scholarly journals Energy cost and muscular activity required for propulsion during walking

2003 ◽  
Vol 94 (5) ◽  
pp. 1766-1772 ◽  
Author(s):  
Jinger S. Gottschall ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Muscular Activity ◽  
Metabolic Cost ◽  
Medial Gastrocnemius ◽  
Emg Activity ◽  
Horizontal Force ◽  
Normal Walking ◽  
The Mean ◽  
The Cost ◽  
Muscle Actions

We reasoned that with an optimal aiding horizontal force, the reduction in metabolic rate would reflect the cost of generating propulsive forces during normal walking. Furthermore, the reductions in ankle extensor electromyographic (EMG) activity would indicate the propulsive muscle actions. We applied horizontal forces at the waist, ranging from 15% body weight aiding to 15% body weight impeding, while subjects walked at 1.25 m/s. With an aiding horizontal force of 10% body weight, 1) the net metabolic cost of walking decreased to a minimum of 53% of normal walking, 2) the mean EMG of the medial gastrocnemius (MG) during the propulsive phase decreased to 59% of the normal walking magnitude, and yet 3) the mean EMG of the soleus (Sol) did not decrease significantly. Our data indicate that generating horizontal propulsive forces constitutes nearly half of the metabolic cost of normal walking. Additionally, it appears that the MG plays an important role in forward propulsion, whereas the Sol does not.

Energy cost and muscular activity required for leg swing during walking

2005 ◽  
Vol 99 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Jinger S. Gottschall ◽  
Rodger Kram
Keyword(s):  
Muscle Activity ◽  
Center Of Mass ◽  
Muscular Activity ◽  
Metabolic Cost ◽  
Rectus Femoris ◽  
Medial Gastrocnemius ◽  
Propulsive Force ◽  
Normal Walking ◽  
Initiation And Propagation ◽  
Pulling Force

To investigate the metabolic cost and muscular actions required for the initiation and propagation of leg swing, we applied a novel combination of external forces to subjects walking on a treadmill. We applied a forward pulling force at each foot to assist leg swing, a constant forward pulling force at the waist to provide center of mass propulsion, and a combination of these foot and waist forces to evaluate leg swing. When the metabolic cost and muscle actions were at a minimum, the condition was considered optimal. We reasoned that the difference in energy consumption between the optimal combined waist and foot force trial and the optimal waist force-only trial would reflect the metabolic cost of initiating and propagating leg swing during normal walking. We also reasoned that a lower muscle activity with these assisting forces would indicate which muscles are normally responsible for initiating and propagating leg swing. With a propulsive force at the waist of 10% body weight (BW), the net metabolic cost of walking decreased to 58% of normal walking. With the optimal combination, a propulsive force at the waist of 10% BW plus a pulling force at the feet of 3% BW the net metabolic cost of walking further decreased to 48% of normal walking. With the same combination, the muscle activity of the iliopsoas and rectus femoris muscles during the swing phase was 27 and 60% lower, respectively, but the activity of the medial gastrocnemius and soleus before swing did not change. Thus our data indicate that ∼10% of the net metabolic cost of walking is required to initiate and propagate leg swing. Additionally, the hip flexor muscles contribute to the initiation and propagation leg swing.

Independent metabolic costs of supporting body weight and accelerating body mass during walking

2005 ◽  
Vol 98 (2) ◽  
pp. 579-583 ◽  
Author(s):  
Alena Grabowski ◽  
Claire T. Farley ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Body Mass ◽  
Center Of Mass ◽  
Metabolic Cost ◽  
Added Mass ◽  
Normal Walking ◽  
Reduced Gravity ◽  
The Cost ◽  
Support Body Weight

The metabolic cost of walking is determined by many mechanical tasks, but the individual contribution of each task remains unclear. We hypothesized that the force generated to support body weight and the work performed to redirect and accelerate body mass each individually incur a significant metabolic cost during normal walking. To test our hypothesis, we measured changes in metabolic rate in response to combinations of simulated reduced gravity and added loading. We found that reducing body weight by simulating reduced gravity modestly decreased net metabolic rate. By calculating the metabolic cost per Newton of reduced body weight, we deduced that generating force to support body weight comprises ∼28% of the metabolic cost of normal walking. Similar to previous loading studies, we found that adding both weight and mass increased net metabolic rate in more than direct proportion to load. However, when we added mass alone by using a combination of simulated reduced gravity and added load, net metabolic rate increased about one-half as much as when we added both weight and mass. By calculating the cost per kilogram of added mass, we deduced that the work performed on the center of mass comprises ∼45% of the metabolic cost of normal walking. Our findings support the hypothesis that force and work each incur a significant metabolic cost. Specifically, the cost of performing work to redirect and accelerate the center of mass is almost twice as great as the cost of generating force to support body weight.

