Posts from Apr 2012

Promontory Point in the 1940s

Apr 02 2012

A recent Digital Library, taken by Charles Cushman between 1938 and 1969.

Of particular interest are the Promontory Point in the early 1940s. Through Cushman’s keen eye, we can see the Point was a special place even back then, when its great trees were mere saplings.

But Cushman was apparently drawn less to the landscape and water features of the Point than to the… human features. Specifically, women in bathing attire. The Point just happened to be an unusually rich source of subjects.

Here’s a sampling of Cushman’s work, with his original captions. The entire collection is available here.

Lake front on clear day. View north from 55 St. Prom., 7/12/1946

Big fleecy clouds in blue sky above 55 st. Promontory with Anonymous summer transient in foreground, 7/5/1945

Girl bathers and girl fisher -Pt. Of rocks, 7/18/1942

Comely and Blonde Mrs. Schneider poses astride rock off Promontory point while camera wades, 8/12/1941

A brunette and a tanned blonde, 7/30/1941

3 Girls and a boy form an octopus in sunshine, Promontory Pt, 7/1941

Vacation days for hyde Park schoolgirls at Promontory, 6/27/1941

Flower- suited sun bathers at 55th St. Promontory, 5/29/1941

Wave breaks along 55th St. Promontory, 5/23/1941

Ice floe retreats, Lake Michigan, first hot day of spring Three views of green grass, blue lake & sky, and white ice, from point off 55th St, 4/12/1941

Ice floe retreats, Lake Michigan, first hot day of spring Three views of green grass, blue lake & sky, and white ice, from point off 55th St, 4/12/1941

Snow-covered 55th St Promontory + Lake View south from 55th St. Promontory, 2/9/1941

SWOLF and swimming efficiency

Apr 04 2012

Follow-up posts:

SWOLF, an elision of “swim golf,” is an imperfect but useful metric of swimming efficiency. You only need a pace clock to measure SWOLF, although it is now included on many multi-sport watches such as the Garmin ???.

In brief: SWOLF is the sum of time (in seconds) and stroke count to complete a given distance.

Traditionally, that distance is 50 meters (or yards) - but there’s no reason you can’t get a SWOLF score for a longer distance. I once did a SWOLF face-off with David Barra for the buoy line at Lake Minnewaska, New York. I would not recommend measuring SWOLF for distances less than 50m (e.g., one length of a short-course pool) - the variability is too high.

Traditionally, “stroke count” means strokes (one arm = one stroke) rather than stroke cycles (two arms = one cycle) - but as I will argue later in this article, stroke cycles may be preferable.

In the interest of terminological precision, SWOLF is defined as the measure itself (40 seconds for 20 stroke cycles = SWOLF score of 60); and swim golf is defined as the process or exercise of trying different combinations of stroke rate and stroke length to find an optimally efficient stroke (lowest SWOLF).

It’s important to understand how to use it correctly. Here’s the drill:

  1. Swim one length of the pool
  2. Count the number of strokes you take
  3. Get your time (in seconds)
  4. Take the sum of (2) and (3). That is your SWOLF score.
  5. Repeat steps 1-4, trying different combinations of stroke rate, stroke length, and effort. Which combinations produce the lowest score?

Please note:

The golf analogy works better in a 50m pool, too. An excellent swimmer will score in the low-70s (e.g., 40 seconds in 32 strokes, or 35 seconds in 37 strokes) - just like a “scratch” or zero-handicap golfer. The (unofficial) world record for SWOLF is held by the great Russian sprinter Alexander Popov: 20 strokes + 25 seconds for a mind-boggling SWOLF score of 45.

Interpreting a SWOLF Score

SWOLF is an indirect measure of swim efficiency. Conceptually, swim efficiency can be thought of as [Speed / Effort]; however, measuring effort (% of max HR, V02, blood lactate, calorie burn, etc.) can be inconvenient in the pool. SWOLF uses stroke count as an indicator of effort - but it’s not a particularly good indicator.

