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Background: McKenzie standing trunk extension exercises have been used for the management of low back pain (LBP). However, no study to date has investigated the effect of standing trunk extension postures on spinal height and clinical outcomes., Objective: To evaluate in subjects with LBP following a period of trunk loading how spinal height, pain, symptoms' centralization and function outcome measures respond to two standing postures interventions: (1) repetitive trunk extension (RTE) and (2) sustained trunk extension (STE)., Methods: A consecutive sample of convenience of people with LBP were recruited to participate in 2-session physical therapy using either RTE or STE in standing., Results: Thirty participants (18 women) with a mean age of 53 ± 17.5 years completed the study. The first session resulted in spinal height increase (spinal growth) of 2.07 ± 1.32 mm for the RTE intervention and 4.54 ± 1.61 mm for the STE group (p< 0.001; ES = 1.67), while the second session (2-week following the first session) resulted in spinal growth of 2.39 ± 1.46 mm for the RTE group and 3.91 ± 2.06 mm for the STE group (p= 0.027; ES = 0.85). The STE group presented with the larger reduction in most pain from 6 to 2 as compared to the RTE group from 6 to 4 between Session 1 and Session 2 (p< 0.001). There was no difference between the groups in Modified Oswestry score and symptoms centralization (p= 0.88 and p= 0.77, respectively)., Conclusion: People with LBP experienced greater spine growth and improvements of pain during standing STE as compared to RTE. People with LBP could use such postures and movements to alleviate their LBP and improve spine height while in a weight bearing position.

Background: Upright and slouched sitting are frequently adopted postures associated with increased intradiscal pressure, spinal height loss and intervertebral disc pathology., Objectives: To examine the effects of two sustained propped slouched sitting (PSS) postures on spinal height after a period of trunk loading., Methods: Thirty-four participants without a history of low back pain (LBP) were recruited (age 24.4 ± 1.6 years). Subjects sat in (1) PSS without lumbar support and (2) PSS with lumbar support for 10 min, after a period of trunk loading. Spinal height was measured using a stadiometer., Results: Mean spinal height increase during PSS without lumbar support was 2.94 ± 3.63 mm and with lumbar support 4.74 ± 3.07 mm., Conclusions: Both PSS with and without lumbar support significantly increased spinal height after a period of trunk loading (p < 0.001). Such PSS postures can provide a valuable alternative to upright sitting and may be recommended for recovering spinal height in the working environment following periods of loading., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Introduction: Recurrent lower back pain (rLBP) and neuromuscular fatigue are independently thought to increase the risk of lower extremity (LE) injury. Volitional preemptive abdominal contraction (VPAC) is thought to improve lumbar spine and pelvis control in individuals with rLBP. The effects of VPAC on fatigued landing performance in individuals with rLBP are unknown., Objectives: To determine the effects of VPAC and LE fatigue on landing performance in a rLBP population., Design: Cross-sectional pretest-posttest cohort control design., Setting: A clinical biomechanics laboratory., Subjects: 32 rLBP (age 21.2 ± 2.7 y) but without current symptoms and 33 healthy (age 20.9 ± 2.3 y) subjects., Intervention(s): (i) Volitional preemptive abdominal contraction using abdominal bracing and (ii) fatigue using submaximal free-weight squat protocol with 15% body weight until task failure was achieved., Main Outcome Measure(s): Knee and ankle angles, moments, electromyographic measurements from semitendinosus and vastus medialis muscles, and ground reaction force (GRF) were collected during 0.30 m drop-jump landings., Results: The VPAC resulted in significantly earlier muscle onsets across all muscles with and without fatigue in both groups (mean ± SD, 0.063 ± 0.016 s earlier; P ≤ .001). Fatigue significantly delayed semitendinosus muscle onsets (0.033 ± 0.024 s later; P ≤ .001), decreased GRF (P ≤ .001), and altered landing kinematics in a variety of ways. The rLBP group exhibited delayed semitendinosus and vastus medialis muscle onsets (0.031 ± 0.028 s later; P ≤ .001) and 1.8° less knee flexion at initial contact (P ≤ .008)., Conclusion: The VPAC decreases some of the detrimental effects of fatigue on landing biomechanics and thus may reduce LE injury risk in a rLBP population.

