30o inclination in handles of plastic boxes can reduce postural and muscular workload during handling

Abstract

| Background: The handling of materials, which occurs in the industrial sector, is associated with lesions on the lumbar spine and in the upper limbs. Inserting handles in industrial boxes is a way to reduce work-related risks. Although the position and angle of the handles are significant factors in comfort and safety during handling, these factors have rarely been studied objectively. Objective: To compare the handling of a commercial box and prototypes with handles and to evaluate the effects on upper limb posture, muscle electrical activity, and perceived acceptability using different grips while handling materials from different heights. Method: Thirty-seven healthy volunteers evaluated the handles of prototypes that allowed for changes in position (top and bottom) and angle (0°, 15°, and 30°). Wrist, elbow, and shoulder movements were evaluated using electrogoniometry and inclinometry. The muscle electrical activity in the wrist extensors, biceps brachii, and the upper portion of the trapezius was measured using a portable electromyographer. The recorded data on muscle movements and electrical activity were synchronized. Subjective evaluations of acceptability were evaluated using a visual analog scale. Results and Conclusions: The prototypes with handles at a 30° angle produced the highest acceptability ratings, more neutral wrist positions, lower levels of electromyographic activity for the upper trapezius, and lower elevation angles for the arms. The different measurement methods were complementary in evaluating the upper limbs during handling.Keywords: ergonomic design; usability; electrogoniometry; electromyography; grip perception. HOW TO CITE THIS ARTICLESilva LCCB, Oliveira AB, Silva DC, Paschoarelli LC, Coury HJCG. 30° inclination in handles of plastic boxes can reduce postural and muscular workload during handling. Braz J Phys Ther. 2013 May-June; 17(3):307-318. http://dx

Factores de riesgo, evaluación, control y prevención en el levantamiento y transporte manual de cargas.

“…Con respecto a las medidas de control y prevención sugeridas por la GATISO de dolor lumbar inespecífico, la disminución del peso de la carga, 13 el diseño de puntos de agarre de la carga y las ayudas mecánicas para la manipulación, 34,36,37,39,40 fueron los únicos que coincidieron con la presente investigación, los dispositivos de adaptación al cuerpo, la medidas administrativa del levantamiento de cargas divididas y la implementación del peso máximo aceptable para los trabajadores fueron nuevos aportes.…”

Adding Handles to Optimize Manual Box Handling

“…On the other hand, Shih and Wang [24] recommended inclinations between -10° and 10° to allow neutral wrist posture (0° of deviation) for both genders evaluated. The most recently published paper from Silva et al [25] observed that 30° inclination in handles enabled safer scores on all variables tested at different heights of handling. With better methodological quality, Silva et al [25] used different measurement methods that were complementary in evaluating the upper limbs during handling with different grip designs.…”

“…This handle positioning was associated with the reduction of spinal load due to smaller ranges of flexion, corresponding to a reduction of 4.5 kg of load on the lumbar region. On the other hand, more recent studies [11, 14, 25, 30], which evaluated load on upper limbs, suggested that handle modifications should be made according to the handling height. Handles located at the upper part of the box may create higher demands on upper limbs when the load is placed in higher places.…”