Articles Available for Download
- Quantitative Data Supplements Qualitative Evaluations of Butterfly Swimming
- Applications of Work Physiology Science
- Bicipital Tendonitis
- Brain Injury
- Competitive Swimming Injuries
- Functional Capacity Evaluations
- Peak Performance Swimming
- Physical Impairment & Brain Injuries
- Swim Stroke Pull Test
Theodore J. Becker, Jaclyn J. Morrill, Erin E. Stamper. 'Applications of Work Physiology Science to FCE' Publication: The Rehabilitation Professional 15(4), pp. 45-56. Request a copy here.
Theodore J. Becker, PhD, and Rod Havriluk, PhD. 'Quantitative Data Supplements Qualitative Evaluations of Butterfly Swimming' presented at The XIth International Symposium on Biomechanics and Medicine in Swimming in Oslo, June 16-19 2010. Request a copy here
Abstract
INTRODUCTION
Previous analyses of thousands of trials of synchronized underwater video and hand force data show a dramatic increase in force at the beginning of the butterfly pull immediately following two events: 1) when the hands first submerge below the level of the shoulders and 2) when elbow flexion begins. As both of these events are usually observable by a coach on a pool deck, quantitative data about these events may help coaches to better qualitatively assess technique. As the mechanical advantage increases with both shoulder extension and elbow flexion at the beginning of the pull, it is hypothesized that hand force will significantly increase with these events.
METHOD
Four events were selected for analysis: 1) when the hands first submerge below the level of the shoulders, 2) when elbow flexion begins, 3) when the hands first become medial to the elbows, and 4) when the hands pass perpendicularly below the shoulders. Female swimmers (n = 23) from three university teams were tested with Aquanex+Video swimming butterfly over a 20 m course (as in Becker & Havriluk, 2006). Underwater video and hand force data were collected over the last 10 m. The average hand force over a .1 sec interval before and after each event was calculated.
RESULTS
As hypothesized, there was a significant (p<.01) increase in force for two events: when the hands first submerged below the level of the shoulders (18.0 N) and when elbow flexion began (14.6 N). There was no significant change in force when the hands first became medial to the elbows (.4 N) or when the hands passed perpendicularly below the shoulders (-.2 N). The swimmers required .36 sec to submerge the hands below the shoulders out of the .81 sec total time that the hands were underwater generating force.
DISCUSSION
The large increases in force when the hands first submerged below the level of the shoulders and when elbow flexion began emphasize the importance of a mechanically advantageous angle at both the shoulder and elbow. Based on the quantitative results, coaches can qualitatively evaluate swimmers to ensure they eliminate the wasted time that their hands are above the shoulders by adjusting the entry angle. Coaches can also encourage swimmers to begin elbow flexion as soon as the entry is complete. In addition to improving performance, these technique adjustments will be helpful in reducing the onset of shoulder injury.
REFERENCES
Becker, T., & Havriluk, R. (2006). Bilateral and anterior-posterior muscular imbalances in swimmers. In J. P. Vilas-Boas, F. Alves, A. Marques (Eds.), Biomechanics and Medicine in Swimming X. Portuguese Journal of Sport Sciences, 6(Suppl. 2), 327-328.
