A note on the influence of negative gradients on the energy expenditure of donkeys walking, carrying and pulling loads

1992 ◽  
Vol 54 (1) ◽  
pp. 153-156 ◽  
Author(s):  
J. T. Dijkman
Keyword(s):  
Energy Consumption ◽  
Energy Expenditure ◽  
Energy Cost ◽  
Walking Speed ◽  
Live Weight ◽  
Mean Values ◽  
Measured Range ◽  
Equus Asinus ◽  
Extra Energy ◽  
Entire Male

The extra energy used for walking on the level and on negative gradients above that used when standing still (Ew) (J/m per kg live weight) was measured in two entire male donkeys (Equus asinus). Ew was not affected by speed within the measured range (V = 0·6 to 1·3 m/s) but gradient (0, −10%, −15%) had a significant effect Ew−10% = 0·97 (s.e. 0·02), Ew−10% = 0·55 (s.e. = 0·03) and Ew−15% = 0·67 (s.e. 0·03).The extra energy cost of carrying loads (Ec), defined as J/m per kg carried was measured using the same animals. Loads were placed over the animals shoulders and speed was varied within the range 0·6 to 1·3 m/s (Eclevel = 1·1 (s.e. 0·04), Ec−10% = 2·7 (s.e. 0·17) and Ec−15% = 3·3 (s.e. 0·20) were significantly different.The energy cost of pulling loads (Ep) (f/m per kg) was measured while the animals pulled loads up to proportionately 0·17 of their live weight. The animals wore a breast-plate harness and walking speed was varied within the range 0·6 to 1·3 m/s. Mean values were 26·5 (s.e. 0·72) on the level, 15-3 (s.e. 1·2) on the −10% gradient and 6·2 (s.e. 0·43) on the −15% gradient.The two donkeys used in this experiment were more efficient in both carrying and pulling loads than oxen and buffaloes. Negative gradients have a significant effect on energy consumption and when estimating the energy expenditure of working animals this factor should be taken into account.

scholarly journals The relationship between relative aerobic load, energy cost, and speed of walking in individuals post-stroke

2021 ◽  
Author(s):  
Ilse Johanna Blokland ◽  
Arianne S Gravesteijn ◽  
Mathijs C Busse ◽  
Floor P Groot ◽  
Coen AM van Bennekom ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Aerobic Capacity ◽  
Energy Cost ◽  
Walking Speed ◽  
Ventilatory Threshold ◽  
Research Question ◽  
Walking Ability ◽  
Cross Sectional ◽  
Relative Load ◽  
Post Stroke

Background: Individuals post-stroke walk slower than their able-bodied peers, which limits participation. This might be attributed to neurological impairments, but could also be caused by a mismatch between aerobic capacity and aerobic load of walking. Research question: What is the potential impact of aerobic capacity and aerobic load of walking on walking ability post-stroke? Methods: In a cross-sectional study, forty individuals post-stroke (more impaired N=21; preferred walking speed (PWS)<0.8m/s, less impaired N=19), and 15 able-bodied individuals performed five, 5-minute treadmill walking trials at 70%, 85%, 100%, 115% and 130% of PWS. Energy expenditure (mlO2/kg/min) and energy cost (mlO2/kg/m) were derived from oxygen uptake (VO2). Relative load was defined as energy expenditure divided by peak aerobic capacity (%VO2peak) and by VO2 at ventilatory threshold (%VO2-VT). Relative load and energy cost at PWS were compared between groups with one-way ANOVAs. The effect of speed on these parameters was modeled with GEE. Results: Both more and less impaired individuals post-stroke showed lower PWS than able-bodied controls (0.44[0.19-0.76] and 1.04[0.81-1.43] vs 1.36[0.89-1.53] m/s) and higher relative load at PWS (50.2±14.4 and 51.7±16.8 vs 36.2±7.6 %VO2 peak and 101.9±20.5 and 97.0±27.3 vs 64.9±13.8 %VO2-VT). No differences in relative load were found between stroke groups. Energy cost at PWS of more impaired (0.30[.19-1.03] mlO2/kg/m) was higher than less-impaired (0.19[0.10-0.24] mlO2/kg/m) and able-bodied (0.15[0.13-0.18] mlO2/kg/m). For post-stroke individuals, increasing walking speed above PWS decreased energy cost, but resulted in a relative load above endurance threshold. Significance: Individuals post-stroke seem to reduce walking speed to prevent unsustainably high relative aerobic loads at the expense of reduced economy. When aiming to improve walking ability in individuals post-stroke, it is important to consider training aerobic capacity.

