Biomedical subjects

Edward C Chaloupka

Publications and source records attributed to Edward C Chaloupka.

6 recordsLinked to original sources

PubMed2005

Metabolic and perceptual responses during Spinning cycle exercise.

PURPOSE: The present investigation was undertaken to compare metabolic and perceptual responses between exercise performed at constant intensity (CON) and with a Spinning protocol of variable intensity (VAR). METHOD: Fifteen subjects, including seven males and eight females (23 +/- 5 yr, 72 +/- 17 kg, and 171 +/- 10 cm), underwent two experimental trials. During each trial, subjects performed a 30-min cycle exercise protocol that was followed by a 30-min recovery period. Exercise was performed at 67 +/- 3% (means +/- SD) of HR(max) in CON. In VAR, the similar intensity (68 +/- 4% HR(max)) was also achieved, although the protocol entailed alternating phases of both higher and lower intensity arranged similarly to what is designed for a typical Spinning workout. Oxygen uptake (VO2) and HR were measured at rest and throughout both exercise and recovery, whereas RPE were recorded during exercise only. Plasma lactate concentrations [La] were determined at rest, the end of exercise, and the end of recovery. RESULTS: No differences in average VO2, HR, and RPE were found during exercise between CON and VAR. However, average VO2 and HR were higher (P < 0.05) in VAR than CON (0.33 +/- 0.03 vs 0.26 +/- 0.02 L x min(-1) and 91 +/- 3 vs 80 +/- 2 beats x min(-1), respectively). [La] was higher (P < 0.05) at the end of exercise in VAR than CON (7.2 +/- 0.8 vs 2.7 +/- 0.3 mmol x L(-1)), but became similar at the end of recovery. CONCLUSION: An exercise regimen in which intensity varies exerts no added effect on metabolic and perceptual responses during exercise as long as the average intensity is kept the same. However, VAR resulted in a greater [latin capital V with dot above]O2 after exercise, and this augmented postexercise oxygen consumption may be mediated in part by elevated plasma [La].

Adult↗

PubMed2004

Predicting anaerobic capabilities in 11-13-year-old boys.

Anaerobic exercise is involved in many recreational and competitive sport activities. This study first established regression equations to predict maximal anaerobic power and then cross-validated these prediction equations. Using stepwise multiple regression analysis prediction equations for relative (watts per kilogram of body mass) and absolute (watts) mean and peak anaerobic power using the 30-second Wingate Test as the power measure were determined for 40 boys (age, 11-13 years). Percentage of body fat, free-fat weight, midthigh circumference, and 30-m dash were the independent predictive variables with the generated regression equations subsequently cross-validated using 20 different boys (age, 11-13 years). Significant correlations (Pearson r) were found for the cross-validation subjects between the measured power outputs and predicted power outputs for relative mean power (r = 0.48, p < 0.05), absolute mean power (r = 0.77, p < 0.01), and absolute peak power (r = 0.76, p < 0.01). Using paired t-tests, no significant mean differences (p > 0.05) were found for the same subjects between actual and predicted power outputs for relative mean power, absolute mean power, and absolute peak power. Prediction of maximal anaerobic power from selected anthropometric measurements and 30-m dash appears tenable in 11-13-year-old boys and can be accomplished in a simple cost- and time-effective manner.

Adolescent↗

PubMed2003

Regulating intensity using perceived exertion during extended exercise periods.

The present study was undertaken to examine the validity of using the OMNI scale of perceived exertion to regulate intensity during extended exercise periods. Forty-eight subjects (24 male, 24 female) were recruited and each subject completed a maximal graded exercise test (GXT) and two 20-min submaximal exercises. During the GXT, ratings of perceived exertion (RPE) as well as oxygen uptake (VO(2)) and heart rate (HR) equivalent to 50 and 70% of maximum VO(2) (VO(2max)) were estimated. During each submaximal exercise, subjects were instructed to produce and maintain a workload equivalent to the RPE estimated at 50 or 70% VO(2max), and VO(2) and HR were measured every 5 min throughout the exercise. Of the 48 subjects, 12 (6 male and 6 female) performed both the estimation and production trials on a treadmill (TM/TM), 12 (6 male and 6 female) performed both the estimation and production trials on a cycle ergometer (C/C), 12 (6 male and 6 female) performed the estimation trial on a treadmill and the production trial on a cycle ergometer (TM/C), and 12 (6 male and 6 female) performed the estimation trial on a cycle ergometer and the production trial on a treadmill (C/TM). No differences in VO(2) between the estimation and any 5 min of the production trial were observed at either intensity in TM/TM and C/C. No differences in HR between the estimation and any 5 min of the production trial were also observed at 50% VO(2max) in TM/TM and at both 50 and 70% VO(2max) in C/C. However, HR was higher at 20th min of the production trial at 70% VO(2max) in TM/TM. Both the VO(2) and HR were generally lower in TM/C and higher in C/TM. However, these differences diminished when values were normalized using VO(2max) of the same mode that other groups had attained. These data suggest that under both intra- and intermodal conditions, using the OMNI perceived exertion scale is effective not only in establishing the target intensity at the onset of exercise, but also in maintaining the intensity throughout a 20-min exercise session.

