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OBJECTIVES To determine the activity of the upper trapezius, serratus anterior, anterior deltoid, biceps brachii. and lower trapezius muscles in healthy adults during below-the-knee assembly work. METHODS Fifteen right-handed male subjects participated in this study. The electrical activities, measured by EMG, of the right upper trapezius, serratus anterior, anterior deltoid, biceps brachii. and lower trapezius were measured during below-the-knee assembly work at four workstations of varying height and distance from the participant (workstation 1, below-the-knee assembly work with a height of 15 cm above the floor and a reach distance of 30 cm; workstation 2, height of 15 cm and distance of 45 cm; workstation 3, height of 30 cm and distance of 30 cm; workstation 4, height of 30 cm and distance of 45 cm). Muscle activity at the four workstations was represented as a percentage of the reference voluntary isometric contraction (RVIC). RESULTS Height: Upper and lower trapezius activity increased significantly during below the knee assembly work as height above the floor increased. The activities of the serratus anterior and biceps brachii muscles increased significantly during low-height below-the-knee assembly work. Distance: The activities of the upper trapezius, serratus anterior, anterior deltoid and biceps brachii increased significantly during below-the-knee assembly work at a far distance (45 cm). The lower trapezius muscle activity increased significantly during below-the-knee assembly work at a close distance (30 cm). CONCLUSIONS Below-knee workers should engage in work close to themselves, since distance appears to be a stronger risk factor for injury than height above the floor.

[Purpose] This study compared and analyzed use of an existing ankle ramp and a newly developed ankle ramp for stretching exercises. [Subjects] Fourteen subjects were included; they were stroke patients more than 6 months after onset, with no orthopedic or biological problems in the legs, so independent gait was possible. [Methods] The subjects performed stretching exercises for 5 min with an existing ankle ramp and a newly developed ankle ramp; foot pressure was then measured. [Results] The averaged percentage and kilopascal data for weight bearing and foot pressure on the affected side with the newly developed ankle ramp for stretching exercises were significantly higher than those with the existing ankle ramp. [Conclusion] Our results suggest that stretching exercises using the newly developed ankle ramp more effectively increase foot pressure than the existing ankle ramp.

[Purpose] This study was performed to determine which set of below-knee working conditions minimizes upper extremity muscle activity and which of upward- or downward-direction workstations poses the greater risk of upper extremity disorder. [Subjects] The study population consisted of 15 young male workers. [Methods] EMG activities of the right anterior deltoid, biceps brachii, and lower trapezius muscles were measured in two below-knee assembly workstation positions. [Results] The anterior deltoid and biceps brachii muscle activities of Position 1 were significantly higher than those of Position 2. The lower trapezius muscle activity of Position 2 was significantly higher than that of Position 1. [Conclusion] Upward-direction workstations appear to pose a greater risk of upper extremity disorder than downward-direction workstations in below-knee assembly work.