The impact of intermittent exercise in a hypoxic environment on redox status and cardiac troponin release in the serum of well-trained marathon runners.

Purpose: To investigate the effects of hypoxic training on redox status and cardiac troponin (cTn) release after intermittent exercise.

Method: Nine well-trained male marathon runners (age, 21.7 ± 2.

Chronic and acute inspiratory muscle loading augment the effect of a 6-week interval program on tolerance of high-intensity intermittent bouts of running.

This study examined the hypothesis that chronic (training) and acute (warm-up) loaded ventilatory activities applied to the inspiratory muscles (IM) in an integrated manner would augment the training volume of an interval running program. This in turn would result in additional improvement in the maximum performance of the Yo-Yo intermittent recovery test in comparison with interval training alone. Eighteen male nonprofessional athletes were allocated to either an inspiratory muscle loading (IML) group or control group.

Effects of 14-week Tai Ji Quan exercise on metabolic control in women with type 2 diabetes.

The present study investigated the effects of 14 weeks of practicing Tai Ji Quan (TJQ) on metabolic control and lipid metabolism in women with type 2 diabetes. Twenty Beijing female residents (57.4 +/- 6.

The effect of inspiratory muscle training on high-intensity, intermittent running performance to exhaustion.

The effects of inspiratory muscle (IM) training on maximal 20 m shuttle run performance (Ex) during Yo-Yo intermittent recovery test and on the physiological and perceptual responses to the running test were examined. Thirty men were randomly allocated to 1 of 3 groups. The experimental group underwent a 6 week pressure threshold IM training program by performing 30 inspiratory efforts twice daily, 6 d/week, against a load equivalent to 50% maximal static inspiratory pressure.

Effect of specific inspiratory muscle warm-up on intense intermittent run to exhaustion.

The effects of inspiratory muscle (IM) warm-up on the maximum dynamic IM function and the maximum repetitions of 20-m shuttle run (Ex) in the Yo-Yo intermittent recovery test were examined. Ten men were recruited to perform identical IM function test and exercise test in three different trials randomly. The control trial was without IM warm-up while the placebo and experimental trials were with IM warm-up by performing two sets of 30 breaths with inspiratory pressure-threshold load equivalent to 15% (IMW(P)) and 40% (IMW) maximum inspiratory mouth pressure, respectively.

Reduced sensations of intensity of breathlessness enhances maintenance of intense intermittent exercise.

To identify the effect of normal breathlessness sensation elicited during intense intermittent exercise at exhaustion on limitation of exercise maintenance (Ex), the contribution of the flow-resistive unloading effect of normoxic helium-oxygen breathing on the breathlessness sensation to the change in the Ex was examined. Seven men repeatedly performed 12-s exercise at 160% maximal aerobic power output followed by passive recovery for 18-s under normal (CON) and unloaded (UL) breathing conditions until exhaustion. In UL, Ex was enhanced [mean (SD) 127.

The cardiovascular health of residents in selected metropolitan cities in China.

Background: To better understand the cardiovascular health and leisure-time physical activity of residents in major metropolitan cities in China, 2196 subjects (39.0 +/- 10.7 years) who lived in Beijing, Shanghai and Hong Kong were investigated.

Acute changes in selected serum enzyme and metabolite concentrations in 12- to 14-yr.-old athletes after an all-out 100-m swimming sprint.

The purpose of this study was to investigate the acute effects of an all-out 100-m swimming sprint on changes in serum enzyme and calcium ion concentrations in young (12 to 14 years) male and female swimmers. Changes in serum enzyme concentrations of creatine kinase (CK), lactate dehydrogenase (LDH), glutamic pyruvate transaminase (GPT), glutamic oxaloacetate transaminase (GOT), serum glucose (GL), and calcium ion ((Ca2+) concentrations were measured in 23 elite swimmers (13 boys and 10 girls) before and after a 100-m freestyle all-out sprint. Analysis showed (1) there were significant sex differences in serum CK concentration at baseline (Pretest); (2) significant sex differences in serum CK and LDH concentrations after the 100-m spring; (3) no significant differences in Ca2+ concentration after the 100-m spring; and (4) significant increase in Serum GOT and blood glucose concentrations after the 100-m sprint, suggesting that these might both be useful indicators of anaerobic exercise stress in young swimmers.

Increased sensations of intensity of breathlessness impairs maintenance of intense intermittent exercise.

To identify the reserve of an individual's tolerance of the sensation of breathlessness and metabolic stress in maintaining intense intermittent exercise at exhaustion under conditions of normal breathing, the contribution of the effect of modest inspiratory load on these two responses to the change in the exercise sustainability (Ex(sus)) were examined. Seven men repeatedly performed 12 s exercise at 160% maximal aerobic power output followed by passive recovery for 18 s under normal and ventilatory muscle loaded (VML) breathing conditions until exhaustion. In the VML trial, ventilatory muscle work at exhaustion was double that of the normal control.

Physical development and lifestyle of Hong Kong secondary school students.

Background: Objectives of the present investigation were to study the growth and development of adolescents in Hong Kong, to analyze the interrelationship between their development and lifestyle, and to provide some helpful suggestions for lifestyle modification.

Methods: A total of 404 secondary students ages 12-18 years served as subjects. Morphological measures, blood pressure, blood lipids, aerobic fitness, and body composition were tested.