Treadmill Performance Time Research Articles

Grape Consumption’s Effects on Fitness, Muscle Injury, Mood, and Perceived Health

Compounds found in the skins of grapes, including catechins, quercetin, and resveratrol, have been added to the diet of rodents and improved run time to exhaustion, fitness, and skeletal-muscle mitochondrial function. It is unknown if such effects occur in humans. The purpose of this experiment was to investigate whether 6 wk of daily grape consumption influenced maximal oxygen uptake (VO(2max)), work capacity, mood, perceived health status, inflammation, pain, and arm-function responses to a mild eccentric-exercise-induced arm-muscle injury. Forty recreationally active young adults were randomly assigned to consume a grape or placebo drink for 45 consecutive days. Before and after 42 d of supplementation, assessments were made of treadmill-running VO(2max), work capacity (treadmill performance time), mood (Profile of Mood States), and perceived health status (SF-36 Health Survey). The day after posttreatment treadmill tests were completed, 18 high-intensity eccentric actions of the nondominant elbow flexors were performed. Arm-muscle inflammation, pain, and function (isometric strength and range of motion) were measured before and on 2 consecutive days after the eccentric exercise. Mixed-model ANOVA showed no significant effect of grape consumption on any of the outcomes. Six weeks of supplemental grape consumption by recreationally active young adults has no effect on VO(2max), work capacity, mood, perceived health status, inflammation, pain, or physical-function responses to a mild injury induced by eccentric exercise.

Comparative effects of selected non-caffeinated rehydration sports drinks on short-term performance following moderate dehydration.

BackgroundThe effect of moderate dehydration and consequent fluid replenishment on short-duration maximal treadmill performance was studied in eight healthy, fit (VO2max = 49.7 ± 8.7 mL kg-1 min-1) males aged 28 ± 7.5 yrs.MethodsThe study involved a within subject, blinded, crossover, placebo design. Initially, all subjects performed a baseline exercise test using an individualized treadmill protocol structured to induce exhaustion in 7 to 10 min. On each of the three subsequent testing days, the subjects exercised at 70-75% VO2max for 60 min at 29-33°C, resulting in a dehydration weight loss of 1.8-2.1% body weight. After 60 min of rest and recovery at 22 C, subjects performed the same treadmill test to voluntary exhaustion, which resulted in a small reduction in VO2max and a decline in treadmill performance by 3% relative to the baseline results. Following another 60 min rest and recovery, subjects ingested the same amount of fluid lost in the form of one of three lemon-flavored, randomly assigned commercial drinks, namely Crystal Light (placebo control), Gatorade® and Rehydrate Electrolyte Replacement Drink, and then repeated the treadmill test to voluntary exhaustion.ResultsVO2max returned to baseline levels with Rehydrate, while there was only a slight improvement with Gatorade and Crystal Light. There were no changes in heart rate or ventilation with all three different replacement drinks. Relative to the dehydrated state, a 6.5% decrease in treadmill performance time occurred with Crystal Light, while replenishment with Gatorade, which contains fructose, glucose, sodium and potassium, resulted in a 2.1% decrease. In contrast, treatment with Rehydrate, which comprises fructose, glucose polymer, calcium, magnesium, sodium, potassium, amino acids, thiols and vitamins, resulted in a 7.3% increase in treadmill time relative to that of the dehydrated state.ConclusionsThe results indicate that constituents other than water, simple transportable monosaccharides and sodium are important for maximal exercise performance and effective recovery associated with endurance exercise-induced dehydration.

