A Comparison of Physiological Demand between Self-Propelled and Motorized Treadmill Exercise

2018 ◽  
Vol 7 (4) ◽  
pp. 13-21
Author(s):  
Todd Backes ◽  
Charlene Takacs

There are a wide range of options for individuals to choose from in order to engage in aerobic exercise; from outdoor running to computer controlled and self-propelled treadmills. Recently, self-propelled treadmills have increased in popularity and provide an alternative to a motorized treadmill. Twenty subjects (10 men, 10 women) ranging in age from 19-23 with a mean of 20.4 ± 0.8 SD were participants in this study. The subjects visited the laboratory on three occasions. The purpose of the first visit was to familiarize the subject with the self-propelled treadmill (Woodway Curve 3.0). The second visit, subjects were instructed to run on the self-propelled treadmill for 3km at a self-determined pace. Speed data were collected directly from the self-propelled treadmill. The third visit used speed data collected during the self-propelled treadmill run to create an identically paced 3km run for the subjects to perform on a motorized treadmill (COSMED T150). During both the second and third visit, oxygen consumption (VO2) and respiratory exchange ratio (R) data were collected with COSMED’s Quark cardiopulmonary exercise testing (CPET) metabolic mixing chamber system. The VO2 mean value for the self-propelled treadmill (44.90 ± 1.65 SE ml/kg/min) was significantly greater than the motorized treadmill (34.38 ± 1.39 SE ml/kg/min). The mean R value for the self-propelled treadmill (0.91 ± 0.01 SE) was significantly greater than the motorized treadmill (0.86 ± 0.01 SE). Our study demonstrated that a 3km run on a self-propelled treadmill does elicit a greater physiological response than a 3km run at on a standard motorized treadmill. Self-propelled treadmills provide a mode of exercise that offers increased training loads and should be considered as an alternative to motorized treadmills.

1961 ◽  
Vol 38 (4) ◽  
pp. 695-705
Author(s):  
J. B. BALINSKY ◽  
E. BALDWIN

1. Eighty-two single determinations of ammonia and urea excretion by Xenopus laevis indicated that the percentage of ammonia varied from 40 to 80%, with a mean value of 62%. 2. Measurements of excretion on successive days after feeding showed that a large amount of ammonia was produced soon after feeding, but that ammonia excretion declined rapidly. Urea excretion, not so high initially, remained more or less constant until the third or fourth day, often exceeding ammonia excretion at that time. Thereafter, it also declined and the excretion of both substances reached a constant starvation level by the fifteenth day. 3. Both ammonia and urea excretion were equally affected by temperature. The Q10's were near 2 in the range 20-30° C., but greater in the range 10-20° C. 4. At least 86% of ammonia, and 81% of urea were excreted through the cloaca. 5. The mean 24 hr. urine output of Xenopus at 20% C. was 23.6 ml. per 100 g. body weight. 6. Although the blood ammonia concentration did not appear to be zero, the urine/blood concentration ratio of ammonia was greater than 100. The urine/blood concentration ratio of urea was not significantly different from unity, and constant over a very wide range of concentrations. 7. The above result is interpreted to indicate passive glomerular filtration of urea, and little or no tubular reabsorption of water. 8. It is suggested that ammonia is formed in the kidney, and actively secreted into the glomerular filtrate.


1991 ◽  
Vol 70 (5) ◽  
pp. 1991-1995 ◽  
Author(s):  
S. A. Gu ◽  
J. Ducas ◽  
U. Schick ◽  
R. M. Prewitt