Metabolic energy and muscular activity required for leg swing in running

2005 ◽  
Vol 98 (6) ◽  
pp. 2126-2131 ◽  
Author(s):  
Jesse R. Modica ◽  
Rodger Kram
Keyword(s):  
Stance Phase ◽  
Muscular Activity ◽  
Metabolic Cost ◽  
Rectus Femoris ◽  
Swing Phase ◽  
Metabolic Energy ◽  
Medial Gastrocnemius ◽  
Running Speed ◽  
Pulling Forces ◽  
The Cost

The metabolic cost of leg swing in running is highly controversial. We investigated the cost of initiating and propagating leg swing at a moderate running speed and some of the muscular actions involved. We constructed an external swing assist (ESA) device that applied small anterior pulling forces to each foot during the first part of the swing phase. Subjects ran on a treadmill at 3.0 m/s normally and with ESA forces up to 4% body weight. With the greatest ESA force, net metabolic rate was 20.5% less than during normal running. Thus we infer that the metabolic cost of initiating and propagating leg swing comprises ∼20% of the net cost of normal running. Even with the greatest ESA, mean electromyograph (mEMG) of the medial gastrocnemius and soleus muscles during later portions of stance phase did not change significantly compared with normal running, indicating that these muscles are not responsible for the initiation of leg swing. However, with ESA, rectus femoris mEMG during the early portions of swing phase was as much as 74% less than during normal running, confirming that it is responsible for the propagation of leg swing.

scholarly journals Metabolic cost of generating horizontal forces during human running

1999 ◽  
Vol 86 (5) ◽  
pp. 1657-1662 ◽  
Author(s):  
Young-Hui Chang ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Metabolic Cost ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Order Of Magnitude ◽  
Reaction Forces ◽  
The Cost ◽  
Support Body Weight ◽  
Human Running

Previous studies have suggested that generating vertical force on the ground to support body weight (BWt) is the major determinant of the metabolic cost of running. Because horizontal forces exerted on the ground are often an order of magnitude smaller than vertical forces, some have reasoned that they have negligible cost. Using applied horizontal forces (AHF; negative is impeding, positive is aiding) equal to −6, −3, 0, +3, +6, +9, +12, and +15% of BWt, we estimated the cost of generating horizontal forces while subjects were running at 3.3 m/s. We measured rates of oxygen consumption (V˙o 2) for eight subjects. We then used a force-measuring treadmill to measure ground reaction forces from another eight subjects. With an AHF of −6% BWt,V˙o 2 increased 30% compared with normal running, presumably because of the extra work involved. With an AHF of +15% BWt, the subjects exerted ∼70% less propulsive impulse and exhibited a 33% reduction inV˙o 2. Our data suggest that generating horizontal propulsive forces constitutes more than one-third of the total metabolic cost of normal running.

Metabolic costs of isometric force generation and maintenance of human skeletal muscle

2002 ◽  
Vol 282 (2) ◽  
pp. E448-E457 ◽  
Author(s):  
David W. Russ ◽  
Mark A. Elliott ◽  
Krista Vandenborne ◽  
Glenn A. Walter ◽  
Stuart A. Binder-Macleod
Keyword(s):  
Isometric Force ◽  
Maintenance Phase ◽  
Metabolic Cost ◽  
Force Generation ◽  
Medial Gastrocnemius ◽  
Single Frequency ◽  
Atp Turnover ◽  
Metabolic Costs ◽  
Force Maintenance ◽  
The Cost

During isometric contractions, no true work is performed, so the force-time integral (FTI) is often used to approximate isometric work. However, the relationship between FTI and metabolic cost is not as linear. We tested the hypothesis that this nonlinearity was due to the cost of attaining a given force being greater than that of maintaining it. The ATP consumed per contraction in the human medial gastrocnemius muscle ( n = 6) was determined by use of 31P-NMR spectroscopy during eight different electrical stimulation protocols. Each protocol consisted of 8 trains of a single frequency (20 or 80 Hz) and duration (300, 600, 1,200, or 1,800 ms) performed under ischemic conditions. The cost of force generation was determined from the ATP turnover during the short-duration trains that did not attain a steady force level. Estimates of the cost of force maintenance at each frequency were determined by subtracting the ATP turnover during the shorter-duration trains from the turnover during the long-duration trains. The force generation phase of an isometric contraction was indeed more metabolically costly than the force maintenance phase during both 20- and 80-Hz stimulation. Thus the mean rate of ATP hydrolysis appeared to decline as contraction duration increased. Interestingly, the metabolic costs of maintaining force during 20-Hz and 80-Hz stimulation were comparable, although different levels of force were produced.

