The goal of this observational study is to compare the differences of intracardiac hemodynamics and myocardial strain in athletes with different training levels to adapt to long-term high-level training in rest conditions. The main questions aim to answer are: 1. whether an increase in amplitude and duration of intracardiac hemodynamics and myocardial strain compared with healthy controls; 2. Whether significant correlations exist between the hemodynamic indices and training level.

Participants will be asked to filling out the questionnaire, such as the age, training year (the number of years the athlete has participated in any sport), technical hierarchy (promoted by the Competitive Sports Department of the General Administration of Sport of China, weekly training time in the last 6 months, height, weight, body surface area, heart rate, systolic blood pressure, and diastolic blood pressure; and will be asked to perform an examination of transthoracic echocardiography.

Researchers will compare differences of cardiac structure and function, especially the hemodynamics and myocardial strain to see if training level could affect the cardiac function through hemodynamics and myocardial strain.

Inclusion Criteria:

• athletes and healthy control subjects without regular exercise habits;
• no specific medical history or chronic illness.

Exclusion Criteria:

• A previous history of arterial hypertension, diabetes mellitus, heart, kidney, hepatic, infectious, psychiatric, malignant, disorders, taking drugs that can influence ECG intervals, and electrolyte imbalance;
• poor echocardiographic image quality and abnormal segmental ventricular wall movement.

athletes with training year > 10 and WTT > 20, athletes with training year < 10 and WTT < 20, healthy controls with irregular exercise habits