Gary L. Shum

Effect of low back pain on the kinematics and joint coordination of the lumbar spine and hip during sit-to-stand and stand-to-sit

Study Design. Experimental study to describe lumbar spine and hip joint movements during sit-to-stand and stand-to-sit. Objectives. To examine differences in the kinematics and joint coordination of the lumbar spine and hips during sit-to-stand and stand-to-sit between healthy subjects and patients with subacute low back pain (LBP). Summary of Background Data. There is a paucity of information on the coordination of movements of lumbar spine and hips during sit-to-stand and stand-to-sit. The effect of LBP, with or without nerve root signs, is largely unknown. Methods. A three-dimensional real-time electromagnetic tracking device was used to measure movements of the lumbar spine and hips during sit-to-stand and stand-to-sit. Sixty subacute LBP participants with or without straight leg raise signs and 20 healthy asymptomatic participants were recruited. The kinematic patterns of lumbar spine and hips were analyzed. Coordination between the two joints was studied by relative phase angle analysis. Results. The mobility of the spine and hips was significantly limited in back pain subjects. It was observed that LBP subjects employed various strategies to compensate for the limited motions at the hips and lumbar spine. The contribution of the lumbar spine relative to that of the hip was found to be reduced for subjects with LBP. The lumbar spine-hip joint coordination was significantly altered in back pain subjects, in particular, those with positive straight leg raise sign. Conclusion. Back pain was related to changes in the kinematics and coordination of the lumbar spine and hips during sit-to-stand and stand-to-sit. Assessment of back pain patients should include kinematic analysis of the hips as well as the spine.

Movement coordination of the lumbar spine and hip during a picking up activity in low back pain subjects

The effect of low back pain, with or without nerve root signs, on the joint coordination and kinematics of the lumbar spine and hips during everyday activities, such as picking up an object from the floor, are largely unknown. An experimental study was designed to compare lumbar spine and hip joint kinematics and coordination in subjects with and without sub-acute low back pain, while picking up an object in a sitting position. A three-dimensional real-time electromagnetic tracking device was used to measure movements of the lumbar spine and hips. Sixty participants with subacute low back pain, with or without straight leg raise signs, and twenty healthy asymptomatic participants were recruited. The ranges of motions of lumbar spine and hips were determined. Movement coordination between the two regions was examined by cross-correlation. Results showed that mobility was significantly reduced in subjects with back pain, who compensated for limited motion through various strategies. The contribution of the lumbar spine relative to that of the hip was, however, found to be similar in all groups. The lumbar spine–hip joint coordination was substantially altered in subjects with back pain, in particular, those with a positive straight leg raise sign. We conclude that changes in the lumbar and hip kinematics were related to back pain and limitation in straight leg raise. Lumbar–hip coordination was mainly affected by the presence of positive straight leg raise sign when picking up an object in a sitting position.

Three-dimensional kinetics of the lumbar spine and hips in low back pain patients during sit-to-stand and stand-to-sit

Study Design. Experimental, biomechanical study to determine the kinetics of the lumbar spine and hips during sit-to-stand and stand-to-sit. Objective. To investigate the effects of back pain, with and without limitation in straight leg raise, on the joint moment and power of the lumbar and hips during sit-to-stand and stand-to-sit. Summary of Background Data. Movements of the lumbar spine and hips, and their coordination have been reported to be affected by the presence of low back pain (LBP), especially in those with a positive straight leg raise. However, the literature has no information concerning moment and power characteristics of the lumbar spine and hips during sit-to-stand and stand-to-sit in such patients. Methods. Twenty asymptomatic subjects, 20 LBP patients, and 20 patients with LBP and a positive straight leg raise sign were requested to perform the sit-to-stand and stand-to-sit activities. Electromagnetic sensors were attached to the body segments to measure their kinematics while 2 nonconductive force plates gathered ground reaction force data. Biomechanical models were used to determine the muscle moments and power at the lumbosacral (L5/S1) joint and hips. Results. Muscle moments acting at the lumbar spine and hip in the sagittal plane were found to decrease in subjects with LBP, but there were significant increases in moments in other planes of motion. The power patterns of the spine and hips were also significantly altered, particularly in subjects with a positive straight leg raise sign. Conclusions. Back pain subjects exhibit compensatory movements and altered load sharing strategies during the sit-to-stand and stand-to-sit activities. Exercise therapy should take account of these changes so that the normal kinematic and kinetic characteristics of the spine and hips can be restored.

