Ergo Impact has recently developed The LeanRite™ Chair to provide sedentary workers an innovative solution to their sit-stand problems. The LeanRite is designed to support workers in a variety of positions while accommodating individual preferences, reducing fatigue and facilitating movement without interrupting work. The LeanRite can provide support to the lumbar or gluteal region while standing and can also be used in a sitting position.
An evaluation was conducted to study the effect of the LeanRite product on pain and muscle activity when used in two different positions: standing with lumbar support and standing with gluteus support.
Three healthy subjects in their early twenties were recruited for the evaluation. Subjects used the LeanRite product in three separate one-hour sessions. The test positions studied were 1) standing Alone, 2) standing with lumbar support from the LeanRite, and 3) standing with gluteus support from the LeanRite. An electromyogram (EMG) was used to measure muscle activity during each session and subjects were asked to report pain level overall and in specific muscle regions at the end of each session. The evaluation was performed by Andrew Starsky, PT, PhD, Department of Physical Therapy, at Marquette University in Wisconsin.
Reductions in Muscle Activity:
Results of the EMG measurements show a reduction in muscle activity in gluteus medius (important muscle at the hip), mid trapezius of the upper spine, and the lumbar paraspinal muscle groups of the low back. No significant reduction in muscle activity was discernable at the quadriceps. There was an increase in upper trapezius muscle activity when using the LeanRite with gluteus support versus standing alone. Average muscle activity through maximum voluntary muscle contraction, across the three subjects is shown in the table below:
Comments on Findings:
- Gluteus medius – There was a significant reduction (30%) in gluteus medius activity during the first hour by use of the LeanRite. This muscle unloading may explain the reduced hip and back pain reported.
- Mid-trapezius – Muscle activity was significantly reduced (50%) with both levels of support (lumbar and gluteal) compared to standing alone. This can relate to potential for reduced neck and back pain while using the LeanRite.
- Quadriceps – There was no discernable change in quadriceps muscles activity. It is easy to shut the quads off when standing so this finding is not surprising.
- Upper trapezius – The increase in upper trapezius activity while using the LeanRite in the standing with gluteus support may be the result of engagement of muscles needed to support correct posture. Over time it is expected that these muscles would be better conditioned and muscle activity would be reduced.
Reduction in Pain (as compared to standing alone):
The subjects reported a reduction in overall pain with use of the LeanRite. The healthy subjects most often reported a 10% to 15% reduction (using a 10 point scale) in pain (as surveyed) when using the LeanRite for just one hour.
The data from this evaluation suggest that use of the LeanRite can reduce (even nominal) pain and fatigue when compared to standing alone. We believe that the reductions are likely to be even more significant among users that have existing health (back) issues and when used for longer sessions that more closely represent a typical workday.
Research has shown that incorporating standing while working versus sitting (only) has definite health benefits.[i] However, without the proper support or having the ability to easily shift positions throughout the workday, standing ends up with its own set of problems such as foot and leg pain and general discomfort.[ii] The LeanRite solves these problems with its versatility, allowing sitting, standing, perching, or leaning while working.
[i] Is sitting the new smoking? Why Companies are buying more sit to stand desks. Accessed at: http://www.mlive.com/business/west-michigan/index.ssf/2015/06/is_sitting_the_new_smoking_why.html/
Sitting at work is bad but is standing actually better? Accessed at: https://www.bostonglobe.com/lifestyle/health-wellness/2014/11/03/yes-sitting-work-bad-but-standing-actually-better/7ceei6fb0B7QjgAH3FlOrK/story.html
[ii] Chester, M.R., Rys, M.J., Konz, S.A. Leg swelling, comfort and fatigue when sitting, standing and sit/standing. International Journal of Industrial Ergonomics 29 (2002) 289 – 296