Quantitative genetics of maximal oxygen consumption in a garter snake

1990 ◽  
Vol 259 (5) ◽  
pp. R986-R992 ◽  
Author(s):  
T. Garland ◽  
A. F. Bennett
Keyword(s):  
Oxygen Consumption ◽  
Maximal Oxygen Consumption ◽  
Genetic Correlations ◽  
Hemoglobin Level ◽  
Broad Sense ◽  
Thamnophis Sirtalis ◽  
Regression Equations ◽  
Garter Snakes ◽  
Environmental Correlation ◽  
Coefficients Of Variation

Broad-sense heritabilities and genetic correlations of maximal oxygen consumption (VO2max), blood hemoglobin levels, and ventricle mass were estimated in a natural population of snakes. Traits were measured for six or fewer presumed full-sibling offspring from each of 45 wild-caught gravid garter snakes (Thamnophis sirtalis). VO2max was highly reproducible between replicate trial days (r = 0.88). In an attempt to reduce maternal effects, correlations of each character with body mass, snout-vent length, age at testing, litter size, dam mass, and dam snout-vent length were removed by computing residuals from multiple-regression equations. These residuals were used in subsequent genetic analyses. Approximate coefficients of variation of residuals were 16% for VO2max, 19% for hemoglobin level, and 13% for ventricle mass. Broad-sense heritabilities were highly significant for all characters [P less than 0.0001; VO2max heritability (h2) = 0.88; hemoglobin level h2 = 0.63; ventricle mass h2 = 0.41], suggesting that they could respond genetically to selection. Phenotypic correlations (rP) among residual characters were significant only between VO2max and ventricle mass (rP = +0.27). VO2max and ventricle mass exhibited a significant (broad-sense) genetic correlation of +0.64; this might facilitate the correlated evolution of these two traits in response to natural or artificial selection. Ventricle mass and hemoglobin level showed a significant environmental correlation of +0.43. Treadmill endurance crawling time (Evolution 42: 335-350, 1988) showed a weak but significantly positive rP with VO2max (rP = +0.17).

Field performance, C effects, and their relationship to initial rooting ability for western hemlock clones

1993 ◽  
Vol 23 (9) ◽  
pp. 1947-1952 ◽  
Author(s):  
A.D. Paul ◽  
G.S. Foster ◽  
D.T. Lester
Keyword(s):  
Clonal Selection ◽  
Genetic Correlations ◽  
Broad Sense ◽  
Total Variance ◽  
Western Hemlock ◽  
Regression Equations ◽  
Indirect Measure ◽  
Environmental Correlations ◽  
Rooting Ability ◽  
Initial Root

Rooted cuttings from 30 clones of western hemlock (Tsugaheterophylla (Raf.) Sarg.) were established in a field trial in northwest Oregon. A secondary cloning approach was used to partition C effects variance from genetic variance. Clonal variance in total height was significant at 1 (HT1) and 5 (HT5) years and represented 9.2% and 10.6% of the total variance at the two ages, respectively. C effects variance (among primary ramets within clones) was nonsignificant and represented 2.4% and 0% of the total variance at the two ages, respectively. Broad-sense heritabilities of HT1 and HT5 were relatively low, being 0.10 and 0.13, respectively. When calculated on a clone-mean basis, the broad-sense heritabilities increased substantially, reaching 0.53 and 0.61 for HT1 and HT5, respectively. Phenotypic correlations paired between the rooting traits and either HT1 or HT5 were low and not significant. Genetic correlations were 0.42 and 0.29 between an indirect measure of initial root system volume (VOL) and HT1 or HT5, respectively. The genetic correlations between rooting ability and HT1 or HT5 were 0.61 and 0.69, respectively. No genetic correlation existed between length of the longest initial root and field height. Environmental correlations between initial rooting traits and field height were essentially zero. Of the three initial rooting traits tested via regression analysis, VOL served as the only significant predictor or either HT1 or HT5, although the R2 values were less than 0.03, hence, the regression equations were of no practical value. Based on these results, clonal selection of western hemlock for increased early height growth should be aided by indirect selection for clonal rooting ability via a multiple trait selection.

β-Adrenergic receptor number in human lymphocytes is inversely correlated with aerobic capacity

1998 ◽  
Vol 274 (6) ◽  
pp. E1106-E1112 ◽  
Author(s):  
Nobuharu Fujii ◽  
Sachiko Homma ◽  
Fumio Yamazaki ◽  
Ryoko Sone ◽  
Takeshi Shibata ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Aerobic Capacity ◽  
Adrenergic Receptor ◽  
Ventilatory Threshold ◽  
Human Lymphocytes ◽  
Mrna Level ◽  
Maximal Oxygen Consumption ◽  
Subsequent Degradation ◽  
Intracellular Compartments ◽  
Model Cell

