Thoracolumbar proprioception in individuals with and without low back pain: intratester reliability, clinical applicability, and validity

Extended physiological proprioception is affected by transhumeral Socket-Suspended prosthesis use

The objective of this study was to define targeted reaching performance without visual information for transhumeral (TH) prosthesis users, establishing baseline information about extended physiological proprioception (EPP) in this population. Subjects completed a seated proprioceptive targeting task under simultaneous motion capture, using their prosthesis and intact limb. Eight male subjects, median age of 58 years (range 29-77 years), were selected from an ongoing screening study to participate. Five subjects had a left-side TH amputation, and three a right-side TH amputation. Median time since amputation was 9 years (range 3-54 years). Four subjects used a body-powered prosthetic hook, three a myoelectric hand, and one a myoelectric hook. The outcome measures were precision and accuracy, motion of the targeting hand, and joint angular displacement. Subjects demonstrated better precision when targeting with their intact limb compared to targeting with their prosthesis, 1.9 cm2 (0.8-3.0) v. 7.1 cm2 (1.3-12.8), respectively, p = 0.008. Subjects achieved a more direct reach path ratio when targeting with the intact limb compared to with the prosthesis, 1.2 (1.1-1.3) v. 1.3 (1.3-1.4), respectively, p = 0.039 The acceleration, deceleration, and corrective phase durations were consistent between conditions. Trunk angular displacement increased in flexion, lateral flexion, and axial rotation while shoulder flexion decreased when subjects targeted with their prosthesis compared to the intact limb. The differences in targeting precision, reach patio ratio, and joint angular displacements while completing the targeting task indicate diminished EPP. These findings establish baseline information about EPP in TH prosthesis users for comparison as novel prosthesis suspension systems become more available to be tested.

Role of proprioceptors in chronic musculoskeletal pain

Proprioceptors are non-nociceptive low-threshold mechanoreceptors. However, recent studies have shown that proprioceptors are acid-sensitive and express a variety of proton-sensing ion channels and receptors. Accordingly, although proprioceptors are commonly known as mechanosensing neurons that monitor muscle contraction status and body position, they may have a role in the development of pain associated with tissue acidosis. In clinical practice, proprioception training is beneficial for pain relief. Here we summarize the current evidence to sketch a different role of proprioceptors in 'non-nociceptive pain' with a focus on their acid-sensing properties.

Immediate Effects of Mulligan Mobilization on Elbow Proprioception in Healthy Individuals: A Randomized Placebo-Controlled Single-Blind Study

OBJECTIVE

The aim of this study was to investigate the immediate effects of Mulligan's mobilization with movement (MWM) on elbow proprioception.

METHODS

The study included 26 participants in the intervention group and 30 participants in the control group. The intervention group received MWM, while the control group received a sham application. Proprioception was assessed with joint position sense error at baseline, immediately after mobilization, and 30 minutes after mobilization with 70° and 110° of elbow flexion. The hypothesis of interest was the group × time interaction.

RESULTS

At 110° of elbow flexion, group × time interaction was significant (F[2, 108] = 11.48, P = .001). In the paired comparisons, there was a statistically significant difference in favor of the control group in the first measurement (P = .003). No difference was detected in other time points (P = 1.00). At 70° of elbow flexion, there was no significant difference between the time point × group interaction (F[2, 108] = 1.37, P = .10). Therefore, no pairwise comparison was made.

CONCLUSION

In this study of healthy participants, no immediate difference was found between MWM and sham application on elbow proprioception.

The dynamic postural steadiness and stabilization time between older adults with and without recurrent low back pain

BACKGROUND

Although postural control measures were reported to identify neuromuscular impairments, postural steadiness and stabilization time were not carefully investigated between subjects with and without recurrent low back pain (LBP). Research QuestionAre there group differences in the stabilization time, direction of sway, and dynamic postural steadiness index (DPSI) during one-leg standing?

METHODS

Thirty-four control subjects and 29 subjects with recurrent LBP participated in the study. Each subject stood upright on a single leg with and without visual input. The outcomes were measured for standing duration (sec), direction of sway, and the DPSI, which included the vertical steadiness index (VSI). The VSI assesses fluctuations to standardize the vertical ground reaction forces on the force plate.

RESULTS

The control group demonstrated significantly longer standing duration compared to the LBP group during the eyes-open condition (t = 3.55, p = 0.001). The LBP group demonstrated significantly faster stabilization time (t = 2.53, p = 0.01) in the sagittal plane. The DPSI demonstrated an excellent relationship with the VSI without visual input in the control group (r = 0.98, p = 0.001). The directions of sway demonstrated a significant interaction between groups (F = 9.29, p = 0.004).

SIGNIFICANCE

Although standing duration in the eyes-open condition decreased in the LBP group, a faster stabilization time in the sagittal plane was evident compared to the control group to adapt postural stability. These results indicated that vertical dynamic steadiness with visual input might be important to enhance compensatory postural control.

Reliability and Validity of the Double Inclinometer Method for Assessing Thoracolumbar Joint Position Sense and Range of Movement in Patients with a Recent History of Low Back Pain

The study was aimed at examining the reliability of the Double Inclinometer (DI) method for the assessment of thoracolumbar Range of Movement (ROM) and Joint Position Sense (JPS) in patients with a recent history of Low Back Pain (LBP). Twenty patients with a history of LBP in the last three months participated. The thoracolumbar ROM and JPS were examined from a standing position by using both the DI and the tape measure method. The DI method was found to have moderate to good intra-rater (ICC = 0.68-0.79, SEM = 2.20-2.77°, SDD = 6.09-7.67°), moderate inter-rater (ICC = 0.59-0.62, SEM = 2.96-3.35°, SDD = 8.19-9.27°) and poor test-retest reliability (ICC = 0.13-0.17, SEM = 3.98-4.32°, SDD = 11.02-11.96°) for the assessment of thoracolumbar JPS. For the assessment of thoracolumbar ROM, the DI method was found to have good to excellent intra-rater (ICC = 0.88-0.94, SEM = 4.25-6.20°, SDD = 11.77-17.17°), excellent inter-rater (ICC = 0.90-0.91, SEM = 7.26-7.74°, SDD = 20.11-21.43°) and excellent test-retest reliability (ICC = 0.91-0.93, SEM = 6.03-6.87°, SDD = 16.70-19.02°). The concurrent validity of the DI method with the tape measure method was found to be very weak for the assessment of thoracolumbar JPS (r = 0.02, p = 0.93) and strong for the assessment of thoracolumbar ROM (r = 0.66, p = 0.001). The DI method seems to be a very reliable method for the assessment of thoracolumbar ROM in individuals with a recent history of LBP.

The reliability of P300 and the influence of age, gender and education variables in a 50 years and older normative sample

OBJECTIVES

The present study aims to investigate the effects of age, gender, and level of education on P300 in a healthy population, aged 50 years and over; and determine the reliability metrics for different conditions and measurement methods.

METHOD

Auditory and visual oddball recordings of 171 healthy adults were investigated. A fully automated preprocessing was applied to elicit ERP P300. Maximum peak amplitude, latency and mean amplitudes were measured. Data were stratified by age, gender, and education to determine group-level differences by using repeat measures of ANOVA. The internal consistency of P300 was calculated by a split-half method using odd-even segments. Test-retest reliability was assessed by calculating the intraclass correlation coefficient (ICC).

RESULTS

Maximum peak P300 amplitudes were higher in the 50-64 years age group compared to the >65 years age group; and females showed increased P300 amplitudes compared to males. P300 measures showed fair to good internal consistency and poor to good test-retest reliability.

CONCLUSION

Age and gender should be taken into account when designing ERP studies with elderly individuals. P300 showed good internal consistency in general, between gender groups and age groups. Long-term test-retest reliability was lower but acceptable. These findings can be interpreted as the strength of P300 by being an objective and reliable method independent of cultural differences. Here we underline several factors that may affect P300 measures and discuss other possible factors that should be standardized for P300 to be used in clinical settings.

