulsive impulse were found in patients with PAD compared to healthy controls. No significant differences were observed between patients with COPD and controls., Conclusions: The results of this study demonstrate that while gait patterns are impaired for patients with PAD, this is not apparent for patients with COPD (without PAD). PAD (without COPD) causes changes to the muscle function of the lower limbs that affects gait even when subjects walk from a fully rested state. Altered muscle function in patients with COPD does not have a similar effect., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Peripheral arterial disease (PAD) produces abnormal gait and disproportionately affects older individuals. The current study investigated PAD gait biomechanics in younger (<65 yr) and older (>/=65 yr) subjects. The study included 61 patients with PAD (31 younger, age: 57.4 +/- 5.3 yr, and 30 older, age: 71.9 +/- 5.2 yr) and 52 nondisabled age-matched control subjects. Patients with PAD were tested during pain-free walking and compared with control subjects. Joint kinematics and kinetics (torques) were compared using a 2 x 2 analysis of variance (groups: patients with PAD vs control subjects, age: younger vs older). Patients with PAD had significantly increased ankle and decreased hip range of motion during the stance phase as well as decreased ankle dorsiflexor torque compared with control subjects. Gait changes in older individuals are largely constrained to time-distance parameters. Joint kinematics and kinetics are significantly altered in patients with PAD during pain-free walking. Symptomatic PAD produces a consistent ambulatory deficit across ages definable by advanced biomechanical analysis. The most important finding of the current study is that gait, in the absence of PAD and other ambulatory comorbidities, does not decline significantly with age based on advanced biomechanical analysis. Therefore, previous studies must be examined in the context of patients with potential PAD being present in the population, and future ambulatory studies must include PAD as a confounding factor when assessing the gait function of elderly individuals.

Insufficient blood flow is one possible mechanism contributing to altered gait patterns in lower extremity peripheral arterial disease (PAD). Previously, our laboratory found that induced occlusion alters gait variability patterns in healthy young individuals. However the effect of age was not explored. The purpose of this study was to account for age by investigating gait variability following induced vascular occlusion in healthy older individuals and to identify amount of change from baseline to post vascular occlusion between younger and older individuals. Thirty healthy younger individuals and 30 healthy older individuals walked on a treadmill during baseline and post vascular occlusion conditions while lower extremity joint kinematics were captured. Vascular occlusion was induced by thigh cuffs inflated bilaterally on the upper thighs. Amount and temporal structure of gait variability was assessed. Older individuals exhibited significantly increased values of temporal structure of variability post vascular occlusion. Post vascular occlusion values were similar between younger and older individuals after adjusting for baseline measurements. Results show blood flow contributes to altered gait variability. However alterations were less severe than previously documented in symptomatic PAD patients, suggesting that neuromuscular problems in the lower extremities of PAD patients also contribute to gait alterations in these patients.

Background: Walking is problematic for patients with peripheral arterial disease. The purpose of this study was to investigate the frequency domain of the ground reaction forces during walking to further elucidate the ambulatory impairment of these patients., Methods: Nineteen bilateral peripheral arterial disease patients and nineteen controls were included in this study. Subjects were matched for age and gait speed. Participants walked over a force plate sampling at 600 Hz. PAD patients were tested before (pain-free condition) after the onset of claudication symptoms (pain). We calculated median frequency, frequency bandwidth, and frequency containing 99.5% of the signal for the vertical and anterior-posterior ground reaction forces., Findings: Our results showed reduced median frequency in the vertical and anterior-posterior components of the ground reaction forces between the control group and both peripheral arterial disease conditions. We found reduced frequency bandwidth in the anterior-posterior direction between controls and the peripheral arterial disease pain-free condition. There were no differences in median frequency or bandwidth between peripheral arterial disease pain-free and pain conditions, but an increase in the frequency content for 99.5% of the signal was observed in the pain condition., Interpretation: Reduced frequency phenomena during gait in peripheral arterial disease patients compared to velocity-matched controls suggests more sluggish activity within the neuromotor system. Increased frequency phenomena due to pain in these patients suggest a more erratic application of propulsive forces when walking. Frequency domain analysis thus offers new insights into the gait impairments associated with this patient population., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Peripheral arterial disease (PAD) is a manifestation of atherosclerosis resulting in intermittent claudication (IC) or leg pain during physical activity. Two drugs (cilostazol and pentoxifylline) are approved for treatment of IC. Our previous work has reported no significant differences in gait biomechanics before and after drug interventions when PAD patients walked without pain. However, it is possible that the drugs are more efficacious during gait with pain. Our aim was to use advanced biomechanical analysis to evaluate the effectiveness of these drugs while walking with pain. Initial and absolute claudication distances, joint kinematics, torques, powers, and gait velocity during the presence of pain were measured from 24 patients before and after 12 weeks of treatment with either cilostazol or pentoxifylline. We found no significant improvements after 12 weeks of treatment with either cilostazol or pentoxifylline on the gait biomechanics of PAD patients during pain. Our findings indicate that the medications cilostazol and pentoxifylline have reduced relevance in the care of gait dysfunction even during pain in patients with PAD.

