No abstract available.
Exercise Test* ; Physiology*

Exercise-associated muscle cramps (EAMC) is prevalent among athletes during training or competitions where they are subjected to strenuous activities for a prolonged period. To manage this painful condition, health practitioners have used numerous treatment modalities having massage done with adjunct application such as cold compress or liniment. Studies show that it is debatable which combination of treatment modalities is more effective on people affected by EAMC. Hence, this study aimed to present evidence-based data to show if there is a difference in the effectiviteness of the two modalities in treating EAMC. A total of thirty-two (32) athletic participants were enrolled in this study and a total of 40 treatment trials were included in the analysis of data. Each participant performed strenuous exercises meant to induce muscle cramps. The onset of muscle cramps was identified using a set criteria. After which, treatment was applied and the length of time that the cramp was resolved was recorded. Determining relief from muscle cramps was based on the characteristic of muscle hardness and the level of pain by using a numerical rating scale. Results showed that though majority of the participants verbalized preference for the ice treatment, analysis of data using one-way ANOVA revealed that there is no evidence to prove that there is a difference in the effectivity among the treatment modalities performed. In conclusion, though all modalities performed were able to relieve the EAMC, the use of adjunct treatment in addition to massage and stretching may have a placebo effect component, which improves the patient's perception of greater efficacy.
Exercise ; Muscle Cramp ; Massage ; Physiology

Altitude ; Exercise/physiology* ; Heart Rate/physiology* ; Humans ; Lung ; Respiration

OBJECTIVEDynamic exercise is often used to evaluate the backlog function of cardiovascular system, and the treadmill test is a commonly used dynamic exercise protocol. The study aimed to assess the exercise capacity and cardiovascular response to treadmill exercise in healthy children, and create normal reference values of exercise testing in native children.

METHODSTwo huadveds and ninety-four healthy children aged 5 to 14 years were tested using the Bruce protocol on treadmill.

RESULTSMean exercise capacity in boys increased from 12.2 METs at the age of 5 to 6 years, to 15.2 METs at the age of 13 to 14 years. Mean exercise capacity in girls increased from 11.7 METs at the age of 5 to 6 years, to 12.6 METs at the age of 13 to 14 years. Sex difference was obvious in exercise capacity of children except those at the age of 5 to 6 years. There was no obvious correlation between exercise capacity and the ratio of weight to height. Maximal heart rate ranged from 187 to 235 beats/min. Systolic blood pressure increased gradually until peak exercise was achieved. The mean systolic blood pressure of boys at maximal exercise increased by 38.6 percent compared to resting level, and the girls increased by 34.4 percent. After maximal exercise, mean systolic blood pressure reached resting level in 6 minutes but diastolic blood pressure varied. All children had sinus rhythm at rest. No arrhythmia was recorded during treadmill exercise. However, arrhythmia was found in five children in early recovery period. The incidence of exercise-induced arrhythmia was 1.7 percent.

CONCLUSIONSex difference and age difference was obvious in exercise capacity. In the 21st century, the exercise capacity of children in Shanghai area has approached to the developed country. Using MET as the standardized criterion of exercise capacity is advantageous to standardize maximal or submaximal exercise workloads of all kinds of protocols. Exercise-induced arrhythmia in the early recovery period in children without structural heart disease may not be pathological, but it is necessary for those children to be followed-up.

Adolescent ; Blood Pressure ; physiology ; Child ; China ; Electrocardiography ; Exercise Test ; Exercise Tolerance ; physiology ; Female ; Heart Rate ; physiology ; Humans ; Male ; Sex Factors

Respirator breathing resistance impacts performance of wearers during constant work load. However, it is less clear as to how breathing resistance affects the tolerant capacity of users during graded work load. The present study investigated the tolerant capacity of 8 individuals during incremental work load. The 8 subjects were required to wear two matched respirators (respirators I and II which were designed to have different breathing resistances and the same dead space) respectively on separate days and then work to end points. Minute ventilation (V(E)), breathing frequency (BF), oxygen consumption (VO(2)) and heart rate (HR) were recorded during exercise, while tolerant time, response time and breathing discomfort were measured at the end of each test trial. The test variables were compared between the two respirators by using matched-pairs t-test. The results showed that the tolerant time was significantly reduced for the respirator I with higher level of breathing resistance when compared with its counterpart with lower breathing resistance (respirator II) (P<0.05). The same changes occurred for response time. Results also showed a significant increase in V(E) and BF for respirator I wearers when the work load was above 125 W. The O(2) consumption was similar under the two breathing resistance conditions. These findings suggested that the respiratory resistance caused by self-contained breathing apparatus (SCBA) has an impact on the tolerant capacity of users.
Airway Resistance ; physiology ; Exercise ; physiology ; Exercise Tolerance ; physiology ; Humans ; Male ; Oxygen Consumption ; physiology ; Physical Exertion ; physiology ; Respiration, Artificial ; methods ; Respiratory Mechanics ; physiology ; Young Adult

