Search PubMed⌕ Search

Biomedical subjects

R R Pate

Publications and source records attributed to R R Pate.

At least 73 records · Page 4Linked to original sources
PubMed1992

Training for endurance sport.

1) An endurance athlete's performance level is determined largely by three physiological variables: maximal aerobic power, lactate threshold, and economy. Training strategies should be directed toward improvement of these factors. 2) Successful endurance training programs typically include an individually constructed combination of three major training strategies. These are long duration, moderate intensity training; moderate duration, high intensity training; and short duration, very high intensity training. 3) Endurance training involves a large daily expenditure of energy, and much of this energy is derived from catabolism of carbohydrates. Accordingly, it is essential that the endurance athlete's diet be rich in complex carbohydrates and provide the total amount of energy needed to maintain energy balance.

Diet↗
PubMed1992

Physiological, anthropometric, and training correlates of running economy.

Potential physiological, anthropometric, and training determinants of running economy (RE) were studied in a heterogeneous group of habitual distance runners (N = 188, 119 males, 69 females). RE was measured as VO2 (ml.kg-1.min-1) during level treadmill running at 161 m.min-1 (6 mph) (VO2-6). Examined as potential determinants of RE were heart rate and ventilation while running at 6 mph (HR6, VE6), VO2max (ml.kg-1 x min-1), % fat, age, gender, height, weight, estimated leg mass, typical training pace, training volume, and sit-and-reach test performance. RE was entered as the dependent variable and the potential determinants as independent variables in zero-order correlation and multiple regression analyses. Zero-order correlation analysis found VO2max, HR6, and VE6 to be significantly, positively correlated with VO2-6 (P < 0.001). Multiple regression analysis, in which the independent effect of each predictor variable was examined, revealed VO2-6 to be positively correlated with VO2max (P < 0.001), HR6 (P < 0.001), VE6 (P < 0.001), and age (P < 0.05) and negatively correlated with weight (P < 0.01). These findings indicate that, in a diverse group of runners, better RE (VO2-6) is associated with lower VO2max, lower submaximal exercise VE and HR, lower age, and greater weight.

Adult↗
PubMed1992

Effect of iron supplementation on endurance capacity in iron-depleted female runners.

The purpose of this investigation was to examine the effects of oral iron supplementation on endurance performance in initially iron-depleted, nonanemic female distance runners. Eighteen iron-depleted (serum ferritin less than 20 ng.ml-1, hemoglobin greater than or equal to 12 g.dl-1) women (22-39 yr) performed a VO2max test and an endurance run to exhaustion. Subjects were pair-matched on the basis of endurance time and then randomly assigned to an iron supplement or a placebo group. Following supplementation, the iron group had a significantly higher (P = 0.03) mean serum ferritin concentration (23.4 vs 15.7 ng.ml-1) and lower (P = 0.04) mean total iron-binding capacity than the placebo group. Both groups increased their time to exhaustion (25.5% and 22.2% for the iron and placebo groups, respectively) but were not significantly different (P = 0.72) from each other. There were also no differences (P greater than 0.05) between the groups with respect to lactate concentrations and physiological measures taken during the two exercise tests. The results of this study suggest that 8 wk of oral iron supplementation improves iron status in iron-depleted female distance runners, but does not enhance endurance capacity.

Adult↗
PubMed1991

Reliability of long-term recall of participation in physical activity by middle-aged men and women.

The reliability of long-term recall of physical activity participation was examined in 322 women and 129 men in a worksite health study conducted at the Liberty Corporation, Greenville, South Carolina during 1976-1987. Leisure time physical activity was assessed at baseline; and energy expenditure in total, light, moderate, and vigorous activities was calculated. The long-term recall of baseline activities was determined 1-10 years after the examination. The relation between actual baseline and recalled activity was positive and in most cases the coefficients were statistically significant at p less than 0.05. The correlations were modest, most in the range of 0.20 to 0.50. Percent agreement between baseline and recalled activity generally ranged from 60 to 75%. Multiple regression analyses suggested that recalled activity was a significant predictor of baseline activity, but recall interval and age were not important contributors to the regression model. R2 values for the model were 0.10 for light activity and 0.26 for vigorous activity. Questionnaire assessment of long-term physical activity recall appeared to be reliable, length of recall interval up to 10 years was not an important factor, and recall of vigorous activity was more accurate than for less intensive activities.

Female↗
PubMed1991

Exercise and the incidence of upper respiratory tract infections.

We examined illness patterns in a cohort of 530 male and female runners who completed a monthly log for 12 months. The average number of upper respiratory tract infections (URTIs) per person per year for the cohort was 1.2. An upper respiratory tract infection was indicated by the report of any of the following symptoms; runny nose, sore throat, or cough. Using a multiple logistic regression model, the following factors were found to be associated with having one or more URTIs in the follow-up period: living alone (odds ratio = 2.27, 95% CI = 1.01, 5.09), running mileage (486-865 miles, odds ratio = 2.00, 95% CI = 1.01, 2.78; 866-1388 miles, odds ratio = 3.50, 95% CI = 1.52, 4.44; greater than 1388 miles, odds ratio = 2.96, 95% CI = 1.30, 3.68), body mass index greater than the 75th percentile (odds ratio = 0.58, 95% CI = 0.35, 0.94), and male gender (odds ratio = 0.14, 95% CI = 0.03, 0.68). A significant interaction was found to exist between gender and alcohol use, with the association between alcohol use and upper respiratory tract infections being positive in males and negative in females. These results suggest that running dosage (mileage) is a significant risk factor for upper respiratory tract infections in this group of exercisers.