The Effects of Respiratory-Muscle Training on Exercise in Older Women

This research examined the effects of respiratory-muscle (RM) training on RM function and exercise performance in older women. Twenty-six women (60-69 yr of age) were assessed for spirometry, RM strength (maximal inspiratory and expiratory pressure), inspiratory-muscle endurance, and walking performance to a perceived exertion rating of "hard." They were randomly allocated to a threshold RM training group (RMT) or a nonexercising control group (CON) for 8 wk.After training, the 22% (inspiratory) and 30% (expiratory) improvements in RM strength in the RMT group were significantly higher than in the CON group (p < .05). The RMT group also displayed several significant performance improvements, including improved within-group treadmill performance time (12%) and reductions in submaximal heart rate (5%), percentage of maximum voluntary ventilation (16%), and perceived exertion for breathing (8%). RM training appears to improve RM function in older women. Furthermore, these improvements appear to be related to improved submaximal exercise performance.

Frequency of Verbal Encouragement Effects Sub-Maximal Exertional Perceptions During Exercise Testing in Young Adult Women

0915 PURPOSE: The purpose of this investigation was to determine the effect of frequency of verbal encouragement on ratings of perceived exertion (RPE) at sub-maximal exercise test intensities in young (18 to 21 year old) healthy females. METHODS: Thirty-six healthy females were randomly assigned to either a control group (no verbal encouragement), a 20 second encouragement group (verbal encouragement every 20s) or a 60 second encouragement group (verbal encouragement every 60s). All subjects completed two maximal exercise tests, a baseline test (without verbal encouragement) and an experimental test, using the Bruce treadmill protocol. Subjects were oriented to the OMNI-Walk/Run Scale which was used to assess RPE during the last 20 seconds of each exercise stage. RESULTS: Groups did not differ in age, body composition or baseline maximal aerobic power. Sub-maximal RPE-Overall was significantly lower for the 20 second encouragement group during stages II and III than baseline response (2.2 ± .75 vs. 3.5 ± 1.24, P < 0.01; 4.6 ± 1.0 vs. 6.1 ± 1.37, P < 0.01, respectively). Sub-maximal RPE-Overall responses were also significantly lower for the 60 second encouragement group during stage II and stage III than the baseline condition (2.25 ± .86 vs. 3.4 ± 1.0, P < 0.01; 5.0 ± 1.13 vs. 6.2 ± 1.33, P < 0.05, respectively). Submaximal RPE-Leg responses were significantly lower for the 20 second encouragement group during stages II and III than baseline response (2.3 ± 1.07 vs. 3.5 ± 1.16, P < 0.05; 4.6 ± 1.37 vs. 6.1 ± 1.6, P < 0.05, respectively). In addition, verbal encouragement every 60 seconds resulted in a significantly lower RPE-Legs response during stage II than in the baseline condition (2.3 ± .77 vs. 3.5 ± 1.0, P < 0.01). No between group differences were observed for any sub-maximal VO2 and HR response. There were no between or within group differences in maximal oxygen consumption and treadmill performance time. CONCLUSIONS: The findings suggest that the mechanisms underlying the psychological impact of verbal encouragement during sub-maximal exercise are complex but may include a dampening of unpleasant stimuli as they travel to the sensory cortex for coding and ultimately conscious expression as an exertional estimate.

PREDICTION OF PERFORMANCE TIME ON A TREADMILL STRESS TEST FOLLOWING A BRUCE PROTOCOL

Graded exercise stress testing is a widely used procedure for the diagnosis of coronary artery disease. To reduce variability in test results, American Heart Association guidelines state that an optimum treadmill test time should be six to twelve minutes following an acceptable protocol. Thus, we asked if screening tools could be developed to determine if a patient would reach the six minute threshold. PURPOSE: To determine if treadmill performance time following a Bruce protocol could be predicted from a self-reporting questionnaire and resting physiological variables. METHODS: Prior to undergoing a treadmill stress test using the Bruce protocol, 108 patients (64 males, 57 ± 12 yr and 44 females, 57 ± 13 yr) completed a physical work capacity questionnaire, and had heart rate, blood pressure, grip strength, heart rate after 5 sec hand-grip, and time for heart rate to return to baseline after 5 sec hand-grip measured. A stepwise regression analysis was used to develop prediction equations for treadmill time. RESULTS: Separate prediction equations were developed for males and females. For males, predicted time (sec) = 640.842–6.945(age) + 32.473(highest self-reported MET level). For females, predicted time (sec) = 275.474 + 33.451 (highest self-reported MET level)–4.934(SBP) + 7.164(DBP). Of the 108 patients, 52 males and 33 females had actual treadmill test times of six min or more. The prediction equations predicted that 59 males and 35 females would exceed the six min threshold. Thus, the accuracy rate of prediction was 88% for males and 94% for females. CONCLUSION: These results suggest that a self-reporting questionnaire and resting physiological data can be used as screening tools to identify with reasonable accuracy those patients who can meet or exceed a six min stress test performance time.

