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J D George

Publications and source records attributed to J D George.

At least 19 recordsLinked to original sources
PubMed1998

Evaluation of the developmental toxicity of methacrylamide and N,N'-methylenebisacrylamide in Swiss mice.

Timed-pregnant CD-1 outbred albino Swiss mice received either methacrylamide (MAC; 0, 60, 120, or 180 mg/kg/day) or N,N'-methylenebisacrylamide (BAC; 0, 3, 10, or 30 mg/kg/day) p.o. in distilled water on gestational days (GD) 6 through 17. Maternal clinical status was monitored daily. At termination (GD 17), confirmed-pregnant females (27-30 per group, MAC; 24-25 per group, BAC) were evaluated for clinical status and gestational outcome; live fetuses were examined for external, visceral, and skeletal malformations. For MAC, no treatment-related maternal mortality was observed. Maternal body weight on GD 17, maternal weight gain during treatment and gestation, and corrected maternal weight gain were reduced at the high dose. Relative maternal food and water intake was not adversely affected; neurotoxicity was not observed. Relative maternal liver weight was increased at > or = 120 mg/kg/day; gravid uterine weight was decreased at 180 mg/kg/day. The maternal no-observed adverse effect level (NOAEL) was 60 mg/kg/day. The NOAEL for developmental toxicity was also 60 mg/kg/day. At > or = 120 mg/kg/day, mean fetal body weight was reduced. At 180 mg/kg/day, increased postimplantation death per litter was observed. Morphological development was not affected. The maternal NOAEL for BAC was 10 mg/kg/day. At 30 mg/kg/day, decreased maternal body weight on GD 17, maternal body weight change during treatment and gestation, corrected maternal body weight, and gravid uterine weight were observed. Relative maternal liver weight increased at 30 mg/kg/day. The developmental NOAEL was 3 mg/kg/day BAC. Mean fetal body weight was reduced at 30 mg/kg/day. At > or = 10 mg/kg/day, an increased incidence of fetal variations (extra rib) was observed, although fetal malformation rate was unaffected. MAC and BAC were not teratogenic to Swiss mice at the doses tested. BAC was more potent than MAC in causing adverse maternal and developmental effects.

Abnormalities, Multiple↗
PubMed1998

Coincident resection-recession (tenectomy-recession) of the medial rectus muscle, bilaterally, for the treatment of esotropia: results in 18 cases.

PURPOSE: To study the effect of preceding tenectomy of the medial rectus tendon on the results of medial rectus muscle recession. SUBJECTS AND METHODS: Eighteen consecutive cases of incomitant esotropia were retrospectively reviewed. The average preoperative esotropia was 35 PD with an incomitant deviation between 10 PD and 30 PD. All patients underwent 7 mm bilateral medial rectus muscle recession after 4 mm tenectomy of the anterior medial rectus muscle. RESULTS: Fourteen patients (78%) had "satisfactory" results (within 10 PD static esodeviation and 12 PD dynamic deviation [incomitance]). Four (22%) were undercorrected. One showed a postoperative consecutive exotropia of 4 PD at distance only. CONCLUSIONS: Tenectomy of the anterior muscle tendon preceding large recessions of the medial rectus was effective in reducing the frequency of overcorrection (consecutive exotropia). Undercorrection did not appear to be more common.

Child↗
PubMed1997

Non-exercise VO2max estimation for physically active college students.

This study sought to develop a maximal oxygen consumption (VO2max) regression model derived strictly from self-reported non-exercise (N-EX) predictor variables. The VO2max (mean +/- SD; 44.05 +/- 6.6 ml.kg-1.min-1) of 100 physically active college students (50 females, 50 males), aged 18 to 29 yr, was measured using a treadmill protocol and open circuit calorimetry. Questionnaire-based predictor variables used in the N-EX regression model included (a) the subject's perceived functional ability (PFA) to walk, jog, or run given distances, (b) habitual physical activity (PA-R) data, (c) body mass index (BMI), and (d) gender. BMI (kg.m-2) was computed from self-reported body weight in pounds and self-reported body height in feet and inches. The questionnaire-based N-EX regression model (R = 0.85, SEE = 3.44 ml.kg-1.min-1) developed in this study exceeded the accuracy of previously developed N-EX regression models and is comparable to many exercise-based regression models in the literature. Cross-validation using PRESS (predicted residual sum of squares) statistics demonstrated minimal shrinkage (R = 0.84, SEE = 3.60 ml.kg-1.min-1) of the present regression model. The PFA data were useful in explaining observed VO2max variance (squared partial r2 = 0.155, P < 0.0001) and enhanced the ability of the N-EX regression model to accurately predict criterion VO2max. These results suggest that a questionnaire-based N-EX regression model provides a valid and convenient method for predicting VO2max in physically active college students.

