Technique
12:06 AM
Importance Of Streamline
In the beginning, it's a good study to end the argument about the streamline head position as for so many years the coaches asked there swimmers to tight there streamline and some of them highlight the head position must be in the middle and the need to squees their arms against the ears and the others highlighted Michele Phelps Hyperd streamline we the head down before we discuss this study we need to explain what is The term “passive drag” relates to the hydrodynamic resistance forces that occur when a swimmer remains in a stable position and is not moving any part of the body.
this study has been done on A total of ten male swimmers (age: 21 ± 2 years; body height: 1.80 ± 0.06 m; body mass: 75.9 ± 6.9 kg) participated in this study after giving their informed consent. All of the swimmers were regional-level and had at least 10 years of competitive swimming experience. The investigation was performed during the winter of 2014 when the swimmers were in the competition period.
Results:
Regarding the swimmer’s head position, passive drag was found to be significantly lower in with the arms in front of the head for the Head Down and Head in Middle than the Head-Up at all speeds. No differences were observed in passive drag between the Head Down and Head in Middle at all speeds. The statistical analysis revealed that with the arms alongside the body (arm down), the significant highest values of passive drag were only in the Head-Up rather than in the Head Down at the two fastest speeds (1.7 and 1.9 m/s). However, the pairwise comparison showed no significant differences for the Head in Middle rather than for the Head-Up and Head Down at all speeds.
The results show a reduction of 4–5.2% in average passive drag when the head was down or aligned with the swimmer’s arms alongside the body(Arm down), in comparison to the head-up position. There was a major decrease of 10.4–10.9% in passive drag when the head was down or aligned with the swimmer’s arms above the swimmer’s head (in streamline position). it shows in the graph with the yellow dot.
Conclusion:
Regarding to this study and the related studies the in passive drag position, the streamline with the head down is less drag by 10.4 - 10.9% but also we have to mention that in the speed of 1.9 the streamlined with the head down and the head between the arms almost equal. we have to focus on the streamline in our day to day workouts. And don't forget that 30% of all the races are on the walls for start and turns and the streamline is a valuable key to success in that we need to use and develop.
Cortesi, M., & Gatta, G. (2015). Effect of The Swimmer’s Head Position on Passive Drag. Journal of Human Kinetics, 49, 37 - 45.
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