Currently, the most popular platform for tracking and reporting swim data is Garmin. However there are a number of newer competitors on the market with both watches as well as goggles having the ability to track, report and visualize swimming information.
One of the most intriguing and easily accessible metrics provided is the SWOLF score. SWOLF, short for “Swim Golf,” is a score obtained by adding together the number of strokes per length and the time it takes to complete that length.
For example, if you swim 25 yards in 30 seconds and it takes you 20 strokes, your SWOLF score would be 50.
Take a look at the screenshot below, captured from Garmin Connect, showcasing this informative metric:
And here is a similar example from Finis, the makers of the Swim Sense, which is no longer sold, but you can see another way the information is presented. (do you use another brand of watch or goggle to record your swimming? Send a screenshot our way and we may feature it in an update to this series!).
Unveiling the Secrets of SWOLF: What Does It Really Tell Us?
When it comes to SWOLF, many coaches consider it a measure of efficiency, believing that a lower SWOLF score indicates a more efficient stroke. While striving for a lower SWOLF score is a common goal, there are two important factors to consider when analyzing SWOLF and its relationship to efficiency. Let’s explore these factors and uncover new ways to leverage SWOLF in your workout analysis.
Firstly, It’s essential to grasp the concept of efficiency in swimming. Efficiency refers to the ratio between the energy you invest in your strokes and the resulting forward movement. Accurately measuring efficiency would involve quantifying the amount of oxygen a swimmer consumes while swimming at a particular speed, which requires specialized tools for measuring oxygen consumption. Since swim watches cannot provide a precise efficiency value, we must explore alternative indicators that can offer insights into stroke efficiency.
Now, let’s delve into the second reason why SWOLF alone cannot provide a comprehensive picture of efficiency. While SWOLF is calculated by combining two parameters—Strokes per Length (SPL) and the time taken to complete the length—we still need independent knowledge of both SPL and time to make meaningful interpretations of the SWOLF score.
In essence, SWOLF offers valuable insights into stroke efficiency but should be analyzed alongside additional information to gain a comprehensive understanding. By examining factors such as stroke technique, stroke rate, and overall swimming mechanics, you can paint a more complete picture of efficiency and make informed adjustments to enhance your performance in the water.
Exploring Swim Golf Variations: Understanding Time and SPL Matrix
Let’s explore different combinations of Stroke Per Length (SPL) and time in a simple two by two matrix to understand how they affect SWOLF and what it indicates. Take some time to go through each scenario, and it will provide you with new perspectives on these metrics.
Four Scenarios: A) High SPL and high time = High SWOLF and inefficient swimming B) High SPL and low time = Medium SWOLF and improved efficiency C) Low SPL and high time = Medium SWOLF and very efficient swimming D) Low SPL and low time = Very low SWOLF and inefficient swimming
If if SPL * rate = time, then we are curious about what SPL + time or SWOLFÂ can tell us?
Four Scenarios:
| SPL | |||
| HIGH | LOW | ||
| Time | HIGH | A | C |
| LOW | B | D | |
A) SPL is high and time is high = high SWOLF and inefficient swimming
B) SPL is high and time is low = medium SWOLF and improved efficiency
C) SPL is low and time is high = medium SWOLF and very efficient swimming
D) SPL is low and time is low = very low SWOLF and inefficient swimming
A) When SPL and time are both high, it suggests a lot of drag or an inefficient catch. Swimmers in Scenario A can learn a lot by tracking SWOLF and observing its improvement. A decrease in SPL or an increase in speed indicates improved swim efficiency.
B) As speed increases, it’s normal for SPL to increase (SWOLF may remain the same) in efficient swimming. Swimmers in Scenario B can expect a lower SWOLF for slower swimming and a higher SWOLF for faster swimming. They should aim for a sustainable faster speed and be satisfied with a higher SWOLF while identifying their specific SPL and pace targets for different training distances or race settings.
C) Scenario C suggests a very low stroke rate with a significant amount of glide, indicating highly efficient swimming (SWOLF may be the same as in Scenario B). Swimmers in Scenario C should strive to increase their SWOLF by increasing their tempo since they already possess a highly efficient stroke.
D) Achieving a low SPL while swimming at a high speed requires considerable power and strength. Although SWOLF will be low, true efficiency may be compromised. However, in a race, the fastest time, not the highest efficiency, determines the winner. Swimmers in Scenario D are skilled and powerful, allowing them to adapt their strokes based on the task at hand.
Each scenario provides valuable insights into stroke efficiency, and understanding these variations can help swimmers refine their technique and optimize their performance.