Skeletal muscle function and water permeability in aquaporin-4 deficient mice.

It has been proposed that aquaporin-4 (AQP4), a water channel expressed at the plasmalemma of skeletal muscle cells, is important in normal muscle physiology and in the pathophysiology of Duchenne's muscular dystrophy. To test this hypothesis, muscle water permeability and function were compared in wild-type and AQP4 knockout mice. Immunofluorescence and freeze-fracture electron microscopy showed AQP4 protein expression in plasmalemma of fast-twitch skeletal muscle fibers of wild-type mice. Osmotic water permeability was measured in microdissected muscle fibers from the extensor digitorum longus (EDL) and fractionated membrane vesicles from EDL homogenates. With the use of spatial-filtering microscopy to measure osmotically induced volume changes in EDL fibers, half times (t(1/2)) for osmotic equilibration (7.5-8.5 s) were not affected by AQP4 deletion. Stopped-flow light-scattering measurements of osmotically induced volume changes in plasmalemma vesicles also showed no significant differences in water permeability. Similar water permeability, yet approximately 90% decreased AQP4 protein expression was found in EDL from mdx mice that lack dystrophin. Skeletal muscle function was measured by force generation in isolated EDL, treadmill performance time, and in vivo muscle swelling in response to water intoxication. No differences were found in EDL force generation after electrical stimulation [42 +/- 2 (wild-type) vs. 41 +/- 2 (knockout) g/s], treadmill performance time (22 vs. 26 min; 29 m/min, 13 degrees incline), or muscle swelling (2.8 vs. 2.9% increased water content at 90 min after intraperitoneal water infusion). Together these results provide evidence against a significant role of AQP4 in skeletal muscle physiology in mice.

Physical Fitness Is Inversely Related to Heart Disease Risk: A Factor Analytic Study

We measured cardiorespiratory endurance, muscular strength and endurance, anaerobic run time, coronary risk factors, and dietary habits in male fire fighters (n = 779, ages 18 to 64 years) and performed factor analysis to determine the interrelationships and underlying factor structure of the data set. Principal component analysis produced nine factors (eigenvalues greater than 1.0) accounting for 61% of the total variance. However, the variable loadings were inconsistent, preventing a meaningful interpretation of the factor solution. These problems were solved through the principal axis method of common factor analysis, which revealed three factors (eigenvalues greater than 1.0) accounting for 29% of the total variance. Orthogonal rotation (varimax method), showed Factors 1, 2, and 3 accounting for 52%, 29%, and 19%, respectively, of the common variance. Factor 1, labeled physical fitness capacity (PFC), included age, situps, treadmill performance time, pushups, maximum exercise heart rate, and anaerobic run time. Factor 2, designated coronary risk status (CRS), included body mass index, resting systolic and diastolic blood pressure, triglycerides, and the total cholesterol-high density lipoprotein cholesterol ratio. Factor 3, termed food frequency intake (FFI), included the weekly intake of fried foods, beef, pork, eggs, caffeine, and cheese. Percentage body fat loaded on both PFC and CRS. Measures such as blood pressure, grip strength, resting heart rate, maximum exercise systolic blood pressure, cigarettes smoked per day, and weekly frequency of milk, fish, fowl, and alcohol intake contributed little to the factor solution. Correlation coefficients after oblique rotation showed PFC to be inversely related to CRS (r = -0.48). However, FFI was independent of PFC (r = 0.07) and CRS (r = -0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise time relationship to coronary risk factors in Kuwaiti adult males 1985-1986.

