Traps and legs, take off and landing
### Original Concept
> So next in the legs to do both, we're saying that, I don’t want the legs to land me and then try at the same to Propel me when we want the opposite, it's on this next demo. I'm going to show you how the trapezius, the upper body starts the action to propulsion part and then the legs land land on the legs and then boom. So use the trap to raises up. It's a lot of times we wondering about why the hamstring is bothering us on the start of something like that because it's gripping the ground trying to pull you forward and put them into strain on it because it's trying to do both things. It's trying to land you and Propel you. Instead. We wanted just to land us and let the upper body propellers. So fold the traps towards each other, like a stingray.
>
### The Dyad System Integration: Landing Gear vs. Lift
The lower body and upper body form a functional Dyad with two distinct mechanical roles. The lower body is strictly the landing gear—functioning like the static skids of a helicopter to manage payload capacity. The upper body is the elevator, providing the lift. You cannot lift off a 20k payload if your landing gear only has a 10k capacity.
Here is how this mechanical relationship operates across the three demo movements:
#### 1. The Sprint Start
*The Landing Gear:** The lower body acts as the static skids of a helicopter. It does not strike the track; it simply accepts the downward transfer of weight as the body moves forward. It provides the rigid payload capacity to support the load without buckling.
*The Lift:** The upper body (traps/Stingray engagement) acts as the rotors. It creates the actual lift that pulls the payload up and forward, un-weighting the skids so they can move to the next position.
#### 2. The Tennis Forehand
*The Landing Gear:** As the athlete shifts weight to change direction, the plant leg acts purely as landing gear to receive the oncoming payload. It holds the structural capacity of the braking forces.
*The Lift:** With the landing gear securely holding the load, the upper body is free to rotate and lift through the stroke.
#### 3. The Tennis Serve
*The Landing Gear:** The peak payload moment. Upon descent, the landing leg functions exactly like a helicopter touching down. It is pure structural capacity designed to absorb and hold multiple times the body's weight.
*The Lift:** The upper back and traps provide the vertical lift during the launch phase, trusting the landing gear to handle the capacity when the payload returns to the ground.