Energy Cost Of Walking Research Articles

Energy-saving walking mechanisms in obese adults.

Energy-saving mechanisms are used in human walking. In obese adults the energy cost of walking (Cw) is higher compared with normal-body mass adults. However, the biomechanical factors involved in this extra cost should result in a higher Cw. The aim of this study was to compare energy-saving walking mechanisms [i.e., mechanical energy saved via pendulum (Recovery) and maximum possible elastic energy usage (MPEEu)] and their influence on Cw in obese vs. lean individuals. The net Cw (NetCw), external work (Wext), Recovery, MPEEu, and gait weight transfer duration (gWT) were computed for 13 lean [L; body mass index (BMI) 21.9 ± 1.5 kg/m2] and 13 obese (O; BMI 33.8 ± 2.5 kg/m2) individuals during treadmill walking at five speeds (0.56, 0.83, 1.11, 1.39, 1.67 m/s). No significant difference was found between groups in relative (per kg of body mass) NetCw (P = 0.13). Relative positive Wext was significantly lower at the three fastest speeds (P ≤ 0.003) whereas Recovery was higher at the two fastest speeds (P ≤ 0.01) in O than in L individuals. MPEEu tended to be lower in O than in L (P = 0.06), with significantly lower values in O compared with L at 1.39 and 1.67 m/s (P ≤ 0.017). gWT was significantly shorter in O than in L individuals at 1.67 m/s (P = 0.001). The present results reveal that obese adults rely more on the pendular mechanism than on the storage and release of elastic energy for decreasing the amount of positive Wext and thus limiting the increase in the relative NetCw. NEW & NOTEWORTHY We observed that obese individuals had a lower maximum possible elastic energy usage per kilogram of body mass than their lean counterparts and they may rely more on the pendular mechanism of walking than on the storage and release of elastic energy for decreasing the external mechanical work and thus limiting the increase in the relative net energy cost of walking.

Combined effects of exposure to hypoxia and cool on walking economy and muscle oxygenation profiles at tibialis anterior

ABSTRACTWe investigated combined effects of ambient temperature (23°C or 13°C) and fraction of inspired oxygen (21%O2 or 13%O2) on energy cost of walking (Cw: J·kg−1·km−1) and economical speed (ES). Eighteen healthy young adults (11 males, seven females) walked at seven speeds from 0.67 to 1.67 m s−1 (four min per stage). Environmental conditions were set; thermoneutral (N: 23°C) with normoxia (N: 21%O2) = NN; 23°C (N) with hypoxia (H: 13%O2) = NH; cool (C: 13°C) with 21%O2 (N) = CN, and 13°C (C) with 13%O2 (H) = CH. Muscle deoxygenation (HHb) and tissue O2 saturation (StO2) were measured at tibialis anterior. We found a significantly slower ES in NH (1.289 ± 0.091 m s−1) and CH (1.275 ± 0.099 m s−1) than in NN (1.334 ± 0.112 m s−1) and CN (1.332 ± 0.104 m s−1). Changes in HHb and StO2 were related to the ES. These results suggested that the combined effects (exposure to hypoxia and cool) is nearly equal to exposure to hypoxia and cool individually. Specifically, acute moderate hypoxia slowed the ES by approx. 4%, but acute cool environment did not affect the ES. Further, HHb and StO2 may partly account for an individual ES.

Periodic motion generation for the impactless biped walking up slopes via genetic algorithm

The angular positions of the lower limb joints play important roles on the energy consumption and stability for the bipedal walking up slopes. In this study, the ranges of angular position of lower limb joints are confined and the velocity of swing foot is zero when it touches the ground, which result in the construction of the impactless planar bipedal model. Motion/force control scheme combined with genetic algorithm (GA) is used to ensure stability and low energy cost of bipedal walking at different speeds. The optimized parameters of gaits are obtained by GA, which include walking speed, step length and the maximum height of swing ankle joint. The results demonstrate that more energy is consumed when the optimal walking speed increases for the biped walking on slopes with the same gradient. There are no great differences in optimal step length of the biped when the walking speed changes. The optimal step length declines as the slope increases at the same walking speed. The ankle torques of standing leg have higher values in single support phase at fast speed compared to those at slow and normal speeds. Modifications of boundary conditions can not only be used to realize the stable walking for the biped negotiating slopes, but also be applied to analyze bipedal gaits for walking on stairs and uneven surfaces.

