On Thu, Jun 18, 2009 at 12:15 AM, Diane wrote:

I have a question…how do you increase your thigh muscle density/strength in the pool? I feel I’ve lost muscle with my 2-Beat Free Kick….

My Reply: How do you know you’ve lost muscle? Have you checked circumference with a tape measure?

Even if you have, the pool is not the place to think about building up your thigh muscles. That’s because, in the water (turns excluded) there’s nothing to push against. l imagine that a fair number of people may think that a 2-Beat Kick (2BK) will result in "neglecting" your leg muscles. A basic understanding of muscle physiology can therefore be helpful.

1) Don’t confuse hypertrophy (increasing the size of a muscle) with strength. Hypertrophy may look good, but strength is: (a) more influenced by neural patterning that gets multiple muscle groups to work together (no functional movements – i.e. movements that accomplish something other than lifting a weight) ever uses a single muscle group; and (b) limited by the skill with which you apply it — in the water, the vast majority of swimmers "waste" their strength by producing turbulence, rather than propulsion.
If muscle-size mattered in swimming, weightlifters would outswim Michael Phelps.

2) Hypertrophy is produced by overloading the muscle. Load is usually inversely proportional to frequency. The fewer times you perform a movement, and the greater the interval between movements, the greater will be your capacity to fire up more fibers. Load in 2BK is actually considerably greater  than in 6BK, because you can fire up more fibers. The most powerful kicking movement in swimming is the dolphin kick. 2BK is a one-legged equivalent.

3) Going back to muscle function — the capacity of the muscle to help you perform a movement, a key limiting factor will be energy supply — a good network of blood vessels to supply energy and carry off waste products. Swimming, as a rhythmic and aerobic activity helps promote "capillarization" – an increase in the density of blood vessels – of the most used muscles.

So, if you want strong (or shapely) legs, do squats or lunges in the gym. If you also want those stronger and trimmer legs to help you swim better, practice the highest level skills you can. And if you’d rather swim 1500m well than 100m, that’s the 2BK.