Reliability of hip joint position sense tests using a clinically applicable measurement tool in elderly participants with unilateral hip osteoarthritis

Hip joint proprioception is vital in maintaining posture and stability in elderly individuals. Examining hip joint position sense (JPS) using reliable tools is important in contemporary clinical practice. The objective of this study is to evaluate the intra-rater and inter-rater reliability of hip JPS tests using a clinically applicable measurement tool in elderly individuals with unilateral hip osteoarthritis (OA). Sixty-two individuals (mean age = 67.5 years) diagnosed with unilateral hip OA participated in this study. The JPS tests were evaluated using a digital inclinometer in hip flexion and abduction directions. The absolute difference between target and reproduced angle (repositioning error) in degrees was taken to measure JPS accuracy. The intraclass correlation coefficient (ICC (2.k), was used to assess the reliability. The Intra rater-reliability for hip JPS tests showed very good agreement in the lying position (hip flexion-ICC = 0.88–0.92; standard error of measurement (SEM) = 0.06–0.07, hip abduction-ICC = 0.89–0.91; SEM = 0.06–0.07) and good agreement in the standing position (hip flexion-ICC = 0.69–0.72; SEM = 0.07, hip abduction-ICC = 0.66–0.69; SEM = 0.06–0.08). Likewise, inter-rater reliability for hip JPS tests demonstrated very good agreement in the lying position (hip flexion-ICC = 0.87–0.89; SEM = 0.06–0.07, hip abduction-ICC = 0.87–0.91; SEM = 0.07) and good agreement in the standing position (hip flexion-ICC = 0.64–0.66; SEM = 0.08, hip abduction-ICC = 0.60–0.72; SEM = 0.06–0.09). The results support the use of hip JPS tests in clinical practice and should be incorporated in assessing and managing elderly participants with hip OA.

Intra-rater and inter-rater reliability of neutral and target lumbar positioning tests in subjects with and without non-specific lower back pain

BACKGROUND

Proprioception, one's sense of movement and position, is a common term used in back rehabilitation. Kinesthetic rehabilitation may be useful in managing lower back pain; however, reliable measures are required to quantify lumbar proprioception sense.

OBJECTIVE

To investigate intrarater and interrater reliability of neutral lumbar positioning (NLP) and target lumbar positioning (TLP) tests and compare the position sense errors in subjects with non-specific low back pain and healthy controls.

METHODS

Intrarater (between-day) and interrater (within-day) reliability of NLP and TLP tests were assessed in 30 subjects with low back pain and 30 healthy subjects using a digital inclinometer. NLP is evaluated when the subject is repositioned to neutral from flexion, while TLP is evaluated in lumbar flexion, by bending laterally left and right.

RESULTS

Intrarater reliability for NLP tests had ICC values of 0.85 and 0.89 and TLP tests had 0.78 and 0.92. Likewise, interrater reliability for NLP had ICC values of 0.75 and 0.85, and for the TLP test, the interrater reliability had 0.78 and 0.93. Subjects with back pain had significantly larger neutral and target lumbar proprioceptive errors compared to healthy controls (p< 0.001).

CONCLUSIONS

Intrarater and interrater reliability showed good agreement for both NLP and TLP tests of lumbar proprioception. Subjects with nonspecific low back pain have impaired lumbar proprioceptive sense.

Sense of effort is distorted in people with chronic low back pain

BACKGROUND

Proprioceptive deficits in people with low back pain (LBP) have traditionally been attributed to altered paraspinal muscle spindle afference and its central processing. Studies conducted in the upper limb demonstrated that sense of effort is also an important source of kinaesthetic information.

OBJECTIVES

To better understand proprioceptive deficits in people with chronic LBP (cLBP), this study aimed to test whether sense of effort is affected in people with cLBP.

DESIGN

Cross-sectional study.

METHOD

Fourteen participants with cLBP and fourteen healthy participants performed a 120 s force matching task with their trunk extensor muscles at a low intensity.

RESULTS

When visual feedback of the generated force was provided, both groups performed the task accurately. Removal of visual feedback resulted in an increase in error for both groups (p < 0.0001), but the increase in error was significantly larger for the cLBP group (p = 0.023). This larger error could be attributed to undershooting of the target force (p = 0.020). The control group did not consistently undershoot or overshoot the target force (p = 0.93). Furthermore, the amount of undershooting for the cLBP group increased as the task progressed (p = 0.016), which was not observed for the control group (p = 0.80).

CONCLUSIONS

The results of this study revealed that sense of effort is affected in cLBP. People with cLBP overestimated the trunk extension force they generated, and the error increased as the trial progressed. With visual feedback however, people with cLBP were able to compensate and perform the task as accurately as people without cLBP.

The Neurophysiological Impact of Experimentally-Induced Pain on Direct Muscle Spindle Afferent Response: A Scoping Review

Background: Musculoskeletal pain disorders are among the leading causes of years lived with disability worldwide representing a significant burden to society. Studies investigating a “nociceptive-fusimotor” relationship using experimentally-induced pain/noxious stimuli and muscle spindle afferent (MSA) response have been published over several decades. The purpose of this scoping review was to systematically identify and summarize research findings related to the impact of experimentally-induced pain or noxious stimulation on direct MSA discharge/response.

Methods: PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane and Embase were searched from database inception to August 2020. Eligible studies were: (a) published in English; (b) clinical or pre-clinical studies; (c) original data studies; (d) included the investigation of MSA response to experimentally-induced pain or noxious stimulation; (e) included quantification of at least one direct physiological measure associated with MSA activity/response. Two-phase screening procedures were conducted by a pair of independent reviewers and data extracted from eligible studies.

Results: The literature search resulted in 195 articles of which 23 met inclusion criteria. Six studies (26%) were classified as clinical and 17 (74%) as pre-clinical. Two clinical studies investigated the effects of sacral dermatome pin-pricking on MSA response, while the remaining 4 studies investigated the effects of tonic muscle and/or skin pain induced by injection/infusion of hypertonic saline into the tibialis anterior muscle or subdermal tissues. In pre-clinical studies, muscle pain was induced by injection of noxious substances or the surgical removal of the meniscus at the knee joint.

Conclusion: Clinical studies in awake humans reported that experimentally-induced pain did not affect, or else slightly decreased MSA spontaneous discharge and/or response during weak dorsiflexor muscle contraction, thus failing to support an excitatory nociceptive-fusimotor relationship. However, a majority of pre-clinical studies indicated that ipsilateral and contralateral muscle injection of noxious substances altered MSA resting discharge and/or response to stretch predominately through static fusimotor reflex mechanisms. Methodological differences (use of anesthesia, stretch methodology, etc.) may ultimately be responsible for the discrepancies between clinical and pre-clinical findings. Additional investigative efforts are needed to reconcile these discrepancies and to clearly establish or refute the existence of nociceptive-fusimotor relationship in muscular pain.

Effect of a Spinomed orthosis on balance performance, spinal alignment, joint position sense and back muscle endurance in elderly people with hyperkyphotic posture: A randomized controlled trial

BACKGROUND

Hyperkyphosis may cause balance impairment in elderly people. Although the effectiveness of orthoses for improving balance in hyperkyphotic elderly people has received much attention, the mechanisms by which devices affect balance remain unknown.

OBJECTIVES

The objective of this study was to evaluate changes in balance performance, thoracic kyphosis angle, craniovertebral angle, back muscle endurance and joint position sense after 3 months of wearing a Spinomed orthosis. The study also included a secondary exploratory analysis to determine whether changes in any of the above-mentioned outcome measures can predict balance performance improvement in elderly people with hyperkyphosis.

STUDY DESIGN

Parallel group randomized controlled trial.

METHODS

In total, 44 hyperkyphotic elderly people were randomly allocated to an experimental group, who wore a Spinomed orthosis and a control group, who did not. No other treatment or change in physical activity was permitted during the study. A blinded assessor evaluated thoracic kyphosis angle, joint position sense, craniovertebral angle, back muscle endurance, Timed Up and Go Test time and Berg Balance Scale score at baseline and after 5, 9 and 13 weeks. All dependent variables were measured without the orthosis and analyzed separately using a 2 × 4 (time × group) mixed model analysis of variance. Based on the results of correlation analysis, thoracic kyphosis angle, back muscle endurance and joint position sense were selected as independent variables in a stepwise multiple regression model.

RESULTS

The two-way (group × time) interactions were significant in terms of Berg Balance Scale (F = 11.6, P ⩽ 0.001, ηp2=0.59), Timed Up and Go Test (F = 3.74, P = 0.013, ηp2=0.46), thoracic kyphosis angle (F = 43.39, P ⩽ 0.001, ηp2=0.96), craniovertebral angle (F = 5.245, P = 0.002, ηp2=0.59) and joint position sense (F = 4.44, P = 0.005, [Formula: see text]). The two-way interaction was not significant in terms of back muscle endurance; however, the main effect of group was significant for this variable (F = 3.85, P = 0.025). Stepwise multiple regression showed that thoracic kyphosis angle and joint position sense were significant determinants of Timed Up and Go Test time (R² = 0.155, P = 0.037 and R² = 0.292, P = 0.012, respectively).

CONCLUSION

Wearing a Spinomed orthosis for 3 months improved the posture, position sense and muscle performance of hyperkyphotic elderly people. Orthoses may improve balance performance by correcting spinal alignment and increasing proprioceptive information.