Physical activity in mild multiple sclerosis: contribution of perceived fatigue, energy cost, and speed of walking

Purpose: To clarify the relationship between leisure-time physical activity, perceived fatigue, and energy expenditure while walking in people with multiple sclerosis.Methods: Sixty-six people afflicted with multiple sclerosis (MS) (32 women) with a mild neurological disability, participated in this study. Energy expenditure was separately measured at rest, during comfortable walking and during fast walking via a portable metabolic device using breath-by-breath technology (COSMED K5, COSMED Srl, Rome, Italy). The Godin leisure-time exercise questionnaire assessed leisure-time physical activity. The Modified Fatigue Impact Scale determined the level of perceived fatigue.Results: Seventeen people with MS were classified as physically active; 49 were insufficiently active. Scores recorded on the Godin Leisure-Time Exercise Questionnaire were 47.8 (SD = 18.4), 7.0 (SD = 8.2), respectively. Insufficiently physically active people with MS walked slower at both normal and fast walking conditions. However, no differences between groups were observed in energy expenditure measures in both walking speeds. O2 cost was 0.20 (SD = 0.13) and 0.21 (SD = 0.06) in the active and insufficiently active group, respectively. The insufficiently active group reported more perceived fatigue compared with the active patients; 33.3 (SD = 18.6) vs. 15.0 (SD = 19.0), p value = 0.002. Perceived fatigue was a significant variable maintaining a 10.4% variance related to leisure-time physical activity.Conclusions: Leisure-time physical activity was inversely associated with perceived fatigue and walking speed in persons with mild MS. Rehabilitation professionals should be aware of these relationships when planning rehabilitation strategies.Implication for rehabilitationThis study found that perceived fatigue is a barrier to physical activity participation even in people with mild multiple sclerosis and minimal disability.Insufficiently active people with multiple sclerosis expend the same amount of energy while walking as active multiple sclerosis individuals, though walking slower.The relationship between perceived fatigue and physical activity participation requires further exploration in the multiple sclerosis population.

Stiffness modification of two ankle-foot orthosis types to optimize gait in individuals with non-spastic calf muscle weakness \u2013 a proof-of-concept study

BackgroundTo reduce gait problems in individuals with non-spastic calf muscle weakness, spring-like ankle-foot orthoses (AFOs) are often applied, but they are not individually optimized to treatment outcome. The aim of this proof-of-concept study was to evaluate the effects of modifying the stiffness for two spring-like AFO types with shoes-only as reference on gait outcomes in three individuals with calf muscle weakness due to polio.MethodsWe assessed 3D gait biomechanics, walking speed and walking energy cost for shoes-only and five stiffness conditions of a dorsal-leaf-spring AFO and a spring-hinged AFO. Outcomes were compared between stiffness conditions in the two AFOs and three subjects.ResultsMaximum ankle dorsiflexion angle decreased with increasing stiffness in both AFOs (up to 6–8°) and all subjects. Maximum knee extension angle changed little between stiffness conditions, however different responses between the AFOs and subjects were observed compared to shoes-only. Walking speed remained unchanged across conditions. For walking energy cost, we found fairly large differences across stiffness conditions with both AFOs and between subjects (range 3–15%).ConclusionsModifying AFO stiffness in individuals with non-spastic calf muscle weakness resulted in substantial differences in ankle biomechanics and walking energy cost with no effect on speed. Our results provide proof-of-concept that individually optimizing AFO stiffness can clinically beneficially improve gait performance.