Adolescent↗
PubMed1990

Associations between physical activity and physical fitness in American children.

Associations between two measures of physical fitness, 1.6-km run/walk performance and sum of three skinfold thicknesses, and selected physical activity factors were studied in a nationally representative sample of third- and fourth-grade students (1150 boys, 1202 girls). Twenty physical activity variables measured via parent and teacher questionnaires were factor analyzed, and for each of the resultant eight factors, individual factor scores were generated. These were used in two multiple regression analyses in which 1.6-km run/walk time and sum of skinfold measurements were the dependent variables. Multiple R2 for these two analyses were .21 and .18. Significant factors in both analyses were global ratings of the child's activity level, age, vigorous community activities, and gender. The results indicate that physical activity and physical fitness are significantly, although moderately, associated in young children and suggest that interventions directed toward enhancement of physical activity in children are worthy of investigation.

Child↗
PubMed1990

Dietary intake of women runners.

One hundred and three women who were habitual distance runners and 74 age-matched physically inactive women provided three-day diet records. Intergroup differences in intakes of energy nutrients, micronutrients, cholesterol and fiber were evaluated via analysis of variance and, to assess qualitative differences, via analysis of covariance with total caloric intake entered as the covariate. Women runners reported consuming more carbohydrate (192.4 vs 165.0 g.d-1) and less fat (57.5 vs 66.1 g.d-1) than did the inactive women (p less than .05). After controlling for the non-significant intergroup difference in caloric intake, these differences persisted and protein intake was lower in the runners. Cholesterol and saturated fat intakes were lower and fiber intake was greater in the runners, with and without control for differences in caloric intake. These data suggest that female runners, when compared to inactive counterparts, tend to follow dietary practices that conform more closely to the current recommendations of health authorities.

Adult↗
PubMed1990

Glucose feedings and exercise in rats: glycogen use, hormone responses, and performance.

This study compared the effects of glucose feeding and water on endurance performance, glycogen utilization, and endocrine responses to exhaustive running in rats. Forty-eight trained rats ran at approximately 70% peak O2 consumption (VO2) while receiving, via gavage, 1 ml of an 18% glucose solution or water every 30 min. Glucose- (GF) and water-fed rats (WF) were pair matched and killed at rest, at 25 or 50% of their previously determined run time to exhaustion, or at exhaustion. Run times to exhaustion were 4.6 +/- 1.0 and 3.0 +/- 0.9 h in GF and WF rats, respectively. In WF rats, plasma glucose declined continuously from a resting value of 7.4 +/- 0.5 to 1.8 +/- 0.5 mM at exhaustion and was lower than in GF rats at all exercise time points. In GF rats, glucose was maintained at 7.4 +/- 0.5 mM for 3 h before dropping to 3.9 +/- 0.6 mM at exhaustion. In both groups, liver and muscle glycogen decreased dramatically during the 1st h and changed only slightly thereafter. During the 3rd h, glycogen levels were maintained in GF rats but continued to decrease in WF rats (P less than 0.05). Insulin decreased during exercise and was not significantly different between groups. Glucagon, epinephrine, norepinephrine, and corticosterone increased to a greater extent in WF than in GF rats during the first 3 h of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Menstrual dysfunction among habitual runners.

The association of menstrual dysfunction and weekly running mileage was investigated in a group of habitual women runners, categorized into high mileage runners (30 or more miles/week) and low mileage runners. Both mileage groups reported menstrual changes and weight loss since starting to run. Menstrual irregularities (35 or more days between cycles) were reported more often among the high mileage women than among the low mileage women (p = 0.001). However, after controlling for cycle irregularity before starting a running program, the effect of mileage was no longer statistically significant. While these results suggest that pre-running menstrual irregularity is more important than higher doses of weekly mileage, further investigations are needed to assess the role of potentially confounding factors such as stress, diet, and other lifestyle changes that may occur with increased exercise.

Adult↗
PubMed1989

Predicting lower-extremity injuries among habitual runners.

This prospective study of 583 habitual runners used baseline information to examine the relationship of several suspected risk factors to the occurrence of running-related injuries of the lower extremities that were severe enough to affect running habits, cause a visit to a health professional, or require use of medication. During the 12-month follow-up period, 252 men (52%) and 48 women (49%) reported at least one such injury. The multiple logistic regression results identified that running 64.0 km (40 miles) or more per week was the most important predictor of injury for men during the follow-up period (odds ratio = 2.9). Risk also was associated with having had a previous injury in the past year (odds ratio = 2.7) and with having been a runner for less than 3 years (odds ratio = 2.2). These results suggest that the incidence of lower-extremity injuries is high for habitual runners, and that for those new to running or those who have been previously injured, reducing weekly distance is a reasonable preventive behavior.