An illustrative example:

Here is the famous final length of Sun Yang’s world-record setting 1500m last year (33 strokes in 26 seconds = SWOLF score of 59):

And here’s the final length of Janet Evans’ gold-medal winning 800m at the Seoul Olympics (49 strokes in 30 seconds = SWOLF score of 79).

Should we interpret Sun Yang’s much lower SWOLF score to indicate he is a much more efficient swimmer than Janet Evans? No. He is probably slightly more efficient, because he’s slightly faster - but we know nothing about their respective levels of effort. Sun Yang’s stroke count is lower than Janet Evans’ because he is 6’6” and she is 5’4”. He has a naturally longer stroke.

I can pretty easily hit the low-70s for SWOLF; does that mean I’m more efficient than Janet Evans? Not likely.

The point being: SWOLF is usually not meaningful in comparing different swimmers. It’s meaningful in comparing different data-points for the same individual. If I can move from a SWOLF of 75 to 70, that probably means I’ve improved my efficiency. But my SWOLF of 70 doesn’t mean I’m more efficient than someone else with an 80.

(Though, this rule has a limit: What about a SWOLF of 110? Most likely, I’m more efficient than that swimmer.)

At any given level of effort, each swimmer has a certain combination of stroke rate and stroke length that is most efficient in producing speed. SWOLF is a great drill to help swimmers zero in on that combination.

To watch a video of me doing SWOLF drill, see this post.

Evan Morrison coaches at Fog City Masters in San Francisco, California. He is a USMS Level 1 and Level 2-certified coach.

A chlorinated swim

Apr 06 2012

Last weekend I drove 90 minutes for a 19-minute swim - which would be unusual for me nowadays, even for an open-water swim. But this was a pool swim! Heresy!

There were other good reasons for the trip, however. I met up with my old buddy Rob D., as well as fellow SBCSA director Dave VM. Dave joined me for 30 lengths of freestyle, while Rob lap counted and shot some video with his GoPro. Later, we caught up on the latest OW/marathon swimming gossip over beer and burritos. Good times.

San Luis Obispo Swim Club occasionally puts on combined USA-S/USMS meets, and this was one such occasion. I had no interest in hanging out on a pool deck all day dodging 10-year olds… but they were offering a 1500 (LCM) as the last event of the day, and it was tempting. I could sleep in, show up early afternoon… get in, get out…. one and done.

When I showed up, the kids’ meet was still in full swing and they were running only a single warm-up lane. Which led to scenes like this:

Photo by Rob D.

Soon enough the non-1500 portion of the meet concluded and most of the kids cleared out. There were four heats of age-group milers, followed by a final Masters heat with me and Dave VM.

It would be my first long-course 1500 since… wait for it… August 1997. Almost 15 years ago! As a Masters swimmer I’ve done the SCY 1650 (twice) and the SCM 1500 (once), but not the LCM version. So I was interested to see what I could do (albeit unshaved, untapered, etc.)

Rob brought his GoPro to film the proceedings. He attached it to the lap counter, resulting in some cool underwater & turn footage.

Evan's 1500m at SLO LCM from Rob D on Vimeo.

My time: 18:56.72. Average pace per 100m of 1:15.8. This was… okay. I wanted to be under 19, and I was (barely). My splits were reasonable:

1:12.2, 1:14.9, 1:15.3, 1:15.8, 1:16.0 = 6:14.1

1:16.3, 1:16.4, 1:16.3, 1:16.1, 1:16.3 = 6:21.4

1:16.0, 1:16.2, 1:16.9, 1:16.8, 1:15.3 = 6:21.2

For shits & giggles, I plotted these 100 splits against two other swims from earlier in my life.  The blue line shows last weekend’s swim. The red line shows my first-ever 1500, just after I aged up as a 13-year old. The green line shows my last-ever 1500, as a 17-year old.

I won’t be offering any heavy interpretation here, but what I’ll say is: This is why I do open water.