Swimming Efficiency Comparison: Stroke Counts, Times, and SWOLF Scores
In this video, Jai demonstrates an interesting comparison between two lengths of swimming. In the first length, he completes it with 16 strokes in 31 seconds, resulting in a SWOLF score of 47. In the second length, he maintains the same 16 strokes but completes it in just 18 seconds, resulting in a lower SWOLF score of 34.
Despite the faster time in the second length, it’s important to note that the slower length is actually more efficient considering the amount of effort required relative to the forward movement achieved. While Jai could sustain the effort of the first length for a significant distance, the second length would likely be sustainable for a shorter distance, possibly around 100 meters or less.
SWOLF: More Than Just Efficiency
Let’s delve into an interesting aspect: the connection between speed and SWOLF. Imagine plotting different combinations of speed and SWOLF at various stroke rates. We might uncover a valuable self-coaching tool. My hunch, however, is that we can’t rely solely on SWOLF to gain insights. To truly analyze data and improve our swimming practices, we need to consider at least two out of three metrics: stroke count (SPL), time, and speed.
For me, SWOLF serves as a quick measure of consistency rather than an absolute measure of efficiency. When I review my athletes’ watch data, the SWOLF graph tells me if they are taking too much rest or swimming too easily. It also reveals if they are becoming more consistent in their performance during specific sets, such as a set of 10 x 100. While pace alone or SPL alone won’t provide the full picture, SWOLF alone doesn’t tell us much either.
Consider this: If I observe a set of 10 x 100 with a consistent SWOLF and unchanging SPL, it indicates that the swimmers are maintaining a steady level of performance, which is a positive sign. However, to truly understand their progress and enhance their performance as triathletes, I need to combine SWOLF with either pace or SPL. By reducing rest intervals, increasing the distance of each repetition, or ramping up the pace, we can aim for faster swimming and improved fitness, which may impact SWOLF in different ways.
Going Beyond SWOLF: Practical Strategies for Improving Swimming
I hope this discussion has shed light on the significance of various metrics and how to make the most of the information. In my experience, focusing on stroke count ranges, discovering your optimal SPL, experimenting with different SPLs, and maintaining your chosen stroke count—coupled with the use of a tempo trainer (steady, ascending, descending, etc.)—offer greater control and guidance compared to relying solely on SWOLF.
In an upcoming article, I will analyze specific watch data graphs to provide insights into executing swim sets and planning practice sessions for improved skill development. I’m eager to hear your thoughts and learn how you use the watch data you collect. Share your experiences and ideas in the comments section below. Together, we can continue to enhance our swimming performance.
hi,
you wrote : “The slower length is actually the more efficient stroke considering the amount of effort compared to the forward movement.”
What I understand is : You seem to define efficiency by dividing the effort (energy spent) by the distance covered. Of course he could sustain this pace for a long time, it’s slow.
I think it should be efficiency = effort / time for a specified distance
and we should have different target SWOLF for each race distance. for example (from the video) : 200 m race (swolf 34), 20 km race (swolf 47)
What if you combine heart rate data from a swim HRM with the SPL and Time?
Do you mean combine it as in add it in? At least one other coach has written about al “alternative swim golf” adding in HR. I don’t think it’s as useful as SPL & time because there’s little reason to think that a heart beat and a stroke are equivalent or temporally related as a stroke and a second are much more tightly correlated. However, being observant of your HR at various speeds and efforts is a good metric to track over time. Swimming the same speed at a lower HR indicates improved efficiency, and can be done within a single session by searcing for ways to swim easier, adjusting technique or focus.
we add in # of breathes taken as well, not HR. allows for some tracking of effort higher efforts = more breathes reduced (SWgolf) score working in all 3 (time+strokes+breathes) helps look at swim efficency at different efforts
I agree with you Dimitri. We can go back and discuss what we understand by “efficiency” in swimming. The way I see it a very efficient swimmer will swim a given distance with the lowest SPL in the shortest time possible.
Efficiency has a definition in exercise physiology defined as the ratio of work generated to the
total metabolic energy cost. Work is defined as force that creates displacement, or travel. In the case of swimming that displacement needs to be in the direction we want to travel. Lowest SPL and shortest time both increase the workload which can actually reduce the efficiency, even if it results in a faster speed.
Dimitri,
Good job, you are understanding just the point that SWOLF threatens to obscure. And if a swimmer is going to use SWOLF, they should be aware that there will be different combinations that allow them to swim different distances at their own ability & fitness limits.
Efficiency has a scientific definition however, I’m not making it up, and it is the ratio of work done (forward movement) to the energy used.
So intuitively both lengths in the video cover the same distance, yet the faster one uses more energy, it is less efficient. Yet it also has a lower SWOLF score.
For those not understanding what SWOLF is and isn’t measuring, this could be very misleading.
As you suggest, a lower SWOLF is not necessarily better if your target distance is a 20k race any more than if you are training for a sprint. It’s incomplete information.
