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: