Summary
Most footrests tip or slide when you push them with your foot. The LC99 solves this with three design principles: a 512mm wide base, TPR non-slip pads, and a low center of gravity. It stays stable under pressure, yet moves smoothly when you want to reposition it.
Why Footrests Keep Sliding Away
You place a footrest under your desk, use it for a while, and then — it's slid out of position again. You pushed it with your foot without thinking, or it shifted when you changed positions.
When this keeps happening, you stop using the footrest altogether. Inconvenient objects get abandoned. From a behavioral design perspective, this is a product failure. The product is actively preventing the intended behavior — maintaining good posture.
When ROUMO designed the LC99, solving this problem was the first priority.
512mm: The Number Behind the Philosophy
The LC99 is 512mm (20.2 inches) wide. Most footrests sit between 400–450mm — the LC99 is noticeably broader.
This width wasn't chosen arbitrarily. It represents approximately 70–75% of average adult shoulder width — the minimum measurement needed for both feet to rest naturally side-by-side without hanging over the edges.
A wider base creates two effects.
First, greater stability. The wider the support surface, the harder it is to tip. When you push from the side with your foot, it doesn't budge easily.
Second, more natural foot placement. Narrow footrests force you to alternate feet. At 512mm, you can rest both feet simultaneously in a natural, shoulder-width position.
TPR Non-Slip: "Hold On, But Let Go When Needed"
The bottom of the LC99 uses TPR (thermoplastic rubber) non-slip pads. This material must satisfy two seemingly contradictory requirements at once.
Requirement 1: It must not slide when your feet are on it.
While in use with weight applied, the footrest must stay firmly in place. If it slides forward while you're using it, you'll constantly be pulling it back with your foot.
Requirement 2: It must be easy to move when you want to reposition it.
If it's completely immovable, that's inconvenient. You should be able to push it under the desk with your foot or shift it slightly to one side.
TPR pads provide strong friction in the vertical direction (downward pressure from body weight) while offering measured resistance in the horizontal direction (pushing with your foot). Weight holds it in place; a foot push moves it smoothly. That's the balance.
Low Center of Gravity: A Structure That Won't Tip Over
The main reason footrests tip over is a high center of gravity. Height-adjustable footrests are particularly prone to this — raise it to maximum height and the center of gravity rises, making it easy to tip sideways.
The LC99 solves this structurally.
Height and angle adjustment changes the position of the top plate and support rods. The heavy lower base itself stays the same. Whether you set the height to 5cm or 19cm, the base structure remains just as stable on the floor.
This is why the LC99 doesn't tip easily even at its maximum height of 19cm.
Stability as Behavioral Design
ROUMO's design philosophy — Behavioral Design — aims to create products where users naturally do the right thing without thinking about it.
Stability is part of that philosophy. You don't need to consciously decide "I'm going to use my footrest today." If the LC99 is sitting under your desk, your feet will naturally find it. That's why ROUMO obsesses over stability.
A footrest that tips or slides breaks the habit-formation loop. A stable footrest builds it.
Within a few days of placing the LC99 under your desk, resting your feet on it shifts from a conscious decision to an unconscious habit.
FAQ
Q. Does it stay in place on carpet?
A. Yes, the LC99's TPR pads work effectively on carpet. On very thick or plush carpet, some minor movement may occur — in that case, positioning it against a desk leg adds extra stability.
Q. Does it stay stable at maximum height (19cm)?
A. Yes. The 512mm wide base and low center of gravity keep it stable even at full height under typical foot pressure.
Q. What about hardwood or laminate floors?
A. Hard floors are actually ideal for TPR pads. The friction coefficient works best on smooth surfaces — often more stable than carpet.
Q. Does it wobble after adjusting the height?
A. No. Once the knob is tightened, there is no wobble. Hand-tightening without any tools provides sufficient hold.
Q. What if a child kicks it?
A. It's designed to handle repeated foot pressure in everyday use. Normal contact — including from children — poses no issue.
Related Posts
- 81 Height & Angle Combinations, One Knob — The Design Secret Behind the LC99
- Why Silver Film? — The Heating Technology Behind the LC99 Heat
- Do Footrests Really Make a Difference? — 5 Research-Backed Facts
📚 References
- ISO 9241-5 (1998). Ergonomic requirements for office work — Workstation layout and postural requirements.
- NIOSH. "Ergonomics and Musculoskeletal Disorders." National Institute for Occupational Safety and Health.
- Pheasant, S. & Haslegrave, C. M. (2006). Bodyspace: Anthropometry, Ergonomics and the Design of Work. Taylor & Francis.
- Kroemer, K.H.E. & Grandjean, E. (1997). Fitting the Task to the Human. Taylor & Francis.
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