scholarly journals The CAT-CAM socket and quadrilateral socket: A comparison of energy cost during ambulation

1993 ◽  
Vol 17 (2) ◽  
pp. 95-100 ◽  
Author(s):  
R. S. Gailey ◽  
D. Lawrence ◽  
C. Burditt ◽  
P. Spyropoulos ◽  
C. Newell ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Energy Cost ◽  
Randomized Trials ◽  
Walking Speed ◽  
Vascular Pathology ◽  
Control Group ◽  
Alignment Method ◽  
Normal Walking ◽  
Post Hoc ◽  
Healthy Males

Twenty unilateral trans-femoral amputees fitted with either the Contoured Adducted Trochanteric-Controlled Alignment Method (CAT-CAM) socket (n=10) or the quadrilateral (QUAD) socket (n=10), and a “non-amputee” control group (n=10) participated in the study. Subjects meeting the following criteria were studied: healthy males between the ages of 18 and 55 years, amputation due to non-vascular pathology, an unaffected sound limb, at least six months use of the test prosthesis, and a minimal stump length of 15 cm. Subjects ambulated in two randomized trials separated by 20 minutes of rest at 2 assigned speeds: a pace reflecting normal walking speed (97 m/min=2.5 mph) or a slower speed (48.5 m/min=1.25 mph). Heart rate (HR) and Oxygen uptake (VO2) measured during steady state walking were analyzed via two-way ANOVA. Differences among means were further analyzed using Tukey post hoc and simple effects tests. Significant differences were observed between the control group and CAT-CAM subjects with respect to VO2 (p < 0.05) and HR (p < 0.01) at the slower speed. The control group and subjects using the QUAD socket also differed with respect to VO2 (p < 0.01) and HR (p < 0.01) at the slower pace. Faster pace required more energy expenditure (p < 0.01) and produced higher HR (p < 0.01) than slower speeds. At faster pace, a significantly higher energy expenditure in the QUAD than the CAT-CAM group was observed (p<0.01). It is concluded that ambulating at normal pace using the CAT-CAM socket design uses less energy than when using a QUAD socket design.

The energy costs of walking, carrying and pulling loads on flat surfaces by Brahman cattle and swamp buffalo

1990 ◽  
Vol 50 (1) ◽  
pp. 29-39 ◽  
Author(s):  
P. R. Lawrence ◽  
R. J. Stibbards
Keyword(s):  
Energy Cost ◽  
Water Buffalo ◽  
Live Weight ◽  
Energetic Efficiency ◽  
Energy Costs ◽  
Flat Surfaces ◽  
Extra Energy ◽  
Brahman Cattle ◽  
Swamp Buffalo ◽  
Work Done

ABSTRACTThe extra energy for walking compared with standing still (EW) (J/m per kg live weight) was measured in three Brahman cattle and two water buffalo. Ew was not affected by species or speed within the most comfortable range of speeds (V = 0·6 to 1·0 m/s) but over the whole range tested, Ew = 0·947F + 1·99 (r = 0·66, no. = 61) with average Ew = 2·1 (s.e. 0·06).The extra energy cost of carrying loads while walking (Ec) (J/m per kg carried) was measured using two Brahman cattle, two water buffalo and a pony. Ec was independent of load (up to 70 kg) and speed but was generally lower when loads were placed over the animals' shoulders instead of on their backs. Average values for the cattle, buffaloes and the pony were 2·6, 4·2 and 3·3, respectively.The efficiency of doing work defined as: work done/energy expended was measured in two Brahman cattle and two water buffalo and gave average values of 0·30 and 0·37 respectively for the two species. Efficiency was proportionately about 0·03 higher for animals wearing a collar than when wearing a single yoke but was unaffected by whether the animals wore single or double yokes, by the speed of travel, the size of the load or whether the load was steady or variable.Along with appropriate values for the energetic efficiency of raising body weight when walking uphill, these data are used to derive a factorial equation for estimating the energy expenditure of animals working in the field.

scholarly journals Estimation of the energy costs of locomotion in the Iberian pig(Sus mediterraneus)

