Front-crawl stroke-coordination and symmetry: a comparison between timing and net drag force protocols

Area of Science:

• Sports Science
• Biomechanics
• Swimming Performance

Background:

• Assessing swimming technique is crucial for performance enhancement.
• Traditional timing methods may not fully capture stroke dynamics.
• Net drag force analysis offers a novel approach to evaluating symmetry.

Purpose of the Study:

• To compare stroke coordination and symmetry in elite swimmers using traditional timing and net drag force methods.
• To investigate the influence of gender and breathing on swimming symmetry.
• To explore the utility of combined methods for technique intervention.

Main Methods:

• Twenty elite front-crawl swimmers (FINA ranking 908 ± 59) participated.
• Six randomized free-swimming trials were conducted: three with breathing, three without.
• Net drag forces were measured using an assisted towing device to create a stroke symmetry index.

Main Results:

• Significant differences in symmetry indices were found between timing and net drag force methods during breathing conditions.
• Timing indices indicated symmetry in most swimmers, while net drag force indices showed less symmetry, particularly in males.
• Gender influenced the location of maximum net drag force and stroke overlap during breathing and non-breathing conditions.

Conclusions:

• Traditional timing and net drag force methods yield different symmetry assessments in elite swimmers.
• Gender and breathing significantly impact stroke symmetry, especially when analyzed via net drag force.
• Combining both methods can inform more effective swimming technique interventions.