EMG and Heart Rate Used to Validate Ergonomic Benefits of a Bent-Handled Floor Finish Applicator

Abstract

Prior to releasing the design of a new bent-handled floor finish applicator for full-scale production, its manufacturer commissioned a quantitative research study to validate its intended ergonomic benefits. Unlike the traditional braided mop and bucket, this new design dispensed finish from a 2.5 liter replaceable reservoir purposefully positioned on a bent handle to afford balance and control. Electromyography (EMG), heart rate (HR), timed activity analysis, and subjective self-report measures were used to quantify the design's physiological impact, both actual and perceived, on 6 representative users. The new bent-handled design was compared to three other commercially available applicator systems: a traditional mop and bucket commonly used in the United States, a flat mop preferred in Europe and Asia, and a commercially available backpack system. Compared to the traditional mop and bucket, the average combined set-up, finish application, and clean-up of the bent-handled applicator cumulatively required 36% less forearm flexor effort, 35% less deltoid effort, 23% less trapezius effort, and 36% less erector spinae effort. The bent-handled applicator required 18% less forearm flexor effort, 54% less deltoid effort, 40% less trapezius effort, and 49% less erector spinae effort when compared to the European flat mop. Compared to a backpack system, the bent-handled applicator required 10% more forearm flexor effort, 2% less deltoid effort, 8% less trapezius effort, and 8% more erector spinae effort. Taking into account both heart rate (beats per minute) and duration (min) over the set-up, finish application, and clean-up, the bent-handled applicator required 23% fewer average heart beats than the mop and bucket, 32% fewer than a flat mop, and 0.5% more than a backpack system. These statistically significant findings validated the subjective measures, indicating that this new bent-handled design decreases effort and increases comfort.