2000 ◽  
Vol 83 (1) ◽  
pp. 35-41 ◽  
Author(s):  
M. Lachica ◽  
J. F. Aguilera
Keyword(s):  
Heat Production ◽  
Energy Cost ◽  
Live Weight ◽  
Energy Costs ◽  
Net Energy ◽  
Mean Values ◽  
A Value ◽  
Cost Of Locomotion ◽  
Iberian Pig ◽  
Energy Cost Of Locomotion

The energy cost of locomotion of four Iberian pigs was measured in two experiments conducted when the animals averaged 41·3 (se 0·1) kg (first experiment) and 84·1 (se 0·1) kg (second experiment). The heat production of the pigs was determined when standing or walking at a speed of 0·555 m/s on a treadmill enclosed in a confinement-type respiration chamber, on different slopes (-10·5, 0, and +10·5 % in the first experiment, and -5·25, 0 and +10·5 % in the second experiment). The energy costs of locomotion, estimated from the coefficients of linear regressions of heat production per kg body weight (BW) on distance travelled, were in the first experiment 2·99, 3·31 and 5·88 J/kg BW per m for -10·5, 0, and +10·5 % inclines respectively, and 2·56, 2·84 and 7·13 J/kg BW per m for -5·25, 0 and +10·5 % inclines respectively, in the second experiment. The net energy cost of locomotion on the level appeared to be independent of live weight, attaining a value of 2·98 J/kg BW per m. Also, it was found that within experiments the net energy cost of walking on negative slopes was similar to that for locomotion on the level, indicating that no energy was recovered on vertical descent. Mean values were 3·11 and 2·72 kJ/kg BW per m for the light and heavy pigs respectively. The energy cost of raising 1 kg BW one vertical metre was found to be 27·1 J/kg BW per m in the first experiment and 40·0 J/kg BW per m in the second experiment. Correspondingly, the calculated efficiency for upslope locomotion appeared to decline with increasing BW, resulting in average values of 36·2 and 24·5 %.

scholarly journals 2188

2017 ◽  
Vol 1 (S1) ◽  
pp. 58-58
Author(s):  
Nathaniel Makowski ◽  
Rudi Kobetic ◽  
Lisa Lombardo ◽  
Kevin Foglyano ◽  
Gilles Pinault ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Electrical Stimulation ◽  
Energy Consumption ◽  
Energy Cost ◽  
Walking Speed ◽  
Pulse Generator ◽  
Extensor Muscles ◽  
Study Population ◽  
Minute Walk Distance ◽  
Minute Walk

OBJECTIVES/SPECIFIC AIMS: Evaluate the effect of multijoint functional electrical stimulation (FES) on energy consumption during post-stroke walking. METHODS/STUDY POPULATION: A 67-year-old male with chronic stroke was implanted with an 8-channel implanted pulse generator to stimulate flexor and extensor muscles of the hip, knee, and ankle. Oxygen consumption was measured with a k2b4 portable pulmonary gas analyzer during walking with and without FES assistance. Data were analyzed during steady state oxygen consumption within the last 2 minutes of a 5 minute walk. Distance and walking speed were also measured. RESULTS/ANTICIPATED RESULTS: Electrical stimulation increased walking speed from 0.29 to 0.64 minute/second. Faster walking corresponded with increased oxygen consumption from 10.1 to 14.4 mL O2/kg per minute. Energy cost, consumption as a function of distance, decreased from 3.7 to 2.9 mL O2/kg per minute walking with stimulation compared with without. DISCUSSION/SIGNIFICANCE OF IMPACT: These preliminary data suggest improvements in walking speed with FES are accompanied by increased energy consumption and decreased energy cost. Oxygen consumption during FES assisted walking was <50% of the peak for able bodied individuals of similar age; patients may successfully use the system for community ambulation.