Thanks for the comment and for prompting me to clarify.
Hi Coach Suzanne,
Thank you for covering this and for the great explanation….I only have 16 months of self-taught TI under my belt and got a 910XT for my recent birthday and the SWOLF was driving me nuts because it was getting higher even though I was feeling more efficient in the water…the stroke counter may not be perfect either as I am currently testing it’s accuracy.
Best,
Steve
I agree a lot with the points made here and totally agreeing with Dimitri. I would like to add though that:
1. The definition of efficiency you are talking about is not the correct one I think. It is true that scientifically we also can say that for example an engine is more efficient when it uses a single liter on 100km as opposed to 2.0 liters on 100km. We would say it’s twice as efficient. But under the covers something must have changed.
Over time people will also gain a better physical condition. All of a sudden the same 225 kcal that you had to spend 5 months ago for a single length all of a sudden is giving you 1.5 lengths. Same energy but both better time and spl. It is your body that has changed to improve on the energy consumption.
2. SWOLF is EVER ONLY a PERSONAL number and to NEVER COMPARE other than to yourself under the same circumstances!
A. It cannot be compared to other swimmers (which you seem to be doing)
B. It cannot be compared to other stroke types (and distances)
C. It cannot be compared to different size pools and especially open water.
One person is never B and C at the same time. A person’s SWOLF on 50m front crawl will be different in a 25m and 50m pool. Probably not by much…. but it is not the same.
I think still every individual should strive to reach ‘D’.
If you are a ‘B’ swimmer you should work on maintaining your time but improve your number of strokes. Whatever you need to change to improve the quality.
If you are a ‘C’ swimmer you should work on your on adding more power to the stroke but maintain the stroke quality.
2. I agree with your table a bit but there is a ‘hidden’ relationship in the formula.
Higher stroke power implies lesser stroke count and frankly with a little bit of nicer stroke you spare energy!
The movie clip of Jay is a nice visual however I would like to add though that if he would even add a little bit more power you cannot even make stroke 16 anymore. Putting this extra power (not necessarily effort, as muscle power grows when we train) into the stroke he would actually also lower the stroke count. The little bit of extra power then is reflected in both numbers. Even though this is a these are figurative numbers:
220 kcal => 16 strokes, 17.80 => 33.8
225 kcal => 15 strokes, 16.70 => 31.7
This brings us to the point where we could say (and agree): if we have 900 kcal to spend on a race it is important what race that is. Is that freestyle 400m in a 25 meter pool or is that 50m in a 50m pool. Without a doubt the SWOLF values for both these races will and should never be the same.
To achieve improvement though you want to look at yourself and say:
1. I am on 1.04.53 right now
2. Set a target: by the end of the season I want to be on 1.00.00
3. That is 15s/length (25 meter pool)
4. Determine your current SWOLF
5. Determine which component of it is easier to change at the moment (lets say 1st from 22 to 21 strokes)
6. Train and measure
7. repeat 5 and six. Anytime a different minor improvement
Hello Suzanne,
Thank you for your interesting article.
I was wondering if adding (a part of) heartrate to the swolf wouldn’t be a better indicator for the efficiency. Heartrate is in my perspective a good indicator for the energy output.
One could look at the evolution of the SWOLF at a given heartrate.
Can you comment on that ?
Kind regards,
Johan
Johan,
yes, HR can be a good indicator of energy spent. In the big picture speed vs. HR would be the most helpful tool. But improving economy as measured by Same effort or speed with a lower heart rate can be a nice thing to add. The Finis AquaPulse has been used by several coaches to see if they can maintain tempo or SPL while lowering the HR by focusing on various skills during the swim, eliminating the need to stop and check HR manually (during which time HR drops and focus also wanders)
Well I guess my point is that swolf is not really a measure of efficiency. Certainly adding HR or perceived effort is a good way to calibrate your efforts to make sure you are actually saving energy. I don’t think a direct comparision of swolf to HR is as helpful as simply comparing your pace or speed to HR as a measure of your energy use.
Hi, have you made a mistake in your Scenario C when you say “Scenario C swimmers should strive to increase their SWOLF, more specifically by increasing their tempo as they already have a very efficient stroke.” ?
Surely if a swimmer increases their tempo they will reduce their SWOLF, as shown in your video of Jai where he increases his tempo in length two and reduces his SWOLF from 47 to 34.
My Garmin Forerunner 735 watch calculates SWOLF. The watch definites ONE stroke as the right arm pull AND the left arm pull. To me that is TWO strokes. As it is in your video. I wonder what the standard definition of a stroke is?
Hi Bill, The majority of professional coaches (and athletes) count the way I describe in my articles. You can decide what you want to do with the data and how to use it, and make up your mind about the best way for you to count.