Key words: Carpal tunnel syndrome, integrated surface electromyogram, gripping force, bus driving Abbreviations: CTS: carpal tunnel syndrome iEMG: integrated surface electromyogram Abstract: The calculated gripping force, based on the integrated surface electromyogram iEMG of the long forearm flexors has been measured on four experienced bus drivers while driving the IKARUS type vehicle equipped with a power steering system.
Surface electrodes were secured above the capita of long finger flexors and the iEMG was recorded. The iEMG was recorded under different experimental setups. These included: moving the steering wheel at different angles on carpal tunnel syndrome treatment vehicle with running engine to insure that the power steering system was operating; slalom driving; driving on an 8-shape; driving on a model path that was constructed on the basis of ergonomical observations and driving in real traffic situation.
The gripping force changes followed an impulsive pattern with peak values less than the ergonomically allowed long-term limit for gripping force and with an average duration of less than 4 to 6 seconds, depending upon the task performed. The average calculated gripping force did not exceed the high-risk limit of 4 kp in either task. According to these results it is concluded that driving the IKARUS type vehicle even under heavy traffic conditions does not represent high enough strain of the finger flexors that could provoke the signs and symptoms of carpal tunnel syndrome.
Received: 10 January