The author is pursuing his PhD degree in the Faculty of Rehabilitation Medicine in the University of Alberta. HIs research interests are the neutral zone of spine and the effect of manipulation on biological tissues. He has been awarded 18 awards and scholarships since he started his Physiotherapy study.
Abstract: Instrumented spinal stiffness measurements have shown high test-retest reliability. However, factors that may affect reliability have yet to be investigated. The objective of this study was to compare the: 1) within- and between-day reliability of a mechanical indentation device (MID) in measuring spinal stiffness, 2) measurement precision of averaging multiple measurements, and 3) reliability of stiffness measurements between individuals with and without LBP.
The spinal stiffness of 26 volunteers with and without LBP was measured 3 times by MID in each of two visits 1 to 4 days apart. Two stiffness measures were calculated from the resulting force-displacement data: global stiffness and terminal stiffness. Intraclass correlation coefficients were used to estimate reliability. Measurement precision was measured by minimal detectable changes, bias and 95% limits of agreement.
Using the mean of three spinal stiffness measurements, the measurement precision was improved by 33.7% over a single measurement. Averaging three measurements, the within- and between-day reliability point estimates of both global and terminal stiffness were 0.99 and 0.98, respectively. The reliability estimates of spinal stiffness measurement using MID were not significantly altered by the participantsâ LBP status across all circumstances (95% confidence intervals overlapped).
With our experimental protocol, averaging three spinal stiffness measurements using MID produces reliable stiffness measurements regardless of individualsâ LBP status.
Abstract: Although individual reports suggest that baseline morphometry or activity of transversus abdominis or lumbar multifidus predict clinical outcome of low back pain (LBP), a related systematic review is unavailable. Therefore, this review summarized evidence regarding the predictive value of these muscular characteristics. Candidate publications were identified from six electronic medical databases. After review, 5 cohort studies were included. Although this review intended to encompass studies using different muscle assessment methods, all included studies coincidentally used ultrasound imaging. No research investigated the relation between static morphometry and clinical outcomes. Evidence synthesis showed limited evidence supporting poor baseline transversus abdominis contraction thickness ratio as a treatment effect modifier favoring motor control exercise. Limited evidence supported that high baseline transversus abdominis lateral slide was associated with higher pain intensity following various exercise interventions at 1-year follow-up. However, there was limited evidence for the absence of relation between the contraction thickness ratio of transversus abdominis or anticipatory onset of lateral abdominal muscles at baseline and the short- or long-term LBP intensity after exercise interventions. There was conflicting evidence for a relation between baseline percent thickness change of lumbar multifidus during contraction and the clinical outcomes of patients following various conservative treatments. Given study heterogeneity, the small number of included studies, and the inability of conventional grey-scale B-mode ultrasound imaging to measure muscle activity, our findings should be interpreted with caution. Further large-scale prospective studies, employing the appropriate technology (i.e. electromyography to assess muscle activity), should be conducted to investigate the predictive value of morphometry or activity of these muscles with respect to LBP-related outcomes measures.
Abstract: Previous research describes an inconsistent relation between temporal changes in transversus abdominis or lumbar multifidus and temporal changes in clinical outcomes. Unfortunately, a relevant systematic review is unavailable. As a result, this systematic review was designed to summarize evidence regarding the association between temporal changes in muscle morphometry and activity in response to treatment and temporal changes in clinical outcomes. Candidate publications were identified from six electronic databases. Fifteen articles were included after scrutinization by two reviewers using the predetermined selection criteria. The methodological quality of these articles was appraised using a standard tool. These methods revealed strong evidence that temporal alterations in transversus abdominis thickness change during contraction (as measured by B-mode or M-mode ultrasound) or feedforward activation of transversus abdominis (assessed via electromyography, tissue Doppler imaging or M-mode ultrasound) were unrelated to temporal changes in LBP/LBP-related disability. There was limited evidence that temporal changes in transversus abdominis lateral sliding or lumbar multifidus endurance were unrelated to temporal changes in LBP intensity. Conflicting evidence was found for the relation between temporal changes in lumbar multifidus morphometry and temporal changes in LBP/LBP-related disability. This review highlights that temporal changes in transversus abdominis features tend to be unrelated to the corresponding LBP/LBP-related disability improvements while the relation between multifidus changes and clinical improvements remains uncertain.
Perspective: This systematic review highlighted that changes in morphometry or activation of transversus abdominis following conservative treatments tend not to be associated with the corresponding changes in clinical outcomes. The relation between post-treatment changes in characteristics of lumbar multifidus and clinical improvements remains uncertain.
