For underfoot support and cushioning, the GTS 12s have a Profile Sockliner that is made with a lightweight, biodegradable material called BioMoGo. BioMoGo works together with Brooks DNA technology in the heel and forefoot to provide customized shock absorption and comfort based on a runner's size, foot shape and speed. For stabilization, the GTS 12's midsole also features Progressive Diagonal Roll Bar® (PDRB®) and DRB Accel technology. These technologies support the foot and prevent over-pronation but still allow for independent movement in the heel and forefoot. Lastly, the GTS 12s have a decoupled heel construction, known as Caterpillar Crash Pad technology, so parts of the heel can move independently of each other and smooth out transitions in the gait cycle.
The LG4s have a foam insole that provides lightweight cushioning, but, if you customize your shoes, you can opt for a responsive or cushioned sockliner. The Nike+ Sensor fits underneath the sockliner in the left shoe in all models. The LG4's midsole features the Dynamic Support system, which is made up of Lunarlon and a firmer carrier foam, to provide additional stability, cushioning and comfort during the gait cycle. Lunarlon foam is 30% lighter than traditional Phylon and offers responsive cushioning that exceptionally resilient even after long runs. Unlike previous LunarGlide+ models, the LG4's Lunarlon component is now independent from the firmer carrier foam and much more substantial.