Background: A volitional preemptive abdominal contraction (VPAC) supports trunk stability during functional activity. Pain-free individuals can sustain VPAC during function, but such has not been reported for individuals with current low back pain (cLBP)., Objective: To examine whether cLBP affects VPAC performance during a loaded forward reach (LFR) task., Design: Observational crossover study., Setting: Laboratory., Participants: A total of 18 controls and 17 subjects with cLBP with pain ratings of 1/10 to 4/10 on a visual analog scale., Interventions: Transverse abdominis (TrA) thickness measurements were recorded by blinded researchers from M-mode ultrasound imaging during 4 conditions: (1) quiet standing without abdominal drawing-in maneuver (ADIM); (2) quiet standing with ADIM; (3) LFR without ADIM; and (4) LFR with ADIM. A physical therapist with 29 years of experience collected historical and examination data., Main Outcome Measures: TrA muscle thickness (mm)., Results: A 2 (group) × 2 (contraction) × 2 (reach) analysis of variance demonstrated a significant group × contraction interaction (F [1, 31] = 4.499, P = .04) where ADIM produced greater TrA thickness increases in PLBP subjects (2.18 mm) versus controls (1.36 mm). We observed a significant main effect for reach (F [1, 31] = 14.989, P < .001), where LFR activity produced a greater TrA thickness (6.15 ± 2.48 mm) versus quiet standing (5.30 ± 2.12 mm)., Conclusions: Subjects with cLBP demonstrated a greater increase in TrA activation during ADIM versus controls., (Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Objectives: To determine the effects of current LBP (cLBP) and LBP history (hxLBP) on Y-Balance Test (YBT) reach and establish relationships between YBT performance and demographic, behavioral, and disability measures., Design: Cross-sectional comparative study., Setting: Research laboratory., Participants: Forty-two participants (24 males, 18 females) aged 18-50 years (30.9 ± 8.2 yr) in three groups: cLBP, hxLBP, and healthy controls., Interventions: Three YBT trials in anterior (ANT), posterolateral (PL), and posteromedial (PM) directions., Main Outcome Measures: YBT reach (relative to leg length) was measured and compared amongst groups. Pearson correlations were calculated between reach distances and pain, disability, and fear avoidance scores in the cLBP and hxLBP groups and age and activity level in all participants., Results: For PL reach, cLBP (94.7 ± 10.6 cm) and hxLBP (94.2 ± 9.2 cm) groups demonstrated shorter distances versus controls (105.8 ± 6.6 cm). For PM reach, cLBP (100.7 ± 8.4 cm) and hxLBP (102.3 ± 7.6 cm) groups' distances were shorter versus controls (109.3 ± 6.7 cm). No significant difference was found for ANT reach (control = 66.4 ± 7.0 cm; cLBP = 66.2 ± 6.2 cm; hxLBP = 66.4 ± 3.1 cm). No significant correlations were identified., Conclusion: YBT performance is reduced in individuals with cLBP and hxLBP in the PL and PM directions but not ANT. The YBT is useful for measuring balance deficits in these populations., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Study Design: Controlled laboratory study., Background: Recurrent low back pain (LBP) and neuromuscular fatigue are independently thought to increase the risk of spine injury. Volitional preemptive abdominal contraction (VPAC) is thought to improve lumbar spine and pelvis control in individuals with recurrent LBP. The effects of VPAC on fatigued landing performance in individuals with recurrent LBP are unknown., Objectives: To determine the effects of VPAC and lower extremity fatigue on trunk control during landing in a population of individuals with recurrent LBP., Methods: Thirty-two recurrent LBP (mean ± SD age, 21.2 ± 2.7 years) and 33 healthy (age, 20.9 ± 2.3 years) subjects performed 0.30-m drop-jump landings with and without VPAC and fatigue. Trunk, pelvis, and hip biomechanical and electromyographic variables were obtained using 3-D motion capture. Hypotheses were tested using analysis of variance., Results: Volitional preemptive abdominal contraction resulted in significantly earlier muscle onsets across all muscles, with and without fatigue, in both groups (mean ± SD, 0.058 ± 0.019 seconds earlier; P≤.001) and altered lumbar lateral flexion (1.4° ± 14.8° greater right lateral flexion; P = .002). Fatigue significantly delayed muscle onsets (0.040 ± 0.014 seconds later; P≤.001) and altered pelvic obliquity (1.4° ± 11.0° greater; P≤.001) and trunk side flexion (2.0° ± 14.8° less; P≤.001). The recurrent LBP group exhibited delayed muscle onsets (0.039 ± 0.031 seconds later; P≤.004) and 4.2° less hip abduction at initial contact (P≤.008) in comparison to healthy controls., Conclusion: Volitional preemptive abdominal contraction decreases some of the detrimental effects of fatigue on landing biomechanics and thus may reduce spine injury risk in individuals with recurrent LBP.