Cardiac contractility variability (CCV) is a new concept which is introduced in the research field of cardiac contractility in recent years, that is to say, there are some disparities between cardiac contractilities when heart contracts. The changing signals of cardiac contractility contain a plenty of information on the cardiovascular function and disorder. In order to collect and analyze the message, we could quantitatively evaluate the tonicity and equilibrium of cardiac sympathetic nerve and parasympathetic nerve, and the effects of bio-molecular mechanism on the cardiovascular activities. By analyzing CCV, we could further understand the background of human being's heritage characteristics, nerve types, the adjusting mechanism, the molecular biology, and the adjustment of cardiac automatic nerve. With the development of the computing techniques, the digital signal processing method and its application in medical field, this analysis has been progressing greatly. By now, the assessment of CCV, just like the analysis of heart rate variability, is mainly via time domain and frequency domain analysis. CCV is one of the latest research fields in human cardiac signals being scarcely reported in the field of sports medicine; however, its research progresses are of important value for cardiac physiology and pathology in sports medicine and rehabilitation medicine.
Autonomic Nervous System ; physiology ; Exercise ; physiology ; Humans ; Myocardial Contraction ; physiology ; Phonocardiography ; methods ; Signal Processing, Computer-Assisted

OBJECTIVETo explore the response of electroencephalography (EEG) signal to biceps brachii fatiguing induced by sustained isometric (non-maximal) voluntary contraction (non-MVC) and to lay a foundation for effective and reliable fatigue evaluation system and for understanding fatigue mechanisms.

METHODSTen male undergraduates performed two different isometric fatiguing tasks with the elbow flexion muscles under a load of 5 and 10 kg respectively, and synchronously EEG signals were collected from scalp. Then amplitude, spectral and Lempel-Ziv complexity C(n) of EEG were calculated.

RESULTSThe average EEG(AEEG) increased while the average mean power frequency (MPF) and complexity of EEG decreased in muscle fatigue. Furthermore, this phenomenon was distributed evenly across the entire scalp, but load only influenced AEEG, MPF and C(n) at Fz.

CONCLUSIONAEEG of EEG increases generally while MPF and C(n) increase generally during local muscle fatigue. This pattern of EEG reflects the central mechanism of muscle fatigue. AEEG, MPF and C(n) at prefrontal area show load dependence.

Adult ; Electroencephalography ; Exercise ; physiology ; Humans ; Isometric Contraction ; physiology ; Male ; Muscle Fatigue ; physiology

Diastole ; physiology ; Exercise ; physiology ; Fractional Flow Reserve, Myocardial ; Heart Rate ; Humans ; Systole ; physiology ; Young Adult

This review discusses human thermoregulation during exercise and the measurement of body temperature in clinical and exercise settings. The thermoregulatory mechanisms play important roles in maintaining physiological homeostasis during rest and physical exercise. Physical exertion poses a challenge to thermoregulation by causing a substantial increase in metabolic heat production. However, within a non-thermolytic range, the thermoregulatory mechanisms are capable of adapting to sustain physiological functions under these conditions. The central nervous system may also rely on hyperthermia to protect the body from "overheating." Hyperthermia may serve as a self-limiting signal that triggers central inhibition of exercise performance when a temperature threshold is achieved. Exposure to sub-lethal heat stress may also confer tolerance against higher doses of heat stress by inducing the production of heat shock proteins, which protect cells against the thermolytic effects of heat. Advances in body temperature measurement also contribute to research in thermoregulation. Current evidence supports the use of oral temperature measurement in the clinical setting, although it may not be as convenient as tympanic temperature measurement using the infrared temperature scanner. Rectal and oesophagus temperatures are widely accepted surrogate measurements of core temperature (Tc), but they cause discomfort and are less likely to be accepted by users. Gastrointestinal temperature measurement using the ingestible temperature sensor provides an acceptable level of accuracy as a surrogate measure of Tc without causing discomfort to the user. This form of Tc measurement also allows Tc to be measured continuously in the field and has gained wider acceptance in the last decade.
Body Temperature ; physiology ; Body Temperature Regulation ; physiology ; Exercise ; physiology ; Humans ; Monitoring, Physiologic ; methods

Adolescent ; Exercise Tolerance ; physiology ; Female ; Humans ; Male ; Oxygen Consumption ; physiology ; Swimming ; physiology ; Young Adult