Two hundred and sixty-nine apparently healthy Kuwaiti men, aged 20-49, from 800 randomly selected Kuwaiti families, were examined for cardiovascular fitness and risk factors for coronary heart diseases (CHD). The risk factors were examined by exercise stress test on Quinton-2000 ECG monitor and treadmill Q-model 24-26, Bruce protocol, along with Ergo-oxyscreen, by laboratory tests of fasting blood lipid levels, and by interview using a questionnaire. The sample was stratified into three age groups, 20-29, 30-39, and 40-49. For the entire sample, the results showed that a number of the investigated factors were significantly correlated with the duration of treadmill exercise time. Univariate analysis indicated that performance was inversely correlated with age, cholesterol levels, cholesterol:HDL ratio, triglycerides and uric acid, weight, body-build indexes, body density, resting heart rate, blood pressure (BP), personal history of CHD, and smoking habits. Most of the observed significant correlations were particularly pronounced in the younger age groups, 20-39 years. In this group, significant results in the analysis of variance were found between the treadmill performance time and a number of risk factors, including: cholesterol levels, age, cholesterol:HDL ratios, triglycerides, uric acid, heart rate, elevated systolic blood pressure, and obesity.

Adherence to Unsupervised Exercise.

In brief: Forty-seven male police officers (mean age 41.0 years) were randomly assigned to three exercise groups: unsupervised, supervised, and control. Training consisted of walking and jogging three days per week for 20 weeks. The attrition rate for the unsupervised group (35%) was lower than for the supervised group (45%). The main reason the subjects gave for dropping out was lack of time. Both groups increased significantly compared to the control group in treadmill performance time, maximum oxygen uptake, and maximum oxygen pulse; and decreased significantly in resting heart rate, heart rate response to a step test, percent body fat, total skinfold fat, and waist girth.

Effect of induced erythrocythemia on hypoxia tolerance during physical exercise.

The effect of induced erythrocythemia on hypoxia tolerance during physical exercise was determined for five male mountain climbers. Treadmill testing was performed under four conditions: 1) prereinfusion, normoxia (Pre-N); 2) prereinfusion, hypoxia (Pre-H); 3) postreinfusion, normoxia (Post-N); and 4) postreinfusion, hypoxia (Post-H). An altitude of 3,566.2 m was simulated by having subjects breath a gas mixture of 13.5% O2-86.5% N2 at normal barometric pressure. Tests were administered immediately before and 24 h after autologous transfusion of 750 ml of red blood cells. Hematocrit increased from 43.3% at prereinfusion to 54.8% at postreinfusion. Hemoglobin concentration increased from 13.80 g X 100 ml-1 at prereinfusion to 17.63 g X 100 ml-1 at postreinfusion. Maximal O2 uptake (VO2 max, 1 X min-1) increased (P less than 0.05) by 12.8% (3.28 to 3.70) from Pre-N to Post-N and 13.0% (2.62 to 2.96) from Pre-H to Post-H. Treadmill performance time (s) increased (P less than 0.05) by 15.8% (793 to 918) from Pre-N to Post-N and 8.9% (687 to 748) from Pre-H to Post-H. VO2 max decreased by 20.1% from Pre-N to Pre-H and by 9.8% from Pre-N to Post-H. Treadmill time decreased by 13.4% from Pre-N to Pre-H and 5.7% from Pre-N to Post-H. The calculated change in hypoxia tolerance following reinfusion indicated that physiological altitude was improved by 463.6 m. It was concluded that induced erythrocythemia increased hypoxia tolerance during physical exercise.

