Stroking parameters during continuous and intermittent exercise in regional-level competitive swimmers.

Area of Science:

• Sports Science
• Exercise Physiology
• Swimming Biomechanics

Background:

• Maximal lactate steady state (MLSS) is a key physiological marker in endurance sports.
• Understanding the relationship between physiological limits and technical execution in swimming is crucial for performance optimization.

Purpose of the Study:

• To investigate if maximal lactate steady state (MLSS) serves as a threshold for physiological and technical alterations in swimmers.
• To analyze changes in stroke rate (SR), distance per stroke (DS), and stroke index (SI) at and above MLSS.

Main Methods:

• 13 male swimmers performed a 400-m all-out swim, continuous MLSS (MLSSc) tests, and intermittent MLSS (MLSSi) tests.
• Stroke parameters (SR, DS, SI) were measured during sub-maximal swims at and above determined MLSSc and MLSSi intensities.
• Blood lactate concentrations were monitored to confirm steady-state conditions.

Main Results:

• Intermittent MLSS (MLSSi) was significantly higher than continuous MLSS (MLSSc), with similar blood lactate levels.
• Significant increases in stroke rate (SR) and decreases in distance per stroke (DS) and stroke index (SI) were observed at and above both MLSSc and MLSSi.
• DS significantly decreased during MLSSc without changes in SR or SI, indicating a subtle technical adjustment.

Conclusions:

• Swimming technique, including stroke rate and distance per stroke, is altered at intensities at or above maximal lactate steady state.
• These technical changes occur during both continuous and intermittent swimming protocols, even when blood lactate remains stable.
• The findings suggest that MLSS is a critical intensity where swimmers may compromise technique for speed.