Adolescent↗
PubMed1996

Nitrofurazone: reproductive assessment by continuous breeding in Swiss mice.

Nitrofurazone (NTFZ), a nitrofuran antibiotic, was evaluated for reproductive toxicity in Swiss CD-1 mice using the Reproductive Assessment by Continuous Breeding protocol. Male and female mice were cohabited for 15 weeks and exposed to NTFZ in feed at concentrations of 0, 100, 375, and 750 ppm (14-102 mg/kg/day). Fzero 750-ppm breeding pairs had significantly reduced fertility after 7 days of exposure to NTFZ (17% fertile compared to 98% for control pairs) and were infertile after the second litter. Fzero mid-dose pairs had progressively decreasing fertility (47% by the fifth litter), reduced litter size, and reduced proportion of pups born alive. Crossover breeding of control and high-dose Fzero animals confirmed infertility in high-dose males and reduced litter size and pup weight in high-dose females when compared to the control x control group. At necropsy, there were no effects on body weight, but Fzero males had reduced testis weight at the high dose and reduced epididymal sperm concentration and abnormal sperm morphology at all doses of NTFZ. Increased liver as well as kidney and adrenal weights (combined) were observed at 375 and 750 ppm; hepatic hypertrophy was noted microscopically at 750 ppm. Fzero females had reduced body weight, hepatic hypertrophy, and altered estrous cycles at 750 ppm and reduced ovarian weight at all doses. In the second generation, F1 mice at 375 ppm had reduced postnatal survival and body weight and produced smaller F2 litters compared to control mice. At necropsy, F1 males had reduced testes weight and epididymal sperm concentration, abnormal sperm morphology, hepatic hypertrophy at 375 ppm, and borderline nephropathy at 100 and 375 ppm. F1 females had decreased body, liver, and ovarian weight at 375 ppm and altered estrous cycles at 100 and 375 ppm. Thus, NTFZ at > or = 100 ppm (> or = 14 mg/kg/day) caused adverse reproductive effects in Fzero male and female and F1 female mice in the presence of relatively mild systemic toxicity.

Animals↗
PubMed1996

Evaluation of the developmental toxicity of methacrylonitrile in Sprague-Dawley rats and New Zealand white rabbits.

Timed-pregnant Sprague-Dawley (CD) outbred rats and New Zealand White rabbits were dosed by gavage with methacrylonitrile (MACR) in distilled water during major organogenesis. Rats were dosed on Gestational Days (GD) 6 through 15 (0, 5, 25, or 50 mg MACR/kg/day) and rabbits on GD 6 through 19 (0, 1, 3, or 5 mg MACR/kg/day). Maternal clinical status was monitored daily during treatment. At termination (GD 20, rats; GD 30, rabbits), confirmed-pregnant females (25-26 per group, rats; 17-22 per group, rabbits) were evaluated for clinical status and gestational outcome; each live fetus was examined for external, visceral, and skeletal malformations. In rats, no treatment-related maternal clinical signs or mortality were observed, nor was there any adverse effect on maternal body weight or food or water consumption. At necropsy, absolute, relative, and adjusted maternal liver weight was increased at the mid- and high-dose groups, an effect that may be indicative of induction of hepatic enzymes rather than toxicity. In the absence of any indication of maternal toxicity, the no-observed-adverse-effect level (NOAEL) for maternal toxicity in this study was >/=50 mg MACR/kg/day. The NOAEL for developmental toxicity in rats was also >/=50 mg MACR/kg/day. There was no effect of treatment on postimplantation loss, mean fetal body weight per litter, or morphological development. In rabbits, maternal mortality and clinical signs were not dose related. Maternal food consumption, body weight, and liver weight were not adversely affected by treatment. Thus, the maternal NOAEL was >/=5 mg MACR/kg/day. Maternal toxicity, including death, was observed >/=7.5 mg/kg/day in preliminary studies. The developmental NOAEL was also >/=5 mg MACR/kg/day. There was no adverse effect of treatment on postimplantation loss or fetal body weight. A significant decrease in the percentage male fetuses per litter was observed, although there was no effect on total live litter size, suggesting that the reduction in the ratio of live male fetuses in the high-dose group was not biologically significant. MACR had no adverse effect on morphological development. In summary, oral administration of MACR to rats and rabbits during organogenesis, at doses that did not cause persistent maternal toxicity (50 mg MACR/kg/day, rats; 5 mg MACR/kg/day, rabbits), also did not cause any adverse developmental effects.