Relationship Between Proprioception and Pain and Disability in People With Non-Specific Low Back Pain: A Systematic Review With Meta-Analysis

STUDY DESIGN

Systematic review with meta-analysis.

OBJECTIVE

To examine the association between proprioception and pain and disability in people with non-specific low back pain (NSLBP) and the impact of potential moderators on the strength of the association.

SUMMARY OF BACKGROUND DATA

NSLBP is a common musculoskeletal disorder and a leading cause of disability. Proprioception deficit has been associated with low back pain and correlated with pain and disability; however, the correlation coefficients presented are conflicting.

METHODS

Systematic literature search was performed in eight databases and Google scholar. Two independent reviewers assessed the literature and extracted data. Data of interest included participant characteristics of NSLBP group, pain and disability, proprioception test protocol, and the correlation coefficient between proprioception and pain/disability. Meta-analysis of data from homogeneous studies was performed according to proprioception test methods. Subgroup of movement directions was analyzed. The methodological quality of studies was assessed.

RESULTS

The literature search identified 3067 records of which 14 studies were included for meta-analysis. Proprioception was measured by active joint repositioning sense (AJRS), passive joint repositioning sense (PJRS), and threshold to detect passive motion (TTDPM). Meta-analysis revealed no significant correlation coefficient between any proprioception measures and pain or disability (P > 0.05). The subgroup analysis showed little correlation between absolute error (AE) of passive lumbar flexion and pain (r = 0.225, 95% CI 0.040-0.395), and between AE of passive lumbar extension and disability (r = 0.196, 95%CI 0.010-0.369).

CONCLUSION

AJRS and TTDPM are not correlated with pain and disability in people with NSLBP. The AE of passive lumbar movement is correlated to a small degree with pain and disability. However, the degree of correlation is small and should be interpreted with caution. Therefore, the differences in proprioception observed between people with pain and people without pain seem to be independent of the symptoms.

LEVEL OF EVIDENCE

1.

Feasibility of Incorporating Test-Retest Reliability and Model Diversity in Identification of Key Neuromuscular Pathways During Head Position Tracking

To study the complex neuromuscular control pathways in human movement, biomechanical parametric models and system identification methods are employed. Although test-retest reliability is widely used to validate the outcomes of motor control tasks, it was not incorporated in system identification methods. This study investigates the feasibility of incorporating test-retest reliability in our previously published method of selecting sensitive parameters. We consider the selected parameters via this novel approach to be the key neuromuscular parameters, because they meet three criteria: reduced variability, improved goodness of fit, and excellent reliability. These criteria ensure that the parameter variability is below a user-defined value, the number of these parameters is maximized to enhance goodness of fit, and their test-retest reliability is above a user-defined value. We measured variability, the goodness of fit, and reliability using Fisher information matrix, variance accounted for, and intraclass correlation, respectively. We also incorporated model diversity as a fourth optional criterion to narrow down the solution space of key parameters. We applied this approach to the head position tracking tasks in axial rotation and flexion/extension. A total of forty healthy subjects performed the tasks during two visits. With variability and reliability measures ≤0.35 and ≥0.75, respectively, we selected three key parameters out of twelve with the goodness of fit >69%. The key parameters were associated with at least two neuromuscular pathways out of four modeled pathways (visual, proprioceptive, vestibular, and intrinsic), which is a measure of model diversity. Therefore, it is feasible to incorporate reliability and diversity in system identification of key neuromuscular pathways in our application.

Kinematic chain reactions on trunk and dynamic postural steadiness in subjects with recurrent low back pain

Although subjects with recurrent low back pain (LBP) demonstrate altered trunk control, the kinematic and kinetic responses of the trunk have not been carefully investigated. This study was conducted to compare the standing time, spine range of motion (ROM), and dynamic postural steadiness index (DPSI) based on visual condition between subjects with and without recurrent LBP during upright one leg standing. Sixty-three individuals participated in the study, including 34 control subjects and 29 subjects with recurrent LBP. The DPSI was a composite of the medio-lateral (MLSI), anterior-posterior (APSI), and vertical steadiness indices (VSI) on a force platform. The control group demonstrated longer standing time (s) during the eyes-open condition than the LBP group (26.82±6.03 vs. 19.87±9.36; t=2.96, p=0.01). Regarding spine ROM, visual condition was significantly different between groups (F=7.09, p=0.01) and demonstrated interactions with spine region and group (F=5.53, p=0.02). For the kinetic measures, there was a significant interaction between visual conditions and indices (F=25.30, p=0.001). In the LBP group, the DPSI was significantly correlated with the MLSI (r=0.59, p=0.002), APSI (r=0.44, p=0.03), and VSI (r=0.98, p=0.01) in the eyes-closed condition. Overall, the results of this study indicated that the LBP group decreased thorax and lumbar spine rotations during the eyes-closed condition. The LBP group also demonstrated positive correlations with the kinetic indices, enhancing dynamic postural steadiness in the eyes-closed condition in order to possibly avoid pain or further injury. This dynamic postural steadiness strategy is necessary to improve kinetic and kinematic chain reactions in the LBP group. This compensatory pattern supports the development of optimal postural correction strategies to prevent LBP recurrence and might represent a chain reaction to protect trunk control without visual input.

Interseason variability of a functional movement test, the 9+ screening battery, in professional male football players

BACKGROUND

The Nine Plus screening battery test (9+) is a functional movement test intended to identify limitations in fundamental movement patterns predisposing athletes to injury. However, the interseason variability is unknown.

AIM

To examine the variability of the 9+ test between 2 consecutive seasons in professional male football players.

METHODS

Asymptomatic Qatar Star League players (n=220) completed the 9+ at the beginning of the 2013 and 2014 seasons. Time-loss injuries in training and matches were obtained from the Aspetar Injury and Illness Surveillance Program. No intervention was initiated between test occasions.

RESULTS

A significant increase in the mean total score of 1.6 points (95% CI 1.0 to 2.2, p<0.001) was found from season 1 (22.2±4.1 (SD)) to season 2 (23.8±3.3). The variability was large, as shown by an intraclass correlation coefficient (ICC) of 0.24 (95% CI 0.11 to 0.36) and a minimal detectable change (MDC) of 8.7 points. Of the 220 players, 136 (61.8%) suffered a time-loss injury between the 2 tests. There was an improvement in mean total scores in the injured (+2.0±0.4 (SE), p<0.001) group but not in the uninjured group (+0.9±0.5, p=0.089). The variability from season 1 to season 2 was large both in the injured (ICC 0.25, 0.09 to 0.40, MDC 8.3) and uninjured (ICC 0.24, 0.02 to 0.43, MDC 9.1) groups.

CONCLUSIONS

The 9+ demonstrated substantial intraindividual variability in the total score between 2 consecutive seasons, irrespective of injury. A change above 8 points is necessary to represent a real change in the 9+ test between seasons.

Is There a Relationship Between Lumbar Proprioception and Low Back Pain? A Systematic Review With Meta-Analysis

OBJECTIVE

To systematically review the relationship between lumbar proprioception and low back pain (LBP).

DATA SOURCES

Four electronic databases (PubMed, EMBASE, CINAHL, SPORTDiscus) and reference lists of relevant articles were searched from inception to March-April 2014.

STUDY SELECTION

Studies compared lumbar proprioception in patients with LBP with controls or prospectively evaluated the relationship between proprioception and LBP. Two reviewers independently screened articles and determined inclusion through consensus.

DATA EXTRACTION

Data extraction and methodologic quality assessment were independently performed using standardized checklists.

DATA SYNTHESIS

Twenty-two studies (1203 participants) were included. Studies measured lumbar proprioception via active or passive joint repositioning sense (JRS) or threshold to detection of passive motion (TTDPM). Data from 17 studies were pooled for meta-analyses to compare patients with controls. Otherwise, descriptive syntheses were performed. Data were analyzed according to measurement method and LBP subgroup. Active JRS was worse in patients compared with controls when measured in sitting (standard mean difference, .97; 95% confidence interval [CI], .31-1.64). There were no differences between groups measured via active JRS in standing (standard mean difference, .41; 95% CI, -.07 to .89) or passive JRS in sitting (standard mean difference, .38; 95% CI, -.83 to 1.58). Patients in the O'Sullivan flexion impairment subgroup had worse proprioception than the total LBP cohort. The TTDPM was significantly worse in patients than controls. One prospective study found no link between lumbar proprioception and LBP.

CONCLUSIONS

Patients with LBP have impaired lumbar proprioception compared with controls when measured actively in sitting positions (particularly those in the O'Sullivan flexion impairment subgroup) or via TTDPM. Clinicians should consider the relationship between sitting and proprioception in LBP and subgroup patients to guide management. Further studies focusing on subgroups, longitudinal assessment, and improving proprioception measurement are needed.

