Just How Much Does This Poor Swimmer Benefit From a Wetsuit?

I’m not a swimmer, I think by now we all know that.  I don’t (well, didn't) own a wetsuit.   I've rented one (from wetsuiterental.com) a few times for HIM races but I've never worn one in a full distance IM race or swim.  Of course, this year will be different as IMAZ should be wetsuit legal, so that had me thinking about wetsuits and wanting to swim in one before Arizona.

Long story short, I rented a wetsuit for a race this past weekend but then ended up skipping the race. So on Monday night I did the bottom third of my scheduled swim workout wearing the rental suit. I figured that would help me confirm the fit so I could ask the rental company for the same exact suit for Arizona.

Prior to Monday, I had worn a wetsuit while swimming exactly four times, twice in a pool to test fit and twice in HIM distance open water swims. It had been over a year since the last time I wore one and I had no specific memory of the previous pools swims: they were unremarkable.

That was not the case on Monday. My previous “fit swims” were during taper so maybe this is the first time I've really worked out in a wetsuit, I don’t know, but what I do know is I was markedly faster in the pool while wearing the suit.

I know, this is a duh type of comment, but this is the first time I’ve really noticed the benefit and it’s the first time I have actual data to support my feelings. The rest of this post will focus on the data that I have and the conclusions that I’ve drawn from said data.

But first, I will start with a disclaimer. This was not a scientific study and I’m not here trying to pass it off as one. This is one set of data that I collected during a regularly scheduled swim workout. I did not design the workout with the idea of testing the benefits of a wetsuit; I simply wore the suit for part of the workout that was on my plan for Monday. I know that I was swimming 150s without the suit and 100s and 50s with the suit, that’s what was on my plan. This is nothing more than data that I collected and that I found interesting; your mileage may vary. If you’re looking for a scientific study of the benefits of a wetsuit, try reading this great article - The 2013 Triathlon Wetsuit Performance Test, by Aaron Hersh, published Jul 30, 2013

So with the disclaimer out of the way, let’s get on to the data.

The wetsuit:
A Blueseventy Fusion, full-sleeve.  Size M/L. For reference, I’m ~5’11” and 175 lbs.

The Scheduled Workout:

• 200 WU
• 6x200
• 8x150
• 7x100
• 6x50
• 200 CD

Here is the data collected by my 910XT during the swim:

Interval	Time	Pace (/100 m)	Strokes	Stroke Rate (/min)	Stroke Distance (m)	SWOLF	Efficiency
200m Freestyle	04:23.4	02:11.7	103	23.5	1.9	46	45.8
200m Freestyle	04:11.6	02:05.8	98	23.4	2	44	43.7
200m Freestyle	04:12.4	02:06.2	101	24	2	44	44.2
200m Freestyle	04:15.5	02:07.7	99	23.2	2	44	44.3
200m Freestyle	04:15.4	02:07.7	100	23.5	2	44	44.4
200m Freestyle	04:19.3	02:09.7	99	22.9	2	45	44.8
200m Freestyle	04:17.3	02:08.7	101	23.6	2	45	44.8
150m Freestyle	03:07.8	02:05.2	76	24.3	2	44	44
150m Freestyle	03:12.4	02:08.3	77	24	1.9	45	44.9
150m Freestyle	03:13.3	02:08.9	75	23.3	2	45	44.7
150m Freestyle	03:12.4	02:08.3	78	24.3	1.9	45	45.1
150m Freestyle	03:15.6	02:10.4	81	24.8	1.9	46	46.1
150m Freestyle	03:15.4	02:10.2	79	24.3	1.9	46	45.7
150m Freestyle	03:16.6	02:11.1	81	24.7	1.9	46	46.3
150m Freestyle	03:18.8	02:12.5	81	24.4	1.9	47	46.6
100m Freestyle	01:52.0	01:52.0	49	26.3	2	40	40.2
100m Freestyle	01:48.3	01:48.3	48	26.6	2.1	39	39.1
100m Freestyle	01:47.4	01:47.4	48	26.8	2.1	39	38.8
100m Freestyle	01:47.2	01:47.2	48	26.9	2.1	39	38.8
100m Freestyle	01:48.7	01:48.7	49	27.1	2	39	39.4
100m Freestyle	01:51.3	01:51.3	50	27	2	40	40.3
100m Freestyle	01:50.9	01:50.9	50	27	2	40	40.2
100m Freestyle	01:47.0	01:47.0	44	24.7	2.3	38	37.7
50m Freestyle	00:52.5	01:45.0	22	25.1	2.3	37	37.2
50m Freestyle	00:55.4	01:50.8	23	24.9	2.2	39	39.2
50m Freestyle	00:54.4	01:48.9	23	25.4	2.2	39	38.7
50m Freestyle	00:51.0	01:42.0	22	25.9	2.3	36	36.5
50m Freestyle	00:55.0	01:50.0	24	26.2	2.1	40	39.5
50m Freestyle	00:53.8	01:47.6	24	26.8	2.1	39	38.9
200m Freestyle	03:53.3	01:56.7	100	25.7	2	42	41.7