Letters from Connie: Why?

Apr 18 2012

The second in a series of posts inspired by Conrad Wennerberg‘s classic Wind, Waves, and Sunburn: A Brief History of Marathon Swimming.

In a brief chapter titled, simply, “Why?”, Chairman Connie ponders marathon swimmers’ reasons. In the end he concludes, basically, Why ask why? - but he offers some intriguing thoughts and observations along the way. One passage is particularly striking:

In my twenty years of observing the world-champion swimmers I have discovered an interesting common denominator. It became evident while discussing their personal lives with them. Hours of conversation with fourteen swimmers… brought to light the fact that twelve of them were under severe emotional tension during the time they were champions. Only two were not under such tension and seemed to have planned a course of action that led to their achievement without emotional involvement.

The others were reacting to the tensions incurred by: (1) the breakup of a marriage and divorce; (2) loss of a job; (3) sexual maladjustments. Physiologists tell us that such serious threats to one’s personal life are manifested by bodily response. The pituitary gland lying at the base of their brain secretes more of the substances that monitor brain and bodily functions. One of the repsonses is extreme nervousness and tension. Luckily, those professional swimmers reacted normally to the stimulus by working it off in training. They were tranquilizing themselves in the most sensible fashion: action.

I think this is keenly observed… though my inner social scientist feels compelled to note: correlation does not imply causation. In two respects:

Wind, Waves, and Sunburn

First, the fact that many champion marathon swimmers’ personal lives were in disarray does not mean their swimming somehow benefited from the personal stress. On the contrary, I think it’s always better to approach a gargantuan physical undertaking such as a marathon swim from a position of stability - with a clear mind and a fat wallet. Of course, it doesn’t always work out that way!

Second, though Connie implies that swimmers’ personal tensions, in a sense, motivated their training and eventual success - the opposite relationship is quite plausible. Anybody remember this story?

Finally, apropos of nothing in particular, I wanted to reproduce the closing passage of “Why?”… I’m not sure why, I just love it.

All that can be said is that man is attracted to water in the same fashion as he is attracted to a beautiful woman or a tasty meal. Would we say it was a matter of chemistry? Such things are the mysteries of life.

Sharks Live in the Ocean

Apr 29 2012

So, there was this local news item last week. While Santa Barbara isn’t typically a hotbed of shark activity, this was a reminder that indeed, sharks do live in the ocean.

That’s right, readers. Sharks live in the ocean.

great white shark

It’s always interesting to observe how ocean swimmers deal with this fact.

Some take a spiritual, new-agey approach: If you just, you know, become one with the ocean and don’t give off the “fear signal,” the sharks will leave you alone. Fittingly and rather ironically, these people often are residents of San Francisco. (It’s OK, I used to be one.)

Others avoid the issue with euphemisms: “Man in the Grey Suit,” or “The Landlord,” or “Old Whitey”… or, most comically of all, “the S-word.” I guess the idea is, if you don’t talk about it, maybe it’ll go away.

Others put their faith in technology. Because obviously, the 6-meter, 2-ton “fish” attacking from below at 25mph is going to respect the little Shark Shield zapper dangling off the end of the kayak. Good luck with that.

And then there are kooks like this guy. Ah, well.

Me? I guess I’m somewhere in the middle. Sharks are fearsome creatures… but I’m still going to swim in the ocean. It’s a small risk - somewhere between an asteroid falling on your head and being struck by lightning - but still a risk.

And I think that’s the healthiest way to think about sharks as an ocean swimmer: as one of many risks we all take (often unwittingly) in everyday life. I drive a car, in which I could be smashed at any moment. I hike in the mountains, where venomous rattlesnakes lurk around every bend in the trail. And I swim in the ocean… where sharks live.

Swimming in sharky waters is a small risk - but not a constant one. It varies in predictable ways - and can therefore be minimized to our advantage. Some tips:

And, if all else fails, just close your eyes.