I decided to add this extra blog today with more information for all the swim enthusiasts since swimming is such a popular Olympic sports.
The purpose of the following study was to analyze the relationships between energy cost,swimmingvelocity, stroke frequency and stroke length in top-level swimmers. Eighteen elite swimmers (four freestylers, fivebackstrokers, five breaststrokers and four butterflyers) performed an intermittent set of nx200 m swims (n<or=8) with increasing velocity. The study examined the oxygen consumption, lung ventilation, expiratory gases and blood lactate concentration.
Backstroke, Breaststroke and Butterfly strokes: increases of stroke frequency were associated to increases of energy cost, even when controlling the velocity.
Breaststroke: Increases in stroke length promoted significant decreases in the energy cost.
All competitiveswimmingtechniques: There was a significant and polynomial relationship between velocity and stroke frequency.
Freestyle and Butterfly stroke: The polynomial relationship between velocity and stroke length was significant.
It is concluded that manipulation of stroke mechanics variables (stroke frequency and stroke length) may be one of the factors through which energy cost in competitiveswimmingcan be altered for a given velocity.( Barbosa TM. Fernandes RJ. Keskinen KL. Vilas-Boas JP.The influence of stroke mechanics into energy cost of elite swimmers.[Comparative Study. Journal Article]European Journal of Applied Physiology. 103(2):139-49, 2008 May)
Another study using kinetic (3-D force plate), kinematic (videography) and temporal characteristics ofbackstroketurns by 20 male and 16 female swimmers were recorded to identify and describe key elements ofbackstroketurning performance. Data were recorded during a 50 m maximum effort swim in a 25 metre pool.
Four key factors were identified from a principle components factor analysis–anthropometry and force, post-turn velocity, force preparation and rotational skills. Implications from the findings were that age-groupbackstrokers should 'hit the wall hard' with relatively extended legs to reduce swim distance and push-off deceleration; use minimal wall contact time, and maximise forces to develop high horizontal velocities in a streamlined position. (Blanksby B. Skender S. Elliott B. McElroy K. Landers G.An analysis of the rolloverbackstroketurn by age-group swimmersSports Biomechanics. 3(1):1-14, 2004)
Competitiveswimmingconsists of four strokes and utilizes both upper and lower extremities in moving forward through the water. Shoulder and arm mechanics are similar in the freestyle, butterfly, andbackstroke. Much of the forward propulsion created during the pull-through phase of these strokes is the result of lift forces produced by the traversing motion of the hand and forearm.
Shoulder adduction and internal rotation (primarily performed by pectoralis major and latissimus dorsi) are important in stabilizing the shoulder and allowing the body to be moved forward over the hand duringswimming.
The same is true of the rapid motion portion of the breaststroke pull-through. Similarly, the flutter, or dolphin, kicks used in freestyle,backstroke, and butterfly produce forward motion by creating forward lift, and the lower leg "paddles" against the water. Knee motion is from approximately 0 to 90 degrees. In breaststroke, water is "whipped" out from between the rapidly closing legs; flexion is up to 140 degrees. All these forces are meant to overcome drag, which is the force resisting forward motion.( Richardson AR.The biomechanics ofswimming: the shoulder and knee.Clinics in Sports Medicine. 5(1):103-13, 1986)