Background: Recent research demonstrated that intermittent claudication patients have increased gait variability prior to the onset of claudication. However, it is unknown if these patients experience additional gait adaptations after the onset of claudication. Thus, we sought to determine how gait variability is affected by claudication in an effort to contribute to improved clinical management., Methods: Twenty-six intermittent claudication patients and 20 controls walked on a treadmill at self-selected speed; intermittent claudication patients were tested before (pain free) and after (pain) the onset of claudication. Variability of the ankle, knee, and hip joint angles was assessed using the largest Lyapunov exponent, standard deviation and coefficient of variation. Dependent t-tests were used to compare the pain free and pain conditions. Independent t-tests were used to compare intermittent claudication patients and controls., Findings: Pain free and pain conditions were not significantly different for any of the parameters evaluated except the ankle. Compared to controls, patients had significantly greater values for the largest Lyapunov exponent in both conditions for all joints., Interpretation: Gait variability was essentially the same before and after the onset of claudication at the knee and the hip, and was increased in both conditions compared to controls. This indicates altered cooperation between components of the locomotor system of intermittent claudication patients, likely due to the associated myopathy since differences were present even before the onset of claudication. This research helps provide essential biomechanical knowledge of intermittent claudication that contributes to improved clinical management., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: The role of ischemia reperfusion contributing to functional impairment in lower extremity peripheral arterial disease (PAD) patients has not previously been elucidated. The evaluation of gait variability patterns has proven useful in many pathologic populations. Therefore, the purpose of this study is to isolate and determine the specific effect of the acute reperfusion phase of ischemia-reperfusion on gait variability in young individuals with no vascular disease., Materials and Methods: Thirty healthy young individuals walked on a treadmill during baseline and the acute reperfusion phase of ischemia-reperfusion conditions while lower extremity joint kinematics were captured. Stride to stride variability was assessed using the largest Lyapunov exponent, approximate entropy, standard deviation, and coefficient of variation. Differences in gait variability between conditions were assessed using dependent t-tests., Results: The largest Lyapunov exponent values and approximate entropy values were significantly higher in the acute reperfusion phase of ischemia-reperfusion condition for the ankle, knee, and the hip. Coefficient of variation was significantly higher at the hip and standard deviation was higher at the knee and the hip during the acute reperfusion phase of ischemia-reperfusion condition., Conclusions: The acute reperfusion phase of the ischemia-reperfusion cycle alters gait variability patterns at the ankle, knee, and the hip in healthy young individuals. Our findings indicate increased noise and irregularity of gait variability patterns post-ischemia. In young healthy individuals who do not have neuromuscular impairments, significant gait alterations are present during walking after a period of interruption of blood flow., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Pharmacological treatment has been used to alleviate the claudication symptoms and improve walking performance in peripheral arterial disease (PAD) patients. However, the effects of claudication treatments on gait mechanics have not been objectively identified with biomechanical techniques. For this study, 20 PAD patients were assigned to take either pentoxifylline (n=11) or cilostazol (n=9), the two FDA-approved pharmacological therapies used to treat intermittent claudication symptoms. All patients completed a gait evaluation protocol that involved the acquisition of kinematic and kinetic gait data before use of the medication and after 12 weeks of treatment. Results showed that treatment with either pentoxifylline or cilostazol resulted in limited overall improvement in gait parameters including joint angles and joint moments. Walking speed was unchanged, in either treatment group, as a result of the medication. These results suggest that to improve biomechanical walking parameters of PAD patients, clinicians cannot rely on drug therapies alone.