We investigated the effects of hypoxic ventilation on the pulmonary arterial pressure- (P) flow (Q) relationship in an intact canine preparation. Mean pulmonary P-Q coordinates were obtained during hypoxic ventilation and during ventilation with 100% O2 at normal and at increased left atrial pressure. Specifically, we tested the hypothesis that, over a wide range, changes in left atrial pressure would alter the effects of hypoxic ventilation on pulmonary P-Q characteristics. Seven dogs were studied. When left atrial pressure was normal (5 mmHg), the mean value of the extrapolated intercept (PI) of the linear P-Q relationship was 10.9 mmHg and the slope (incremental vascular resistance, IR) of the P-Q relationship was 2.2 mmHg.l-1.min. Hypoxic ventilation increased PI to 18 mmHg (P less than 0.01) but did not affect IR. Subsequently, during ventilation with 100% O2, when left atrial pressure was increased to 14 mmHg by inflation of left atrial balloon, PI increased to 18 mmHg. IR was 1.6 mmHg.l-1.min. Again, hypoxic ventilation caused an isolated change in PI. Hypoxia increased PI from 18 to 28 mmHg (P less than 0.01). As in the condition of normal left atrial pressure, hypoxic ventilation did not affect IR. We conclude that, in an anesthetized intact canine preparation, hypoxic ventilation causes an isolated increase in the extrapolated pressure intercept of the pulmonary P-Q relationship. Furthermore the effects of hypoxic ventilation on pulmonary P-Q characteristics are not affected by the resting left atrial pressure.


Author(s):  
Mahmood Karimi ◽  
Ramesh R. Rao

Recently, a nonlinear dynamic system has been presented to model the heart rate (HR) response during and after treadmill exercise. The parameters of the model can be estimated and individualized. Based on the nonlinear model, several control techniques for the regulation of HR during treadmill exercise have been proposed. But commercial treadmills may not have equipments to be computer-controlled. In this paper, an optimal manual method is presented to track a predefined HR trajectory. A piecewise constant speed profile is considered as the input to the system and computed by an optimization procedure offline. The objective function is constituted in term of heart rate deviation from its desired. The subject must change manually the speed of the treadmill according to the optimal protocol periodically. The time interval between two speed changes should be long enough so that the subject is able to change the speed. Also, the proposed method is such that, limited attention for control is needed and the controller is not always active.


Author(s):  
Hidayat . ◽  
Nina Susana Dewi ◽  
Nadjwa Zamalek Dalimoenthe

Normoblast is an immature form of erythrocyte in erythropoietin system. Normally, normoblast can be found in peripheral blood healthy neonates. The existence of normoblast in peripheral blood might be the sign of pathologic conditions such as hemolytic anemia,acute blood loss, and ischemia and bone marrows abnormalities like malignancy or leukemia. In acute leukemia (Acute MyeloblasticLeukemia and Acute Lymphoblastic Leukemia), normoblast existence in peripheral blood may due to erythropoietin system suppression.The aim of this study is to compare normoblast count between AML and ALL, and also to find out the correlation between leukocyte andnormoblast count in AML and ALL. The subject of this study were patient diagnosed as AML (30) and ALL (30) in Hematology Divisionof Clinical Pathology Department at Dr.Hasan Sadikin Hospital Bandung in July 2006–August 2008. In this study we examined 30peripheral blood smears from AML and 30 peripheral blood smears from ALL. Leukocyte count result was derived from CBC performedwith Sysmex KX-21. The mean value of normoblast count from AML blood smear patients is 1930.60 (3.60/100 WBC) while ALL bloodsmear patients is 309.60 (0.43/100 WBC). Statistically this difference is significant (p < 0.001). There are strong correlation betweenleukocyte count and normoblast count within both group (r = 0.851, r = 0.948; p < 0.001).


Author(s):  
J. Van den Bosch ◽  
C.F. Mercer

Clover cyst nematode (Heterodera trifolii) reduces growth and nutrient uptake of white clover (Trifolium repens) in New Zealand, and breeding resistant cultivars is the preferred control method for ecological and economic reasons. Resistant and susceptible selections were taken from a wide range of white clover seedlines. Selected plants were intercrossed and reselected over two cycles of selection. Cysts per gram of root dry weight (cysts/ g) was the measure of resistance used, with low cysts/g plants being more resistant. The mean cysts/ g value of the progenies from resistant parents was 69% of the mean value of the progenies from susceptible parents in the first generation, and 38% in the second generation. Root weights were similar, while the resistant selections had 58% and 34% (first and second generations respectively) of the number of cysts in the susceptible selections. There were no immune plants (0 cysts) in the first generation and only two in the second. Counts were made of cysts, eggs per cyst and eggs per plant on clones of two resistant and two susceptible genotypes. The resistant genotypes had lower counts than the susceptible genotypes in terms of cysts per plant (means of 6 cf. 108), eggs per cyst (11 cf. 21) and eggs per plant (35 cf. 1650). The differences in numbers of cysts between resistant and susceptible lines increased during two generations of selection, supporting earlier results that indicated that progress in breeding for resistance was possible. Furthermore, the resistance is also acting on clover cyst nematode egg production which would further reduce recruitment to later generations of clover cyst nematode. Keywords: breeding, Heterodera trifolii, resistance, screening, selection, Trifolium repens


