Swimmer's Daily

  • We believe swimming, like walking, hiking, running, and cycling, is a critical healthy activity within our communities. Swimming does not require direct contact between teammates or coaches and social distancing can be maintained throughout practice. As with all exercise and activity at this time, swimming must comply with standards for social distancing and safety within aquatic facilities. We know, with collaboration between USA Swimming coaches, public health officials, and facility operators we can create safe plans for using aquatic facilities to promote physical and mental health opportunities compliant with public health directives. The CDC has indicated that there is no evidence the disease spreads through treated water. Proper operation and maintenance (including disinfection with chlorine and bromine) of these facilities should inactivate the virus in the water.

    Read USA Swimming via SwimSwam

  • Get inside the mind of one of the greatest female athletes of all time. In this episode of #FFTLIVE we interviewed TWELVE-TIME OLYMPIC MEDALIST and Legend Jenny Thompson. She was joined on the webinar by 5-time Olympian as both a swimmer and coach Brett Hawke along with Fresno State head coach Jeanne Fleck and McKendree University head coach Jimmy Tierney.

  • Milton Marlin alumnus Madison Macor was hoping to compete in the Olympic trials for the first time this year. Of course, the Covid-19 pandemic put a stop to that goal. Macor is finding ways to keep training while waiting for the pools to open.

  • Lawyer Daniel Uhlfelder went viral last weekend after lurking around Florida beaches dressed as death himself in protest of beachgoers enjoying the sun without proper social distancing, putting their communities at risk of COVID-19. While many states around the country are extending their stay-at-home mandates, others, like Georgia, are easing into reopening nonessential businesses.

    Uhlfelder is not a fan — he, along with health experts like Dr. Anthony Fauci, are cautious of society returning to normal so soon. He made an appearance on a local ABC station Friday to warn Floridians against flocking to beaches while the pandemic rages on.

    See Mashable

     

  • The parking lot was deserted. Classrooms were empty. There was an eerie silence on the last day of April while walking around Encino Crespi. Usually it’s a regular school day bustling with activity. But the coronavirus pandemic has left students and faculty communicating via on line. The main activity was taking place at the $10 million aquatics center under construction adjacent to the football field.

    The construction crew wore masks as they worked toward completing a long-awaited project that will include a 50-meter Olympic-size Myrtha pool, boys and girls team rooms and a separate plunge pool that will be used for rehabilitation.

    Crespi, joined by its sister school Louisville, hopes to unveil the new facility in August.

    “It’s really exciting,” said Crespi president Ken Foersch. “We’ve been looking forward to cutting the ribbon for a long time. We hope in August to cut the ribbon, to go into the classroom and jump into the pool.”

    Read Los Angeles Times

  • The European Aquatics Championships, originally scheduled to be held in Budapest from May 11 to 24, 2020, will be postponed to 2021 in view of the novel coronavirus epidemic, the organisers said.

    The exact dates will be decided at the European swimming league LEN’s November congress, Sándor Wladár, the head of the Hungarian swimmers’ association, told public news channel M1.

    The championships have already been postponed once, from May to August, he noted.

    Read Hungary Today

    budapest photo
    Photo by PHeen0

  • The LEN Bureau held a videoconference and decided to cancel the European Junior Championships in all disciplines for 2020.

    This summer would have seen the best young swimmers racing in Aberdeen, the divers in Edinburgh, the artistic swimmers in Malta, the open water swimmers in France while Rome and Volos would have hosted the respective editions of the U19 water polo Europeans.

    Due to the Covid-19 crisis in Europe, the LEN Bureau had to take the painful decision to cancel all these events. The respective technical committees will prepare proposals if those age groups who have lost their chance to compete this summer (as they are to become over-aged next year) should be eligible to take part in 2021 or not.

    The summer and autumn legs of the LEN Open Water Cup are also canceled.

    In the coming weeks, the Bureau will discuss the options to finish the water polo club season and to find best possible dates for the 2020 European Aquatics Championships. The event would have started in ten days in Budapest but has already been postponed.

    Press release from LEN

    aberdeen photo
    Photo by marsupium photography

  • Why some swimmers are able to swim significantly faster with smaller average force?

    I tried to answer this question by looking at the acceleration of the hand stroke. We know that when the velocity of the hand increases in backward direction, it produces high force forward and increasing speed of the swimmer. If the velocity of the hand starts to decrease, the production of force diminishes and leads to decreasing speed of the swimmer. Long periods of decreasing speed leads in turn to a high-speed variation and inefficient use of force.

    The assumption was: The efficiency of the handstroke increases with the fraction of time hands accelerate in backward direction.

    Efficient swimmers should swim faster with a lower amount of average force and have a higher stroke length. If the assumption is correct, we could rate swimmers stroke efficiency using the duration of the acceleration.

