Intense Triceps Surae Contraction Increases Lower Extremity Venous Blood Flow

Area of Science:

• Vascular physiology
• Exercise science
• Thromboprophylaxis

Background:

• Venous thromboembolism (VTE) is a significant clinical concern.
• Physical prophylaxis, including active ankle exercise (AAE), complements pharmacological treatments for VTE prevention.
• The relationship between triceps surae (TS) exercise intensity and venous flow, particularly in immobilized patients, requires clarification.

Purpose of the Study:

• To determine the intensity of TS isotonic contraction needed to elevate superficial femoral vein peak blood velocity (PV) above baseline.
• To assess the efficacy of TS isometric contraction in increasing PV.
• To explore potential thromboprophylactic applications of TS exercise in immobilized patients.

Main Methods:

• A prospective, nonrandomized controlled trial involving 20 healthy adult males.
• Doppler ultrasonography was used to measure PV at rest and during TS contractions.
• Isotonic contraction intensities tested were 1RM (no resistance, maximum effort, 25%, 50%, 75%, 100%).
• Isometric contraction intensities ranged from 15-35% to 90-100% of maximal voluntary contraction.

Main Results:

• Isotonic contractions at 75% and 100% of 1RM significantly increased superficial femoral vein PV compared to no resistance.
• All tested intensities of isometric TS contraction significantly elevated PV.
• P-values indicated statistical significance for all positive findings.

Conclusions:

• Resistance training of the TS muscle at ≥75% 1RM enhances venous blood flow.
• TS isometric contractions demonstrate potential as a method for physical thromboprophylaxis, especially for patients with leg cast immobilization.
• These findings support the integration of specific exercise protocols into VTE prevention strategies.