Abnormalities, Drug-Induced↗
PubMed1996

Navy review of nasopharyngeal radium treatments of submarine candidates.

From approximately 1945 through 1960 nasopharyngeal radium treatments were used to treat barotrauma incurred during submarine escape training by submarine candidates. Concern has been expressed that the treatments placed submarine candidates at significantly increased risk of having brain cancer develop. The concern is based on brain cancer incidence rates reported in a study of Washington County children. Using comparable populations' risk coefficients and secondary brain tumor incidence rates, the excess number of brain cancers per 10,000 subjects during the 42.5 years after treatment was calculated to be 0.5 to 2.8 cases and 1 case, respectively. Personnel records of a sample of those treated and others whose treatment status was unknown were reviewed to determine the feasibility of an epidemiologic study to confirm the cancer risk. The records indicated treatments were not consistently documented to confirm who was treated. In addition, social security numbers are not known to aid in determination of vital status. In conclusion, nasopharyngeal irradiation does not appear to pose a significant risk to submariners, and it is not feasible to use the submariner population to do a meaningful epidemiologic study to clarify the cancer risk.

Adolescent↗
PubMed1995

Carisoprodol: reproductive assessment by continuous breeding in Swiss mice.

Carisoprodol (CARI), a commonly prescribed neuromuscular relaxant, was evaluated for reproductive toxicity in Swiss CD-1 mice using the Reproductive Assessment by Continuous Breeding (RACB) protocol. Male and female mice were given CARI in corn oil suspension by daily gavage at doses of 0, 300, 750, and 1200 mg/kg body wt/day. Clinical signs of general toxicity in F0 animals included sedation, primarily in the high-dose group during the first week of exposure, and reduced body weight in high-dose females. CARI administration for 14 weeks did not affect the ability of the F0 animals to produce litters. However, decreases in proportion of pups born alive (4%) and absolute (5%) and adjusted live pup weight (7%) were observed at 1200 mg/kg CARI when compared to controls. In a crossover mating trial to determine the affected sex, there were no significant differences in the measured reproductive parameters. CARI at the high dose increased the proportion of time spent in proestrus and estrus, but cycle length was unaffected. At F0 necropsy (Week 27 of treatment), all sperm parameters were normal. Right epididymis and liver weights, relative to body weight, were increased (12 and 23%, respectively) over the control group for high-dose males. A mating trial to determine the fertility and reproductive competence of the F1 generation showed no effect of CARI on indices of mating, pregnancy, or fertility, the proportion of F2 pups born alive, the sex ratio of live F2 pups, live F2 pup weight, or gestation length.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

The evaluation of the developmental toxicity of hydrochlorothiazide in mice and rats.

Timed-pregnant CD-1 outbred albino Swiss mice and CD Sprague-Dawley rats were administered hydrochlorothiazide (HCTZ, USP) in corn oil by gavage during major organogenesis, Gestational Days (GD) 6 through 15. The doses administered were 0, 300, 1000, or 3000 mg/kg/day for mice and 0, 100, 300, or 1,000 mg/kg/day for rats. Maternal clinical status was monitored daily during treatment. At termination (GD 17, mice; GD 20, rats), confirmed pregnant females (20-27 per group, mice; 36-39 per group, rats) were evaluated for clinical status and gestational outcome; each live fetus was examined for external, visceral, and skeletal malformations. In mice, no maternal mortality was observed. However, clinical signs including dehydration, piloerection, lethargy, and single-day weight loss appeared to be dose-related. HCTZ had no effect on maternal weight gain or water consumption, gravid uterine weight, relative maternal liver weight, or relative maternal kidney weight. There was no definitive evidence of embryotoxicity or fetal toxicity for mice on GD 17. Thus, the no observed adverse effect level (NOAEL) for both maternal and developmental toxicity was 3000 mg/kg/day. In rats, HCTZ had no effect on maternal survival, clinical signs, or water consumption. Clinical signs were not dose-related. Maternal weight gain during treatment was depressed at 1000 mg/kg/day. Gravid uterine weight and relative maternal liver weight were unaffected. Relative maternal kidney weight was slightly (7-8%) increased at all dose levels, but there was no evidence of a dose response. Thus, the maternal NOAEL for rats was 300 mg/kg/day, based on decreased maternal weight gain during treatment at 1000 mg/kg/day.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

The reproductive and neural toxicities of acrylamide and three analogues in Swiss mice, evaluated using the continuous breeding protocol.