    In order to evaluate the importance of the acceleration, I compared the stroke length and average force of six swimmers against their swimming speed. The measurements consisted of 3-4 x 50 meters freestyle with increasing speed. The average values for the whole set were applied in the calculation of the results.

    The definitions were as follows:

    Stroke length – the average distance body travels forward during one stroke cycle

    stroke length = swimming speed x (60/stroke frequency)

    *Note that the effect of the push-off from the wall is not considered. Swimmers in long tract seem slower and have a shorter stroke length in comparison.

    Average force – the average force of both hands combined

    Average force = ((Impulse x fraction forward)right hand + (Impulse x fraction forward)left hand) x (60/str. freq.)

    Duration of the acceleration

    Duration = time(max hand speed) – time(v = 0)

    *Time difference between the red dots below

    Stroke with long acceleration Stroke with short acceleration

     

    The fraction of acceleration – percentage of the stroke cycle either hand is accelerating in backward direction

    Fraction of acceleration [%] = (Durationright hand + Durationleft hand) / (60/str. freq.)

    All parameters used in the calculations are available from the web. The swimming speed has been checked and corrected if there has been significant difference between the hands.

    Results

    Fraction of time for hands in acceleration Average force applied at different swimming speed
    Stroke length at different swimming speed

     

    Emilia has the highest fraction of acceleration at lower swimming speeds. She is also using the least amount of force and has a decent stroke length. As a sprinter, Emilia was the only swimmer exhausted already after three trials and asked for a longer recovery period before the last 50 m. At the last trial, her hands didn’t accelerate as long as in the previous measurements, which may be due to exhaustion.

    Tuomas had a significantly higher fraction of acceleration especially at higher swimming velocities than anybody else. He was able to keep the mean average force very low even when sprinting. He also had the longest stroke. The fraction of the time for acceleration increased with swimming speed as the duration of the glide phase decreased substantially.

    For Eemil the fraction of stroke acceleration was fairly low at low speed but rather high at sprint. As a sprinter such a result is to be expected. The stroke length was fairly high, especially at top speed. However, Eemil used the highest average force of all swimmers. It is likely that part of the measured force is due to pressure drop forming on the back of his hand.

    Siri was the only swimmer, whose fraction of acceleration decreased with increasing speed. This a clear deficiency in the swimming technique that should be corrected. She was also the only swimmer measured at long track. Her swimming speed and stroke length are therefore lower than swimmers measured at 25 m pool. Siri has the strongest leg kicks of the swimmers in this comparison. She was able to increase the swimming speed substantially, even if her average force didn’t increase in the last trial. The increase in the speed can thus be attributed completely to the kicks.

    Mirka’s fraction of acceleration was fairly low in comparison. At low speed, her stroke length can be attributed to a relatively long glide phase. Nevertheless, the average force remained also rather low. It may be that as a result of low fraction of acceleration, Mirka didn’t reach as high top speed as the others. It should be considered also that the average values applied in the calculation may not represent Mirka’s technique as her stroke to stroke variation was much higher than that of the other swimmers.

    Nelli’s fraction of acceleration remained comparatively low in all measurements. She had also the shortest stroke and used fairly high average force second only to Eemil. Nelli’s maximum speed was the lowest of all in this measurement.

    Conclusions

    Mirka’s results for average force and stroke length seem much better than what would be expected if hand acceleration would explain the efficiency of the stroke. Her high stroke to stroke variation may give misleading values for average hand speed. Also, Eemil’s average force is clearly too high, which can easily be explained by his excessive hand speed. All other results seem to agree well with the assumption. So, it seems that the fraction of acceleration is a number that reflects well the efficiency of the strokes. Increasing the fraction would either lead to faster speed or decreased use of force.

    Discussion

    Other factors that contribute to the stroke length and average force include i.e. swimmers drag, the strength of the leg kicks, stroke impulse, balance between the left and the right side as well as the stroke to stroke variation. It was surprising that the swimmers in the comparison ended up about in the correct order without considering any of these effects.

    The calculated values are sensitive to the correct swimming speed. The measured distance should always be longer that one lap in order to minimize the possible error in the timing.

    It is likely that the same criteria for stroke efficiency could be applied also for butterfly and backstroke. Its applicability for breaststroke is however by no means certain.

    It is quite unlikely that the measured swimmers could maintain their stroke technique for a longer distance. Therefore, the measurements should reflect the competition distance which is of interest.

    SmartPaddles is a wearable device that measures force of the swimmer in real-time.  Swimmers need consistent movement patterns; as soon as the propulsive force drops the body will quickly slow down.  The SmartPaddle helps to visualize when and where the changes occur during the stroke cycle.  The SmartPaddles help the swimmers to understand “if they are using the right amount of propulsive force in the right direction at the right time”.

    By Ari Auvinen a Founder of Trainesense Ltd.