The frontcrawl downsweep: shoulder protection and/or performance inhibition

Area of Science:

• Sports Biomechanics
• Human Movement Science
• Exercise Physiology

Background:

• Understanding muscle activation patterns is crucial for optimizing swimming technique.
• Electromyography (EMG) provides insights into the intensity and timing of muscle use during swimming.
• Front crawl swimming requires coordinated effort from multiple shoulder and arm muscles.

Purpose of the Study:

• To investigate the electromyographic (EMG) activity of shoulder and arm muscles during front crawl swimming.
• To analyze the relationship between muscle intensity, timing, and swimming phases.
• To explore potential technique modifications for improved shoulder joint loading and performance.

Main Methods:

• Measured EMG activity in nine swimmers using telemetric EMG system with active electrodes.
• Analyzed six muscles: two monoarticular, two biarticular shoulder muscles, and two elbow/wrist muscles.
• Combined kinematic analysis with EMG data during maximal effort 4x100m swims to exhaustion.

Main Results:

• The downsweep phase exhibited the longest duration but lowest muscular intensity among the four cyclic arm movement phases.
• This lower intensity during downsweep is hypothesized to reduce shoulder joint load.
• Higher muscular participation during the insweep phase was observed.

Conclusions:

• Optimizing front crawl technique may involve initiating the insweep earlier to coincide with the pull phase.
• This adjustment could shorten the low-intensity downsweep and increase overall shoulder loading.
• A more constant, higher shoulder loading might lead to improved swimming performance.