The Determinants of the Preferred Walking Speed in Individuals with Obesity

Background: The preferred walking speed (PWS), also known as the “spontaneous” or “self-selected” walking speed, is the speed normally used during daily living activities and may represent an appropriate exercise intensity for weight reduction programs aiming to enhance a more negative energy balance. Objectives: The aim of this study was to examine, simultaneously, the energetics, mechanics, and perceived exertion determinants of PWS in individuals with obesity. Methods: Twenty-three adults with obesity (age 32.7 ± 6.8 years, body mass index 33.6 ± 2.6 kg/m²) were recruited. The participants performed 10 min of treadmill familiarization, and PWS was determined. Each subject performed six 5-min walking trials (PWS 0.56, 0.83, 1.11, 1.39, and 1.67 m/s). Gas exchanges were collected and analyzed to obtain the gross energy cost of walking (G_Cw), rated perceived exertion (RPE) was measured using a 6–20 Borg scale, and the external mechanical work (W_ext) and the fraction of mechanical energy recovered by the pendular mechanism (Recovery) were computed using an instrumented treadmill. Second-order least-squares regression was used to calculate the optimal walking speed (OWS) of each variable. Results: No significant difference was found between PWS (1.28 ± 0.13 m/s) and OWS for G_Cw (1.28 ± 0.10 m/s), RPE cost of walking (1.38 ± 0.14 m/s), and Recovery (1.48 ± 0.27 m/s; p > 0.06 for all), but the PWS was significantly faster than the OWS for W_ext (0.98 ± 0.56 m/s; p < 0.02). Multiple regression (r = 0.72; p = 0.003) showed that ∼52% of the variance in PWS was explained by Recovery, W_ext, and height. Conclusion: The main finding of this study was that obese adults may select their PWS in function of several competing demands, since this speed simultaneously minimizes pendular energy transduction, energy cost, and perceived exertion during walking. Moreover, recovery of mechanical work, external work, and height seem to be the major determinants of PWS in these individuals.

Effect of Treadmill Training on Energy Cost of Walking, Functional walking capacity and Postural Stability in Children with Cerebral Palsy:A Randomized Controlled Trial

Abstract Background: Independent efficient ambulation and postural stability are two main objectives in the rehabilitation program for children with cerebral palsy (CP). Purpose: The purpose of

Energy Cost of Land and Shallow Water Walking in Females who are Overweight and Obese

Energy Cost of Land and Shallow Water Walking in Females who are Overweight and Obese

Effect of heat load and dietary protein on oxygen pulse and energy cost for locomotion in heifers

The objectives of the present study were to evaluate the effect of heat load, bodyweight and dietary protein on oxygen pulse of heifers, to obtain the energy cost of walking on flat and sloping terrain, and to compare the energy cost of heifers during continuous walking and intermittent walking. In Experiment 1, the correlations of oxygen consumption, heart rate and oxygen pulse (O2P) with bodyweight, black globe temperature and temperature and humidity index were examined. Moreover, the effect of dietary protein on O2P was evaluated. The temperature and humidity index and black globe temperature had a low positive correlation with O2P and oxygen consumption, and a low negative correlation with heart rate. However, weight had no correlation with O2P. There was a linear increase in O2P with a very low adjustment with an increasing dietary crude protein concentration. In Experiment 2, the energy cost of heifers walking continuously at a constant speed in a terrain with 0%, 6% and 12% gradient was measured. The energy expenditure was similar among the terrain gradients. The heifers walking had a 16.6% higher energy expenditure than when they were standing. In Experiment 3, a comparison of the energy cost was made among heifers standing, continuously walking and intermittently walking at a constant speed on flat ground. The energy cost for walking was similar between continuous and intermittent walking. The heat load, bodyweight and dietary protein concentration had a low effect on O2P in dairy heifers. Therefore, measurements over a short time (5–15 min) are a reliable estimator of O2P through the day. Both intermittent and continuous walking can be used to evaluate energy expenditure.

On the biological mechanics and energetics of the hip joint muscle–tendon system assisted by passive hip exoskeleton

Passive exoskeletons have potential advantages in reducing metabolic energy cost. We consider a passive elastic exoskeleton (peEXO) providing hip flexion moment to assist hip flexors during walking, our goal is to use a biomechanical model to explore the biological mechanics and energetics of the hip joint muscle–tendon–exotendon system for obtaining the optimum stiffness of this peEXO at the muscle-level. Based on our developed hip musculoskeletal model capable of replicating human-like behaviors, the hip peEXO is firstly abstracted as a spring (i.e. exotendon), we then simulate the peEXO assisted human walking over a series of stiffnesses, the biological muscle–tendon dynamics is optimally solved by minimizing the total metabolic cost of muscles. The simulation results are consistent with the experimental data of walking with an exoskeleton prototype. We find peEXO of minor stiffness helps reducing the muscle force, activation, and metabolic energy cost of hip flexors, especially the iliopsoas; while stiffer peEXO causes extra metabolic energy cost of antagonist muscles especially the gluteus maximus. With an optimum rotational stiffness of 350 Nm rad−1, the peEXO can reduce the metabolic energy cost of walking by ~7.1% and the hip joint muscles simultaneously have a 3% muscle efficiency promotion. The changes in muscle–tendon dynamics indicate it is more economical to assist the hip joint compared with the ankle joint, and periods of high muscle activation are ideal assistance phases for hip joint muscles. The modeling framework provides deep insights into the potential muscle-level mechanisms which are difficult to study via experiments alone, which is helpful to recover the mechanism of how energy cost is reduced under the external passive assistance and guide the design of passive hip EXOs.

THE EFFECTS OF PHYSICAL AND COGNITIVE TRAINING ON MOBILITY AND EXECUTIVE FUNCTIONS IN OLDER ADULTS

Studies suggest that physical exercise and cognitive training interventions can help improve cognitive functions and mobility in older adults. However, the specific impact of different types of exercise programs and cognitive training on mobility and cognition in sedentary older adults is not fully understood. To investigate this, 68 healthy sedentary participants over the age of 60 (M=68.58, SD=4.68) have been randomized to one of the three 12 weeks training programs (Aerobic (AE)=23, Motor Functions (MF)=24, Cognition(COG)=21). Before and after the training program, the participants underwent physical fitness tests (VO2Max; timed-up-and-go – TUG; metabolic energy cost of walking – MECW), and cognitive evaluations (MMSE, and a modified computerized Stroop task). The AE consisted of high intensity training on a recumbent bicycle. The MF consisted of full-body exercises focusing on coordination, balance, stretching, flexibility without raising the heart rate. The COG training consisted of Ipad exercises focusing on executive functions. Repeated measures ANOVAs revealed a mobility improvement in TUG in all three groups (F(1,65)=9.25, P<.00), an improvement in VO2Max only in the AE group (F(2,65)=4.68, P<.01), an improvement in MECW only in the HM group (F(2,65)=3.35, P<.04), an improvement in Stroop inhibition reaction time only in the COG and MF groups (F(2,65)=25.83, P<.00), and an improvement in Stroop switching reaction time in all groups, with the highest benefit in the COG group (F(2,65)=38.75, P<.00). The study shows that three separate training programs targeting specific mechanisms can improve mobility and confirms the beneficial effects of exercise on cognition.

An Untethered Ankle Exoskeleton Improves Walking Economy in a Pilot Study of Individuals With Cerebral Palsy.

