Reduced variability of postural strategy prevents normalization of motor changes induced by back pain: a risk factor for chronic trouble?

Variability is fundamental to biological systems and is important in posturomotor learning and control. Pain induces a protective postural strategy, although variability is normally preserved. If variability is lost, does the normal postural strategy return when pain stops? Sixteen subjects performed arm movements during control trials, when the movement evoked back pain and then when it did not.

The lumbar multifidus: does the evidence support clinical beliefs?

The contribution of the trunk muscles to spinal stability is well established. There is convincing evidence for the role of multifidus in spinal stability. Recently, emphasis has shifted to the deep fibres of this muscle (DM) and five key clinical beliefs have arisen: (i) that DM stabilizes the lumbar spine whereas the superficial fibres of lumbar multifidus (SM) and the erector spinae (ES) extend and/or rotate the lumbar spine, (ii) that DM has a greater percentage of type I (slow twitch) muscle fibres than SM and ES, (iii) that DM is tonically active during movements of the trunk and gait, whereas SM and ES are phasically active, (iv) that DM and the transversus abdominis (TrA) co-contract during function, and (v) that changes in the lumbar paraspinal muscles associated with LBP affect DM more than SM or ES.

Effect of knee joint angle on motor unit synchronization.

Activity of the vasti has been argued to vary through knee range of movement due to changes in passive support of the patellofemoral joint and the relative contribution of these muscles to knee extension. Efficient function of the knee is dependent on optimal control of the patellofemoral joint, largely through coordinated activity of the medial and lateral quadriceps. Motor unit synchronization may provide a mechanism to coordinate the activity of vastus medialis (VMO) and vastus lateralis (VL), and may be more critical in positions of reduced passive support for the patellofemoral joint (i.

Do you know where your arm is if you think your head has moved?

Reproduction of a previously presented elbow position is affected by changes in head position. As movement of the head is associated with local biomechanical changes, the aim of the present study was to determine if illusory changes in head position could induce similar effects on the reproduction of elbow position. Galvanic vestibular stimulation (GVS) was applied to healthy subjects in supine lying.

Disorders of breathing and continence have a stronger association with back pain than obesity and physical activity.

Although obesity and physical activity have been argued to predict back pain, these factors are also related to incontinence and breathing difficulties. Breathing and continence mechanisms may interfere with the physiology of spinal control, and may provide a link to back pain. The aim of this study was to establish the association between back pain and disorders of continence and respiration in women.

An endurance-strength training regime is effective in reducing myoelectric manifestations of cervical flexor muscle fatigue in females with chronic neck pain.

Objective: The purpose of this study was to investigate whether an endurance-strength training program is effective in reducing myoelectric manifestations of sternocleidomastoid (SCM) and anterior scalene (AS) muscle fatigue which have been found to be greater in people with chronic neck pain.

Methods: Fifty-eight female patients with chronic non-severe neck pain were randomized into one of two 6-week exercise intervention groups: an endurance-strength training regime for the cervical flexor muscles or a referent exercise intervention involving low load retraining of the cranio-cervical flexor muscles. The primary outcomes were a change in maximum voluntary contraction (MVC) force and change of the initial value and rate of change of the mean frequency, average rectified value and conduction velocity detected from the SCM and AS muscles during sub-maximal isometric cervical flexion contractions at 50, 25 and 10% MVC.

Effects of tensioning the lumbar fasciae on segmental stiffness during flexion and extension: Young Investigator Award winner.

Study Design: Biomechanical study of unembalmed human lumbar segments.

Objective: To investigate the effects of tensioning the lumbar fasciae (transversus abdominis [TrA]) aponeurosis) on segment stiffness during flexion and extension.

Summary Of Background Data: Animal and human studies suggest that TrA may influence intersegmental movement via tension in the middle and posterior layers of lumbar fasciae (MLF, PLF).

Case report: inspiratory muscle training in chronic critically ill patients--a report of two cases.

Background And Purpose: Inspiratory muscle weakness and fatigue has been documented following prolonged mechanical ventilation despite successful weaning from mechanical ventilation. This report describes the application of inspiratory muscle training in two patients following successful discharge from an intensive care unit (ICU) after prolonged mechanical ventilation.

Methods: Both patients undertook inspiratory muscle training in conjunction with standard physiotherapy rehabilitation.

Scaling and non-scaling of muscle activity, kinematics, and dynamics in sit-ups with different degrees of difficulty.

The purpose of this study was to investigate how the CNS adjusts motor patterns for variants of a complex axial movement-the sit-up. Adjustments were induced by changing the support surface contact and mass distribution of the body. Healthy adults performed straight-legged sit-ups, 3 s in duration, with support added to or removed from the lumbar trunk, or with mass added to the head or to the legs.

Patellar taping does not change the amplitude of electromyographic activity of the vasti in a stair stepping task.

Objectives: To investigate the effect of patellar taping on the amplitude of electromyographic activity (EMG) of vasti activation in subjects with and without patellofemoral pain (PFP).

Methods: Ten participants with PFP and 12 asymptomatic controls were recruited to the study. The study was designed as a randomised crossover trial.

Leg muscle recruitment in highly trained cyclists.

In this study, we examined patterns of leg muscle recruitment and co-activation, and the relationship between muscle recruitment and cadence, in highly trained cyclists. Electromyographic (EMG) activity of the tibialis anterior, tibialis posterior, peroneus longus, gastrocnemius lateralis and soleus was recorded using intramuscular electrodes, at individual preferred cadence, 57.5, 77.

