Post-warm-up muscle temperature maintenance: blood flow contribution and external heating optimisation.

Area of Science:

• Exercise Physiology
• Sports Science
• Thermoregulation

Background:

• Passive muscle heating enhances post-warm-up muscle temperature (Tm) maintenance and sprint performance.
• Leg blood flow plays a role in the decline of muscle temperature after exercise cessation.

Purpose of the Study:

• To investigate the role of leg blood flow in post-warm-up muscle temperature decline.
• To determine if optimizing passive heating protocols can improve muscle temperature maintenance.

Main Methods:

• Ten male cyclists underwent a 15-min warm-up followed by 30 min of recovery.
• Muscle temperature (Tmvl) was measured at various depths under different heating conditions: water-perfused trousers (43°C), electrically heated trousers (40°C), and a control.
• The influence of leg blood flow (BF) versus no blood flow (NBF) on Tmvl was assessed.

Main Results:

• Warm-up increased Tmvl by ~3°C. Post-recovery, leg blood flow (BF) resulted in a lower Tmvl (~0.3°C) compared to no blood flow (NBF).
• Water-perfused trousers at 43°C significantly reduced the drop in deep-Tmvl compared to 40°C heating and control conditions.
• Higher temperature passive heating (43°C) led to an increase in superficial muscle temperatures during recovery.

Conclusions:

• Thigh blood flow contributes to the decrease in muscle temperature after warm-up.
• Optimizing passive heating, specifically by increasing temperature, is crucial for maintaining muscle temperature post-exercise.
• A modest 3°C increase in heating temperature effectively preserves and can even enhance muscle temperature, highlighting temperature as the key factor.