Inspiratory muscle training affects proprioceptive use and low back pain

PURPOSE

We have shown that individuals with recurrent nonspecific low back pain (LBP) and healthy individuals breathing against an inspiratory load decrease their reliance on back proprioceptive signals in upright standing. Because individuals with LBP show greater susceptibility to diaphragm fatigue, it is reasonable to hypothesize that LBP, diaphragm dysfunction, and proprioceptive use may be interrelated. The purpose of this study was to investigate whether inspiratory muscle training (IMT) affects proprioceptive use during postural control in individuals with LBP.

METHODS

Twenty-eight individuals with LBP were assigned randomly into a high-intensity IMT group (high IMT) and low-intensity IMT group (low IMT). The use of proprioception in upright standing was evaluated by measuring center of pressure displacement during local muscle vibration (ankle, back, and ankle-back). Secondary outcomes were inspiratory muscle strength, severity of LBP, and disability.

RESULTS

After high IMT, individuals showed smaller responses to ankle muscle vibration, larger responses to back muscle vibration, higher inspiratory muscle strength, and reduced LBP severity (P < 0.05). These changes were not seen after low IMT (P > 0.05). No changes in disability were observed in either group (P > 0.05).

CONCLUSIONS

After 8 wk of high IMT, individuals with LBP showed an increased reliance on back proprioceptive signals during postural control and improved inspiratory muscle strength and severity of LBP, not seen after low IMT. Hence, IMT may facilitate the proprioceptive involvement of the trunk in postural control in individuals with LBP and thus might be a useful rehabilitation tool for these patients.

Assessing Proprioception: A Systematic Review of Possibilities

Proprioception is a vital aspect of motor control and when degraded or lost can have a profound impact on function in diverse clinical populations. This systematic review aimed to identify clinically related tools to measure proprioceptive acuity, to classify the construct(s) underpinning the tools, and to report on the clinimetric properties of the tools. We searched key databases with the pertinent search terms, and from an initial list of 935 articles, we identified 57 of relevance. These articles described 32 different tools or methods to quantify proprioception. There was wide variation in methods, the joints able to be tested, and the populations sampled. The predominant construct was active or passive joint position detection, followed by passive motion detection and motion direction discrimination. The clinimetric properties were mostly poorly evaluated or reported. The Rivermead Assessment of Somatosensory Perception was generally considered to be a valid and reliable tool but with low precision; other tools with higher precision are potentially not clinically feasible. Clinicians and clinical researchers can use the summary tables to make more informed decisions about which tool to use to match their predominant requirements. Further discussion and research is needed to produce measures of proprioception that have improved validity and utility.

Measuring lumbar reposition accuracy in patients with unspecific low back pain: systematic review and meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To evaluate if patients with nonspecific chronic low back pain (NSCLBP) show a greater lumbar reposition error (RE) than healthy controls.

SUMMARY OF BACKGROUND DATA

Studies on lumbar RE in patients with NSCLBP present conflicting results.

METHODS

A systematic review and meta-analysis of the available literature were performed to evaluate differences in RE between patients with NSCLBP and healthy controls. Data on absolute error, constant error (CE), and variable error were extracted and effect sizes (ESs) were calculated. For the CE flexion pattern and active extension pattern, subgroups of patients with NSCLBP were analyzed. Results of homogeneous studies were pooled. Measurement protocols and study outcomes were compared. The quality of reporting and the authors' appraisal of risk of bias were investigated.

RESULTS

The original search revealed 178 records of which 13 fulfilled the inclusion criteria. The majority of studies showed that patients with NSCLBP produced a significantly larger absolute error (ES, 0.81; 95% confidence interval [95% CI], 0.13-1.49) and variable error (ES, 0.57; 95% CI, 0.05-1.09) compared with controls. CE is direction specific in flexion and active extension pattern subgroups of patients with NSCLBP (ES, 0.39; 95% CI, -1.09 to 0.3) and ES, 0.18; 95% CI, -0.3 to 0.65, respectively). The quality of reporting and the authors' appraisal of risk of bias varied considerably. The applied test procedures and instrumentation varied between the studies, which hampered the comparability of studies.

CONCLUSION

Although patients with NSCLBP seemed to produce a larger lumbar RE compared with healthy controls, study limitations render firm conclusions unsafe. Future studies should pay closer attention to power, precision, and reliability of the measurement approach, definition of outcome measures, and patient selection. We recommend a large, well-powered, prospective randomized control study that uses a standardized measurement approach and definitions for absolute error, CE, and variable error to address the hypothesis that proprioception may be impaired with CLBP.

A cognitive dual task affects gait variability in patients suffering from chronic low back pain

Chronic pain and gait variability in a dual-task situation are both associated with higher risk of falling. Executive functions regulate (dual-task) gait variability. A possible cause explaining why chronic pain increases risk of falling in an everyday dual-task situation might be that pain interferes with executive functions and results in a diminished dual-task capability with performance decrements on the secondary task. The main goal of this experiment was to evaluate the specific effects of a cognitive dual task on gait variability in chronic low back pain (CLBP) patients. Twelve healthy participants and twelve patients suffering from CLBP were included. The subjects were asked to perform a cognitive single task, a walking single task and a motor-cognitive dual task. Stride variability of trunk movements was calculated. A two-way ANOVA was performed to compare single-task walking with dual-task walking and the single cognitive task performance with the motor-cognitive dual-task performance. We did not find any differences in both of the single-task performances between groups. However, regarding single-task walking and dual-task walking, we observed an interaction effect indicating that low back pain patients show significantly higher gait variability in the dual-task condition as compared to controls. Our data suggest that chronic pain reduces motor-cognitive dual-task performance capability. We postulate that the detrimental effects are caused by central mechanisms where pain interferes with executive functions which, in turn, might contribute to increased risk of falling.

Comparing lumbo-pelvic kinematics in people with and without back pain: a systematic review and meta-analysis

BACKGROUND

Clinicians commonly examine posture and movement in people with the belief that correcting dysfunctional movement may reduce pain. If dysfunctional movement is to be accurately identified, clinicians should know what constitutes normal movement and how this differs in people with low back pain (LBP). This systematic review examined studies that compared biomechanical aspects of lumbo-pelvic movement in people with and without LBP.

METHODS

MEDLINE, Cochrane Central, EMBASE, AMI, CINAHL, Scopus, AMED, ISI Web of Science were searched from inception until January 2014 for relevant studies. Studies had to compare adults with and without LBP using skin surface measurement techniques to measure lumbo-pelvic posture or movement. Two reviewers independently applied inclusion and exclusion criteria, and identified and extracted data. Standardised mean differences and 95% confidence intervals were estimated for group differences between people with and without LBP, and where possible, meta-analyses were performed. Within-group variability in all measurements was also compared.

RESULTS

The search identified 43 eligible studies. Compared to people without LBP, on average, people with LBP display: (i) no difference in lordosis angle (8 studies), (ii) reduced lumbar ROM (19 studies), (iii) no difference in lumbar relative to hip contribution to end-range flexion (4 studies), (iv) no difference in standing pelvic tilt angle (3 studies), (v) slower movement (8 studies), and (vi) reduced proprioception (17 studies). Movement variability appeared greater for people with LBP for flexion, lateral flexion and rotation ROM, and movement speed, but not for other movement characteristics. Considerable heterogeneity exists between studies, including a lack of detail or standardization between studies on the criteria used to define participants as people with LBP (cases) or without LBP (controls).

CONCLUSIONS

On average, people with LBP have reduced lumbar ROM and proprioception, and move more slowly compared to people without LBP. Whether these deficits exist prior to LBP onset is unknown.

Effect of subject restraint and resistance pad placement on isokinetic knee flexor and extensor strength: implications for testing and rehabilitation

BACKGROUND

In clinical practice, several subject restraint and resistance pad placement variations are used when an isokinetic knee flexion/extension test is performed. However, it is unknown if these variations affect the outcome measures. The aims of this study were to determine if these setup variations affect isokinetic outcomes and to establish the smallest detectable difference for these setup variations.

HYPOTHESIS

Variation in isokinetic setup affects outcome measures.

STUDY DESIGN

Cross-sectional repeated-measures crossover study.

METHODS

Ten recreationally active adult men were examined with isokinetic dynamometry on 4 separate days. In the first 3 days, fully strapped and trunk-unstrapped testing was conducted with the resistance pad placed distally on the shin. On days 1 and 3, the unstrapped condition was performed first, followed by the strapped condition. On day 4, the resistance pad was placed proximal on the shin (anterior cruciate ligament testing).