Physiological Responses of Men to 1, 3, and 5 Day per Week Training Programs

Abstract The purpose of this study was to examine the physiological responses of county jail inmates to running programs of 1-day, 3-day, and 5-day/week frequencies. Fifty-five volunteer male inmates, age 20 to 35 years, were evaluated on the following variables: resting heart rate and blood pressure; treadmill performance time; maximum oxygen intake ([Vdot]O2 max) and related metabolic measures; lung volumes; body composition; and serum lipids. Subjects were assigned randomly into a control, 1-day, 3-day, or 5-day/week conditioning group. The training were 30 min/session and were conducted at approximately 85 to 90% maximum heart rate for 20 weeks. Results indicated no significant changes in the four groups for resting and recovery blood pressures, maximum heart rates, spirometry measures, body weight, and serum lipids. Significant improvements occurred in direct proportion to frequency of training in resting and recovery heart rates, treadmill performance time, [Vdot]O2 max, max O2 pulse, and [Vdot]E ma...

Effects of Different Durations of Physical Training on Cardiorespiratory Function, Body Composition, and Serum Lipids

Abstract The purpose of the study was to determine the effects of 15, 30, and 45 min of conditioning on maximum performance and cardiorespiratory fitness variables, body composition, pulmonary function, and serum lipids. Subjects, ages 20 to 35, were 59 inmates at a California state prison. The conditioning included running and walking and was performed three days/week at approximately 85 to 90% max HR for 20 weeks. The distance covered per exercise session was approximately 1.75, 3.25, and 5.1 miles for the 15-, 30-, and 45-min groups, respectively. Improvements in treadmill performance time. [Vdot]O2 max, max O2 pulse, diastolic blood pressure, and total skinfold fat were proportional to duration of the training session; i.e., the subjects training in the longer duration sessions showed the greater improvements. The control group showed no significant change during the same period. Compared to the control group, the 15-min group made significant reductions in resting HR, total skinfold fat, percent fat,...

Effects of Breathing High Concentrations of Oxygen on Treadmill Performance

Abstract The effects of breathing high concentrations of oxygen on treadmill performance time, the exercise and postexercise pulse, and the relationship between excess lactic acid and oxygen debt were studied. The breathing of oxygen during the maximal performance test improved the performance time of each test. Oxygen debt was significantly reduced for the first minute of recovery after breathing oxygen during the test. The excess lactic acid was reduced after the first minute of recovery and was found to peak during the third minute of recovery. A linear relationship was observed between excess lactic acid and oxygen debt while breathing air or oxygen during the test.

RELATIONSHIP BETWEEN OBESITY AND TREADMILL PERFORMANCE IN SEDENTARY AND ACTIVE YOUNG MEN.

Abstract Thirty-four healthy but inactive young men were subjected to measures of: gross body weight, relative body weight, height, percent body fat, fat-free body weight, and the Balke test of treadmill performance. A multiple regression analysis of the data indicated that 52.21 percent of the total interpersonal variance in treadmill performance time of the inactive group under study was accounted for by the five anthropometrical variables. Body fat (38.87 percent), fat-free body weight (9.72 percent), and relative body weight (1.72 percent) each accounted for a significant portion of the total variance. A decline in these relationships observed with seven subjects undergoing training indicated that treadmill performance time had improved somewhat independently of changes in body composition or body mass. The interdependence of anatomical and physiological variables as determinants of submaximal cardiovascular performance was discussed.

Effect of Blood Loss upon Performance in the Balke-Ware Treadmill Test

Abstract Two groups of six subjects were equated on the Balke-Ware Test. One group gave 500 cc of blood, the other group did not but believed it had. The treadmill test was repeated (a) immediately following, (b) 24 hr. after, and (c) seven days after the donation or supposed donation. There were no statistically significant changes in treadmill performance time. Recovery measures were difficult to interpret because of variability in work capacity from trial to trial.