The high energy cost of walking in individuals with cerebral palsy (CP) contributes significantly to reduced mobility and quality of life. The purpose of this paper was to develop and clinically evaluate an untethered ankle exoskeleton with the ability to reduce the metabolic cost of walking in children and young adults with gait pathology from CP. We designed a battery-powered device consisting of an actuator-and-control module worn above the waist with a Bowden cable transmission used to provide torque to pulleys aligned with the ankle. Special consideration was made to minimize adding mass to the body, particularly distal portions of the lower-extremity. The exoskeleton provided plantar-flexor assistance during the mid-to-late stance phase, controlled using a real-time control algorithm and embedded sensors. We conducted a device feasibility and a pilot clinical evaluation study with five individuals with CP ages five through thirty years old. Participants completed an average of 130 min of exoskeleton-assisted walking practice. We observed a 19±5% improvement in the metabolic cost of transport (p = 0.011) during walking with untethered exoskeleton assistance compared to how participants walked normally. These preliminary findings support the future investigation of powered ankle assistance for improving mobility in this patient population.

Randomized Controlled Trial of Exercise to Improve Walking Energetics in Older Adults.

Background and ObjectivesMobility limitation is common and has been linked to high energetic requirements of daily activities, including walking. The study objective was to determine whether two separate forms of exercise could reduce the energy cost of walking and secondary outcomes related to activity and participation domains among older adults with mobility limitation.Research Design and MethodsCommunity-dwelling older adults with self-reported mobility limitation (n = 72) were randomized to 12 weeks of twice-weekly, group-based, instructor-led timing and coordination, aerobic walking, or stretching and relaxation (active control) programs. The primary outcome was the energy cost of walking (mL O2/kg/m), assessed by a 5-minute treadmill walking test (0.8 m/s). Secondary outcomes were fatigability, physical activity, endurance, physical function, and life-space. Baseline-adjusted ANCOVAs were used to determine mean differences between exercise and control groups at 12 and 24 weeks.ResultsExercise session attendance was high: 86% for timing and coordination, 81% for aerobic walking, and 90% for stretching and relaxation. At 12 weeks, timing and coordination reduced the mean energy cost of walking by 15% versus stretching and relaxation (p = .008). Among those with high baseline cost, timing and coordination reduced mean energy cost by 20% versus stretching and relaxation (p = .055). Reductions were sustained at 24 weeks. Aerobic walking had no effect on the energy cost of walking at 12 or 24 weeks. At 12 weeks, there was a trend toward faster gait speed (by 0.1 m/s) in timing and coordination versus stretching and relaxation (p = .074). Fatigability, physical activity, endurance, physical function, and life-space did not change with timing and coordination or aerobic walking versus stretching and relaxation at 12 or 24 weeks.Discussion and ImplicationsTwelve weeks of timing and coordination, but not aerobic walking, reduced the energy cost of walking among older adults with mobility limitation, particularly among those with high baseline energy cost; reductions in energy cost were sustained following training cessation. Timing and coordination also led to a trend toward faster gait speed.

Compensations in lower limb joint work during walking in response to unilateral calf muscle weakness

BackgroundPatients with calf muscle weakness due to neuromuscular disorders have a reduced ankle push-off work, which leads to increased energy dissipation at contralateral heel-strike. Consequently, compensatory positive work needs to be generated, which is mechanically less efficient. It is unknown whether neuromuscular disorder patients compensate with their ipsilateral hip and/or contralateral leg; and if such compensatory joint work is related to walking energy cost. Research questionDo patients with calf muscle weakness compensate for the increase in negative joint work by increasing positive ipsilateral hip work and/or positive contralateral leg work? And is the total mechanical work related with walking energy cost? MethodsSeventeen patients with unilateral flaccid calf muscle weakness and 10 healthy individuals performed the following two tests: i) a barefoot 3D gait analysis at comfortable speed and matched control speed (i.e. 0.4 non-dimensional) to assess lower limb joint work and ii) a 6-minute walk test at comfortable speed to assess walking energy cost. ResultsPatients had a lower comfortable walking speed compared to healthy individuals (1.05 vs 1.36 m/s, p < 0.001) and did not increase positive lower limb joint work at comfortable speed. At matched speed (1.25 m/s), patients showed increased positive work at their ipsilateral hip (0.38 ± 0.08 vs 0.27 ± 0.07, p = 0.001) and/or contralateral leg (0.99 ± 0.14 vs 0.69 ± 0.14, p < 0.001). Patients with weakest plantar flexors used both strategies. No relation between total positive work and walking energy cost was found (r = 0.43, p = 0.122). SignificancePatients with unilateral calf muscle weakness compensated for reduced ankle push-off work by lowering their comfortable walking speed or, at matched speed, by generating additional positive joint work at the ipsilateral hip and/or contralateral leg. The additional positive joint work at matched speed did not explain the elevated walking energy cost at comfortable speed, which needs further exploration.

