Inclusion Criteria:
Group 1 (Aerobically Trained)
* 20-60 years old
* actively training or competing over the past 2 years
* 3 or more days of vigorous activity accumulating approximately least 1500 MET min/week or 7 days of any combination of walking, moderate, or vigorous intense activities achieving a minimum of 3000 MET min/week
Group 2 (Strength trained)
* 20-60 years old
* actively training or competing over the past 2 years
* 3 or more days of muscle-strengthening exercise at an intensity of approximately 5 out of 10
Group 3 (Not actively training)
* 20-60 years old
* actively training or competing over the past 2 years
* 3 or more days of muscle-strengthening exercise at an intensity of approximately 5 out of 10
Group 5 (High flexibility)
* 20-60 years old
* Sit-and-reach performance is categorized as "very good" or excellent based on the American College of Sports Medicine's sit-and-reach evaluation criteria (Table 4.16 of ACSM's Guidelines for Exercise Testing and Prescription 9th edition).
Exclusion Criteria:
Exclusion criteria are the same for all groups.
* History of cardiovascular disease (Cardiac, peripheral vascular, or cerebrovascular disease)
* History of stable or unstable angina
* History of cardiac dysrhythmias causing symptoms or hemodynamic consequences
* History of hypertrophic cardiomyopathy
* History of cardiac valvular disease (e.g., aortic stenosis)
* History of pulmonary disease (Chronic obstructive pulmonary disease, asthma, interstitial lung disease, or cystic fibrosis)
* History of pulmonary embolus
* History of suspected or known aneurysm
* History of metabolic disease (Diabetes mellitus (type I or II), thyroid disorders, renal or liver disease
* History of renal disease
* History of neuromotor, musculoskeletal, or rheumatoid disorders that are exacerbated by exercise
* Current acute systemic infection, accompanied by fever and body aches.
* Pain or discomfort in the chest, neck, jaw, arms, or other areas that may be due to myocardial ischemia (lack of adequate circulation)
* Shortness of breath at rest, during daily activities, or with mild exertion
* Dizziness or syncope (fainting)
* Orthopnea (breathing discomfort when not in an upright position) or paroxysmal nocturnal dyspnea (interrupted breathing at night)
* Ankle edema (swelling)
* Palpitations (abnormal rapid beating of the heart) or tachycardia (rapid heartbeat)
* Intermittent claudication (cramping pain and weakness in legs, especially calves, during walking due to inadequate blood supply to muscles)
* Known heart murmur (atypical heart sound indicating a structural or functional abnormality)
* Unusual or unexplained fatigue
* Severe arterial hypertension (i.e., systolic blood pressure of \>200 mm Hg and/or a diastolic blood pressure of \>110 mm Hg) at rest.