Objective: Claudication is the most common manifestation of peripheral arterial disease, producing significant ambulatory compromise. Our study evaluated patients with bilateral lower limb claudication and characterized their gait abnormality based on advanced biomechanical analysis using joint torques and powers., Methods: Twenty patients with bilateral claudication (10 with isolated aortoiliac disease and 10 with combined aortoiliac and femoropopliteal disease) and 16 matched controls ambulated on a walkway while 3-dimensional biomechanical data were collected. Patients walked before and after onset of claudication pain. Joint torques and powers at early, mid, and late stance for the hip, knee, and ankle joints were calculated for claudicating patients before and after the onset of claudication pain and were compared to controls., Results: Claudicating patients exhibited significantly reduced hip and knee power at early stance (weight-acceptance phase) due to decreased torques produced by the hip and knee extensors. In mid stance (single-limb support phase), patients had significantly reduced knee and hip power due to the decreased torques produced by the knee extensors and the hip flexors. In late stance (propulsion phase), reduced propulsion was noted with significant reduction in ankle plantar flexor torques and power. These differences were present before and after the onset of pain, with certain parameters worsening in association with pain., Conclusions: The gait of claudication is characterized by failure of specific and identifiable muscle groups needed to perform normal walking (weight acceptance, single-limb support, and propulsion). Parameters of gait are abnormal with the first steps taken, in the absence of pain, and certain of these parameters worsen after the onset of claudication pain., (Copyright (c) 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Background: Pharmacological treatment has been advocated as a first line therapy for Peripheral Arterial Disease (PAD) patients suffering from intermittent claudication. Previous studies document the ability of pharmacological treatment to increase walking distances. However, the effect of pharmacological treatment on gait biomechanics in PAD patients has not been objectively evaluated as is common with other gait abnormalities., Methods: Sixteen patients were prescribed an FDA approved drug (Pentoxifylline or Cilostazol) for the treatment of symptomatic PAD. Patients underwent baseline gait testing prior to medication use which consisted of acquisition of ground reaction forces and kinematics while walking in a pain free state. After three months of treatment, patients underwent repeat gait testing., Results: Patients with symptomatic PAD had significant gait abnormalities at baseline during pain free walking as compared to healthy controls. However, pharmacological treatment did not produce any identifiable alterations on the biomechanics of gait of the PAD patients as revealed by the statistical comparisons performed between pre and post-treatment and between post-treatment and the healthy controls., Conclusions: Pharmacological treatment did not result in statistically significant improvements in the gait biomechanics of patients with symptomatic PAD. Future studies will need to further explore different cohorts of patients that have shown to improve significantly their claudication distances and/or their muscle fiber morphology with the use of pharmacological treatment and determine if this is associated with an improvement in gait biomechanics. Using these methods we may distinguish the patients who benefit from pharmacotherapy and those who do not.