Acrylamide is a known genetic, reproductive, and neural toxicant, although it is not known if one effect is predominant. The toxicities of several structural analogues of acrylamide have been incompletely characterized, and the relative sensitivity of the second generation is not known. The present studies were designed to explore the relationship between neurotoxicity and reproductive toxicity, to further characterize the toxicities of three acrylamide analogues, and to evaluate the relative sensitivity of a second generation to these compounds. For the F0 generation, male and female Swiss CD-1 mice were provided drinking water containing acrylamide (ACR; 3, 10, 30 ppm), N,N'-methylenebisacrylamide (MBA; 10, 30, 60 ppm), N-(hydroxymethyl)acrylamide (HMA; 60, 180, 360 ppm), or methacrylamide (MACR; 24, 80, 240 ppm) during and after a 14-week cohabitation. The last litter was reared and dosed after weaning until mating at 74 +/- 10 days of age with the same level of compound given to the parents Neurotoxicity was assessed at several times in both generations by measuring forelimb and hindlimb grip strength. In the F0 generation, ACR caused an 11% decrease in pup number without measurable neurotoxicity; female fertility was not affected. Although both generations consumed the same amount of ACR, there were larger changes in the fertility-related endpoints in the F1 mice than in the F0's, with no concomitant change in organ weights or sperm parameters. In F0 mice, MBA reduced the number of live pups and their adjusted weight, with no neurotoxicity and no change in F0 female reproduction. MBA caused greater adverse effects in the second generation, concomitant with increased consumption. In the F0 generation, HMA caused the largest decrease in pup number during cohabitation (26%) together with a small effect on grip strength. Female reproduction was not affected. The second generation consumed more HMA and showed slightly greater toxic effects. In both generations, MACR was negative for both neurotoxicity and reproductive toxicity. Dominant-lethal studies showed that the fertility effects for ACR, MBA, and HMA could be explained by a male-mediated increase in postimplantation loss. These studies found that dominant lethality occurred without structural effects on the reproductive system in the presence of only minor effects on grip strength and without detectable neural histopathology. Female reproduction was not significantly affected by these compounds at the doses used. Thus, these data confirm the male as the affected gender and that the reproductive toxicity was greater than motoneuron toxicity when measured as grip strength.

Acrylamide↗
PubMed1994

Reproductive effects of 4-vinylcyclohexene in Swiss mice assessed by a continuous breeding protocol.

4-Vinylcyclohexene (VCH), a dimer of 1,3-butadiene, was evaluated for reproductive toxicity in Swiss (CD-1) mice using the continuous breeding protocol (NTP, 1989). VCH in corn oil was administered by gavage at doses of 0, 100, 250, and 500 mg/kg/day to animals that were housed in same sex pairs for 1 week and then cohabited in breeding pairs for 14 weeks. During cohabitation, newborn litters were euthanized immediately after evaluation on postnatal Day (PND) 0. Litters born after Week 15 were reared until PND 21, when all F0 animals and low- and mid-dose F1 weanlings were humanely killed without a necropsy. At PND 74 +/- 10, control and high-dose F1 animals were cohabited within groups for 1 week and necropsied after delivery of the litters. In F0 breeding pairs, VCH did not affect measures of reproductive competence, including initial fertility, litters per pair, live litter size, or the proportion of pups born alive. Pup weight was decreased (4%) in the high-dose group relative to controls. High-dose F0 females exhibited slight general toxicity, manifested as an 8% difference in body weight compared to controls. VCH did not adversely affect preweaning growth or survival in the F1 generation. VCH had no effect on the reproductive competence of the F1 generation. High-dose F1 adult males and females had decreased body weight. At necropsy, increased relative liver weight (males 9% and females 8%) and sperm motility (although not thought to be biologically significant) were observed in the 500 mg/kg VCH group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Assessment of the reproductive and developmental toxicity of pesticide/fertilizer mixtures based on confirmed pesticide contamination in California and Iowa groundwater.