Symptomatic and asymptomatic movement coordination of the lumbar spine and hip during an everyday activity

Study Design. This experimental study analyzed the movements of the lumbar spine and hip while putting on a sock. Objectives. To examine differences in kinematics and coordination of the lumbar and hip movements in subjects with and without subacute low back pain. Summary of Background Data. There is no information on the coordination of movements of lumbar spine and hips during activities of daily living such as putting on a sock. The effect of low back pain, with or without nerve root signs, is unknown. Methods. A real-time three-dimensional electromagnetic tracking device was used to measure movements of the lumbar spine and hips in 60 subacute low back pain subjects with or without straight leg raise (SLR) signs and 20 asymptomatic subjects. Movement coordination between the two regions was examined by cross-correlation. Results. Mobility was significantly reduced in back pain subjects. Symptomatic subjects compensated for limited motion through various strategies, but in all cases the contribution of the lumbar spine relative to that of the hip was significantly reduced. The lumbar spine-hip joint coordination was substantially altered in back pain subjects, in particular, when putting on a sock on the side with positive SLR sign. Conclusion. Changes in the lumbar and hip kinematics when putting on a sock were related to back pain and limitation in SLR. Low back pain will affect lumbar-hip coordination.

The effect of closed-kinetic chain exercises and open-kinetic chain exercise on the muscle activity of vastus medialis oblique and vastus lateralis.

Irish, SE, Millward, AJ, Wride, J, Haas, BM, and Shum, GLK. The effect of closed-kinetic chain exercises and open-kinetic chain exercise on the muscle activity of vastus medialis oblique and vastus lateralis. J Strength Cond Res 24(5): 1256-1262, 2010-Patellofemoral pain syndrome (PFPS) is one of the most prevalent musculoskeletal conditions of the lower limb. The muscle imbalance between the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles is one of the main factors leading to the development of PFPS. The disparity in research and the necessity to add to the existing literature base led to the development of this study. The aim of this study was to investigate the effect of 2 closed kinetic chain exercises and 1 open kinetic chain exercise on VMO and VL muscle activity. Twenty-two healthy asymptomatic individuals participated in this study. The surface electromyography (EMG) of VMO and VL was measured and used to calculate the VMO:VL ratio during 3 different quadriceps-strengthening exercises (a double leg squat with isometric hip adduction exercise, an open kinetic chain knee extension exercise, and a lunge exercise). The double leg squat with isometric hip adduction exercise was shown to produce a significantly greater VMO:VL ratio (1.14:1) than the other 2 exercises (p = 0.015 and p = 0.005). The open kinetic chain knee extension exercises produced significantly greater activation of VL than the lunge exercise (p = 0.001 and p = 0.036). The lunge exercise produced the VMO:VL ratio (1.18:1) closest to the idealized ratio of 1:1. Potential clinical recommendations can be made proposing the lunge exercise as a key tool in early rehabilitation when restoring preferential VMO:VL ratio is essential. The double leg squat with isometric hip adduction exercise would be useful in maintaining correct patella tracking and selectively strengthening VMO.

Energy Transfer Across the Lumbosacral and Lower-Extremity Joints in Patients With Low Back Pain During Sit-to-Stand

OBJECTIVE To examine the transfer of energy through the pelvis and the lower limb during sit-to-stand (STS) in low back pain (LBP) subjects with or without a straight-leg raise sign. DESIGN Cross-sectional. SETTING Biomechanics laboratory. PARTICIPANTS Three groups, each of 20 subjects, participated. The first group consisted of asymptomatic subjects, and the other 2 groups of consisted of LBP subjects (duration between 7 days and 12 weeks) with and without a straight-leg raise sign. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES The work done and the power of the pelvis, thigh, and leg segments during STS were determined. RESULTS Energy was transferred from the pelvis to the thigh segment and then to the leg segment, and this was achieved mainly by passive mechanisms. The power flow of the pelvis segment was significantly decreased in subjects with LBP. Although the power of the lower-limb segments was decreased, the total work done of these segments was increased. CONCLUSIONS STS is a more energy-demanding and less efficient task for subjects with LBP, either with or without a positive straight-leg raise sign. Such increases in energy demand may further exacerbate back pain, and treatment should be developed to restore a more efficient energy transfer pattern.