Nutrition of draught oxen in semi-arid west Africa. 1. Energy expenditure by oxen working on soils of different consistencies

1997 ◽  
Vol 64 (2) ◽  
pp. 209-215 ◽  
Author(s):  
A. Fall ◽  
R. A. Pearson ◽  
P. R. Lawrence
Keyword(s):  
Metabolic Rate ◽  
Energy Cost ◽  
Walking Speed ◽  
Marked Effect ◽  
Live Weight ◽  
Sandy Soils ◽  
Work Done ◽  
Arid West ◽  
Energy Cost Of Walking ◽  
Semi Arid

AbstractThe Oxylog, a portable breath-by-breath gas analyser, was used on seven animals to determine standing metabolic rate, energy cost of walking on soils of different consistencies and efficiency of work ploughing and carting. The average standing metabolic rate of animals was 5·63 (s.e. 0·12) W/kg M00·75. The consistency of the soil on which animals worked had a marked effect on their energy cost of walking which was 1·59 (s.e. 0·069) on unploughed soil, 2·15 (s.e. 0·084) on ploughed soil and 1·0 (s.e. 0·10) J/m per kg live weight on laterite tracks. The efficiency of ploughing sandy soils (i.e. ratio of work done to energy used for work) was 0·32 and was not significantly different from the efficiency of carting with different loads. The efficiency of doing work was not influenced by the type of work performed, the draught force exerted or the walking speed.

The energy expenditure of cattle and buffaloes walking and working in different soil conditions

1997 ◽  
Vol 128 (1) ◽  
pp. 95-103 ◽  
Author(s):  
J. T. DIJKMAN ◽  
P. R. LAWRENCE
Keyword(s):  
Energy Expenditure ◽  
Energy Cost ◽  
Walking Speed ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Ground Surface ◽  
Mechanical Efficiency ◽  
Open Circuit ◽  
Soil Conditions ◽  
Energy Cost Of Walking

At the Centre for Tropical Veterinary Medicine, Scotland, during the summer months of 1987, two adult water buffaloes, two Brahman cattle and two Brahman × Friesian steers walked round a circular track on concrete or through 300 mm deep mud. Average walking speed (m/s) when unloaded, or average walking speed (m/s) when pulling 324 N, energy for walking (J/m/kg) and net mechanical efficiency (%) were 1·05 and 0·81 (P < 0·01), 1·03 and 0·80 (P < 0·001), 1·49 and 3·34 (P < 0·001) and 31·0 and 31·8 for concrete and mud respectively. Energy values were calculated from gaseous exchange measured with an open circuit system.In Central Nigeria, from September 1991 to May 1992, the energy expenditure of eight Bunaji (White Fulani) bulls was monitored using portable oxygen measuring equipment (modified ‘Oxylog’) when walking, ploughing and harrowing on six soil surfaces ranging from hard, smooth earth to ploughed, waterlogged clay. Average walking speeds (m/s), pulling speeds (m/s) and energy cost of walking (J/m/kg) varied from 0·97 to 0·65, 0·55 to 0·47 and 1·47 to 8·58 respectively. Net mechanical efficiency averaged 31·4% and was unaffected by ground surface.The energy cost of walking for the Bos indicus cattle on smooth ground (1·47 J/m/kg) in this trial was less than that previously reported for Bos taurus (1·80 J/m/kg) and the reported average value for cattle (Bos indicus and Bos taurus) on treadmills (2·09 J/m/kg). The implications for practical agriculture of the higher levels of energy expenditure for walking in muddy conditions are discussed.

scholarly journals DEVELOPMENT AND APPLICATION OF A MATHEMATICAL MODEL FOR EVALUATING EXTRA ENERGY COST DUE TO DISPROPORTIONAL ENERGY CONSUMPTION

2007 ◽  
Vol 8 (2) ◽  
pp. 155-161
Author(s):  
Sunday Ayoola Oke ◽  
Oluwafemi Isaac Oyedokun
Keyword(s):  
Energy Consumption ◽  
Energy Cost ◽  
Energy Requirement ◽  
Time Frame ◽  
Energy Losses ◽  
Manufacturing Processes ◽  
Air Conditioner ◽  
Manufacturing Companies ◽  
Cost Rate ◽  
Extra Energy

In this investigation, a scientific approach is presented in quantifying energy losses associated with production facilities. The corresponding analytical approach in estimating energy requirement of equipment is shown. In particular, mathematical information on how extra energy cost due to extra energy losses that occur in equipment is measured has been shown. The premise of the study is based on the fact that the value of the efficiency of the equipment determines the value of the energy that can be lost for a time frame. Similarly, the heat generated in some equipment, like lamps and air conditioner, can constitute energy lost in equipment. The paper then further shows that the energy cost paid for the energy losses that occur in equipment can be determined by using the energy cost rate used for calculating the cost paid for the useful work done. As manufacturing companies strive to meet and exceed the expected needs of the customer with cost saving manufacturing processes, a major hurdle is the losses in energy transfer as a result of inefficiencies in operations. This paper is geared towards achieving effective and efficient manufacturing processes by researching into trends in energy losses. The results obtained show the feasibility of the applied procedure. There is no previous documentation that has addressed the current problem using the approach presented. This is therefore a new way of viewing energy consumption.