Adolescent↗
PubMed1988

Effects of ingesting 6% and 12% glucose/electrolyte beverages during prolonged intermittent cycling in the heat.

This study compared the effects of ingesting 6% (MC) and 12% (HC) glucose/electrolyte beverages, and a flavored water placebo (P) on markers of fluid absorption, palatability, and physiological function during prolonged intermittent cycling in the heat. On three occasions, 15 trained male cyclists performed two 60 min cycling bouts at 65% VO2max (E1 and E2). A brief exhaustive performance ride (approximately 3 min) was completed after E1 and E2, and after 20 min recovery (P1, P2, P3). Every 20 min, subjects consumed 275 mL of P, MC or HC. The first drink contained 20 mL of D2O, a tracer of fluid entry into blood plasma. Plasma D2O accumulation was slower for HC than for P and MC (P less than 0.001). HC caused more nausea (P less than 0.01) and fullness (P less than 0.05) than MC or P, and subjects said they would be less likely to consume HC during training or competition (P less than 0.10). Sweat rates, HR, Tre, Tsk, VO2, and PV were similar for all drinks. Performance of P1, P2, P3 were not different among drinks. However, four cyclists failed to maintain the prescribed work rate during E2 for HC but only one failed for MC and P. These data suggest that the slow absorption of a 12% glucose/electrolyte beverage during prolonged intermittent exercise in the heat may increase the risk of gastrointestinal distress and thereby limit performance.

Adult↗
PubMed1988

The use of proportional hazards regression in investigating dropout rates in a longitudinal study.

One difficulty with the interpretation of data from longitudinal studies is the bias associated with those who do not complete the study. In a 12-month study on the occurrence of musculoskeletal problems in 966 runners (583 of whom completed the study), a proportional hazards model with time-dependent covariates was used to assess factors associated with dropout at the various stages of the study. This approach allowed examination of baseline factors as well as the effect of change in mileage, the occurrence of a musculoskeletal problem, or the occurrence of another health problem on the rate of dropout. Those most likely to drop out of the study were younger and heavier at baseline and, prior to drop out, were less likely to experience general health problems and more likely to show a 40% decline in weekly running mileage in the month before dropout. Examination of factors associated with dropout is important since factors influencing dropout may also affect the study outcome for the risk factor analysis (a musculoskeletal problem severe enough to be seen by a physician). The results of the dropout analysis can be used to guide in the choice of analytic methods and to aid in the interpretation of the risk factor analyses.

Adult↗
PubMed1988

Foot impact force and intravascular hemolysis during distance running.

This study was designed to examine the relationship between foot impact force and the magnitudes of the changes in markers of intravascular hemolysis during distance running. Fourteen male distance runners (VO2 max = 66.1 +/- 5.0 ml.kg-1.min-1, mean +/- SD) completed two treadmill runs and a resting control procedure. The two treadmill tests involved running at 215 m.min-1 for 10,000 footstrikes at elevations of either +6% (uphill) or -6% (downhill). Mean foot impact force was 11% greater with the downhill than the uphill running. The three procedures were ordered randomly and separated by 7 days. Hemoglobin concentration (Hb), hematocrit (Hct), plasma free hemoglobin (PFHb), and haptoglobin (Hp) concentrations were assayed in blood samples collected via venipuncture 15 min and immediately before exercise, and immediately, 1 h, and 2 h after the exercise. Repeated measures ANOVA revealed that Hp was significantly decreased and PFHb was significantly increased after treadmill running (P less than 0.05) and that these changes were significantly greater with downhill than uphill running (P less than 0.05). These findings support the theory that mechanical trauma to red blood cells occurring at footstrike is a major cause of hemolysis during running.

Adult↗
PubMed1988

Prescribing physical activity to prevent disease.

Despite an increase in the public's awareness of the ample health benefits of physical activity, less than 20% of US adults regularly participate in moderate to vigorous physical activity. For most adults, increasing physical activity even moderately is likely to benefit health. Physicians can prescribe physical activity and incorporate an emphasis on physical activity into clinical practice.

Adult↗
PubMed1988

Carbohydrate-electrolyte drinks: effects on endurance cycling in the heat.

On three occasions cyclists completed, as fast as possible, two exercise tasks (T1 and T2) separated by 30 min rest. T1 and T2 were equivalent to the work performed during 2 h cycling at 75% VO2max and 30 min at 75% VO2max, respectively. Every 20 min subjects drank 275 mL of a 6% (MC) or 2.5% (LC) carbohydrate-electrolyte beverage or a water placebo (P). The initial drink during both T1 and the rest period contained 20 g D2O as a marker for entry of ingested fluid into blood. No differences in drink effects were found for heart rate, sweat rate, change in plasma volume, rectal temperature, or D2O accumulation in blood. Blood glucose and respiratory exchange ratios were higher and T2 was performed faster with MC than with P. Ingestion of MC can help maintain blood glucose and enhance performance of prolonged cycling exercise without compromising fluid replenishment.

Adolescent↗