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The physiology of aquafit (and pool running)

March 7th, 2011

This week’s Jockology column looks at the physiological differences between land- and water-based exercise — aquafit, water running and activities where you’re vertical in the water rather than horizontal like swimming:

[...] The differences between water and land might seem obvious, but there are some subtleties. For example, the pressure exerted by water against your body is strongest at the bottom of the pool, where your feet are, and weakest at the top. This pressure gradient helps push blood back towards your heart, making its job easier. [Read the whole article...]

The article focuses mainly on the advantages of water-based exercise for people with balance, joint or weight concerns that make land-based exercise more difficult. But there’s a special bonus for pool-running aficionados: a brutal 60-minute workout that Canadian mile record-holder Kevin Sullivan used when he had a stress fracture in his sacrum. He got it from 1984 Olympic bronze medalist (and fellow Michigan alum) Brian Diemer, who relied on it to stay in shape prior the 1984 Olympic Trials — Diemer apparently had a stress fracture and came out of the pool only three weeks before the Trials, but was still fit enough to make the team and go on to medal later that summer.

I did it myself, every third day, when I had a sacral stress fracture in 2004. There’s something about the symmetry of the workout that I love — I’m always surprised when all those parts manage to add up to exactly 59:55.

  1. April 7th, 2012 at 22:32 | #1

    My daughter is an NCAA All American runner. However over the last 4 years she has suffered 5 fractures and most recently a stress reaction in her left sacrum. She has been doing pool workouts for the last 4 weeks. She also has access to an alter G treadmill. In your opinion, how would you transition from pool to track workouts.

  2. alex
    April 8th, 2012 at 04:34 | #2

    Sorry to hear about your daughter’s stress fractures, Trish. I had a stress fracture in my sacrum at one point — not fun. When I started running again, I did it very gradually: literally a minute of running at a time, totalling no more than five minutes a day at first, with no consecutive days. (I was still training twice a day in the pool or on the bike to maintain fitness at that point). I think distinguishing between rehab and fitness is important: if you’re going for your run and thinking that this run has to get you fit, you’re more likely to push through discomfort and cause a setback.

    That being said, with five fractures in four years, it sounds like the transition isn’t the biggest challenge for your daughter — it’s staying healthy. I’m sure you’re already looking into possible biomechanical or dietary changes that could help. Until the underlying problem is addressed, no transition, no matter how gradual, will keep her healthy.

  1. March 8th, 2011 at 16:54 | #1