Response to Three Weeks of Sprint Interval Training Cannot Be Explained by the Exertional Level

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• Sprint interval training (SIT) is effective for enhancing sports performance, exercise capacity, and aerobic fitness.
• The underlying mechanisms for varying individual responses to SIT are not well understood.
• Understanding these mechanisms is crucial for optimizing training protocols.

Purpose of the Study:

• To investigate the influence of exertion levels during training on individual responsiveness to SIT.
• To identify potential factors contributing to high versus low responders to SIT.

Main Methods:

• Twenty-eight young untrained men underwent nine SIT sessions over three weeks.
• Training involved 30-second all-out cycling bouts with 4-minute rests.
• Responses were assessed via heart rate, blood lactate, maximal voluntary knee extension torque (MVC), and peak oxygen uptake (VO2peak).

Main Results:

• All participants improved VO2peak, but anaerobic power gains varied significantly, identifying 17 high and 9 low responders.
• Heart rate during training and lactate kinetics did not differ between high and low responders.
• MVC recovery improved post-training, with no significant differences between response groups.

Conclusions:

• Individual differences in response to SIT are not determined by the exertion level during the training sessions.
• Further research is needed to explore other physiological or genetic factors influencing SIT responsiveness.