Objectives: Symptomatic peripheral arterial disease (PAD) results in significant gait impairment. In an attempt to fully delineate and quantify these gait alterations, we analyzed joint kinematics, torques (rotational forces), and powers (rotational forces times angular velocity) in patients with PAD with unilateral claudication for both the affected and nonaffected legs., Methods: Twelve patients with unilateral PAD (age, 61.69 +/- 10.53 years, ankle-brachial index [ABI]: affected limb 0.59 +/- 0.25; nonaffected limb 0.93 +/- 0.12) and 10 healthy controls (age, 67.23 +/- 12.67 years, ABI >1.0 all subjects) walked over a force platform to acquire gait kinetics, while joint kinematics were recorded simultaneously. Data were collected for the affected and nonaffected limbs during pain free (PAD-PF) and pain induced (PAD-P) trials. Kinetics and kinematics were combined to quantify torque and powers during the stance period from the hip, knee, and ankle joints., Results: The affected limb demonstrated significantly (P <.05) reduced ankle plantar flexion torque compared to controls during late stance in both PAD-PF and PAD-P trials. There were significant reductions in ankle plantar flexion power generation during late stance for both the affected (P <.05) and nonaffected limbs (P <.05) compared to control during PAD-PF and PAD-P trials. No significant differences were noted in torque comparing the nonaffected limbs in PAD-PF and PAD-P conditions to control for knee and hip joints throughout the stance phase. Significant reductions were found in knee power absorption in early stance and knee power generation during mid stance for both limbs of the patients with PAD as compared to control (P <.05)., Conclusion: Patients with PAD with unilateral claudication demonstrate significant gait impairments in both limbs that are present even before they experience any claudication symptoms. Overall, our data demonstrate significantly reduced ankle plantar flexion torque and power during late stance with reduced knee power during early and mid stance for the affected limb. Further studies are needed to determine if these findings are dependent on the location and the severity of lower extremity ischemia and whether the changes in the nonaffected limb are the result of underlying PAD or compensatory changes from the affected limb dysfunction., (Copyright 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: Claudication is the most common presentation of peripheral arterial disease (PAD), producing significant ambulatory compromise. Claudicating patients, most of whom are elderly, have reduced mobility and poor health outcomes, including an increased risk of falls. The gait of elderly fallers is characterized by increased variability. Increase in the variability of the locomotor system makes the gait more noisy and unstable. The purpose of this study is to investigate gait variability in patients with PAD., Methods: Nineteen symptomatic PAD patients (age, 63.6 +/- 9.8 years; body mass, 82.1 +/- 18.5 kg; height, 1.71 +/- 0.06 m) walked on a treadmill in the absence of pain or claudication symptoms while joint flexion and extension kinematics were captured. Results were compared with results obtained from 17 matched healthy controls (age, 65.2 +/- 12.5 years; body mass, 82.0 +/- 25.9.5 kg; height, 1.73 +/- 0.08 m). Relative joint angles were calculated for the ankle, knee, and hip flexion/extension, and the stride-to-stride variability of joint flexion and extension was calculated from at least 30 consecutive footfalls. Variability was expressed using the largest Lyapunov exponent, standard deviation, and coefficient of variation. Independent t tests were used to compare gait variability between groups., Results: Symptomatic PAD patients had significantly higher largest Lyapunov exponent values and coefficient of variation values for all joints, and higher standard deviation values at the ankle and the hip (P < .05)., Conclusion: Symptomatic PAD patients have increased gait variability at the ankle, knee, and hip joints at baseline ambulation in the absence of claudication pain. Our findings indicate significant baseline deterioration in the locomotor system of symptomatic PAD patients. This deterioration results in increased noise and instability of gait and is a potential contributing factor to the falls and mobility problems experienced by symptomatic PAD patients.

Objective: Claudication is the most common manifestation of peripheral arterial disease (PAD) producing significant ambulatory compromise. The purpose of this study was to use advanced biomechanical analysis to characterize the kinematic ambulatory pattern of claudicating patients. We hypothesized that compared with control subjects, claudicating patients have altered kinematic gait patterns that can be fully characterized utilizing advanced biomechanical analysis., Methods: The study examined fourteen PAD patients (age: 58 +/- 3.4 years; weight: 80.99 +/- 15.64 kg) with clinically diagnosed femoro-popliteal occlusive disease (Ankle Brachial Index (ABI): 0.56 +/- 0.03, range 0.45 to 0.65) and five healthy controls (age: 53 +/- 3.4 years; weight: 87.38 +/- 12.75 kg; ABI >or= 1). Kinematic parameters (hip, knee, and ankle joint angles in the sagittal plane) were evaluated during gait in patients before and after the onset of claudication pain and compared with healthy controls. Joint angles were calculated during stance time. Dependent variables were assessed (maximum and minimum flexion and extension angles and ranges of motion) and mean ensemble curves were generated. Time to occurrence of the discrete variables was also identified., Results: Significantly greater ankle plantar flexion in early stance and ankle range of motion during stance was observed in PAD patients (P < .05). Time to maximum ankle plantar flexion was shorter and time to maximum ankle dorsiflexion was longer in PAD patients (P < .05). These differences were noted when comparing PAD patients prior to and after the onset of claudication with healthy controls. The analysis of the kinematic parameters of the knee and the hip joints revealed no significant differences between PAD patients and controls., Conclusion: PAD patients with claudication demonstrate significant gait alterations in the ankle joint that are present prior to the onset of claudication pain. In contrast, the joint motion of the hip and knee did not differ in PAD patients when compared with controls. Further research is needed to verify our findings and assess the impact of more proximal disease in PAD patients as well as the effect of revascularization on joint kinematics.

