First in a series of performance measurement postings for high performance swim coaches and swimmers.
Originally by Damien Gogoll, Head Coach, PLC Aquatic Swim Club, silver license
At the end of the day, a swimming race is all about time. Who swims the fastest time on the day wins the race. We measure improvement by time. Coaching comes down to what we can change, manipulate and improve in order to get our swimmers swimming the fastest time possible.
Technique, fitness, strength, flexibility and efficiency are just some of the aspects coaches look at in order to improve the swimmers time. The challenge is to find a simple, reliable and valid way to measure these aspects so we can be sure if an improvement has been made. This is the start of a series of articles that covers common and less common ways to measure performance.
Since Forbes Carlile, being an innovator with his pace clock and many other measurement tools, coaches have introduced various tools to measure key components of swimming. Below are some key measurements used by coaches and sports scientists to evaluate swimmers’ performance.
Times and Splits
All swimming coaches have one major tool: a stopwatch.
The stopwatch is trustworthy and reliable. The stopwatch is the coach’s tape measure. Just as a builder measures everything, so does the swimming coach. The basic stopwatch is able to measure the swimmers' time for specific distances (the race or training set) and their lap-times or split-times within this distance. The words lap-times, split-times and splits are interchangeable. Likewise, laps and lengths are often interchangeable.
Lap-times are extremely useful data for the swimmer and coach in highlighting the strengths and weaknesses in a race. Identifying the slower lap-times and setting goal lap-times for training to improve the slower lap-time is one way to use the data from a race to improve.
It is important to consider that a single lap is made up of different components which can be measured individually.
Common sections of a two length swim race that get measured include:
(start of race)
(end of race)
By breaking the laps into the above sections, coaches can identify specific skills that might need improving. Tracking these consistent measurements helps in identifying improvements over time. For example: if you identify the turn is slow in a race and you have timed the 5-meters-in-and-10-meters-out in a race, you can then set a goal time for this distance. This will give the swimmer a specific target to reach.
The finer skill as a coach is then identifying the specific movements and techniques that can be improved to reach the goal time for the turn.
Be consistent with the measurements you take during races and training. Take the measurements at the same distance for accurate comparisons. It is wise to get the spots directly at the 15-meter and 35-meter marks.
While splits (lap times) and times are extremely useful for the swimmer and coach, the ability to measure a swimmers efficiency is even more helpful. Measuring the stroke rate (SR, number of strokes per minute) allows coaches to identify the swimmer's tempo and is easily measured in the majority of stop watches (either 1, 2 or 3 stroke cycles are used depending on the stop watch’s set up).
Stroke rates can identify areas in the race where a swimmer slows his or her tempo. Slower tempo measurements could possibly be due to fatigue or various reasons. or where the swimmer over rates - this is common in breaststroke. There are guidelines on the ideal stroke rate for each distance and stroke for males and females. However, it is important to work out what works best for each swimmer.
By taking swimmers' ratings in sprint sets and several races, coaches can begin to develop an ideal rating for each swimmer. It then comes down to the swimmers and coaches abilities to identify the important measures and to determine if the ratings needs to be modified in coordination with the development and improvement of the swimmers. Youngsters grow. Fitness improves. These measurements can be accurate but they often move and trend in certain directions.
Comparing ratings within a race can help identify sections of the race that can be improved. For example if a male in the 100-meter freestyle event has a rating of 80 in the first 25-meters, then a 60 in the second and third lengths, and finally in the fourth length the number drops to 40, it would appear that the swimmer is over rating in the first length, which is affecting the rating in the last length. If you were analyzing just the ratings, it would be smart for the swimmer to focus on controlling the rating in the first 25-meters so he can maintain a consistent rating throughout the race.
The number of strokes a swimmer does each lap is a vital measurement in establishing the efficiency of their strokes. This simple but often under used measure is vital in teaching swimmers to be efficient in their movements and increasing the ‘hold’ or ‘feel’ of the water. For junior squads, having stroke count sets during training can begin the process of the swimmers' awareness of their strokes. As swimmers develop it is important to vary the speed when doing stroke count (SC) so it can be compared to their race. It is easy to have a low stroke count when swimming easy, however when racing, it is much harder to keep the stroke count down.
The Efficiency set is a great way to develop effective stroke counts at varying speeds. The Efficiency set is 8 x 50-meters on 1:30, recording the time and stroke count,
#1 is Personal Best time (PB) + 15-seconds;
#2 is PB + 13;
#3 is PB + 11;
#4 is PB + 9;
#5 is PB + 7;
#6 is PB + 5;
#7 is PB + 3;
#8 is PB + 1.
See the chapter in the Swimming Test Set eBook on the Efficiency Set for a form to help administer this test set within your program.
The aim is to keep a consistent stroke count over all 50-meters swims while reaching the target time. The challenge for the swimmer is to not swim too fast in the first three repeats and not swim too slow in the last two repeats.
The second challenge is to hold a consistent stroke count. It might take several attempts to master the set, but it is a great tool for identifying swimmers who are unable to maintain a low stroke count at high speeds.
Distance Per Stroke, also called DPS
The distance a swimmer travels during each stroke cycle is a fantastic measurement that tells how far a swimmer is travelling (in meters or yards) for each stroke cycle. In training, swimmers can be reminded to aim for more distance per stroke which will reduce their stroke count. However, actually measuring DPS is harder than stroke count. For a rough guide you can use the lane-rope sections. In some pools, the lane lines are built with one-meter sections. In the USA, the lane lines are often built with different color beads in one-yard sections. Each pool is different and often each lane rope is different.
DPS can be measured using video analysis software. However, few coaches
have access to that software. Furthermore, few coaches have the time to figure out DPS for each swimmer.
Stroke Count could be seen as an indirect measure of Distance Per Stroke (DPS).
For example, if a swimmer does 25 strokes in 50-meters, a quick calculation says the swimmer travels 2-meters per stroke. However most coaches will up the mistaken assumption and neglect the swimmer's push off distance and the swimmer's several underwater kicks. Therefore, the distance swam was reduced. The value of the DPS was not true. How far did the swimmer actually swim is a valid concern when trying to figure out the DPS by length. Plus, did the swimmer's stroke rate change throughout the length? A change in stroke rate would affect the distance the swimmer travels in the stroke cycle, perhaps. Be careful when using stroke count (SC) as a measure for
calculating distance per stroke (DPS).
Velocity (displacement / time)
Knowing a swimmers velocity for each length (or within a length) of a race is useful in identifying where a swimmer is slowing down and where improvements can be made.
Unfortunately this measurement is rarely used as it is complex to calculate and the majority of coaches use ratings and times to evaluate this. If used, however it can be an informative tool for both the swimmers and coach to work out areas of the race where the velocity of the swimmer drops. Often swimmers don’t realize they are slowing down as they feel like they are working harder. However, with fatigue, the swimmers put in more effort and move through the water slower.
DPS, Velocity, Stroke Rates, Stroke Counts are just some examples of what is commonly measured in swimming training and racing. Coaches should not be afraid to experiment. Of course, experiment without putting any harm.
Consider what aspect of a stroke, race or swimmers movement to measure and design sets to help measure this. It is important that your set actually measures what you are wanting to measure. So consider carefully how you will measure it to ensure the change is as a result of the aspect and not something else. It is also important to be consistent with the measurements you take at training and in races.
Continue reading and learn about stroke index and SWOLF.