In the present study, the relationships between β-adrenergic receptor (β-AR) expression and aerobic capacity evaluated by maximal oxygen consumption ([Formula: see text]) and oxygen consumption level at ventilatory threshold (V˙o 2@VT) were investigated. Seventeen physically untrained and 25 trained men participated in the study. After supine resting, the peripheral blood was sampled for preparation of lymphocytes, the model cell used to analyze the β-AR state. The total number of β-AR in lymphocytes (β-ARtotal) was inversely correlated with theV˙o 2 max( r = −0.368; P < 0.05) and theV˙o 2@VT ( r = −0.359; P < 0.05). Similar relationships were also observed between the number of β-AR in cell surface and both V˙o 2 max( r = −0.491; P < 0.05) andV˙o 2@VT ( r = −0.498; P < 0.05). However, no correlation was obtained between the number of β-AR in intracellular compartments and eitherV˙o 2 max orV˙o 2@VT. The β2-AR mRNA level quantified by the use of competitive reverse transcription-polymerase chain reaction was inversely correlated withV˙o 2@VT ( r = −0.567; P < 0.05) and positively correlated with β-ARtotal( r = 0.521; P < 0.05). These findings suggest that the β-AR number in lymphocytes is inversely correlated with aerobic capacity. This relationship may be explained by downregulation of β-AR, including internalization with subsequent degradation of the receptors and inhibition of the β-AR biosynthesis.

Responses to Intermittent Swimming Sets at Velocity Associated With max

2005 ◽  
Vol 30 (5) ◽  
pp. 543-553 ◽  
Author(s):  
Sebastien Libicz ◽  
Belle Roels ◽  
Gregoire P. Millet
Keyword(s):  
Oxygen Consumption ◽  
Maximal Oxygen Consumption ◽  
Interval Training ◽  
Swimming Velocity ◽  
Time Duration ◽  
Incremental Test ◽  
Large Variability ◽  
Equal Time ◽  
Physiological Adaptations ◽  
The Times

While the physiological adaptations following endurance training are relatively well understood, in swimming there is a dearth of knowledge regarding the metabolic responses to interval training (IT). The hypothesis tested predicted that two different endurance swimming IT sets would induce differences in the total time the subjects swam at a high percentage of maximal oxygen consumption [Formula: see text]. Ten trained triathletes underwent an incremental test to exhaustion in swimming so that the swimming velocity associated with [Formula: see text][Formula: see text] could be determined. This was followed by a maximal 400-m test and two intermittent sets at [Formula: see text] (a) 16 × 50 m with 15-s rest (IT50); (b) 8 × 100 m with 30-s rest (IT100). The times sustained above 95% [Formula: see text] (68.50 ± 62.69 vs. 145.01 ± 165.91 sec) and 95% HRmax (146.67 ± 131.99 vs. 169.78 ± 203.45 sec, p = 0.54) did not differ between IT50 and IT100 (values are mean ± SD). In conclusion, swimming IT sets of equal time duration at [Formula: see text] but of differing work-interval durations led to slightly different [Formula: see text] and HR responses. The time spent above 95% of [Formula: see text]max was twice as long in IT100 as in IT50, and a large variability between mean [Formula: see text] and HR values was also observed. Key words: interval training, maximal oxygen consumption, triathletes

Physiological and Metabolic Responses to Exercise on Treadmill, Elliptical Trainer, and Stepper: Practical Implications for Training

2020 ◽  
pp. 1-8
Author(s):  
Andrew N. Bosch ◽  
Kirsten C. Flanagan ◽  
Maaike M. Eken ◽  
Adrian Withers ◽  
Jana Burger ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Physiological Responses ◽  
Maximal Oxygen Consumption ◽  
Metabolic Responses ◽  
Physiological Measures ◽  
Fuel Utilization ◽  
Trained Runners ◽  
Practical Implications

Elliptical trainers and steppers are proposed as useful exercise modalities in the rehabilitation of injured runners due to the reduced stress on muscles and joints when compared to running. This study compared the physiological responses to submaximal running (treadmill) with exercise on the elliptical trainer and stepper devices at three submaximal but identical workloads. Authors had 18 trained runners (male/female: N = 9/9, age: mean ± SD = 23 ± 3 years) complete randomized maximal oxygen consumption tests on all three modalities. Submaximal tests of 3 min were performed at 60%, 70%, and 80% of peak workload individually established for each modality. Breath-by-breath oxygen consumption, heart rate, fuel utilization, and energy expenditure were determined. The value of maximal oxygen consumption was not different between treadmill, elliptical, and stepper (49.3 ± 5.3, 48.0 ± 6.6, and 46.7 ± 6.2 ml·min−1·kg−1, respectively). Both physiological measures (oxygen consumption and heart rate) as well as carbohydrate and fat oxidation differed significantly between the different exercise intensities (60%, 70%, and 80%) but did not differ between the treadmill, elliptical trainer, and stepper. Therefore, the elliptical trainer and stepper are suitable substitutes for running during periods when a reduced running load is required, such as during rehabilitation from running-induced injury.

Sign in / Sign up

Export Citation Format

Share Document