scholarly journals Carbohydrate and fat oxidation in persons with lower limb amputation during walking with different speeds

2017 ◽  
Vol 42 (3) ◽  
pp. 304-310
Author(s):  
Terje Gjovaag ◽  
Peyman Mirtaheri ◽  
Inger Marie Starholm
Keyword(s):  
Energy Expenditure ◽  
Energy Cost ◽  
Walking Speed ◽  
Fat Oxidation ◽  
Total Energy Expenditure ◽  
Maximal Aerobic Capacity ◽  
Carbohydrate Utilization ◽  
Fat Utilization ◽  
Transfemoral Amputees ◽  
Energy Cost Of Walking

Background: Studies suggest that the energy expenditure of healthy persons (control) during walking with the preferred walking speed in steady-state conditions is dominated by fat oxidation. Conversely, carbohydrate and fat oxidation during walking is little investigated in transfemoral amputees. Objectives: To investigate carbohydrate and fat oxidation, energy cost of walking, and percent utilization of maximal aerobic capacity [Formula: see text]during walking. Study design: Eight transfemoral amputees and controls walked with their preferred walking speed and speeds 12.5% and 25% slower and faster than their preferred walking speed. Methods: Energy expenditure and fuel utilization were measured using a portable metabolic analyzer. Metabolic values are means ± standard deviation. Results: For transfemoral amputees (37.0 ± 10.9 years) and controls (39.0 ± 12.3 years), fat utilization at the preferred walking speed was 44.8% ± 7.2% and 45.0% ± 7.2% of the total energy expenditure, respectively. The preferred walking speed of the transfemoral amputees and controls was close to a metabolic cross-over speed, which is the speed where carbohydrate utilization increases steeply and fat utilization decreases. When walking fast, at 90 m min−1 (preferred walking speed plus 25%), transfemoral amputees utilized 70.7% ± 5.6% of their [Formula: see text], while the controls utilized 30.9% ± 4.5% ( p < 0.001) at the matching speed (control preferred walking speed). At 90 m min−1, carbohydrate utilization was 78% ± 4.7% and 55.2% ± 7.2% of the total energy expenditure for the transfemoral amputees and controls, respectively ( p < 0.01). Compared to the control, energy cost of walking was higher for the transfemoral amputees at all speeds (all comparisons; p < 0.001). Conclusion: At the preferred walking speed, carbohydrate, not fat, dominates energy expenditure of both transfemoral amputees and controls. For the transfemoral amputees, consequences of fast walking are very high [Formula: see text] utilization and rate of carbohydrate oxidation. Clinical relevance Research on the relationships between physical effort and fuel partitioning during ambulation could provide important insights for exercise-rehabilitation programs for lower limb amputees (LLA). Regular endurance exercise will improve maximal aerobic capacity and enable LLA to walk faster and at the same time expend less energy and improve fat utilization.

Energy Consumption in Large Acute Hospitals

1995 ◽  
Vol 6 (2) ◽  
pp. 119-134 ◽  
Author(s):  
J.M. Willliams ◽  
A.J. Griffiths ◽  
D. Jones ◽  
P.N. Eaton
Keyword(s):  
Energy Consumption ◽  
Energy Expenditure ◽  
National Health ◽  
Energy Cost ◽  
Fossil Fuels ◽  
Health Sector ◽  
Electricity Consumption ◽  
Department Of Health ◽  
Acute Hospitals

This paper examines energy cost and consumption in large acute hospitals. Energy represents the third largest cost in the National Health Service behind staff wages and drugs, hence it is recognised as a major cost area. The Department of Health has established a target of reducing energy consumption in the National Health Sector by 15% in the five year period up to 1996. The experience of hospitals suggests that savings of up to 20% are possible on predicted levels. The largest energy cost in hospitals is electricity, this accounts for 42% of total energy expenditure. There is a sharp upward trend in electricity consumption throughout the Health Sector. The remaining energy expenditure is allocated to fossil fuels. A case study performed at the Royal Gwent Hospital, Newport, identified electricity as the major energy cost and examined the areas where the greatest consumption was occurring.

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