Adaptation, Physiological↗

PubMed2002

Physiological and biomechanical analysis of treadmill walking up various gradients in men and women.

This investigation was undertaken to examine the physiological and biomechanical responses during treadmill walking up various gradients in men and women. Groups of 11 men and 11 women took part in four experiments consisting of 8 min treadmill walks at 1.3 m.(-1) up gradients of 0%, 5%, 10% and 15%. The subjects also underwent an anthropometric assessment during which their height, body mass (BM), percentage (%) body fat, lean body mass (LBM), and waist-to-hip ratio (WHR) were obtained. During exercise, each subject was videotaped during three walking cycles so that sagittal kinematics including stride length (SL) and frequency (SF) and ranges of motion achieved at the shoulder, hip and knee during a walking cycle could be determined using a motion analysis system. The motion capture was followed by a measurement of steady-state oxygen uptake (VO(2)) and heart rate (HR) using indirect calorimetry and a HR monitor. Compared to men, women were higher in % body fat, but lower in height, BM, LBM, and WHR. The VO(2) in millilitres per kilogram per minute and HR were similar between men and women at 0% and 5%, but greater in women than men at 10% and 15%. The SL and SF were greater and smaller, respectively, in men than women up all gradients. Shoulder extension was greater up gradients of 10% and 15% in women than men, whereas no sex difference in shoulder flexion was noted. Hip extension and flexion as well as knee flexion remained the same between men and women up all gradients. An inverse relationship was observed between VO(2) in millilitres per kilogram per minute and BM, LBM, and WHR when men and women were combined. In conclusion, the mass-specific metabolic cost of treadmill walking up high gradients is greater in women than men. Such an increase in relative metabolic cost may be attributable to the fact that women are smaller in size, and/or have relatively more BM distributed peripherally. This sex difference may also be due to a greater movement of the upper limbs in women during walking uphill, although direct evidence is needed to support this contention.

Adult↗

PubMed2002

Effect of carbohydrate ingestion on ratings of perceived exertion during a marathon.

PURPOSE: The purpose of this study was to investigate the effects of carbohydrate substrate availability on ratings of perceived exertion (RPE) and hormonal regulation during a competitive marathon. METHODS: A randomized, double-blind study design was used in which subjects ran the marathon, and every 3.2 km, RPE and heart rate were measured. The marathoners were randomly assigned to receive carbohydrate (C) (N = 48) or placebo (P) (N = 50) beverages at a rate of 1 L x h(-1) during the race. RESULTS: Heart rate (%(HRMAX) ) was lower in P (82.0% +/- 0.6) than C (84.2% +/- 0.6) (P < 0.01), especially during the final 10 km: (78.7% +/- 1.0) and (84.5% +/- 0.7), respectively (P < 0.001). RPE was not significantly different between P and C throughout the marathon (P = 0.08) or during the final 10 km: (16.8 +/- 0.3) and (16.1 +/- 0.3), respectively (P = 0.06). Postrace plasma glucose (P < 0.001), insulin (P < 0.001), and lactate (P < 0.05) levels were significantly lower in P than C, and postrace cortisol (P < 0.05) significantly higher in P compared with C. CONCLUSIONS: Marathoners ingesting carbohydrate compared with placebo beverages were able to run at a higher intensity while reporting a nonsignificant difference in RPEs during a competitive race.

Adult↗

PubMed2002

The effect of flexible magnets on hand muscle strength: a randomized, double-blind study.

The purpose of this study was to determine the effect of a flexible magnet on hand grip and thumb-forefinger pinch strength. Flexible magnet use has become popular in sports medicine and rehabilitation for a number of reasons, including augmenting muscle force output. Thirty-five university students (18 men and 17 women) volunteered for this study. Each subject was tested for grip strength (grip dynamometer) and thumb-forefinger pinch strength (pinch gauge) under 3 different treatment conditions: baseline (no magnet), sham magnet (placebo), and flexible magnet (700-G intensity). The order of treatments was randomly assigned, and all data collection followed a double-blind format. For grip strength measurements, magnet placement was over the bellies of the flexor digitorum profundus and flexor digitorum superficialis, and for pinch strength measurements, it was over the bellies of the flexor pollicis brevis and opponens pollicis. Three trials for each strength measurement for each of the 3 conditions were performed. Magnets (700 G or sham) were placed on the appropriate areas of the skin 3 minutes before the first test trial, with each subsequent test trial separated by 1 minute. Comparison among the 3 treatment conditions was analyzed using a 1-way analysis of variance (ANOVA) with repeated measures. ANOVA revealed no statistically significant (p > 0.05) mean differences for strength among any of the 3 treatments (baseline, 700-G magnet, or sham magnet) for either hand grip or thumb-forefinger pinch within each sex subgroup or for the combined group. The findings indicate that flexible magnets with a field strength of 700 G do not increase muscle strength.

Adult↗