~Function~
As the name suggests, core squeeze is trained by crushing and gaining a load, but its biggest feature is that the load changes depending on the direction of crushing. It is realized by a structure in which the high hardness of the central urethane (gray part) is sandwiched between the low hardness urethane (black part).
Particular attention was paid to the distribution of the thickness of the two types of urethane. There really was no answer to this, so we decided to create several types of balances with samples and find the best balance for training the main rectus abdominus, oblique abdominus, latissimus dorsi, and pectoralis major muscles, which led to the current balance.
~Manufacture~
In addition, the most time-consuming part was deciding on the manufacturing method.
The first method we explored was the possibility of foaming urethane in a mold, but it was abandoned because it was difficult to realize a structure that changed the load depending on the direction of crushing, and crucially, it was pointed out that the finish would be uneven in vacuoles. In addition, we were considering manufacturing locations overseas, but we decided to do it in Japan due to the cost of transportation.
As a result, at the firing urethane processing plant, a cube made of a combination of two types of foam urethane with different hardness is chamfered and cut into this shape.
~Specification~
Size: Diameter 30cm
Weight: 440g
Central density (kg/㎥) 32kg +-2.6
Side (kg/㎥) 18kg +-1.4
~Color~
As a color that does not look out of place in the living room, it has a chic gray and black finish with a sense of unity.