Mechanical Energy Changes and the Oxygen Cost of Running

1981 ◽  
Vol 10 (4) ◽  
pp. 213-217 ◽  
Author(s):  
M R Shorten ◽  
S A Wootton ◽  
C Williams
Keyword(s):  
Energy Transfer ◽  
Energy Expenditure ◽  
Mechanical Energy ◽  
Three Dimensional ◽  
Whole Body ◽  
Net Energy ◽  
Oxygen Cost ◽  
Transfer Condition ◽  
Energy Transfers ◽  
Highly Correlated

The relationship between the oxygen cost of running at submaximal speeds and running mechanics was investigated in a group of trained athletes by means of an energy analysis. Subjects were filmed while running on a motorized treadmill at speeds of 3.58, 4.02, 4.47, 4.92, 5.36, and 5.81 m/s. Segmental potential and kinetic energies were determined using a three-dimensional link-segmental model. Intra-stride changes in the energy of the whole body were computed with no allowance for energy transfer and with various energy transfer constraints imposed on the model. Oxygen consumption was determined by expired air analysis and used to estimate energy expenditure. For each transfer condition, net energy expenditure was more highly correlated with the magnitude of intra-stride energy changes than with running speed per se. The more economic running patterns were characterized by greater within-segment energy transfers. Given the limitations of the kinematic energy model, it is suggested that individual patterns of running are a significant factor in the determination of energy expenditure.

scholarly journals Net energy value of two low-digestible carbohydrates, Lycasin®HBC and the hydrogenated polysaccharide fraction of Lycasin®HBC in healthy human subjects and their impact on nutrient digestive utilization

2002 ◽  
Vol 87 (2) ◽  
pp. 131-139 ◽  
Author(s):  
S. Sinaud ◽  
C. Montaurier ◽  
D. Wils ◽  
J. Vernet ◽  
M. Brandolini ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Energy Content ◽  
Metabolizable Energy ◽  
Whole Body ◽  
Net Energy ◽  
Adaptation Period ◽  
Healthy Men ◽  
Polysaccharide Fraction ◽  
Energy Value ◽  
Net Energy Value

The metabolizable energy content of low-digestible carbohydrates does not correspond with their true energy value. The aim of the present study was to determine the tolerance and effects of two polyols on digestion and energy expenditure in healthy men, as well as their digestible, metabolizable and net energy values. Nine healthy men were fed for 32 d periods a maintenance diet supplemented either with dextrose, Lycasin®HBC (Roquette Frères, Lestrem, France), or the hydrogenated polysaccharide fraction of Lycasin®HBC, at a level of 100 g DM/d in six equal doses per d according to a 3×3 Latin square design with three repetitions. After a 20 d progressive adaptation period, food intake was determined for 12 d using the duplicate meal method and faeces and urine were collected for 10 d for further analyses. Subjects spent 36 h in one of two open-circuit whole-body calorimeters with measurements during the last 24 h. Ingestion of the polyols did not cause severe digestive disorders, except excessive gas emission, and flatulence and gurgling in some subjects. The polyols induced significant increases in wet (+45 and +66 % respectively, P<0·01) and dry (+53 and +75 % respectively, P<0·002) stool weight, resulting in a 2 % decrease in dietary energy digestibility (P<0·001). They resulted also in significant increases in sleeping (+4·1 %, P<0·03) and daily energy expenditure (+2·7 and +2·9 % respectively, P<0·02) compared with dextrose ingestion. The apparent energy digestibility of the two polyols was 0·82 and 0·79 respectively, their metabolizable energy value averaged 14·1 kJ/g DM, and their net energy value averaged 10·8 kJ/g DM, that is, 35 % less than those of sucrose and starch.

scholarly journals Intraglottal aerodynamic pressure and energy transfer in a self-oscillating synthetic model of the vocal folds

2020 ◽  
Author(s):  
Mohsen Motie-Shirazi ◽  
Matías Zañartu ◽  
Sean D. Peterson ◽  
Byron D. Erath
Keyword(s):  
Energy Transfer ◽  
Vocal Fold ◽  
Energy Exchange ◽  
Three Dimensional ◽  
Vocal Folds ◽  
Surface Velocity ◽  
Net Energy ◽  
Aerodynamic Pressure ◽  
Opening And Closing ◽  
Anterior Posterior

Self-sustained oscillations of the vocal folds during phonation are the result of the energy exchange between the airflow and the vocal fold tissue. Understanding this mechanism requires accurate investigation of the aerodynamic pressures acting on the vocal fold surface during oscillation. A self-oscillating silicone vocal fold model was used in a hemilaryngeal flow facility to measure the time-varying pressure distribution along the inferior-superior length of the vocal fold with a spatial resolution of 0.254 mm, and at four discrete locations in the anterior-posterior direction. It was found that the intraglottal pressures during the opening and closing phases of the vocal fold are highly dependent on three-dimensional and unsteady flow behaviors. The measured aerodynamic pressures and estimates of the medial surface velocity were used to compute the intraglottal energy transfer from the airflow to the vocal folds. The energy was greatest at the anterior-posterior midline, and decreased significantly toward the anterior/posterior endpoints. The net energy transfer over an oscillation cycle was positive, consistent with the theory of energy exchange during phonation. The findings provide insight into the dynamics of the vocal fold oscillation and the potential causes of some vocal fold disorders.