Study Design: A 2 (group) × 2 (abdominal contraction) × 2 (reach activity) crossover mixed design with repeated measures for contraction and activity examined the effects of a loaded (4.6 kg) forward-reach activity and abdominal drawing-in maneuver (ADIM) on transversus abdominis (TrA) contraction in subjects with nonspecific low back pain (NSLBP) history versus controls., Objective: We measured TrA contraction during a loaded forward-reach activity while using the ADIM and examined if a NSLBP history affects TrA activity., Summary of Background Data: The ADIM supports trunk stability during function. Clinicians incorporate ADIM during patients' functional tasks. Pain-free individuals can sustain ADIM during function, such as forward-reach. However, this has not been tested in those with a NSLBP history., Methods: Eighteen normal subjects and 18 subjects with a history of NSLBP participated. A blinded investigator recorded M-mode ultrasound imaging measurements of TrA thickness (mm) during 4 conditions as follows: (1) quiet standing without ADIM; (2) quiet standing with ADIM; (3) loaded forward-reach without ADIM; and (4) loaded forward-reach with ADIM., Results: A mixed analysis of variance demonstrated a significant main effect for group (F [1, 34] = 5.404, P = 0.026; ), where TrA thickness was greater for NSLBP history (7.41 + 2.34 mm) versus controls (5.9 + 2.46 mm). A significant main effect was observed for abdominal contraction (F [1, 34] = 49.57, P < 0.0001; ), where TrA thickness was greater during ADIM (7.47 + 2.7 mm) versus without ADIM (5.84, 1.92 m). A significant main effect was observed for forward-reach activity (F [1, 34] = 12.79, P = 0.001; ), where TrA thickness was greater during a loaded forward-reach (7.04 + 2.6 mm) versus quiet standing (6.2 + 2.4 mm). There were no significant interactions., Conclusion: Individuals can use a volitional pre-emptive ADIM for trunk protection during loaded forward-reach, potentially reducing injury risk. A NSLBP history increases TrA activation during ADIM, suggesting an enhanced protective role., Level of Evidence: 2.

Objective: To investigate the effect of aquatic vertical traction on spinal height, pain intensity, and centralization response compared with a land-based supine flexion position for patients with low back pain and signs of nerve root compression., Design: Single-blind, repeated-measures crossover design., Setting: Outpatient physical therapy clinic., Subjects: Ninety-eight subjects were recruited using consecutive sampling, with 28 men and 32 women of a mean ± standard deviation (SD) age of 59.6 ± 11.6 years completing testing., Intervention: Each subject participated in 2 sessions that consisted of loaded walking for 15 minutes, followed by either 15 minutes of land-based supine position or 15 minutes of aquatic vertical traction., Measurements: Spinal height change, measured using a commercial stadiometer, was determined after completing loaded walking and after each intervention., Results: The mean ± SD height change of 4.99 ± 2.88 mm after aquatic vertical traction was similar to that of 4.21 ± 2.53 mm after the land-based supine flexion (P = .0969). Paired t-test indicated that both interventions resulted in significant increased height (P < .0001). Decreases in pain after aquatic intervention (2.7 ± 2.1 cm) were significantly greater than decreases after land intervention (1.7 ± 1.7 cm; P = .0034), and centralization of symptoms was more pronounced after aquatic vertical suspension compared with the supine land-based flexion condition (P < .0001). A significant correlation between height change and both pain reduction (r = 0.39; P = .001) and centralization (r = 0.29; P = .013) was observed for the aquatic intervention only., Conclusion: Although both the aquatic and land interventions produced significant increases in overall spinal height, the aquatic intervention produced greater pain relief and centralization response in subjects with low back pain and signs of nerve root compression., (Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Accurate ability to diagnose lumbar spine clinical instability is controversial for numerous reasons, including inaccuracy and limitations in capabilities of radiographic findings, poor reliability and validity of clinical special tests, and poor correlation between spinal motion and severity of symptoms. It has been suggested that common subjective and objective identifiers are specific to lumbar spine clinical instability. The purpose of this study was to determine if consensual, specific identifiers for subjective and objective lumbar spine clinical instability exist as determined by a Delphi survey instrument. One hundred and sixty eight physical therapists identified as Orthopaedic Clinical Specialists (OCS) or Fellows of the American Academy of Orthopaedic Manual Physical Therapists participated in three Delphi rounds designed to select specific identifiers for lumbar spine clinical instability. Round I consisted of open-ended questions designed to provide any relevant issues. Round II allowed the participants to rank the organized findings of Round I. Round III provided an opportunity to rescore the ranked variables after viewing other participant's results. The results suggest that those identifiers selected by the Delphi experts are synonymous with those represented in related spine instability literature and may be beneficial for use during clinical differential diagnosis.