Metabolic cost of head-stand posture

1962 ◽  
Vol 17 (1) ◽  
pp. 117-118 ◽  
Author(s):  
Shanker Rao
Keyword(s):  
Medical Students ◽  
Energy Expenditure ◽  
Human Body ◽  
Metabolic Cost ◽  
The Body ◽  
Erect Posture ◽  
The Mean ◽  
The Cost ◽  
Mean Cost

Metabolic cost to the human body of various postures has been assessed by many workers. The cost with the body in the topsy-turvy posture, or while “standing on the head,” has not been reported so far. Energy expenditure was calculated indirectly by estimating the amount of oxygen consumed while in a particular posture. A Benedict-type recording spirometer was used for this purpose. The subjects were six healthy medical students. The mean cost of standing on the head was determined to be 336 ml, or 1.62 kcal/min, and that of “suspension by the feet” to be 300 ml, or 1.44 kcal/min. The possible causes of increased consumption in relation to the “standing erect” posture are discussed. Submitted on May 26, 1961

COMPARISON BETWEEN BODY WEIGHT AND PRICES OF EWES IN ZARIA AREA

2021 ◽  
Vol 24 (1) ◽  
pp. 74-75
Author(s):  
S. B. Oladele ◽  
A. Fayomi ◽  
J. O. Ayo ◽  
E. A. Haruna ◽  
G. O. Ogeneyi
Keyword(s):  
Body Weight ◽  
Live Weight ◽  
The Mean ◽  
Cost Of Production ◽  
The Cost

A total of 83 non-pregnant Yankasa ewes were weighed in five markets located in and around Zaria, Ahmadu Bello University (ABU) with the aim of determining the mean body weight, price per head and price per kg of live weight. Ewe sold in ABU farm had the highest live weight of 44.56±2.58kg, while those sold in Kano road market were the lightest with live weight of 37.72±1.07k. Ewe sold in Zaria city market at the price of N4716.56±272.22 per head were most expensive. The cheapest ewes were sold N4,121.82±160.25 in Kano road market. The most expensive price of ewes per kg was N9.04±1.97, in Shika market, while the cheapest price per kg was, N104.40±2.27, in ABU farm. Prices of ewe per head and kg were not different (P>0.05) from one another, except for Kano road market where the price per head was significantly lower than that of Shika market. It was concluded that ewes were heaviest and their price per kg live weight was cheapest in the market of ABU farm, where the management was apparently the best of all the five location and the cost of production the lowest.

scholarly journals ​Production, Reproduction Performance and Cost Economics of Nellore Brown Lambs Reared under Different Systems of Rearing

2021 ◽  
Author(s):  
B. Rangamma ◽  
A. Sarat Chandra ◽  
N. Rajanna ◽  
M. Gnana Prakash ◽  
M. Venkateswarlu ◽  
...  
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Live Weight ◽  
The Body ◽  
Research Station ◽  
Net Income ◽  
Reproductive Parameters ◽  
Ewe Lambs ◽  
The Mean ◽  
The Cost

Background: To know the production and reproductive performance of Nellore brown lambs under three systems i.e. intensive, semi-intensive and extensive system of rearing and which system of rearing was beneficial for the farmer community in terms of cost economics. Methods: 36 Nellore brown lambs of 3 months age from Livestock Research Station, Mamnoor, Warangal district were randomly allotted to three rearing systems i.e. Intensive (G1), Semi-intensive (G2) and Extensive (G3) system of each 12 animals. The body weight and ADG of lambs in the three systems were recorded fortnightly and calculated the cost economics. The reproductive parameters of ewe lambs were recorded. Result: From 3-9 months age, the mean gain in body weight (kg) in the G1 group was significantly (P less than 0.01) higher followed by G2 (10.95 ± 0.18) and G3 (9.33 ± 0.09) groups. The mean ADG (gm) was significantly (P less than 0.01) higher in G1 group (75.14 ± 1.56) than G2 (60.83 ± 1.02) and G3 (51.81 ± 0.47) groups. Significant (P less than 0.05) difference was observed in the mean age at puberty of ewe lambs in the three groups. The mean age at first service was lowest in G1 (329.50 ± 6.99) followed by G2 (360.17 ± 6.56) and G3 (385.17 ± 5.60) groups. The net income (Rs.) obtained from each lamb was 1870.8, 1406.7 and 1217.3, respectively in G1, G2 and G3 groups. The cost per kilogram live weight gain was higher in the G1 group followed by G2 and G3 group.