External, internal and total work in human locomotion.

1995 ◽  
Vol 198 (2) ◽  
pp. 379-393 ◽  
Author(s):  
P A Willems ◽  
G A Cavagna ◽  
N C Heglund
Keyword(s):  
Potential Energy ◽  
Mechanical Energy ◽  
Human Locomotion ◽  
The Body ◽  
Whole Body ◽  
Gravitational Potential Energy ◽  
Total Work ◽  
Centre Of Mass ◽  
Body Segments ◽  
Energy Transfers

The muscle-tendon work performed during locomotion can, in principle, be measured from the mechanical energy of the centre of mass of the whole body and the kinetic energy due to the movements of the body segments relative to the centre of mass of the body. Problems arise when calculating the muscle-tendon work from increases in mechanical energy, largely in correctly attributing these increases either to energy transfer or to muscle-tendon work. In this study, the kinetic and gravitational potential energy of the centre of mass of the whole human body was measured (using a force platform) simultaneously with calculation of the kinetic and potential energy of the body segments due to their movements relative to the body centre of mass (using cinematography) at different speeds of walking and running. Upper and lower boundaries to the total work were determined by including or excluding possible energy transfers between the segments of each limb, between the limbs and between the centre of mass of the body and the limbs. It appears that the muscle-tendon work of locomotion is most accurately measured when energy transfers are only included between segments of the same limb, but not among the limbs or between the limbs and the centre of mass of the whole body.

Quantitative Ratiometric pH Imaging Using a 1,2-Dioxetane Chemiluminescence Resonance Energy Transfer Sensor

2020 ◽  
Author(s):  
Lucas S. Ryan ◽  
Jeni Gerberich ◽  
Uroob Haris ◽  
ralph mason ◽  
Alexander Lippert
Keyword(s):  
Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Whole Body ◽  
Photon Flux ◽  
Ph Homeostasis ◽  
Ph Imaging ◽  
Confounding Variables ◽  
Significant Difference

<p>Regulation of physiological pH is integral for proper whole-body and cellular function, and disruptions in pH homeostasis can be both a cause and effect of disease. In light of this, many methods have been developed to monitor pH in cells and animals. In this study, we report a chemiluminescence resonance energy transfer (CRET) probe Ratio-pHCL-1, comprised of an acrylamide 1,2-dioxetane chemiluminescent scaffold with an appended pH-sensitive carbofluorescein fluorophore. The probe provides an accurate measurement of pH between 6.8-8.4, making it viable tool for measuring pH in biological systems. Further, its ratiometric output is independent of confounding variables. Quantification of pH can be accomplished both using common fluorimetry and advanced optical imaging methods. Using an IVIS Spectrum, pH can be quantified through tissue with Ratio-pHCL-1, which has been shown in vitro and precisely calibrated in sacrificed mouse models. Initial studies showed that intraperitoneal injections of Ratio-pHCL-1 into sacrificed mice produce a photon flux of more than 10^10 photons per second, and showed a significant difference in ratio of emission intensities between pH 6.0, 7.0, and 8.0.</p> <b></b><i></i><u></u><sub></sub><sup></sup><br>

scholarly journals OP0178 IMAGING NEOANGIOGENESIS IN RHEUMATOID ARTHRITIS (INIRA): WHOLE-BODY SYNOVIAL UPTAKE OF A 99MTC-LABELLED RGD PEPTIDE IS HIGHLY CORRELATED WITH POWER DOPPLER ULTRASOUND

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 110.2-111
Author(s):  
L. Attipoe ◽  
S. Subesinghe ◽  
C. Blanco-Gil ◽  
M. Opena ◽  
M. Rosser ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Correlation Coefficient ◽  
Doppler Ultrasound ◽  
Imaging Modality ◽  
Power Doppler ◽  
Whole Body ◽  
Total Power ◽  
Acquisition Time ◽  
Power Doppler Ultrasound ◽  
Highly Correlated

