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: 1.07). 02/2013; 39(1):115-120. DOI: 10.1016/j.ergon.2008.05.004


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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Available from: Rodrigo L Carregaro
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    • "Therefore, when individuals with low hamstring extensibility perform a maximal trunk flexion with knees extended an increase in spinal flexion and posterior pelvic tilt occur (López-Miñarro et al., 2012; Muyor et al., 2012). This invariably leads to the biomechanical changes in the pressure distribution in the spine and consequent spinal disorders (Carregaro and Coury, 2009; Kang et al., 2013). Particularly among young people, poor hamstring extensibility seems to contribute to the increase in the risk of low back pain (Feldman et al., 2001; Jones et al., 2005; Sjölie, 2004) and neck tension (Mikkelsson et al., 2006). "
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    ABSTRACT: The purpose of this study was to examine the effects of a 1-minute stretching programme and 5 weeks of detraining on sit-and-reach score among schoolchildren aged 5–6 years in a physical education setting. Forty-five schoolchildren 5–6 years old from two classes were clustered randomly assigned to an experimental group (n ¼ 23) or a control group (n ¼ 22). During the physical education classes, the students of the experimental group performed a 1-minute stretching programme twice a week for 8 weeks. Subsequently, these participants underwent a 5-week detraining period. The classic sit-and-reach test was performed at the beginning and at the end of the development programme, as well as at the end of the detraining period. The results of the two-way ANOVA showed that the intervention programme increased significantly the students’ sit-and-reach scores ( p < 0.001). However, after 5 weeks of detraining, children’s flexibility reverted back to the baseline levels ( p > 0.05). Although an only 1-minute stretching programme seems to develop the schoolchildren’s flexibility, after the 5-week detraining period students’ score reverts back to its initial level. This knowledge could help physical education teachers to design programmes that permit students to increase and maintain flexibility levels along the entire academic year.
    Full-text · Article · Sep 2014 · European Physical Education Review
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    • "Because the hamstring muscles originate at the ischial tuberosity of the pelvis, it is logical that tension in the hamstring muscles will have an influence on movement and posture of the pelvis [3]. Carregaro and Coury [2] found that participants with reduced hamstring extensibility presented higher trunk movement amplitudes and a restriction on pelvis movements during handling tasks, which can overload the spine during handling of materials. The influence of hamstring extensibility on pelvic and thoracic posture in trunk flexion postures with knees extended has been described in previous studies [15] although hamstring extensibility does not affect pelvic inclination or spinal curvatures in relaxed standing [7] [14]. "
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    ABSTRACT: To determine the effect of a stretching program performed in the workplace on the hamstring muscle extensibility and sagittal spinal posture of adult women. Fifty-eight adult women volunteers (mean age of 44.23 ± 8.87 years) from a private fruit and vegetable company were randomly assigned to experimental (n=27) or control (n=31) groups. The experimental group performed three exercises of hamstrings stretching of 20 seconds per exercise, three sessions a week for a period of 12 weeks. The control group did not participate in any hamstring stretching program. Hamstring flexibility was evaluated through the passive straight leg raise test and toe-touch test, performed both before and after the stretching program. Thoracic and lumbar curvatures and pelvic inclination were measured in relaxed standing and toe-touch test with a Spinal Mouse. Significant increases (p < 0.01) in toe-touch score and straight leg raise angle (in both legs) were found in the experimental group during post-test, while the control group showed a non-significant decrease for both toe-touch score and straight leg raise test. A significant decrease in thoracic curve and significant increase in pelvic inclination were found in the toe-touch test for the experimental group (p <0.05). However, no significant changes were found in standing posture for any group. Hamstring stretching exercises performed in the working place are effective for increasing hamstring muscle extensibility. This increase generates a more aligned thoracic curve and more anterior pelvic inclination when maximal trunk flexion is performed.
    Full-text · Article · Aug 2012 · Journal of Back and Musculoskeletal Rehabilitation
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    • "Gajdosik et al. (1994) reported that short hamstrings were associated with decreased pelvic flexion and lumbar angle and increased thoracic flexion in the toe-touch test. Carregaro and Gil (2009) reported increased trunk angles in subjects with reduced hamstring flexibility during manual handling tasks. López- Miñarro and Alacid (2010) found that hamstring muscles extensibility influences the thoracic and pelvic postures of young paddlers in the sit-andreach test. "
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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.
    Full-text · Article · Sep 2011 · Journal of Human Kinetics
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