Does reduced hamstring flexibility affect trunk and pelvic movement strategies during manual handling?

Department of Physical Therapy, Laboratory of Preventive Physical Therapy and Ergonomics, Federal University of São Carlos (UFSCar), Via Washington Luiz, Km 235, CEP 13565-905, São Carlos, SP, Brazil
International Journal of Industrial Ergonomics (Impact Factor: 1.21). 02/2013; 39(1):115-120. DOI: 10.1016/j.ergon.2008.05.004

ABSTRACT ObjectiveTo evaluate the influence of reduced hamstring flexibility on trunk and pelvic movement strategies adopted by healthy males during manual handling tasks.MethodsSeventeen subjects performed a sagittally symmetrical handling task involving a 15 kg box, and hamstring flexibility was measured by means of the Straight Leg Raise Test. The task was filmed with a 2D acquisition system at a sampling rate of 50 frames/s. The images were digitized and a MatLab® routine was implemented to analyze the trunk and pelvis movement patterns. Kinematic data from trunk movements were plotted against the data from pelvic movements in order to provide coordination analysis.ResultsSubjects with reduced flexibility presented higher trunk movement amplitudes and a restriction on pelvis movements during handling tasks. Movement coordination was also influenced by the reduced flexibility.ConclusionThe results suggest that reduced hamstring flexibility is related to increased trunk angles, which can overload the spine during manual materials handling.Relevance to industryHamstring shortness can influence pelvic dynamics and, consequently, affects trunk movements adopted by subjects during occupational activities. As movement restrictions can reduce the capacity to obtain appropriate postural responses, this should be accounted for in order to provide better comprehension on how to prevent low back injuries in the occupational setting.

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    ABSTRACT: Objective: To evaluate the influence of hamstring extensibility on spinal and pelvic postures adopted by young paddlers in their kayaks.Methods: Sixty-eight young elite kayakers were recruited for the study (mean value 15.23, s=0.68 years). Thoracic and lumbar curvatures and pelvic position were evaluated with a Spinal Mouse system in standing position and in the boat (seated in the kayak with the paddle resting on their thighs, right entry position and left entry position). Hamstring muscle extensibility was determined in both legs by passive straight leg raise test (PSLR). The sample was divided into two groups with regard to straight leg raise angle (Group A, PSLR < 80°, n=32, and group B, PSLR ≥ 80°, n=32).Results: Paddlers with lower extensibility presented higher thoracic and lumbar flexion and a more posterior pelvic tilt in the kayak in all three positions. However, no significant differences were found between the groups when standing.Conclusion: The results suggest that lower hamstring extensibility is related to increased spinal flexion and posterior pelvic tilt, which can overload the spine during paddling training. A systematic and intensive stretching programme to improve hamstring muscle extensibility should be incorporated into the training activities of paddlers.
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    ABSTRACT: The purpose of this study was to determine the influence of hamstring muscles extensibility in standing, maximal trunk flexion with knees extended and on the bicycle in lower handlebar-hands position of highly trained cyclists. Ninety-six cyclists were recruited for the study (mean ± SD, age: 30.36 ± 5.98 years). Sagittal spinal curvatures and pelvic tilt were measured in the standing position, maximal trunk flexion with knees extended (sit-and-reach test) and while sitting on a bicycle in lower handlebar-hand position using a Spinal Mouse system. Hamstring muscles extensibility was determined in both legs by passive straight leg raise test (PSLR). The sample was divided into three groups according to PSLR angle: (1) reduced extensibility (PSLR < 80º; n = 30), (2) moderate hamstring extensibility group (PSLR = 80º - 90º; n = 35), and (3) high hamstring extensibility (PSLR = > 90º; n = 31). ANOVA analysis showed significant differences among groups for thoracic (p < 0.001) and pelvic tilt (p < 0.001) angles in the sit-and-reach test. No differences were found between groups for standing and on the bicycle position. Post hoc analysis showed significant differences in all pairwise comparisons for thoracic angle (p < 0.01) and pelvic angle (p < 0.001) in the sit-and-reach test. No differences were found in lumbar angle in any posture. In conclusion, the hamstring muscles extensibility influence the thoracic and pelvic postures when maximal trunk flexion with knees extended is performed, but not when cyclists are seated on their bicycles.
    Journal of Human Kinetics 09/2011; 29:15-23. · 0.46 Impact Factor
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    ABSTRACT: The aim of this study was to determine acute effects of hamstring stretching in thoracic and lumbar spinal curvatures and pelvic tilt. Fifty-five adults (29.24 ± 7.41 years) were recruited for this study. Subjects performed a hamstring stretching protocol consisting of four exercises. The session consisted of 3 sets of each exercise and subjects held the position for 20 seconds with a 30-second rest period between sets and exercises. Thoracic and lumbar spinal angles and pelvic tilt were measured with a SpinalMouse in relaxed standing, sit-and-reach test and Macrae & Wright position. Hamstring extensibility was determined by active straight leg raise test and sit-and-reach score. All measures were performed before and immediately after the hamstring stretching protocol. Active straight leg raise angle and sitand-reach score significantly improved immediately after the stretching protocol (p<0.001). Greater anterior pelvic tilt (p<0.001) and lumbar flexion (p<0.05) and a smaller thoracic kyphosis in the sit-and-reach (p<0.001) were found after the stretching protocol. However, stretching produced no significant change on spinal curvatures or pelvic tilt in standing and maximal trunk flexion with knees flexed. In conclusion, static stretching of the hamstring is associated to an immediate change in the sagittal spinal curvatures and pelvic position when performing trunk flexion with knees extended, so that allowing for greater lumbar flexion and anterior pelvic tilt and lower thoracic kyphosis. Hamstring stretching is recommended prior to sport activities involving trunk flexion with the knees straight.
    Journal of Human Kinetics 03/2012; 31:69-78. · 0.46 Impact Factor


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May 21, 2014