Terrain coefficients for predicting energy costs of walking over snow

BackgroundPredicting the energy costs of human travel over snow can be of significant value to the military and other agencies planning work efforts when snow is present. The ability to quantify, and predict, those costs can help planners determine if snow will be a factor in the execution of dismounted tasks and operations. To adjust predictive models for the effect of terrain, and more specifically for surface conditions, on energy costs, terrain coefficients (ƞ) have been developed. The physiological demands of foot travel over snow have been studied previously, and there are well established methods of predicting metabolic costs of locomotion. By applying knowledge gained from prior studies of the effects of terrain and snow, and by leveraging those existing dismounted locomotion models, this paper seeks to outline the steps in developing an improved terrain coefficient (ƞ) for snow to be used in predictive modeling. MethodsUsing published data, methods, and a well-informed understanding of the physical elements of terrain, e.g., characterization of snow sinkage (z), this study made adjustments to ƞ-values specific to snow. ResultsThis review of published metabolic cost methods suggest that an improved ƞ-value could be developed for use with the Pandolf equation, where z = depth (h)*(1 - (snow density (ρ0)/1.186)) and ƞ = 0.0005z3 + 0.0001z2 + 0.1072z + 1.2604. ConclusionWhile the complexity of variables related to characteristics of snow, speed of movement, and individuals confound efforts to develop a simple, predictive model, this paper provides data-driven improvements to models that are used to predict the energy costs of dismounted movements over snow.

Effect of type 2 diabetes on energy cost and preferred speed of walking.

Although walking is the most commonly recommended activity for patients with type 2 diabetes (T2D), these patients walk daily less than their healthy peers and adopt a lower self-selected speed. It has been suggested that gait alterations observed in this population could be responsible for a higher metabolic rate (MR) during walking. Thus, the aim of this study was to compare relationship between MR, the energy cost of walking per unit of distance (Cw) and self-selected walking speed in T2D patients and healthy individuals. We measured metabolic and spatiotemporal parameters for 20 T2D patients and 20 healthy control subjects, while they walked on a treadmill at different speeds (0.50-1.75ms-1) using a breath-by-breath gas analyzer and an inertial measurement unit, respectively. Net MR was 14.3% higher for T2D patients on average across all speeds, and they preferred to walk 6.8% slower at their self-selected compared with their non-diabetics counterparts (1.33 vs. 1.42ms-1, respectively; p = 0.045). Both groups naturally walked at a self-selected speed close to their minimum gross Cw per distance, with similar values of minimum gross Cw (3.53 and 3.32Jkg-1m-1 in T2D patients and control subjects, respectively). When compared with healthy subjects, T2D patients walk with a higher MRat any given speed. Thus, the slower self-selected speed observed in T2D patients seems to correspond to the speed at which their gross energy cost per distance was minimized and allows T2D patients to walk at the same intensity than healthy subjects.

