Neuromuscular fatigue during 200 m breaststroke

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Understanding neuromuscular fatigue is crucial for optimizing swimming performance.
• Breaststroke, a complex swimming style, requires significant upper limb engagement.
• Previous research on swimming fatigue often focuses on shorter distances or different strokes.

Purpose of the Study:

• To analyze upper limb muscle activation patterns during a 200m breaststroke.
• To quantify neuromuscular fatigue using kinematic and physiological assessments.
• To investigate the onset and characteristics of fatigue in breaststroke swimming.

Main Methods:

• Surface electromyography (EMG) recorded from biceps brachii, deltoid anterior, pectoralis major, and triceps brachii.
• Nine male swimmers performed a maximal 200m breaststroke trial.
• Kinematic parameters (swimming speed, stroke length, stroke rate, stroke index) and blood lactate levels were measured.

Main Results:

• Swimming speed, stroke length, and stroke index decreased from lap 1 to lap 3.
• Electromyogram average rectified value (ARV) increased for most muscles by the end of the race.
• Mean frequency (MNF) of the power spectral density decreased in the 4th lap for all observed muscles, indicating fatigue.

Conclusions:

• Neuromuscular fatigue in 200m breaststroke begins around the second lap.
• Fatigue manifests as altered kinematic parameters and specific changes in upper limb muscle activity.
• A non-linear fatigue progression was observed, differing from patterns seen in shorter swimming events.