The Immediate Effect of Posteroanterior Mobilization on Reducing Back Pain and the Stiffness of the Lumbar Spine

OBJECTIVE To study the immediate effect of posteroanterior mobilization on back pain and the associated biomechanical changes in the lumbar spine. DESIGN An experimental between-group study. SETTING A biomechanics laboratory. PARTICIPANTS Subjects with low back pain (n=19) and healthy subjects (n=20). INTERVENTIONS Grade III posteroanterior mobilization (3 cycles of 60s) was applied at the L4 level in people with or without back pain on 1 occasion. MAIN OUTCOME MEASURES Pain intensity, active lumbar range of motion, the magnitude of the posteroanterior mobilization loads, bending stiffness of the lumbar spine, and the lordotic curvature of the lumbar spine before and after 3 cycles of posteroanterior mobilization. RESULTS The magnitude of pain of the patients was found to decrease significantly after posteroanterior mobilization treatment. There was also a significant decrease in the bending stiffness of the lumbar spine of the patients, which was derived from the posteroanterior load and the associated change in spine curvature. The stiffness was restored to a level that was similar to that of the asymptomatic subjects. A strong correlation was found between the magnitude of pain and the bending stiffness of the spine before (r=.89) and after posteroanterior mobilization (r=.98). CONCLUSIONS Posteroanterior mobilization was found to bring about immediate desirable effects in reducing spinal stiffness and the magnitude of back pain. The restoration of the mechanical properties of the spine may be a possible mechanism that explains the improvement in pain after manual therapy.

Back pain is associated with changes in loading pattern throughout forward and backward bending

Study Design. Experimental study to determine the kinetics of the lumbar spine (LS) and hips during forward and backward bending. Objective. To investigate the effects of back pain, with and without a positive straight leg raise (SLR) sign, on the loading patterns in the LS and hip during forward and backward bending. Summary of Background Data. Forward and backward bending are important components of many functional activities and are part of routine clinical examination. However, there is a little information about the loading patterns during forward and backward bending in people with back pain with or without a positive SLR sign. Methods. Twenty asymptomatic participants, 20 back pain participants, and 20 participants with back pain and a positive SLR sign performed 3 continuous cycles of forward and backward bending. Electromagnetic sensors were attached to body segments to measure their kinematics while 2 nonconductive force plates gathered ground reaction force data. A biomechanical model was used to determine the loading pattern in LS and hips. Results. Although the loading on the LS at the end of the range decreased significantly, the loading at the early and middle ranges of forward bending actually increased significantly in people with back pain, especially in those with positive SLR sign. This suggests that resistance to movement is significantly increased in people with back pain during this movement. Conclusion. This study suggested that it is not sufficient to study the spine at the end of range only, but a complete description of the loading patterns throughout the range is required. Although the maximum range of motion of the spine is reduced in people with back pain, there is a significant increase in the moment acting through the range, particularly in those with a positive SLR sign.

Comparison of reliability and repeatability of corneal curvature assessment with six keratometers

Keratometric methodology varies between instruments and the differences may have a clinical impact. We investigated the agreement and reproducibility of six keratometers.

Deep abdominal muscle activity following supratentorial stroke

This study assessed the level and symmetry of deep abdominal muscle activation following a supratentorial stroke during a modified hip flexion task. Movement-related activation levels in the transversus abdominus (TrA) and internal oblique (IO) were investigated in people with a subacute (<3.25months) supratentorial stroke (n=11) and a matched control group (n=11). Electromyographic activity in TrA and IO were recorded using fine wires inserted under ultrasound guidance while participants performed a standardised head lift or unilateral hip flexion. During head lift there was no significant difference in the amplitude of activation ipsi- and contra-lateral to the stroke or between groups. During unilateral hip flexion the TrA and IO were activated more on both sides when moving the paretic leg. In the control group muscle activity was modulated by task with activity being higher ipsilateral to the moving leg; in contrast in the stroke group IO muscle activity tended to be higher on the non-paretic side irrespective of moving limb. Greater TrA and IO muscle activity during hip flexion of the paretic leg may represent compensatory activity that acts to facilitate activation of the paretic hip flexors and/or the presence of overflow.