Author(s):  
Carlos A. Hernández J. ◽  
Klaus Gocke

Between January 1987 and January 1988 the primary productivity and related parameters were studied in the Ciénaga Grande de Santa Marta. The Ciénaga is a coastal lagoon with an area of 423 km'2 and mean depth of 1.6 m, which is located at the Caribbean coast of Colombia. The salinity fluctuates seasonally within a wide range. The system is characterized by a high concentration of seston and a great primary productivity. The concentration of chlorophyll " a " ranged from 5.6to 181 ug Ii , the mean value was 59 ug I i . The concentration of proteins was within the extremes of 0.9 and 9.5 mg I"i f the mean value was 4.2 mg I ] . The gross primary productivity in the central part of the Ciénaga amounted to 1690 g C m*2 per year. Considering the temporal fluctuation in the whole system the lowest and highest values were 1.40 and 16.3 g C rrr2 per day. Highest productivity values were encountered when the salinity was low. The primary productivity is controlled by water turbidity and availability of nutrients, thus, seasonal continental waters. The photosynthetic laver ¡s restricted to less than 1.5 m due to the high particle concentration. The mean N: P relation was 4:1 which indicates that the nitrogen compounds are the limiting nutrientes. The high primary productivity sustains an important local fishery. The coastal area in the vicinity of the Ciénaga Grande is benefitted by the export of particulated and dissolved organic matter produced in excess within the coastal lagoon.


2020 ◽  
Author(s):  
Leah E. Morgan

Abstract. 40Ar/39Ar and K-Ar geochronology assume that 40K/K values are invariant among the sample of interest, the co-irradiated neutron fluence monitor (standard), and the material used to measure decay constants. Until recently, this assumption was reasonable due to the small K isotope (41K, 40K, 39K) variability found in many terrestrial samples and the negligible effect of any variation relative to the precision of the determined age. The recent discovery of measurable δ41K variability in terrestrial samples now questions this assumption. Although δ41K values for some neutron fluence monitors have now been reported, potassium isotopes are not routinely measured on samples dated by the 40Ar/39Ar method even though a wide range of silicate materials were found to vary by > 2.5 ‰. Further, the 40K decay constants used in 40Ar/39Ar geochronology are based on activity counting of radioactive decay in K-rich salts. These salts have not been measured for δ41K, yet evaporites have been shown to vary by > 1 ‰ from the mean value of silicates. The potential effects of δ41K variability on 40Ar/39Ar ages are illustrated using the case of the ca. 28.2 Ma Fish Canyon sanidine (FCs) and the ca. 99 Ma Mt. Dromedary Biotite (GA-1550). If the two standards have δ41K values as measured and the material used to determine decay constants is appropriately represented by δ41K of evaporites, the age of FCs is underestimated by ca. 7 ka (0.25 ‰). Although this is a small effect, such bias is becoming important as the analytical precision and accuracy of isotopic measurements and calculation of 40Ar/39Ar ages continue to improve.


