A few definitions in the context of Rebounding:
- Gravity: is a force which tries to pull two objects towards each other. Anything which has mass also has a gravitational pull. The more massive an object is, the stronger its gravitational pull is. Earth’s gravity is what keeps you on the ground and what causes objects to fall. When you are standing still on the Rebounder it is gravity that is keeping your feet on the mat of the rebounder.
- G-Force: is what you feel then you are trying to oppose gravity, it is the strength of the force that is being used. One “g” is the among of force that Earth’s gravitational field exerts on your body when you are standing still on the ground. Every particle that makes up our planet is tugging on you simultaneously. Each one of those pulls is quite weak, but combined they are strong enough to keep your feet on the ground (or on the mat of the rebounder!). Any time an object (in this case a person) changes its speed faster than gravity can change it, the forces (G-Force) will be greater than one-g. At zero-g you would feel weightless. And past 100-g you are almost certainly dead! 5g acceleration is something that race car drivers regularly experience.
- Acceleration: through vertical velocity (which we can refer to as the ‘take off or propulsive launch phase’ is a state of increasing speed as you push up and away from the mat of the Rebounder, opposing gravity to enable your feet to leave the mat surface and accelerate upwards. The entire body is temporarily airborne.
- Deceleration: which we refer to in rebounding is the landing phase of the jump, comes after acceleration, when gravity is pulling you downwards (free falling), your feet land back on the mat of the Rebounder and the spring and mat system assist in slowing you down along with your muscular skeletal system.
In effect, at the top of the bounce you are weightless, defying gravity, floating in space for just a split mili-second. At the bottom of the bounce/jump phase you go beyond the horizontal level surface the mat and use your muscles along with the rebounder spring system to slow you down. This constant, cycle of acceleration and deceleration movement creates a G-Force which is felt by every single cell in your body and is the “magic” behind why Rebounding is the most effective workout on the planet!
How much G-Force can I create on a Rebounder?
The amount of G-Force you will create will depend on the amount of “push” you use and the intensity of the workout. The more you “push” into the mat surface, the more G-Force you will create.
A United States Air Force Study in 1983 by Dr Ward Dean proved that during trampolining / rebound exercise, on a high quality rebounder, a conditioned person can achieve 3.24 G’s. States Air Force,
Ward Dean, M.D., United States Air Force,
Achieving up to 3.24 G’s makes Rebounding extremely efficient. You become stronger and burn more calories because your exercise body weight is heavier and therefore you are working harder than normal. Consider the example of running on a treadmill that allows you to work-out your calorie burn – if you put in a heavier body weight the machine will tell you that you have burnt more calories.
Children will not achieve the full 3.24 G’s – more likely between 1 and 2 G’s. Also, their natural inclination is to “jump up high” and children may take longer to grasp the concept of the “controlled push”. Children are also unlikely to have the strength to push down into the mat as hard as an adult can to gain the extra G’s. That said, at 1 – 2 G’s the health benefits will still be realized.