RESULTS

There were no within-condition differences for days 1, 2, or 3 for the strapped and unstrapped conditions (P > 0.05). Between-condition comparisons were significant (eg, quadriceps peak torque, P < 0.001; hamstring peak torque, P = 0.043) for the strapped, unstrapped, and proximal resistance pad placement conditions. The strapped condition generally showed the largest torques, and the unstrapped, the least. The smallest detectable differences were relatively large (eg, quadriceps peak torque strapped = 20.6%). The greatest intraclass correlation values were found when strapped.

CONCLUSIONS

Subject setup significantly influences isokinetic outcome measures at the knee. Since the strapped condition demonstrated the greatest repeatability, it is recommended. The smallest detectable differences were relatively high for all variables and should be considered in the interpretation of the effect size of interventions.

CLINICAL RELEVANCE

Subject setup strapping must be considered when investigating test-retest values or when comparing subjects after isokinetic testing at the knee. The fully strapped condition has the best repeatability and highest torque values.

Classification-guided versus generalized postural intervention in subgroups of nonspecific chronic low back pain: a pragmatic randomized controlled study

STUDY DESIGN

Pragmatic randomized controlled single-blinded study.

OBJECTIVE

To compare the effects of the classification system guided postural intervention (CSPI) with generalized postural intervention (GPI) in subgroups of nonspecific chronic low back pain (NSCLBP).

SUMMARY OF BACKGROUND DATA

Spinal motor control impairments and the associated alterations in spinal postures adopted by patients with NSCLBP are highly variable. Research evaluating the effect of interventions that target the specific movement/posture impairments in NSCLBP subgroups is therefore warranted.

METHODS

A total of 49 patients with NSCLBP with a classification of flexion pattern (n = 29) and active extension pattern (n = 20) control impairment were recruited from a large cohort study and randomly assigned into CSPI and GPI. The primary outcome was change in Roland-Morris Disability Questionnaire, secondary outcomes were change in pain visual analogue scale, spinal repositioning sense including thoracic and lumbar absolute error, variable error, constant error, and trunk muscle activity during sitting and standing. The intervention was evaluated at baseline, immediately post one-to-one intervention and post 4-week home-based training.

RESULTS

The CSPI produced statistically and clinically significant reduction in disability (4.2 [95% CI, 2.9-5.3]) and pain (2, [95% CI, 1.3-2.6]) compared with minimal change in the GPI disability (0.4, [95% CI, -0.8 to 1.6]) and pain (-0.2, [95% CI, -0.5 to 0.9]). Repeated measures analysis of variance revealed that CSPI significantly reduced absolute error in thoracic (sitting) and lumbar spine (standing) and constant error in lumbar spine (standing) post one-to-one phase, although this was no longer significant at 4 weeks. Neither intervention had an effect on trunk muscle activity.

CONCLUSION

Compared with minimal change in the GPI group, the CSPI produced statistically and clinically significant improvements in disability and pain outcomes and short-term improvements in some parameters of spinal repositioning sense in NSCLBP subgroups.

Lumbar repositioning error in sitting: healthy controls versus people with sitting-related non-specific chronic low back pain (flexion pattern)

Studies examining repositioning error (RE) in non-specific chronic low back pain (NSCLBP) demonstrate contradictory results, with most studies not correlating RE deficits with measures of pain, disability or fear. This study examined if RE deficits exist among a subgroup of patients with NSCLBP whose symptoms are provoked by flexion, and how such deficits relate to measures of pain, disability, fear-avoidance and kinesiophobia. 15 patients with NSCLBP were matched (age, gender, and body mass index) with 15 painfree participants. Lumbo-pelvic RE, pain, functional disability, fear-avoidance and kinesiophobia were evaluated. Participants were asked to reproduce a target position (neutral lumbo-pelvic posture) after 5 s of slump sitting. RE in each group was compared by evaluating constant error (CE), absolute error (AE) and variable error (VE). Both AE (p = 0.002) and CE (p = 0.006) were significantly larger in the NSCLBP group, unlike VE (p = 0.165) which did not differ between the groups. There were significant, moderate correlations in the NSCLBP group between AE and functional disability (r = 0.601, p = 0.018), and between CE and fear-avoidance (r = -0.577, p = 0.0024), but all other correlations were weak (r < 0.337, rs < 0.377) or non-significant (p > 0.05). The results demonstrate increased lumbo-pelvic RE in a subgroup of NSCLBP patients, with the selected subgroup undershooting the target position. Overall, RE was only weakly to moderately correlated with measures of pain, disability or fear. The deficits observed are consistent with findings of altered motor control in patients with NSCLBP. The mechanisms underlying these RE deficits, and the most effective method of addressing these deficits, require further study.

Spinal position sense and trunk muscle activity during sitting and standing in nonspecific chronic low back pain: classification analysis

STUDY DESIGN

A cross-sectional study between subgroups of nonspecific chronic low back pain (NSCLBP) and asymptomatic controls.

OBJECTIVE

To investigate NSCLBP subgroup differences in spinal position sense and trunk muscle activity when repositioning thoracic and lumbar spine into neutral (midrange) spinal position during sitting and standing.

SUMMARY OF BACKGROUND DATA

Patients with NSCLBP report aggravation of symptoms during sitting and standing. Impaired motor control in NSCLBP, associated with sitting and standing postures nearer the end range of spinal motion, may be a contributing factor. Rehabilitation improving neutral (midrange) spinal position control is advocated. Postural and motor control alterations vary in different NSCLBP subgroups, potentially requiring specific postural interventions. There is limited evidence on whether subgroup differences exist when performing neutral spine position tasks.

METHODS

Ninety patients with NSCLBP and 35 asymptomatic controls were recruited. Two blinded practitioners classified NSCLBP into subgroups of active extension pattern and flexion pattern. Participants were assisted into neutral spine position and asked to reproduce this position 4 times. Absolute, variable, and constant errors were calculated. Three-dimensional thoracic and lumbar kinematics quantified the repositioning accuracy and surface electromyography assessed back and abdominal muscles activity bilaterally.

RESULTS

Irrespective of subclassification, patients with NSCLBP produced significantly greater error magnitude and variability than the asymptomatic controls, but subgroup differences were detected in the error direction. Subgroup differences in the trunk muscle activity were not consistently identified. Although both subgroups produced significantly higher abdominal activity, subclassification revealed difference in superficial multifidus activity during standing, with flexion pattern producing significantly greater activity than the asymptomatic controls.

CONCLUSION

Subgroups of NSCLBP had similar neutral spinal position deficits regarding error magnitude and variability, but subclassification revealed clear subgroup differences in the direction of the deficit. The trunk muscle activation was shown to be largely nondiscriminatory between subgroups, with the exception of superficial lumbar multifidus.

Effect of spinal manipulation on sensorimotor functions in back pain patients: study protocol for a randomised controlled trial

Background

Low back pain (LBP) is a recognized public health problem, impacting up to 80% of US adults at some point in their lives. Patients with LBP are utilizing integrative health care such as spinal manipulation (SM). SM is the therapeutic application of a load to specific body tissues or structures and can be divided into two broad categories: SM with a high-velocity low-amplitude load, or an impulse "thrust", (HVLA-SM) and SM with a low-velocity variable-amplitude load (LVVA-SM). There is evidence that sensorimotor function in people with LBP is altered. This study evaluates the sensorimotor function in the lumbopelvic region, as measured by postural sway, response to sudden load and repositioning accuracy, following SM to the lumbar and pelvic region when compared to a sham treatment.

Methods/Design

A total of 219 participants with acute, subacute or chronic low back pain are being recruited from the Quad Cities area located in Iowa and Illinois. They are allocated through a minimization algorithm in a 1:1:1 ratio to receive either 13 HVLA-SM treatments over 6 weeks, 13 LVVA-SM treatments over 6 weeks or 2 weeks of a sham treatment followed by 4 weeks of full spine "doctor's choice" SM. Sensorimotor function tests are performed before and immediately after treatment at baseline, week 2 and week 6. Self-report outcome assessments are also collected. The primary aims of this study are to 1) determine immediate pre to post changes in sensorimotor function as measured by postural sway following delivery of a single HVLA-SM or LVVA-SM treatment when compared to a sham treatment and 2) to determine changes from baseline to 2 weeks (4 treatments) of HVLA-SM or LVVA-SM compared to a sham treatment. Secondary aims include changes in response to sudden loads and lumbar repositioning accuracy at these endpoints, estimating sensorimotor function in the SM groups after 6 weeks of treatment, and exploring if changes in sensorimotor function are associated with changes in self-report outcome assessments.

Discussion

This study may provide clues to the sensorimotor mechanisms that explain observed functional deficits associated with LBP, as well as the mechanism of action of SM.