Postural activity of the abdominal muscles varies between regions of these muscles and between body positions.

The abdominal muscles have an important role in control and movement of the lumbar spine and pelvis. Given there is new evidence of morphological and functional differences between distinct anatomical regions of the abdominal muscles, this study investigated whether there are regional differences in postural activity of these muscles and whether recruitment varies between different body positions. Eleven subjects with no history of low back pain that affected function or for which they sought treatment participated in the study.

The effect of motor control exercise versus placebo in patients with chronic low back pain [ACTRN012605000262606].

Background: While one in ten Australians suffer from chronic low back pain this condition remains extremely difficult to treat. Many contemporary treatments are of unknown value. One potentially useful therapy is the use of motor control exercise.

Ventilatory changes following head-up tilt and standing in healthy subjects.

Passive tilting increases ventilation in healthy subjects; however, controversy surrounds the proposed mechanism. This study is aimed to evaluate the possible mechanism for changes to ventilation following passive head-up tilt (HUT) and active standing by comparison of a range of ventilatory, metabolic and mechanical parameters. Ventilatory parameters (V (T), V (E), V (E)/VO(2), V (E)/VCO(2), f and PetCO(2)), functional residual capacity (FRC), respiratory mechanics with impulse oscillometry; oxygen consumption (VO(2)) and carbon dioxide production (VCO(2)) were measured in 20 healthy male subjects whilst supine, following HUT to 70 degrees and unsupported standing.

Changes in joint stability with muscle contraction measured from transmission of mechanical vibration.

A non-invasive in vivo technique was developed to evaluate changes in wrist joint stability properties induced by increased co-activation of the forearm muscles in a gripping task. Mechanical vibration at 45, 50 and 55 Hz was applied to the radial head in ten healthy volunteers. Vibrations of the styloid process of the radius and the distal end of the metacarpal bone of the index finger were measured with triaxial accelerometers.

Effect of gaze direction on neck muscle activity during cervical rotation.

Control of the neck muscles is coordinated with the sensory organs of vision, hearing and balance. For instance, activity of splenius capitis (SC) is modified with gaze shift. This interaction between eye movement and neck muscle activity is likely to influence the control of neck movement.

Muscle fiber and motor unit behavior in the longest human skeletal muscle.

The sartorius muscle is the longest muscle in the human body. It is strap-like, up to 600 mm in length, and contains five to seven neurovascular compartments, each with a neuromuscular endplate zone. Some of its fibers terminate intrafascicularly, whereas others may run the full length of the muscle.

Reduced inspiratory muscle endurance following successful weaning from prolonged mechanical ventilation.

Study Objectives: Respiratory muscle weakness and decreased endurance have been demonstrated following mechanical ventilation. However, its relationship to the duration of mechanical ventilation is not known. The aim of this study was to assess respiratory muscle endurance and its relationship to the duration of mechanical ventilation.

Collaboration with city agencies: a winning approach to community assessment.

Five graduate nursing students made a difference in the health of San Antonio citizens by conducting a community assessment as part of a standard clinical activity in their community health nursing course. The students and their professor were able to effect city-wide change for health protection and promotion through collaboration with the City of San Antonio Planning Department (CSAPD). By compiling information, linking organizations, and speaking before community groups about the importance of a fluoridated water supply, the students generated public interest and momentum, which resulted in a successful vote to add fluoride to the water supply.

Motor unit synchronization is reduced in anterior knee pain.

Unlabelled: Anterior knee pain (AKP) is common and has been argued to be related to poor patellofemoral joint control due to impaired coordination of the vasti muscles. However, there are conflicting data. Changes in motor unit firing may provide more definitive evidence.

Effect of experimentally induced low back pain on postural sway with breathing.

Although breathing perturbs balance, in healthy individuals little sway is detected in ground reaction forces because small movements of the spine and lower limbs compensate for the postural disturbance. When people have chronic low back pain (LBP), sway at the ground is increased, possibly as a result of reduced compensatory motion of the trunk. The aim of this study was to determine whether postural compensation for breathing is reduced during experimentally induced pain.

Intra-abdominal pressure increases stiffness of the lumbar spine.

Intra-abdominal pressure (IAP) increases during many tasks and has been argued to increase stability and stiffness of the spine. Although several studies have shown a relationship between the IAP increase and spinal stability, it has been impossible to determine whether this augmentation of mechanical support for the spine is due to the increase in IAP or the abdominal muscle activity which contributes to it. The present study determined whether spinal stiffness increased when IAP increased without concurrent activity of the abdominal and back extensor muscles.

Changes in three dimensional lumbo-pelvic kinematics and trunk muscle activity with speed and mode of locomotion.

Background: Control of the trunk is critical for locomotor efficiency. However, investigations of trunk muscle activity and three-dimensional lumbo-pelvic kinematics during walking and running remain scarce.

Methods: Gait parameters and three-dimensional lumbo-pelvic kinematics were recorded in seven subjects.

Are the changes in postural control associated with low back pain caused by pain interference?

Background: Voluntary limb movements are associated with involuntary and automatic postural adjustments of the trunk muscles. These postural adjustments occur prior to movement and prevent unwanted perturbation of the trunk. In low back pain, postural adjustments of the trunk muscles are altered such that the deep trunk muscles are consistently delayed and the superficial trunk muscles are sometimes augmented.