Alotrop ◽  
2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Defrilina Sri Eka Wulandari ◽  
Amrul Bahar ◽  
Elvinawati Elvinawati

[THE  APPLICATION OF INQUIRY LEARNING MODEL WITH  DART BOARDMEDIA TO IMPROVE THE STUDIED RESULTS OF  CHEMISTRY IN CLASS XI IPA 1 SMA NEGERI 9 CITY OF BENGKULU  AT 2016/2017 ACADEMIC YEAR]  This research aims to improve the learning outcomes and student activity model of learning by implementing a inkuiri dart board with media in class XI IPA 1 SMA Negeri 9 Bengkulu city at 2016/2017. Academic year. This research is a class action research. This research was conducted in three cycles consisting of 4 stages each namely planning, implementation, observation, and reflection. The subject of this research is the whole grade X IPA 1 SMA N 9 Bengkulu city on 2016/2017 academic year. From the results, it can be concluded that the process of learning to apply inquiry learning models by using a Dart Board media proved can improve the activity and outcomes of study chemistry grade XI IPA 1 SMA Negeri 9  Bengkulu city on 2016/2017 academic year. It can be seen from the average value of students in Ist cycle are 61.61, classical absorption 77.02% and learning of classical completeness at 19.35%..In Iind Cycle obtained an average score of students amounted to 71.29; absorption of conventional 79.21% and  completeness studied conventional 35.48%. In IIIth cycle received an average rating of students at 84.51; absorption of conventional 84.51% and  completeness  studied classical 90.32%.. For the entire sequence of an increase in the activity of the students which can be seen from the mean value – 1st cycle averages of 22.5, 2nd cycle at 25; and in 3th cycle at 29.


2010 ◽  
Vol 17 (5) ◽  
pp. 836-839 ◽  
Author(s):  
Daniel J. Hackett ◽  
Changpin Zhang ◽  
Carla Stefanescu ◽  
Robert F. Pass

ABSTRACT Measurement of antibody to cytomegalovirus (CMV) glycoprotein B (gB) is valuable in the assessment of the antibody response to infection and to gB-containing vaccines. For this purpose, an enzyme-linked immunosorbent assay (ELISA) with a recombinant CMV gB molecule as the antigen was evaluated. Sera from 168 anti-CMV IgG-positive and 100 seronegative subjects were used to evaluate the anti-gB antibody assay. A cutoff optical density (OD) that would distinguish gB antibody-positive from -negative sera was established. Titers of antibody to gB determined by endpoint dilution were compared with those calculated using regression analysis. The run-to-run and interoperator reproducibilities of results were measured. The mean OD + 5 standard deviations from 50 anti-CMV IgG antibody-negative sera (0.2472) was used as the cutoff between anti-gB antibody-positive and -negative results. All sera from 100 anti-CMV IgG-seronegative subjects were negative for antibody to gB. All but 1 of 168 sera from seropositive subjects were positive for antibody to gB. Observed antibody levels based on titration to the endpoint were very similar to results calculated using linear regression. The run-to-run consistency of endpoints was excellent, with 38 runs from one operator and 48 runs from another all giving results within 1 dilution of the mean value for each of three anti-CMV IgG antibody-positive serum pools. The geometric mean titer of antibody to gB for 99 sera from seropositive blood donors was 1/10,937. This ELISA gives accurate and reproducible results for the relative quantity of anti-CMV gB IgG in serum over a wide range of antibody levels.


2017 ◽  
Vol 6 (2) ◽  
pp. 597
Author(s):  
Sudarmiati Sudarmiati

The background of this research is teaching and learning process in class V SDN 007 Panipahan in IPS subjects which is still dominated by teachers so that students become passive receive just the material given by the teacher and the learning result which not yet satisfy with the mean value under KKM. This study aims to determine whether there is influence of discussion methods, both individually and classically to the results of class V B on the subject of social studies in SDN 007 Panipahan. The study was conducted on 32 students consisting of 20 men and 12 women. Data were collected through observation by observer using observation sheet for discussion method data, and through postes unutuk data learning result. The results showed that the method of discussion can improve student learning outcomes, this is evidenced by: Student learning outcomes have increased, in the cycle I average learning outcomes obtained by students is 70.78. In the second cycle has increased with average learning outcome of 75.31. In addition, the classical completeness also increased on the percentage prasiklus student klasiskal completeness of 56.25%, in the first cycle reached 68.75%, in cycle II classical completeness reached 87.53%.


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