Trial registration

This trial is registered in ClinicalTrials.gov, with the ID number of NCT00830596, registered on January 27, 2009. The first participant was allocated on 30 January 2009 and the final participant was allocated on 17 March 2011.

Spine stability: lessons from balancing a stick

This paper introduces control concepts that are important for ensuring stability. To clarify these concepts, a series of experiments using a simple task of stick balancing will be performed. The lessons from these experiments will be applied to the spine system and illustrated with clinical examples. Insight into the following will be gained: what information is used to stabilize the spine, how does noise in control affect spine performance, how has the spine evolved to allow it to be stabilized and controlled in a metabolically efficient way, how do delays in control affect spine performance, and how do different goals (i.e., maximizing performance versus minimizing fatigue) affect the logic for controlling the spine?

Comparison of trunk proprioception between patients with low back pain and healthy controls

OBJECTIVE

To determine whether proprioceptive impairments exist in patients with low back pain (LBP). We hypothesized that patients with LBP would exhibit larger trunk proprioception errors than healthy controls.

DESIGN

Case-control study.

SETTING

University laboratory.

PARTICIPANTS

24 patients with nonspecific LBP and 24 age-matched healthy controls.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We measured trunk proprioception in all 3 anatomical planes using motion perception threshold, active repositioning, and passive repositioning tests.

RESULTS

LBP patients had significantly greater motion perception threshold than controls (P<.001) (1.3+/-0.9 degrees vs 0.8+/-0.6 degrees ). Furthermore, all subjects had the largest motion perception threshold in the transverse plane (P<.001) (1.2+/-0.7 degrees vs 1.0+/-0.8 degrees for all other planes averaged). There was no significant difference between LBP and healthy control groups in the repositioning tasks. Errors in the active repositioning test were significantly smaller than in the passive repositioning test (P=.032) (1.9+/-1.2 degrees vs 2.3+/-1.4 degrees ).

CONCLUSIONS

These findings suggest that impairments in proprioception may be detected in patients with LBP when assessed with a motion perception threshold measure.

Comparison of lumbar proprioception as measured in unrestrained standing in individuals with disc replacement, with low back pain, and without low back pain

STUDY DESIGN

Cross-sectional laboratory study.

OBJECTIVE

To determine whether individuals with spinal pain and those who have undergone spinal surgery have difficulty discriminating small movement differences using a spinal proprioception test for active flexion movements.

BACKGROUND

Structures contributing to proprioception may be affected during disc replacement surgery. Postsurgical assessment of proprioceptive ability to make discriminations in the range used for maintaining upright postural stability is needed to inform postoperative rehabilitation.

METHODS

Proprioceptive sensitivity to differences between lumbar spine movements of 11 degrees, 13 degrees, 15 degrees, 17 degrees, and 19 degrees of forward flexion was measured in unrestrained standing, with vision of the target obscured. Individuals after disc replacement (n=16), with disc degeneration and discogenic back pain (n=19), and without back pain (n=18) performed 50 movement trials and stated the amount of movement performed for each trial (11 degrees, 13 degrees, 15 degrees, 17 degrees, or 19 degrees).

RESULTS

The pattern of discrimination scores between adjacent lumbar flexion movement pairs shown by the individuals in the discogenic back pain group differed significantly from the disc replacement and healthy control groups (P=.024), which were not significantly different from each other. Although mean discrimination scores averaged over all movement pairs did not differ significantly between the groups, participants with discogenic back pain discriminated between the 2 smallest lumbar flexion movements significantly better than those in the other 2 groups (P=.013).

CONCLUSION

The greater sensitivity of the individuals with disc pain to discriminate between the 2 smallest flexion movements was interpreted as a contrast effect arising from differences between the groups in usual upright posture, with disc replacement restoring the same pattern of posture as seen for healthy controls.

Low back pain history and postural sway in unstable sitting

STUDY DESIGN

A cross-sectional study comparing subjects with self-reported low back pain, recent low back, and no low back pain.

OBJECTIVE

To determine differences in trunk postural control between groups.

SUMMARY OF BACKGROUND DATA

Poor postural control has been demonstrated in patients with low back pain, but the cause of this is unknown.

METHODS

A total of 331 participants of a longitudinal study participated in a seated balancing task. Based on a questionnaire, subjects were subdivided in 3 groups: current-LBP, recent-LBP (last 12 months), no-LBP. Subjects balanced on a seat mounted over a hemisphere during three 30-second trials. Sway amplitudes (RMS), mean power frequency (MPF), short-term diffusion coefficients (DS), and critical point (CP) coordinates of sway were calculated.

RESULTS

RMS values differed significantly between groups, with smaller values in recent-LBP than in no-LBP. MPF values were lowest in current-LBP. DS values were highest in no-LBP, with significant differences between this group and recent-LBP only. CP values were generally lower for recent-LBP than both other groups.

CONCLUSION

In contrast with previous findings, postural sway amplitudes in unstable sitting were not different between LBP and healthy subjects, while subjects with a recent history of LBP showed smaller amplitudes. Higher DS values in subjects without LBP indicated more stochastic sway. These findings may be explained by the disturbing effect of current pain on postural control causing low sway frequencies and by lower effort in balancing in healthy subjects causing high sway amplitudes and diffusion coefficients.

The assessment of the cervical spine. Part 1: Range of motion and proprioception

Neck pain and headache of cervical origin are complaints affecting an increasing number of the general population. Mechanical factors such as sustained neck postures or movements and long-term "abnormal" physiologic loads on the neck are believed to affect the cervical structures and compromise neck function. A comprehensive assessment of neck function requires evaluation of its physical parameters such as range of motion, proprioception, strength and endurance/fatigue. The complicated structure of the cervical spine however, makes it difficult for any clinician to obtain reliable and valid results. The aim of the first part of this systematic critical review is to identify the factors influencing the assessment of range of motion and proprioception of the cervical spine.

Effects of spinal manipulation on trunk proprioception in subjects with chronic low back pain during symptom remission

OBJECTIVE

The purpose of this study was to examine the immediate effects of spinal manipulative therapy (SMT) on trunk proprioception in subjects with asymptomatic chronic low back pain (CLBP) and determine if those effects lasted 1 week.

METHODS

This unbalanced randomized controlled crossover design examined 33 subjects with CLBP. Proprioception was tested via joint position sense, threshold to detect passive motion (TTDPM), direction of motion (DM), and force reproduction. Each subject received lumbar manipulation or a sham procedure followed by proprioception retest. This procedure was repeated 1 week later using the opposing treatment. Subjects receiving SMT in the second session returned a third time receiving the sham procedure again.

RESULTS

Spinal manipulative therapy produced an effect for TTDPM in the manipulation first group (P = .008), the sham procedure produced an effect for joint position sense in the sham first group (P = .005). Spinal manipulative therapy had a 1-week effect for the manipulation first group (P = .006). No effect was noted for either DM or force reproduction.

CONCLUSIONS

Results suggest SMT had minimal immediate effect on trunk proprioception. The effects noted occurred in session 1, implicating learning as a potential source. Learning, from repetitive proprioception training, may enhance neuromuscular control in subjects with CLBP before the use of therapeutic exercise. Subjects showed smaller deficits than previously reported for TTDPM or DM, suggesting proprioception deficits may correlate with pain level.

Sports participation and humeral torsion

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To examine differences between arms in humeral torsion in adult and adolescent throwing and nonthrowing athletes, and nonathletic adults.

BACKGROUND

It is hypothesized that humeral retrotorsion develops by, and is beneficial for, throwing. Thus throwers should demonstrate greater retrotorsion in their dominant arm relative to their nondominant arm and have more side-to-side retrotorsion difference than nonthrowing groups. In addition, adult throwers should have a greater side-to-side retrotorsion difference than adolescent throwers, and swimmers should not demonstrate a retrotorsion difference.

METHODS AND MEASURES

Using ultrasound to standardize the location of the bicipital groove, the amount of humeral torsion was measured in both arms of male baseball players (85 adult, 35 adolescent), female softball players (16 adult, 37 adolescent), 29 elite adolescent swimmers (19 female), and 16 nonathletic adults (8 female).

RESULTS

More retrotorsion was found in the dominant arm of almost all throwing athletes, irrespective of their gender or whether they were adults or adolescents (mean+/-SD side-to-side difference, 11.9 degrees+/-10.5 degrees). This difference was less for swimmers (6.4 degrees+/-9.9 degrees) and nonathletic adults (1.3 degrees+/-8.9 degrees).

CONCLUSION

Greater dominant armhumeral retrotorsion is observed contingent with participation in throwing sports.

