Cardiac rehabilitation (CR) : Use of manual materials handling

• Published in: International journal of industrial ergonomics 1997-08, Vol.20 (2), p.93-99
• Main Authors: Mital, A., Kumar, G.M.
• Format: Article
• Language: English
• Subjects: Cardiac rehabilitation; Cardiovascular training; Coronary heart disease; Manual handling; Overexertion; Ratings of perceived exertion (RPE); Work/exercise intensity
• ISSN: 0169-8141; 1872-8219
• DOI: 10.1016/S0169-8141(96)00042-X

Cardiovascular training is a universally accepted prescription for preventing coronary heart disease (CHD) and outpatient rehabilitation (phase 11) of CHD patients. During cardiac rehabilitation (CR), the intensity of supervised aerobic exercises is adjusted by the patient using the Ratings of Perceived Exertion (RPE) scale. Recent developments have advocated the inclusion of work-related elements in cardiovascular training programs. Since this concept represents a major departure from traditional CR programs, CR researchers are concerned that CHD patients, using the RPE scale, might adjust exercise levels to beyond their capabilities and overexert themselves. The purpose of this work was to investigate if overexertion is likely to result when individuals adjust their manual handling exercise (work) intensity using the RPE scale. Twelve healthy males voluntarily participated in the manual handling study involving 2 box sizes (30 × 30 × 15 cm and 40 × 40 × 25 cm), 3 lifting frequencies (1, 6, and 12/min), 2 lifting heights (floor-83 cm; 83–132 cm), and 2 work performance conditions (psychophysically acceptable maximum work intensities and maximum acceptable work intensities at specified whole body RPE rating). Heart rate (HR), oxygen uptake (Vo 2), maximum acceptable weight of lift (MAWL), and RPE were the response variables under the first work performance condition; RPE was fixed at 13 (somewhat hard), the optimal value, under the second work performance condition (smaller value would mean suboptimization of performance and higher value would lead to certain overexertion). HR, Vo 2, and RPE (in work performance condition 1) values were recorded at the MAWL. The results indicated expected response variable behavior with lifting task factors. The average RPE value when subjects performed under condition 1 was 13.5, slightly higher than the expected RPE value of 13. When subjects performed at the RPE value of 13 (condition 2), all response values (HR, Vo 2, and MAWL) were observed to be lower than in condition 1. This indicated that when subjects adjusted their work intensities corresponding to RPE value of 13, the work intensities were lower than work intensities when RPE value was not specified. Thus, the results indicate that individuals are unlikely to overexert themselves if the CR cardiovascular training programs include work-related elements such as manual lifting.