Notice first that I’m a slow swimmer. Also notice the significant change in pace between the last 150 and the first 100: this is where I put on the wetsuit. I know, if I were to design a study to measure the impact of wearing a wetsuit I would compare across similar lap distances, but this is the data that I have and it’s still interesting.

Here is the chart split out to focus on the last 1200m that I swam without the wetsuit. Again, I realize that these are all 150s but this is the data that I have.

Interval	Time	Pace (/100 m)	Strokes	Stroke Rate (/min)	Stroke Distance (m)	SWOLF	Efficiency
150m Freestyle	03:07.8	02:05.2	76	24.3	2	44	44
150m Freestyle	03:12.4	02:08.3	77	24	1.9	45	44.9
150m Freestyle	03:13.3	02:08.9	75	23.3	2	45	44.7
150m Freestyle	03:12.4	02:08.3	78	24.3	1.9	45	45.1
150m Freestyle	03:15.6	02:10.4	81	24.8	1.9	46	46.1
150m Freestyle	03:15.4	02:10.2	79	24.3	1.9	46	45.7
150m Freestyle	03:16.6	02:11.1	81	24.7	1.9	46	46.3
150m Freestyle	03:18.8	02:12.5	81	24.4	1.9	47	46.6
AVERAGE		02:09.4			1.9	46	45.4

Now here is a chart split out to focus on the last 1200m with the wetsuit. Yes, I realize that these are mostly 100s and 50s, not the 150s I swam above. I also want to point out that these splits represent meters 2700 – 3900 of what, for me, is a long swim.

Interval	Time	Pace (/100 m)	Strokes	Stroke Rate (/min)	Stroke Distance (m)	SWOLF	Efficiency
100m Freestyle	01:48.3	01:48.3	48	26.6	2.1	39	39.1
100m Freestyle	01:47.4	01:47.4	48	26.8	2.1	39	38.8
100m Freestyle	01:47.2	01:47.2	48	26.9	2.1	39	38.8
100m Freestyle	01:48.7	01:48.7	49	27.1	2	39	39.4
100m Freestyle	01:51.3	01:51.3	50	27	2	40	40.3
100m Freestyle	01:50.9	01:50.9	50	27	2	40	40.2
100m Freestyle	01:47.0	01:47.0	44	24.7	2.3	38	37.7
50m Freestyle	00:52.5	01:45.0	22	25.1	2.3	37	37.2
50m Freestyle	00:55.4	01:50.8	23	24.9	2.2	39	39.2
50m Freestyle	00:54.4	01:48.9	23	25.4	2.2	39	38.7
50m Freestyle	00:51.0	01:42.0	22	25.9	2.3	36	36.5
50m Freestyle	00:55.0	01:50.0	24	26.2	2.1	40	39.5
50m Freestyle	00:53.8	01:47.6	24	26.8	2.1	39	38.9
200m Freestyle	03:53.3	01:56.7	100	25.7	2	42	41.7
AVERAGE		01:48.7			2.1	39	39

Notice the average stroke distance in the first chart as compared to the average stroke distance in the second chart. This is the measured benefit, to me, of the wetsuit during my swim.  

Here is a summary chart:

Interval	Pace (/100 m)	Stroke Distance (m)	SWOLF	Efficiency
AVERAGE (without)	02:09.4	1.9	45.5	45.425
AVERAGE (with)	01:48.7	2.1	39	39
Percent Change	-16%	11%	-14%	-14%

Overall I saw an 11% increase in distance per stroke! It’s not the 18% increase reported in the article above, but I’ll take it, and actually, I did. Instead of returning the suit to wetsuitrental.com, I bought the suit and hung it up in my closet!

If I decide to wear the suit during a race rehearsal, maybe I’ll come back and update this post.  My only hesitation with that is how warm they keep the pool where I usually swim.  A 90 minute swim, in a wetsuit, in an 82 degree pool sounds like a bad idea to me.

Now it’s time to rethink my swim goal for IMAZ!

Clark