The effects of stochastic resonance stimulation on spine proprioception and postural control in chronic low back pain patients

STUDY DESIGN

Spine proprioception and postural control in unstable sitting were compared in 18 chronic low back pain patients using a repeated measures design.

OBJECTIVE

The study objective was to determine if stochastic resonance (SR) stimulation of the paraspinal muscles improves spine proprioception and trunk postural control.

SUMMARY OF BACKGROUND DATA

Decreased spine proprioception and larger postural sway have been found in low back pain patients, although several studies have also shown no differences in spine proprioception.

METHODS

Spine proprioception, measuring subjects' sensitivity to change in position, was assessed in 3 orthopaedic planes. Postural control was assessed using an unstable seat with a hemisphere attached to the bottom. Subjects balanced with eyes closed on the most challenging size hemisphere they could manage while center-of-pressure was recorded with a force plate beneath the seat. Both tasks were performed with SR stimulation randomized at 0%, 25%, 50%, and 90% intensity levels.

RESULTS

No significant differences in spine proprioception were observed between SR stimulation levels for any of the 3 orthopaedic planes. SR stimulation significantly improved postural control, but only in the lateral plane. No differences in postural control were observed between stimulation levels 25%, 50%, and 90% in the lateral plane. There was no correlation between spine proprioception and postural control.

CONCLUSION

Results suggest that SR stimulation to the paraspinal muscles can improve postural control; however, this improvement cannot be attributed to improved spine proprioception based on the current study. People with compromised neuromuscular control or those exposed to unstable environments may benefit from SR stimulation.

Head repositioning accuracy to neutral: a comparative study of error calculation

Deficits in cervical proprioception have been identified in subjects with neck pain through the measure of head repositioning accuracy (HRA). Nevertheless there appears to be no general consensus regarding the construct of measurement of error used for calculating HRA. This study investigated four different mathematical methods of measurement of error to determine if there were any differences in their ability to discriminate between a control group and subjects with a whiplash associated disorder. The four methods for measuring cervical joint position error were calculated using a previous data set consisting of 50 subjects with whiplash complaining of dizziness (WAD D), 50 subjects with whiplash not complaining of dizziness (WAD ND) and 50 control subjects. The results indicated that no one measure of HRA uniquely detected or defined the differences between the whiplash and control groups. Constant error (CE) was significantly different between the whiplash and control groups from extension (p<0.05). Absolute errors (AEs) and root mean square errors (RMSEs) demonstrated differences between the two WAD groups in rotation trials (p<0.05). No differences were seen with variable error (VE). The results suggest that a combination of AE (or RMSE) and CE are probably the most suitable measures for analysis of HRA.

Lumbar position sense with extreme lumbar angle

Tasks involving flexed torso postures have a high incidence of low back injuries. Changes in the ability to sense and adequately control low back motion may play a role in these injuries. Previous studies examining position sense errors of the lumbar spine with torso flexion found significant increases in error with flexion. However, there has been little research on the effect of lumbar angle. In this study, the aim of the study was to examine how position sense errors would change with torso flexion as a function of the target lumbar angle. Fifteen healthy volunteers were asked to assume three different lumbar angles (maximum, minimum and mid-range) at three different torso flexion angles. A reposition sense protocol was used to determine a subject's ability to reproduce the target lumbar angles. Reposition sense error was found to increase 69% with increased torso flexion for mid-range target curvatures. With increasing torso flexion, the increase in reposition sense errors suggests a reduction in sensation and control in the lumbar spine that may increase risk of injury. However, the reposition error was smaller at high torso flexion angles in the extreme target curvatures. Higher sensory feedback at extreme lumbar angles would be important in preventing over-extension or over-flexion. These results suggest that proprioceptive elements in structures engaged at limits (such as the ligaments and facet joints), may provide a role in sensing position at extreme lumbar angles. Sensory elements in the muscles crossing the joint may also provide increased feedback at the edges of the range of motion.

A new measurement method for spine reposition sense

Background

A cost effective tool for the measurement of trunk reposition sense is needed clinically. This study evaluates the reliability and validity of a new clinical spine reposition sense device.

Methods

The first part of this three part investigation included 45 asymptomatic subjects examined in the first 20 repeated trials portion assessing spine reposition sense. The second portion, test-retest, examined 57 asymptomatic subjects. Initial testing consisted of subjects sitting on the device and performing 20 trials of a self-determined 2/3 trunk flexion position. The second portion of the study involved 7 trials of trunk flexion performed twice. The angular position for each trial was calculated and the mean reposition error from the initial 2/3 position was determined. For the third portion, the new device was compared to the Skill Technologies 6D (ST6D) Imperial Motion Capture and Analysis System.

Results

ICC (3,1) for trials 4–7 was 0.79 and 0.76 for time one and time two, respectively and the test-retest ICC (3,k) was 0.38. Due to the poor test-retest ICC, the Bland Altman method was used to compare test and retest absolute errors. Most measurement differences were small and fell within the 95% confidence interval. Comparable measures between the two methods were found using the Bland Altman method to compare the reposition sense device to the ST6D system.

Conclusion

The device may be a cost effective clinical technique for sagittal trunk reposition sense measurement.

Paraspinal Muscle Vibration Alters Dynamic Motion of the Trunk

Loss in dynamic stability of the low back has been identified as a potential factor in the etiology of low back injuries. A number of factors are important in the ability of a person to maintain an upright trunk posture including the preparatory stiffness of the trunk and the magnitude and timing of the neuromotor response. A neuromotor response requires appropriate sensing of joint motion. In this research, the role of this sensory ability in dynamic performance of the trunk was examined using a simple pendulum model of the trunk with neuromotor feedback. An increased sensory threshold was found to lead to increased torso flexion and increased delay in neuromotor response. This was confirmed experimentally using paraspinal muscle vibration which is known to alter proprioception of the muscle spindle organs. Before, during and after exposure to bilateral, paraspinal muscle vibration for 20minutes, the dynamic response of subjects to an unexpected torso flexion load was examined. Subjects were found to have a 19.5% slower time to peak muscle activity and a 16.1% greater torso flexion during exposure to paraspinal muscle vibration. Torso flexion remained significantly increased after vibration exposure relative to before exposure. These results suggest that the neuromotor response plays an important role in trunk dynamics. Loss in sensitivity of the sensory system can have a detrimental effect on trunk dynamics, increasing delays in neuromotor response and increasing the motion of the trunk in response to an unexpected load.

Within-day and between-days reliability of quadriceps isometric muscle fatigue using mechanomyography on healthy subjects

This study aimed to examine within-day and between-days intratester reliability of mechanomyography (MMG) in assessing muscle fatigue. An accelerometer was used to detect the MMG signal from rectus femoris. Thirty one healthy subjects (15 males) with no prior knee problems initially performed three maximum voluntary contractions (MVCs) using an ISOCOM dynamometer. After 10 min rest, subjects performed a fatiguing protocol in which they performed three isometric knee extensions at 75% MVC for 40 s. The fatiguing protocol was repeated on two other days, two to four days apart for between-days reliability. MMG activity was determined by overall root mean squared amplitude (RMS), mean power frequency (MPF) and median frequency (MF) during a 40s contraction. RMS, MPF and MF linear regression slopes were also analysed. Intraclass Correlation Coefficients (ICC); ICC1,1 and ICC1,2 were used to assess within-day reliability and between-days reliability respectively. Standard error of measurement (SEM) and smallest detectable difference (SDD) described the within-subjects variability. MMG fatigue measures using linear regression slopes showed low reliability and large between-days error (ICC1,2=0.43-0.46; SDD=306.0-324.8% for MPF and MF slopes respectively). Overall MPF and MF, on the other hand, were reliable with high ICCs and lower SDDs compared to linear slopes (ICC1,2=0.79-0.83; SDD=21.9-22.8% for MPF and MF respectively). ICC1,2 for overall MMG RMS and linear RMS slopes were 0.81 and 0.66 respectively; however, the SDDs were high (56.4% and 268.8% respectively). The poor between-days reliability found in this study suggests caution in using MMG RMS, MPF and MF and their corresponding slopes in assessing muscle fatigue.

Lumbar position sense and the risk of low back injuries in college athletes: a prospective cohort study

Background

Impaired proprioception in the lumbar spine has often been reported in people with low back pain. However, no prospective studies exist to assert the cause and effect of this association. We hypothesized that athletes with a history of low back injury (LBI) would demonstrate poorer lumbar position sense (PS) than athletes without a history of LBI, and that this deficit would be a risk factor for future LBI.

Methods

This was a prospective cohort study with 2–3 year follow-up. Lumbar spine PS in the transverse plane was evaluated in 292 athletes using three tests: 1) passive and 2) active trunk repositioning, and 3) motion perception threshold. Mean absolute (accuracy) and variable (precision) errors were computed.