Observations on the response of Merino weaners to a fodder supplement, a feeding block, and cobalt and selenium treatments

1968 ◽  
Vol 8 (33) ◽  
pp. 405
Author(s):  
P McInnes ◽  
BC Roberts ◽  
PM Finlayson ◽  
JV Russel
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Body Weight Gain ◽  
New South ◽  
South Wales ◽  
Affect Body Weight ◽  
Green Fodder ◽  
Unrestricted Access ◽  
The Mean ◽  
The Cost

Summary-The response to supplementary feeding of weaners was studied at Condobolin, New South Wales. Three equal groups of 120, 3-4-month-old Merino weaners were rotated every six weeks for 18 weeks in a three-paddock system. The pasture consisted mainly of relatively dry heliotrope (Heliotropitlm europaetm) but there was some green fodder provided by other pasture species. Unsupplemented weaners gained 54 g per day and a group supplemented with unrestricted amounts of a hammerrnilled mixture of three parts chopped lucerne hay and one part oat grain gained an additional 7 g per day (P<0.05). The mean greasy fleece growth of the supplemented group (2.86 kg) between birth and approximately 10 months of age was greater than the unsupplemented group (2.68 kg, P*lt;0.05). The cost of the supplement would appear to be greater than the increased returns. Weaners allowed unrestricted access to a mineral feeding block gained a mean weight of 42 g per day which was significantly less than the unsupplemented group (P<0.05) and failed to maintain weight during the last six weeks of the trial. Selenium and cobalt treatments, which were given to some sheep in all groups, did not affect body weight gain or wool production.

Effect of High Plane of Nutrition on Blood Biochemical Profile and Onset of Puberty in Prepubertal HF X Kankrej Crossbred Heifers

2019 ◽  
Vol 15 (02) ◽  
pp. 14-17
Author(s):  
K K Hadiya ◽  
A J Dhami ◽  
D V Chaudhari ◽  
P M Lunagariya
Keyword(s):  
Body Weight ◽  
Treatment Group ◽  
Plasma Levels ◽  
Age Of Onset ◽  
The Body ◽  
Monthly Interval ◽  
Control Group ◽  
Blood Biochemical ◽  
Lower Protein ◽  
The Mean

This study was initiated on 24 prepubertal Holstein x Kankrej crossbred heifers of nearly identical age (7-9 months) and body weight (130-140 kg) at University farm to evaluate the effect of high plane of nutrition on blood biochemical and minerals profile and the age at puberty. Twelve heifers were managed under routine farm feeding (control) and the rest 12 under ideal optimum feeding regime (treatment) that included extra 1 kg concentrate, 30 g min mix and ad-lib dry fodder. The body weight and ovarian ultrasonography together with blood sampling was carried out at monthly interval from 10 to 18 months of age to study the ovarian dynamics and blood biochemical changes. High plane of nutrition to growing heifers was beneficial in reducing the age of onset of puberty (by 2-3 months) compared to routine farm fed group. The mean plasma total protein and cholesterol concentrations showed a rising trend with significant variations from 10 to 16 months of age, where it got mostly stabilized indicating adult profile. The activity of enzymes GOT and GPT also rose gradually and significantly from 10 months till 14-15 months of age, and thereafter it remained more or less static till 18 months of age. The levels of both these enzymes were higher, with lower protein and cholesterol, in control than the treatment group from 15-16 months of age onwards. The mean plasma levels of both calcium and phosphorus increased gradually and significantly with advancing age till 16-17 months of age, with little higher values in supplemented than a control group. The plasma levels of zinc, iron, copper, and cobalt also showed rising trend with significant differences between 10th and 12th-14th months of age, and from 15th to 18th months of age the levels were statistically the same in all the groups with slightly higher values in the treatment group.

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