Background:Power Doppler ultrasound (PDUS) is superior to clinical examination in detecting synovitis in patients with rheumatoid arthritis (RA). Although dynamic and cheap it is impractical to scan large numbers of joints in routine clinical settings. MRI, whilst sensitive for synovitis, is expensive and routine use is limited to targeted joints. Bone scintigraphy produces whole body images but due to limited specificity is not routinely used.99mTc-maraciclatide (Serac Healthcare) is a radiolabelled tracer which binds with high affinity to integrin αvβ3, a cell-adhesion molecule up-regulated on neoangiogenic blood vessels. It therefore has the potential to image synovial inflammation at the whole-body level. We previously showed in a pilot study that uptake was seen in the inflamed joints of five RA patients and that this correlated with PDUS. This study explores correlation with PDUS in a larger groups of patients with varied disease activity.Objectives:To determine the correlation between ultrasound and99mTc-maraciclatide imaging in patients with rheumatoid arthritis.Methods:50 patients with RA fulfilling ACR 2010 classification criteria were recruited. Patients underwent an ultrasound scan of 40 joints with grey scale (GS) and PD quantification. Each joint was scored on a scale of 0-3 for GS and PD with a total score calculated for each patient. Within 3 hours of the ultrasound patients were injected with 740 MBq of99mTc-maraciclatide. Using a gamma camera, whole body planar views and dedicated hand and foot views were taken 2 hours after injection (Figure 1). Acquisition time was 20 minutes for whole body and 20 minutes for hand and foot views.99mTc-maraciclatide images were scored as positive or negative uptake for each joint (binary score). A quantitative score was also calculated for each joint where there was uptake with this corrected for background uptake. Total binary and quantitative scores per patient were calculated.Ultrasound and99mTc-maraciclatide scores were tested for correlation with Pearson’s correlation coefficient (r). Interrater agreement for 2 scorers was calculated using kappa (ĸ) and concordance correlation coefficient (Pc).Results:Strong correlation was seen when total PDUS was compared to binary scores (r=0.92, r2=0.85) (Figure 2) and quantitative scores (r=0.85, r2=0.72). ĸ was 0.82 and 0.79 for binary and ultrasound scores respectively.Pcwas 0.82 for quantitative scores. p was <0.0005 for all results.99mTc-maraciclatide uptake was also seen in inflamed tendons/tendon sheaths. The imaging procedure was well-tolerated. There were no tracer-related adverse events.Figure 1.99mTc-maraciclatide imaging with dedicated hand and foot viewsConclusion:99mTc-maraciclatide uptake was highly correlated with PDUS highlighting its potential as an alternative imaging modality.99mTc-based planar imaging has the unique capacity to image the whole body and hence the total synovial inflammatory load in a quick acquisition. The imaging equipment to perform these scans is already widely available in radiology departments. Interpretation of scans is also much simpler compared to US/MRI. It could therefore have a role in key decision-making points in pathways for diagnosis, treatment failure, and remission prior to dose tapering.Figure 2.Correlation between total power doppler and99mTc-maraciclatide binary scoresDisclosure of Interests:None declared

Kinematic Coordination in Human Gait: Relation to Mechanical Energy Cost

1998 ◽  
Vol 79 (4) ◽  
pp. 2155-2170 ◽  
Author(s):  
L. Bianchi ◽  
D. Angelini ◽  
G. P. Orani ◽  
F. Lacquaniti
Keyword(s):  
Energy Expenditure ◽  
Energy Cost ◽  
Time Course ◽  
Sagittal Plane ◽  
Dimensional Space ◽  
Mechanical Energy ◽  
Direction Cosine ◽  
Lower Limbs ◽  
Human Gait ◽  
Plane Orientation

Bianchi, L., D. Angelini, G. P. Orani, and F. Lacquaniti. Kinematic coordination in human gait: relation to mechanical energy cost. J. Neurophysiol. 79: 2155–2170, 1998. Twenty-four subjects walked at different, freely chosen speeds ( V) ranging from 0.4 to 2.6 m s−1, while the motion and the ground reaction forces were recorded in three-dimensional space. We considered the time course of the changes of the angles of elevation of the trunk, pelvis, thigh, shank, and foot in the sagittal plane. These angles specify the orientation of each segment with respect to the vertical and to the direction of forward progression. The changes of the trunk and pelvis angles are of limited amplitude and reflect the dynamics of both right and left lower limbs. The changes of the thigh, shank, and foot elevation are ample, and they are coupled tightly among each other. When these angles are plotted one versus the others, they describe regular loops constrained on a plane. The plane of angular covariation rotates, slightly but systematically, along the long axis of the gait loop with increasing V. The rotation, quantified by the change of the direction cosine of the normal to the plane with the thigh axis ( u 3 t ), is related to a progressive phase shift between the foot elevation and the shank elevation with increasing V. As a next step in the analysis, we computed the mass-specific mean absolute power ( P u ) to obtain a global estimate of the rate at which mechanical work is performed during the gait cycle. When plotted on logarithmic coordinates, P u increases linearly with V. The slope of this relationship varies considerably across subjects, spanning a threefold range. We found that, at any given V > 1 m s−1, the value of the plane orientation ( u 3 t ) is correlated with the corresponding value of the net mechanical power ( P u ). On the average, the progressive rotation of the plane with increasing V is associated with a reduction of the increment of P u that would occur if u 3 t remained constant at the value characteristic of low V. The specific orientation of the plane at any given speed is not the same in all subjects, but there is an orderly shift of the plane orientation that correlates with the net power expended by each subject. In general, smaller values of u 3 t tend to be associated with smaller values of P u and vice versa. We conclude that the parametric tuning of the plane of angular covariation is a reliable predictor of the mechanical energy expenditure of each subject and could be used by the nervous system for limiting the overall energy expenditure.

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