Claudication is the most common symptomatic manifestation of peripheral arterial disease (PAD), producing significant ambulatory compromise. The purpose of this study was to use advanced biomechanical gait analysis to determine the gait alterations occurring in claudicating patients both before and after onset of claudication pain in their legs. Hip, knee, and ankle joint moments were measured in claudicating patients (age: 64.46+/-8.47 years; body mass: 80.70+/-12.64kg; body height: 1.72+/-0.08m) and were compared to gender-age-body mass-height-matched healthy controls (age 66.27+/-9.22 years; body mass: 77.89+/-10.65kg; body height: 1.74+/-0.08m). The claudicating patients were evaluated both before (pain-free (PF) condition) and after (pain condition) onset of claudication pain in their legs. Thirteen symptomatic PAD patients (26 claudicating limbs) with bilateral intermittent claudication (IC) and 11 healthy controls (22 control limbs) were tested during level walking at their self-selected speed. Compared to controls, PAD hip and ankle joints demonstrated significant angular kinematics and net internal moment changes. Alterations were present both in PF and pain conditions with several of them becoming worse in the pain condition. Both PF and pain conditions resulted in significantly reduced peak hip extensor moment (5.62+/-1.40 and 5.63+/-1.33% BWxBH, respectively) during early stance as compared to controls (7.53+/-1.16% BWxBH). In the pain condition, PAD patients had a significantly reduced ankle plantar flexor moment (7.56+/-1.41% BWxBH) during late stance as compared to controls (8.65+/-1.27% BWxBH). Furthermore, when comparing PF to pain conditions, there was a decreased peak plantar flexor moment (PF condition: 8.23+/-1.37 vs. pain condition: 7.56+/-1.41% BWxBH) during late stance. The findings point to a weakness in the posterior compartment muscles of the hip and calf as being the key factor underlying the PAD gait adaptations. Our findings establish a detailed baseline description of the changes present in PAD patient's joint angles and moments during walking. Since IC is primarily a gait disability, better understanding of the abnormalities in joint and muscle function will enhance our understanding of the gait impairment and may lead to novel, gait-specific treatments.

Objective: Claudication is the most common manifestation of peripheral arterial disease (PAD), producing significant ambulatory compromise. The gait of claudicating patients has been evaluated using primarily temporal and spatial parameters. With the present study, we used advanced biomechanical measures to further delineate the ambulatory impairment of claudicating patients. We hypothesized that the claudicating legs of PAD patients have an altered kinetic gait pattern compared with normal legs from control subjects., Methods: Ambulation kinetics (ground reaction forces) were evaluated in claudicating patients and compared with age-matched healthy controls. Forces were analyzed in the vertical, anterior-posterior, and medial-lateral directions. Time from heel touch-down to toe-off (stance time) and time spent in double-limb support were also evaluated., Results: The study recruited 14 PAD patients (age, 58 +/- 3.4 years; weight, 80.99 +/- 15.64 kg) with femoropopliteal occlusive disease (ankle-brachial index [ABI], 0.56 +/- 0.03) and five controls (age, 53 +/- 3.4 years; weight, 87.38 +/- 12.75 kg; ABI, >or=1.00). Vertical force curve evaluation demonstrated significant flattening in claudicating patients resulting in a lower and less fluctuant center of mass when ambulating. In the anterior-posterior direction, claudicating patients demonstrated significantly decreased propulsion forces. In the medial-lateral direction, they had significantly increased forces consistent with wider steps and an inability to swing their legs straight through. Claudicating patients demonstrated a greater stance time and time in double limb support compared with healthy controls. Most importantly, gait abnormalities were present before the onset of claudication, with gait worsening after the onset of claudication., Conclusion: Claudicating patients demonstrate significant gait impairments that are present even before they experience any limb discomfort. These alterations may make them feel more stable and secure while attempting to minimize use of the affected limb. Advanced biomechanical analysis, using ambulation kinetics, permits objective and quantitative evaluation of the gaits of claudicating patients. Such evaluation may point to new rehabilitation strategies and provide objective measurement of functional outcomes after medical and surgical therapy.