Metabolic and kinematic responses while walking and running on a motorised and a curved non-motorised treadmill

ABSTRACTThe purpose of this study was to assess metabolic and kinematic parameters (contact and flight time, step length and frequency) while walking at the preferred speed (1.44 ± 0.22 m · s−1) and while performing an incremental running test (up to exhaustion) on a motorised treadmill (MT) and on a curved non-motorised treadmill (CNMT). Twenty-five volunteers (24.1 ± 3.4 years; 64.7 ± 11.2 kg) participated in the study. Maximal running speed on MT was significantly larger (P < 0.001) than on CNMT (4.31 ± 0.50 vs. 3.75 ± 0.39 m · s−1) but no differences in heart rate or oxygen uptake were observed at this speed. The energy cost of walking (Cw) and running (Cr) were significantly greater (P < 0.001) on CNMT than on MT (37 and 17%, respectively). No major differences in kinematic parameters were observed at paired, submaximal, running speeds (2.22–3.89 m · s−1) but was systematically larger in CNMT (of about 340 ml · min−1 · kg−1). This systematic difference can be expressed in terms of a larger “equivalent speed” on CNMT (of about 0.42 m · s−1) and should be attributed to factors other than the kinematic ones, such as the belt characteristics (e.g. friction, type of surface and curvature).

Influence of energy cost and physical fitness on the preferred walking speed and gait variability in elderly women

Typically gait speed decreases and gait variability increases in elderly. The aim of this study was to define the influence of energy cost of walking on gait speed and of health-related physical fitness on gait variability. Thirty healthy young and older women were recruited in the study. Energy cost of walking (NetCW) was analyzed with indirect calorimetry while a kinematic analysis was performed with an optoelectronic system to calculate gait variability (GV) during treadmill walking at different speeds. Gait speed was defined as the preferred walking speed (PWS) of the subject and health related physical fitness (HRPF) comprised body fat, strength, flexibility, and cardiorespiratory fitness. In healthy elderly women, the coefficient of variation of step width was found to be a better indicator of GV than stride time, stride length and double support coefficients of variation. GV was not affected by age allowing a high PWS. Furthermore, significant associations, adjusted for age, body mass index and number of falls, were identified neither between NetCW and the PWS, nor between HRPF and GV; only a significant association was found between hand-grip strength and gait stability. Findings highlighted the importance to evaluate hand-grip strength as an indicator of gait efficiency.

Prediction of the oxygen cost of walking in hemiparetic stroke patients

The energy cost of walking is a marker of metabolic solicitation and allows energy quantification of walking. It is strongly correlated to the patient's walking speed with post-stroke sequelae. We wanted to develop a model for predicting the energy cost of walking to create of walking distance recommendations aimed at achieving recommended energy expenditure levels to ensure health benefits (> 1000 kcal/week during physical activities). To verify the close relationship between spontaneous walking speed (S free ) and energy cost of walking at S free (Cw free ) in subjects with post-stroke hemiparetic patients sequelea and to test the validity of a prediction model to estimate Cw free based on S free . Twenty-six mild to moderately disabled chronic participants with stroke aged 65 yrs (± 15.7yrs) walked at S free using mobility aids if necessary, for 6 minutes. The Cw free was measured at a stabilized metabolic rate by indirect calorimetry using the Metamax3B device. The relationship between S free and Cw free was analyzed using the correlation coefficient, coefficient of determination. The Cw free prediction model was developed from a regression equation and then tested on a new population with the same inclusion/exclusion criteria ( n = 29). S free and Cw free had a correlation coefficient of −0.94 and a R 2 of 0.97 enabling to formulate a regression equation and develop the Cw free prediction model based on S free . The prediction model tests yielded accurate results with a mean bias of −0.02 mL.kg −1 .m −1 –MD% = 4%. The limits of agreement were −0.31; 0.26 mL.kg −1 .m −1 MD% = 30.9% of the mean measured Cw free . Cw free can be estimated precisely by a simple measurement of the walking speed. In this way, we can easily define the distance the subject must travel according to his Cw to reach the recommended energy expenditure targets. It is a great help for the practitioner for recommendations in the field of physical activity after stroke.

O 014 – effects of balance support on energy cost of walking with a lower limb prosthesis

O 014 – effects of balance support on energy cost of walking with a lower limb prosthesis