Pesticides and fertilizers, as used in modern agriculture, contribute to the overall low-level contamination of groundwater sources. In order to determine the potential of pesticide and fertilizer mixtures to produce reproductive or developmental toxicity at concentrations up to 100 x the median level found in groundwater, we prepared and studied two mixtures of pesticides and a fertilizer (ammonium nitrate). One mixture containing aldicarb, atrazine, dibromochloropropane, 1,2-dichloropropane, ethylene dibromide, and simazine plus ammonium nitrate was considered to be a representative of groundwater contamination in California (CAL). The other, containing alachlor, atrazine, cyanazine, metolachlor, metribuzin, and ammonium nitrate, simulated groundwater contamination in Iowa (IOWA). Each mixture was administered in the drinking water of either Swiss CD-1 mice during a Reproductive Assessment by Continuous Breeding study or pregnant Sprague-Dawley rats (gd 6-20) at three dose levels (1x, 10x, and 100x) where 1x was the median concentration of each pesticide component as determined in the groundwater surveys in California or Iowa. Unlike conventional toxicology studies, the purpose of this study was to evaluate the health effects of realistic human concentrations. Thus, the testing concentrations are probably well below the maximally tolerated dose. Propylene glycol was used as the solubilizer for the pesticides in drinking water formulations in both studies. In the reproductive study, neither mixture caused any clinical signs of toxicity, changes in food or water consumption, or body weight in either F0 or F1 mice at doses up to 100x the median groundwater concentrations. There were no treatment-related effects on fertility or any measures of reproductive performance of either the F0 or the F1 generation mice exposed to either CAL or IOWA at up to 100x. Similarly, measures of spermatogenesis, epididymal sperm concentration, percentage motile sperm, percentage abnormal sperm, and testicular and epididymal histology were normal. In the developmental study, CAL- or IOWA-exposed females did not exhibit any significant treatment-related clinical signs of toxicity. No adverse effects of CAL or IOWA were observed for measures of embryo/fetal toxicity, including resorptions per litter, live litter size, or fetal body weight. CAL or IOWA did not cause an increased incidence of fetal malformations or variations. In summary, administration of these pesticide/fertilizer mixtures at levels up to 100-fold greater than the median concentrations in groundwater supplies in California or Iowa did not cause any detectable reproductive (mice), general, or developmental toxicity (rats).

Animals↗
PubMed1993

Developmental toxicity evaluation of diethyl and dimethyl phthalate in rats.

Diethyl phthalate (DEP) and dimethyl phthalate (DMP), phthalic acid ester (PAE) plasticizers, were evaluated for developmental toxicity because of reports in the literature that some PAE were embryotoxic and teratogenic. A previous study (Singh et al., '72) suggested that an increased incidence of skeletal defects in rats might result from gestational exposure to DEP (0.6-1.9 g/kg) or DMP (0.4-1.3 g/kg), ip, on gestational days (gd) 5, 10, and 15. In the current study DEP (0, 0.25, 2.5, and 5%) or DMP (0, 0.25, 1, and 5%) in feed (approximately 0.2-4.0 g/kg/day) were supplied to timed-mated rats from gd 6 to 15. Treatment with 5% DMP resulted in increased relative maternal liver weight. Also, animals exhibited reduced body weight gain during treatment (5% DEP or DMP) and during gestation (5% DEP). Weight gain corrected for gravid uterine weight was also reduced in animals fed 5% DEP. However, high-dose treatment with either DEP or DMP resulted in changes in food and water consumption paralleling the body weight reductions, suggesting that apparent toxic effects on maternal body weight may reflect PAE/feed unpalatability. Treatment with 2.5% DEP resulted in only transient changes in body weight during early treatment. The only maternal effects at 0.25 or 1% DMP were minor changes in food and/or water consumption, and there were no effects at 0.25% DEP. Thus, the NOAELs for maternal toxicity were 1% DMP and 0.25% DEP. In contrast to the observed maternal toxicity, there was no effect of DEP or DMP treatment on any parameter of embryo/fetal development, except an increased incidence of supernumerary ribs (a variation) in the 5% DEP group. These results do not support the conclusion of other investigators that DEP and DMP are potent developmental toxicants. Rather, they suggest that the short-chain PAE are less developmentally toxic than PAE with more complex substitution groups, e.g., di(2-ethylhexyl) phthalate, mono(2-ethylhexyl) phthalate, and butyl benzyl phthalate.