The most common symptom of peripheral artery disease (PAD) is intermittent claudication, which consists of debilitating leg pain during walking. In clinical settings, the presence of PAD is often noninvasively evaluated using the ankle–brachial index and imaging of the arterial supply. Furthermore, various questionnaires and functional tests are commonly used to measure the severity and negative effect of PAD on quality of life. However, these evaluations only provide information on vascular insufficiency and severity of the disease, but not regarding the complex mechanisms underlying walking impairments in patients with PAD. Biomechanical analyses using motion capture and ground reaction force measurements can provide insight into the underlying mechanisms to walking impairments in PAD. This review analyzes the application of biomechanics tools to identify gait impairments and their clinical implications on rehabilitation of patients with PAD. A total of 18 published journal articles focused on gait biomechanics in patients with PAD were studied. This narriative review shows that the gait of patients with PAD is impaired from the first steps that a patient takes and deteriorates further after the onset of claudication leg pain. These results point toward impaired muscle function across the ankle, knee, and hip joints during walking. Gait analysis helps understand the mechanisms operating in PAD and could also facilitate earlier diagnosis, better treatment, and slower progression of PAD. [ABSTRACT FROM AUTHOR]

To investigate the acute and long-term effect of using ankle foot orthoses (AFOs) on spatiotemporal gait parameters of patients with peripheral artery disease (PAD). In a cross-over designed study, subjects were randomized into control and AFO groups. Patients in the AFO group wore bilateral AFOs each day for three months while the control group followed the standard of care for the first three months. Both groups returned for a second evaluation, "crossed over" to the other group for three months, then returned for a final assessment. Patients with PAD were recruited from the claudication clinic at Omaha VA Medical Center. Twenty-one patients with PAD completed all required study visits. Participants had no walking limitations except claudication and related systemic pathology. Patients were instructed to wear bilateral AFOs at all times except in bed and showering during AFO intervention. Means and standard deviations (variability) of spatiotemporal gait parameters (step velocity, step length, step time, and step width) were calculated from motion capture analysis while patients were walking at their preferred speed overground with and without AFOs (NAF). While wearing AFOs, patients with PAD had increased step time compared to the NAF condition (p=0.03). However, after a three-month intervention with AFOs, step time decreased (p=0.04), indicating that the AFO intervention had a beneficial effect on gait adaptation. The AFO group preserved the amount of step width variability following three months of intervention, however, the control group experienced a reduced amount of step width variability (p=0.001) when walking without the AFO. The amount of variability of step length (p=0.02) and step velocity (p=0.03) were reduced at the three-month visit compared to baseline. These changes indicate the stepping pattern moved closer to healthy controls after three months of an AFO intervention. All authors declare they have no conflict of interest. [ABSTRACT FROM AUTHOR]

Abstract: External work was utilized to measure differences between the unaffected and the affected limb in patients with unilateral peripheral arterial disease compared to healthy controls. Patients with unilateral peripheral arterial disease have shown deficits in peak joint powers during walking in the unaffected and affected legs. However, no research has detailed the amount of work that is being performed by each leg compared to healthy controls even though such an analysis would provide valuable information on the energy output from the affected and the unaffected legs. Two hypotheses were tested: (a) the unaffected and affected leg would perform less work than healthy controls in a pain-free state, and (b) the onset of symptomatic claudication pain would result in further changes in the external work. Results showed that during a pain-free state, both the unaffected and affected legs perform less work than the healthy controls. After onset of claudication pain, the work output by the affected limb becomes further decreased while the unaffected limb experiences changes in negative external work. These findings combined with recent evidence of decreased peak powers in both legs in unilateral peripheral arterial disease patients reflects altered pathomechanics in both limbs compared to healthy controls. [Copyright &y& Elsevier]

Abstract: Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance (p =0.017), reduced peak knee power absorption in early and late stance (p =0.037 and p =0.020 respectively), and reduced peak ankle power generation in late stance (p =0.021). This study reveals that the gait of patients with peripheral arterial disease walking prior to the onset of any leg symptoms is characterized by failure of specific and identifiable muscle groups needed to perform normal walking and that these gait deficits are independent of reduced gait velocity. [Copyright &y& Elsevier]