The Power of Gravity

I’ve been a Physics experiment this week! 😉 

We’ve been working on sweeps from open guard and spider guard this week.  These positions always make me nervous.  I’m afraid that I’ll drop the guys on top of me.  But, things were different this week.  I learned that in these positions, I can use gravity to my advantage.

I have a very difficult time sweeping the big guys when they are in my guard.  They root their bums to the ground like ancient oak trees.  I realized today that, in this position, they have gravity on their side.  This is my “Evil Gravity”!  😦  Now, if I’m in spider guard,  I can load the weight of the guys onto my legs.  Being a woman, my lower body is stronger than my upper  body.  Also, I have my back on the ground giving me the support of the world, literally.  In this position, their center of gravity is shifted forward.  Now, they are off-balance.  All I have to do is tip them to one side or the other.  Gravity takes over from there.  This is my “Happy Gravity”! 🙂

Newton’s first law of motion states that an object continues in its state of rest unless compelled to change by an external force ( me and gravity).  The object will continue with a constant velocity unless compelled to change by an impressed force ( Earth ).  ( see Linda Huetinck, Ph.D. “Physics” published by Cliff Notes, 1994, Lincoln, Nebraska, p 19)

The other sweeps we drilled were from open guard.  You’re partner is attempting a standing guard pass.  Here you would grab your partner’s sleeve and sweep his legs with your legs.  Don’t let go of the sleeve! The object is to let the force created by your partner’s fall backward, pull you through their legs and into side control.  😉  My partner outweighed me by fifty pounds (22.7 kg)  So, when he would fall back all of that extra mass would catapult me through his legs and right into side control.  With an americana setup, I might add!  However, my fall backward didn’t create enough force to pull my partner through my legs into side control.  This is directly caused by my lack of mass. Poor guy…  He is so nice, too.

Newton’s second law of motion states that if a net force acts on an object, it will cause an acceleration of that object.  The law addresses the cause and effect relationship between force and motion ( F = ma)  Force = F, mass = m, and acceleration = a.  (see Huetinck again) So, you take my mass and multiple it by my acceleration, you would get “Jodi Force”.  Now you take Nice Guy mass and multiple it by his acceleration, you would get “Nice Guy Force”.  Please note, that since Nice Guy’s greater mass will cause a greater acceleration for him.  So, Nice Guy’s greater mass and acceleration created a greater force, which I used shamelessly!  😉

I’m looking forward to hearing from you guys.  Please let me know if my train of thought is going in the right direct.  It lacks a compass most days.

Take care,

Jodi

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7 Responses to The Power of Gravity

  1. Dev says:

    FANTASTIC post! The concept I keep coming back to time after time is control of someone’s center of gravity. Like you said, if they keep their base down, and their center of gravity off of you, it’s WAY tougher to dislodge them. However, using exactly the principles you’re talking about, if they put pressure on you (and you keep your knees in between you and them) then they’re giving you their center of gravity. A basic scissor sweep, for instance, almost necessitates your opponent coming forward – sometimes they do it for you, other times you have to posture up and bring them back down with you. But when you have their center of gravity OVER your hips instead of away from them, the sweep damn near performs itself.

    Solid, solid principles here. Great post!

  2. Kirsch says:

    Seeing as I’ve taken more physics classes than probably necessary, I definitely appreciate the application of F=ma to Jiu Jitsu!

    It also makes me think of how and why it’s effective to fake a sweep one way, so that your opponent defends by leaning their mass in the opposite direction, making it easier to continue to accelerate their mass with the “real” sweep in the direction that you intended from the start (hope that made at least a little bit of sense).

    • @ Kirsch – Oh yeah, I like the fake! 😉 I gues I’m kind of a nerd when it comes to physics. When I was stiking, I would try to figure out all the physics priciples involved in every kick. I ended up with some great kicks, or so everyone said. Thanks for the input.

  3. slideyfoot says:

    Great post!

    For me, one of the the biggest problems is not just realising the power of gravity, but having the confidence to trust in that leverage. For example, there are various sweeps where you’re taking the entire body weight of the other person and lifting them over your head.

    I find it can be tough to trust it is going to work properly, particularly against somebody huge, and it is therefore easy to get discouraged if you miss some detail and struggle to complete the technique.

    • @ Slideyfoot – Thanks for taking the time to read my post. It means a lot to have more experienced people double check my train of thought. You’ve also given me a new phrase to add to my rolling mantra. “Trust the science.” My rolling mantra is a list of trigger phrases that I use to stay focused when I roll. It usually runs something like this:

      “Calm down. Relax. Breath. Work the puzzle. Trust the science.”

  4. Pingback: Vampire on a Tofu Diet | Combat Sports Review Blog

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