A strong correlation between low back pain and tight hamstrings has been reported. However, the effect of tight hamstrings on spinal biomechanics remains unclear. The purpose of the study was to investigate spino-pelvic-rhythm during forward bending of the trunk and to clarify the rhythm features with regard to hamstrings tightness. Eighteen healthy male adults with no history of low back pain volunteered to participate. First, we measured the finger-to-floor distance (FFD) in the upright position and set this parameter to 100 %. Using a spinal mouse, spinal alignment was measured in the following four positions: (1) upright posture—100 % FFD; (2) forward bending—50 % FFD; (3) forward bending—25 % FFD; and (4) forward bending—0 % FFD (fingers in contact with the floor). Changes of the angle of the thoracic and lumbar spine as well as the pelvis were calculated. As an indicator of tight hamstrings, we measured straight leg raising (SLR) angle. From positions 1–2 (phase I), the entire spino-pelvic angle moved in 104°. During this phase, the lumbar spine mainly moved. In the second phase (positions 2–3), it moved in 16°. Interestingly, all but 2 subjects showed a negative angle in the thoracic motion, meaning that the thoracic spine extended 4° during trunk flexion, thus exhibiting paradoxical motion. During this phase, lumbopelvic rhythm showed 2 patterns. In 7 subjects, pelvic motion was greater than lumbar motion, while the remaining subjects showed the opposite. In subjects without tight hamstrings, 83 % showed a pelvis-dominant pattern. Only 7 subjects were capable of position 4. During this phase, only slight motion was noted in the spine, and the majority of the motion occurred in the pelvis. Lumbar and pelvic motion correlated negatively in all phases. SLR angle and pelvic motion correlated strongly during phase III, indicating dominant pelvic movement in flexible subjects. The lumbo-pelvic-rhythm comprises 2 patterns—lumbar dominant and pelvis dominant. In flexible subjects, pelvis movement was dominant. In conclusion, improving tight hamstrings may reduce lumbar loading thereby reducing low back pain.

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Tight hamstrings are reported to be one of the causes of low back pain. However, there have been few reports on effective stretching procedures for the tight hamstrings. The so-called jack-knife stretch, an active-static type of stretching, can efficiently increase the flexibility of tight hamstrings. To evaluate hamstring tightness before and after the 4-week stretching protocol in healthy volunteer adults and patients aged under 18 years with low back pain. For understanding the hamstrings tightness, we measured two parameters including (1) finger to floor distance (FFD) and (2) pelvis forward inclination angle (PFIA). Eight healthy adult volunteers who had no lumbar or hip problems participated in this study (mean age: 26.8 years). All lacked flexibility and their FFD were positive before the experiment. Subjects performed 2 sets of the jack-knife stretch every day for 4 weeks. One set consisted of 5 repetitions, each held for 5 s. Before and during the 4-week experiment, the FFD and PFIA of toe-touching tests were measured weekly. For 17 of the sports players aged under 18, only FFD was measured. In adult volunteers, FFD was 14.1 ± 6.1 cm before the experiment and decreased to -8.1 ± 3.7 cm by the end of week 4, indicating a gain in flexibility of 22.2 cm. PFIA was 50.6 ± 8.2 before the experiment and 83.8 ± 5.8 degrees after. Before and after the experiment, the differences were significant (p < 0.05). For those aged under 18, FFD was 8.1 ± 8.0 and -9.6 ± 6.8, before and after the stretching, respectively. This difference was significant (p < 0.05). The jack-knife stretch is a useful active-static stretching technique to efficiently increase flexibility of tight hamstrings.

Background and Purpose: Most patients become physically inactive after vertebral compression fracture and thus need help for early mobilization. This study sought to investigate the effect of early rehabilitation on activities of daily living in patients following acute vertebral compression fracture. Methods: We conducted this retrospective cohort study with a hospital-based database created by the Japan Medical Data Center and comprising data from a Diagnosis Procedure Combination survey from more than 100 acute care hospitals across Japan. Data of consecutive inpatients hospitalized because of thoracic and/or lumbar compression fractures from 2014 to 2018 were extracted. We compared characteristics and outcomes between patients who underwent early rehabilitation (early rehabilitation group) and those who did not undergo rehabilitation (no rehabilitation group). The primary outcome measure was Barthel Index improvement. Results: After applying exclusion criteria, a total of 8493 eligible patients with acute vertebral compression fracture were included in this study. The unadjusted data showed significantly greater Barthel Index improvement (72.5% vs 60.3, P < .001) and a higher rate of discharge to home (82.9% vs 77.4, P < .001) among patients in the early rehabilitation group compared with the no rehabilitation group. After adjustment by propensity score analysis, significant between-group differences were found. Conclusion: Early rehabilitation could possibly be a feasible alternative for maintenance of the Barthel Index in patients with acute vertebral compression fracture.

: Objectives : To ascertain the dynamic stretch effects of flexibility of the hamstrings on lumbar spine and pelvic kinematics. Background : Tight hamstrings are positively correlated with low back pain. However, it is unclear how flexibility of the hamstrings affects spino-pelvic rhythm. Methods : Twelve healthy men participated in the study. The straight leg raising (SLR) angle, finger floor distance (FFD), and spino -pelvic rhythm was measured before and after the 6-week stretching protocol. The forward bending task was divided into 4 phases. The paired t-test was used to determine significant differences before and after the FFD, SLR angle, lumbar motion, and pelvic motion, and spino-pelvic rhythm in each phase (p 0.05). Results : After 6 weeks of stretching, significant improvements were seen in the FFD with maximum forward bending and in the SLR angle. Total pelvic rotation was also significantly increased in contrast to total lumbar flexion. A decreased spino -pelvic ratio was seen in the final phase. Conclusion : Dynamic stretching could change the spino-pelvic rhythm to a pelvis -dominant motion, indicating that flexible hamstrings are important for preventing low back pain. J. Med. Invest. 63 : 85-90, February, 2016