Abnormalities, Drug-Induced↗
PubMed1993

The effects of feed restriction on reproductive function in Swiss CD-1 mice.

Many test compounds used in toxicity studies produce a "systemic" toxicity manifested as reduced body weight gain. While it is known that reduced weight gain during juvenile growth reduces or delays reproductive competence, the effects of adult-onset feed restriction (FR) and inhibited weight gain on the reproductive system of mice are poorly known. To gain some information on the effects of graded body weight reduction, or reduced body weight gain, on commonly used reproductive endpoints, the studies reported below were conducted at two laboratories, using adult mice that were maintained at 90, 80, and 70% of concurrent control body weight (CBW) for up to 21 weeks. Estrous cyclicity and fertility in the females were significantly affected. While male fertility was variably affected, there was a significant decrease in the number of epididymal sperm and in the number of testicular spermatids in the 70% CBW groups. Testis weight was conserved in both studies; relative testis weight increased in all FR groups. These data can improve the interpretation of future studies by helping to separate chemically induced changes from those produced by reduced body weight gain.

Animals↗
PubMed1993

VO2max estimation from a submaximal 1-mile track jog for fit college-age individuals.

The primary purpose of this study was to develop a submaximal field test for the estimation of maximal oxygen uptake (VO2max) using a 1-mile track jog. A second purpose was to determine the accuracy of the 1.5-mile run in estimating VO2max for both male and female subjects. VO2max was measured in 149 relatively fit college students (males = 88, females = 61) 18-29 yr using a treadmill protocol (mean +/- SD; VO2max = 47.7 +/- 6.3 ml.kg-1 x min-1). Multiple regression analysis (N = 54) to estimate VO2max from the submaximal, steady-state 1-mile track jog yielded the following validation (V) model (r(adi) = 0.87, SEE = 3.0 ml.kg-1 x min-1): VO2max = 100.5 + 8.344* GENDER (0 = female; 1 = male) - 0.1636* BODY MASS (kg) - 1.438* JOG TIME (min.mile-1) - 0.1928* HEART RATE (bpm). To help ensure that a submaximal level of exertion was realized for the 1-mile track jog, elapsed jog time was restricted to > or = 8.0 min for males and > or = 9.0 min for females and exercise HR to < or = 180 bpm. Cross-validation (CV) of the 1-mile track jog comparing observed and estimated VO2max (N = 52) resulted in radj = 0.84, SEE = 3.1 ml.kg-1 x min-1. Multiple regression analysis (N = 50) to estimate VO2max from the 1.5-mile run (V:N = 49, radj = 0.90, SEE = 2.8 ml.kg-1 x min-1; CV: N = 47, radj = 0.82, SEE = 3.9 ml.kg-1 x min-1), used elapsed run time, body mass, and gender as independent variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Development of a submaximal treadmill jogging test for fit college-aged individuals.

The purpose of this study was to develop a single-stage submaximal treadmill jogging test for the estimation of maximal oxygen uptake (VO2max). VO2max was measured in 129 relatively fit individuals (males = 84, females = 45), 18-29 yr, using a maximal treadmill protocol (mean +/- SD; VO2max = 48.3 +/- 6.2 ml.kg-1 x min-1, range = 35.6 to 62.3 ml.kg-1 x min-1). The treadmill test required subjects to sustain a comfortable, submaximal jogging pace (4.3-7.5 mph; level grade) until a steady-state heart rate was achieved (approximately 3 min). To help ensure that a submaximal level of exertion was realized for the treadmill jogging test, treadmill speed and exercise HR criteria were established that restricted treadmill speed to < or = 7.5 mph for males and < or = 6.5 mph for females and steady-state exercise HR < or = 180 bpm. Multiple regression analysis (N = 66) to estimate VO2max from the treadmill jogging test yielded the following validation (V) model (r(adj) = 0.84, SEE = 3.2 ml.kg-1 x min-1): VO2max = 54.07 + 7.062 * GENDER (0 = female; 1 = male) - 0.1938 * WEIGHT (kg) + 4.47* SPEED (miles.h-1) - 0.1453 * HEART RATE (bpm). Cross-validation (CV) of the treadmill jogging test comparing observed and estimated VO2max (N = 63) resulted in r(adj) = 0.88, SEE = 3.1 ml.kg-1 x min-1. The results indicate that this submaximal single-stage treadmill jogging test based on multiple linear regression provides a valid and convenient method for estimating VO2max.

Adolescent↗