Rollers, mats and percussion devices: reading the specifications

Rollers: core, diameter, surface

A roller is a tube you put your body weight on, so the core decides whether it lasts. Hollow rollers with a rigid inner tube keep their shape, while solid foam compresses over months and becomes a different tool from the one you bought.

Diameter changes how the pressure is spread. A large roller covers a broad area and a small one concentrates on a narrow strip, which matters more than the colour or the pattern.

• Hollow with a rigid core: holds its shape and is light to carry.
• Solid foam: softer at first, flattens with use.
• Smooth surface spreads pressure; a textured one concentrates it.

Percussion devices: amplitude and stall force

Two figures describe a percussion device: amplitude, the distance the head travels on each stroke, and stall force, the pressure at which the motor gives up. A short stroke with a long list of speed settings is a different tool from a longer stroke.

Battery and noise come next. A device that needs charging every other session, or that is loud enough to be unpleasant in a flat, gets used less than its specification suggests.

• Amplitude in millimetres rather than the number of speeds.
• Stall force: how much pressure the motor takes before it stops.
• A replaceable battery pack outlasts a sealed one.

Mats: thickness against stability

A thicker mat cushions more and wobbles more. Standing work wants a thin, dense surface, while floor work cares less about thickness than about whether the material still grips.

Density is the figure nobody prints. A dense mat feels heavy in the hand and lies flat from the first session; a soft one creases and slides.

• Around 5 mm is a common middle ground for mixed use.
• A closed-cell surface wipes clean and does not soak up moisture.
• Length: lying down, a short mat leaves your feet on the floor.