Results

There were no significant differences in the repositioning errors or motion perception threshold between athletes with and without a history of LBI or between those who did and did not get injured during the follow-up. Active trunk repositioning resulted in smaller errors than passive repositioning (1.6°± 0.8°) versus 2.1°± 1.0°) and 1.7°± 0.8°) versus 2.3°± 1.1°) for the absolute and relative errors, respectively).

Conclusion

Poor trunk PS in transverse plane is not associated with LBI in athletes, nor does it appear that poor trunk PS predisposes athletes to LBI.

Lumbar functional instability: a critical appraisal of the literature

The goals of this paper were to define the concept of instability, to describe the way it can be assessed, to report on impairments of the spine stabilization system in patients with low back pain (LBP), to cite the recommended exercises and, lastly, to examine the results of programs based on lumbar stabilization. Patients suffering from lumbar instability appear to belong to a particular subgroup of subjects with LBP. In the literature, several definitions of lumbar instability have been proposed. Radiological instability, for instance, differs from functional instability. Diagnosis remains difficult: the relevance of static and dynamic radiographs appears limited whereas several signs and clinical instability tests have been described in the literature but remain controversial. The functional stability system of the spine consists of three interdependent components: the passive, the active and the neuromuscular subsystems. The benefits of lumbar stabilization programs for LBP patients have been underlined. Lumbar stabilization exercises are aimed at sensorimotor reprogrammation of spine stabilizer muscles intended to improve their motor control skill and delay of response and consequently to compensate for weakness of the passive stabilization system.

Are Lumbar Repositioning Errors Larger Among Patients With Chronic Low Back Pain Compared With Asymptomatic Subjects?

OBJECTIVE

To resolve the debate over whether lumbar repositioning acuity is reduced in patients with chronic low back pain (CLBP) by using a study design and methodology to minimize the effects of potential confounders.

DESIGN

A single-blinded, controlled, multigroup comparative study.

SETTING

Vocational rehabilitation center.

PARTICIPANTS

Ninety-two patients with CLBP, divided into subgroups based on severity of symptoms and diagnostic characteristics. An age- and sex-matched group (n=31) of healthy subjects were the control.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We measured repositioning errors (variable, constant) at 3 positions of the lumbar spine. Subjects were guided to a sitting target posture and asked to perform lumbar flexion before reproducing the target posture. Self-assessed pain, self-efficacy, and functional ability were addressed through questionnaires.

RESULTS

There were no differences in repositioning errors between the patients with CLBP or the subgroups of patients and the control group. We found only weak correlations between the repositioning errors and the self-reported data on functional disability, self-efficacy, and pain.

CONCLUSIONS

We suggest that sensorimotor dysfunctions in CLBP should be evaluated with methods other than repositioning tests in order to generate data relevant to the development of rational diagnostic methods and rehabilitation programs.

Lumbar spine reposition sense: the effect of a 'slouched' posture

Proprioceptive control is considered important for spinal stability and prevention of injury. However there is evidence that proprioceptive structures, that are reflexive and viscoelastic, are challenged by commonly adopted 'slouched' postures. The aim of this study was to investigate the effect of such postures on proprioceptive control. The reliability of a flexible electrogoniometer was established (ICC=0.89). Using a repeated measures design (n=32, 80% power detecting 0.5 degrees difference at 95% significance) subjects repositioned their lumbar spine immediately (3 s) and following 300 s in a 'slouched' posture, with a 15-min interval in between. Results showed a significantly reduced lumbar spine reposition sense following 300 s in a 'slouched' posture as compared with 3 s in a 'slouched' posture (P<0.001), mean difference 3.92 degrees (SD 4.35). Based on this sample, there was evidence that a 'slouched' posture, of 5 min duration, would increase reposition error by more than 2.35 degrees and less than 5.48 degrees (n=32, CI 95%). These findings support the practice of postural education to reduce potential to proprioceptive loss and injury. The electrogoniometer shows potential for use in clinical practice.

The effects of a 3-week use of lumbosacral orthoses on proprioception in the lumbar spine

STUDY DESIGN

Longitudinal, repeated-measures, factorial design. The trunk axial rotation repositioning error was the dependent variable, while the orthoses, test mode (passive versus active), and the testing session were the independent variables.

OBJECTIVES

To verify whether lumbosacral orthoses (LSOs) affect proprioception in the lumbar spine and whether these effects change over a 3-week period during which the LSO is consistently worn.

BACKGROUND

To date, there is no compelling evidence that lumbar orthoses support the spine. One hypothesis advanced by several authors is that they may enhance position sense (proprioception) in the lumbar spine.

METHODS AND MEASURES

Fourteen subjects without low back pain wore lumbosacral orthoses 3 hours a day for 3 weeks. Spine proprioception was tested in a seated posture in 3 sessions (days 0, 7, and 21).

RESULTS

A significant 3-way interaction was found between the effects of the orthoses, session, and test mode (P = .03). The ratio of passive to active average error indicated that after 3 weeks of wearing LSO, proprioception in the passive test worsened in relation to the active test with the LSO. In contrast, proprioception in the passive test improved in relation to the active test when performed without the LSO.

CONCLUSIONS

The LSO did affect proprioception in the lumbar spine. These effects most likely changed over time due to sensorimotor adaptation. However, no overall proprioceptive benefits could be ascertained from healthy subjects wearing the LSO.

Cervical joint position sense: an intra- and inter-examiner reliability study

OBJECTIVES

To evaluate the intra- and inter-examiner reliability of neck active joint position sense measurements in different head movements.

METHODS

Participants had to reproduce actively a specific angle-target in all movements (flexion, right/left rotation, right/left side flexion) from two initial positions, sitting and standing by using a 3D ultrasound-based motion analysis device. Three tests were employed to assess intra-examiner reliability and two examiners used for the inter-examiner reliability. Absolute error (AE) and variable error (VE) indices were used to assess the repositioning accuracy. Intraclass correlation coefficient (I.C.C.(1,1)), standard error of measurement (S.E.M.), smallest detectable difference (S.D.D.) indices were calculated for the analysis of the results.

RESULTS

Both AE and VE yielded poor to moderate I.C.C.s in any movement and position (-0.01 to 0.50 and 0.01-0.25, respectively). AE presented higher I.C.C.s estimates than the VE but the S.D.D.s were similar for both indices. Regarding the AE, the standing position yielded higher I.C.C. estimates (0.15-0.68) than the sitting position (-0.01 to 0.43) but the S.E.M. (1.2-3.0 degrees and 1.5-3.5 degrees, respectively) and S.D.D. values (123.3-191.8% and 139.9-203.8%, respectively) showed no specific trend in favour of any position. The VE reliability indices showed that standing position was more reliable with less error than sitting. The inter-examiner data showed similar results to the intra-examiner study.

CONCLUSIONS

The statistical analysis of the present experiments showed that the method employed for measuring cervical joint position sense is unreliable. However, it needs further research to identify the discriminatory power of these tests or if they are clinically unacceptable.

Trunk Repositioning Errors Are Increased in Balance-Impaired Older Adults

BACKGROUND

Controlling the flexing trunk is critical in recovering from a loss of balance and avoiding a fall. To investigate the relationship between trunk control and balance in older adults, we measured trunk repositioning accuracy in young and balance-impaired and unimpaired older adults.

METHODS

Young adults (N = 8, mean age 24.3 years) and two groups of community-dwelling older adults defined by unipedal stance time (UST)-a balance-unimpaired group (UST > 30 seconds, N = 7, mean age 73.9 years) and a balance-impaired group (UST < 5 seconds, N = 8, mean age 79.6 years)-were tested in standing trunk control ability by reproducing a approximately 30 degrees trunk flexion angle under three visual-surface conditions: eyes opened and closed on the floor, and eyes opened on foam. Errors in reproducing the angle were defined as trunk repositioning errors (TREs). Clinical measures related to balance, trunk extensor strength, and self-reported disability were obtained.

RESULTS

TREs were significantly greater in the balance-impaired group than in the other groups, even when controlling for trunk extensor strength and body mass. In older adults, there were significant correlations between TREs and three clinical measures of balance and fall risk, UST and maximum step length (-0.65 to -0.75), and Timed Up & Go score (0.55), and between TREs and age (0.63-0.76). In each group TREs were similar under the three visual-surface conditions. Test-retest reliability for TREs was good to excellent (intraclass correlation coefficients > or =0.74).

CONCLUSIONS

Older balance-impaired adults have larger TREs, and thus poorer trunk control, than do balance-unimpaired older individuals. TREs are reliable and valid measures of underlying balance impairment in older adults, and may eventually prove to be useful in predicting the ability to recover from losses of balance and to avoid falls.