Bosu

BOSU, short for Both Sides Up, is a fitness training device consisting of a rigid platform attached to a flexible rubber hemisphere. The hemisphere can be used dome-side up or flat-side up, enabling a wide range of balance, stability, and strength exercises. The dome is typically inflated to adjustable firmness, allowing the user to tailor difficulty. BOSU Balance Trainers are common in gyms, fitness studios, and home settings.

Origin and name: The device was developed by David Weck in the 1990s and marketed as the BOSU Balance Trainer. The acronym reflects its two usable surfaces, offering both stability and instability in training.

Use and applications: In training, users perform movements such as squats, lunges, push-ups, and planks on the dome, or execute upper- and lower-body drills on the flat side. It is used for balance and proprioception work, core stabilization, athletic conditioning, and rehabilitation under professional guidance.

Benefits and considerations: Proponents cite improvements in balance, coordination, neuromuscular control, and functional strength, with the surface stability providing scalable challenge. Users should maintain proper form, begin with easier tasks on the flat side or near support, and progress gradually. Individuals with certain conditions, such as recent injuries or joint problems, should consult a health professional before use.

Variants and related devices: Similar stability tools include wobble boards and stability discs; the BOSU lines include versions designed for commercial gyms and home use.