Imagine exercising without all that extra body weight dragging you down.


Well, now you can! (Actually you always could but you probably didn’t realize it.)


Step 1: Put on your bathing suit. While this may be optional, depending upon where you are, it is likely that the people around you would appreciate it!


Step 2: Step into the pool. Don’t be shy. Get all the way in there. If the water is up to your waist you have lost ~50% of your body-weight. If you are chest-deep then you have lost ~75% of your body-weight. And if you are submerged up to your neck then you only weight 10% of what you weighed before you got into the water!


Now, this might seem a little crazy. You don’t LOOK like you’ve lost all that weight (sorry!) but that is because there are two competing forces at work. The first is gravity. As you know, this is the force that pulls you down to the ground.


When you are in the water, you also have buoyancy acting in the opposite direction. Buoyancy depends upon 2 things: the density of the water, which is fairly constant, and the density of the object that is being put into the water. Muscle is denser than water, whereas fat is less dense than water. So, fat floats and muscle sinks. The more fat you have on your body, the more buoyant you are.


Bones are also denser than water, so if you have strong bones (ie. You don’t have osteopenia or osteoporosis) then you will most likely feel less of the buoyancy effect.


You can see this physical property in action when you watch someone who is quite muscular try to do a back float vs someone who has more fat on their body. In the water, the fat wins!


Why is this important to your workout? If you are someone who doesn’t need the joint impact to be reduced or the support for the limbs as they move through the various joint ranges of motion, then you may be wondering what the big deal is. But regardless of who you are or what your physical ability is, buoyancy allows you to do 2 things in the water that you can’t do on land:


  1. Do similar exercises in a wide range of positions. For example, you can use the buoyancy of the water to support the upper body while doing straight legged hip extension with a much greater resisted range of motion than you can on land.


  1. Do agility, balance and coordination exercises without the fear of falling. Don’t get me wrong, you may still fall…but it’s not actually the fall that people are afraid of, it’s the landing. And on land, that can result in pain, bleeding and broken bones or torn ligaments. In the water, it can result in your hair getting wet. I’ll take wet hair for the win!


So let’s go back to that observation I posed at the beginning of this post…


How can you lose weight without looking like you lost weight?


Weight is actually mass X gravity. So, while your mass (the amount of material in your body) stays the same, you now have the force of buoyancy opposing the force of gravity. And the more fat you have in your body, the more buoyant you are, so the less you will weigh!


There’s just that one catch…you’ll only feel this effect in the water.


So, if you are serious about wanting to lose fat, once you get into the water you need to work at a moderate to vigorous intensity to burn off the excess energy stored in the body fat. In our next post we will look at ways to increase the intensity of your water workout!


What are some creative ways that you’ve used buoyancy in your classes?


Leah Esplen is a certified canfitpro Pre & PostNatal Fitness Specialist PRO TRAINER, CSEP Certified Exercise Physiologist and BCRPA Trainer of Fitness Leaders in Aquafit, Fitness Theory and Resistance Training who had the crazy idea that she didn’t know enough about health and fitness so she decided to go back to university and get her Masters degree in Biomedical Physiology and Kinesiology when her children were 3 and almost 2. She liked it so much that she decided to continue to teach in the department while running her own Pre&PostNatal Fitness and instructor education company, MommyMoves Fitness & Education, Ltd. Thankfully, her husband supports her many endeavours by cooking delicious and nutritious meals for the family! Her girls, Grace and Rose, started out as being colicky little beans who would never let their mother rest but have blossomed into active teens who enjoy running, hiking, surfing, kayaking, snow-shoeing, taekwondo-ing and, above all else, swimming with their parents!

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