Abstract: STUDY DESIGN: Reliability study
OBJECTIVES: To compare the within- and between-day intra-rater reliability of rehabilitative ultrasound imaging (RUSI) using static images (RUSIs) and video clips (RUSIvc) in quantifying multifidus muscle thickness at rest and while contracted. The secondary objectives were to compare the measurement precision of averaging multiple measures, and the reliability estimates in individuals with and without low back pain (LBP).
BACKGROUND: Although intra-rater reliability of RUSIs in measuring multifidus thickness has been established, using RUSIvc may improve reliability estimates as examiners may select the optimal image from the video clip. Further, multiple measurements, and LBP status may affect RUSI reliability estimates.
METHODS: RUSIs and RUSIvc were used to quantify multifidus muscle thickness at rest and during contraction, and percent thickness change in 27 volunteers (13 without LBP, and 14 with LBP). Three RUSIs and three RUSIvc were collected in each of two sessions 1 to 4 days apart. Reliability and precision were assessed using intraclass correlation coefficients (ICC), standard error of measurement, minimal detectable change, bias and 95% limits of agreement. RESULTS: Using an average of two measures yielded optimal measurement precision for RUSIs and RUSIvc. Based on the average of two measures obtained under the same circumstance, there was no significant difference in the reliability estimates between RUSIs and RUSIvc across all testing conditions. Reliability point estimates (ICC3,2) of multifidus thickness were 0.99 for within-day comparisons and ranged from 0.93 to 0.98 for between-day comparisons. The within- and between-day ICC3,2 of percent thickness change ranged from 0.97 to 0.99, and 0.80 to 0.90, respectively. The exploratory analysis showed no significant difference in the reliability estimates between asymptomatic and LBP participants across most testing conditions.
CONCLUSION: Both RUSI methods yielded high reliability estimates for multifidus muscle measurements. Using the average of two measures obtained optimal measurement precision. Overall, RUSIvc is a reliable surrogate of RUSIs for multifidus muscle measurements with an additional advantage of shorter duration of data collection.
Abstract: OBJECTIVE: To explore the incidence of musculoskeletal injuries in elite able-bodied and wheelchair foil fencers.
DESIGN: A 3-year prospective cohort study of sport injuries during 2006-2009.
SETTING: A sample of elite able-bodied and wheelchair fencers (WFs) from the Hong Kong National Squad.
PARTICIPANTS: A total of 14 wheelchair and 10 able-bodied elite fencers completed the 3-year study.
METHODS: Monthly interviews with fencers to collect data related to their injuries.
MAIN OUTCOME MEASURES: The incidence rate and relative risk of injury were analyzed among able-bodied and WFs with different trunk control ability.
RESULTS: Wheelchair fencers had higher overall injury incidence rate (3.9/1000 hours) than able-bodied fencers (AFs) (2.4/1000 hours). Wheelchair fencers with poor trunk control were more vulnerable to injuries (4.9/1000 hours) than those with good trunk control (3.0/1000 hours). Upper extremity injuries were predominant in WFs (73.8%), with elbow (32.6%) and shoulder strain (15.8%) being the most common injuries. Lower extremity injuries were predominant in AFs (69.4%), with muscle strain over knee and thigh region (22.6%), ankle sprain (14.5%), and knee sprain (11.3%) being the leading injuries.
CONCLUSIONS:
Results of this pilot study highlighted the distinct injury incidence between the 2 different fencer groups. Larg-scale epidemiologic and biomechanical studies are warranted to improve the understanding of fencing injuries to develop specific injury prevention/rehabilitation programs.
Abstract: Background: The emphasis on evidence-based practice in physical therapy has increased the
number of clinicians who perform and interpret clinical research. Unfortunately, the traditional
statistical analysis (frequentist approach) used most often in clinical research (except
meta-analysis) has been criticized by biostatisticians for potential bias and misleading results if
used with data from single studies. Alternatively, Bayesian inference can be used instead of the
traditional frequentist approach although this trend has yet to be seen in rehabilitation research.
Used for at least three decades, the Bayesian approach provides a formal framework for
researchers to incorporate prior knowledge and current evidence to derive new probabilities for
various hypotheses. Since the results are presented in terms of probability, clinicians can
interpret and apply research findings to clinical practice directly.
Objectives: The objectives of this review are to discuss the common misconceptions among
users of the frequentist approach, the inherent limitations of the frequentist approach, as well as
to introduce the characteristics and limitations of the Bayesian approach using illustrated
examples.
Conclusions: The Bayesian approach can be used as an alternative or adjunct to the frequentist
method in future studies. This approach is also robust in situations that are unfavourable to
traditional statistics such as sequential clinical trials. However, biostatisticians may have to be
consulted for some sophisticated Bayesian analysis. As the Bayesian approach may gain
3
popularity, a good understanding of this method will benefit clinicians in interpreting research
papers and planning their future clinical studies.
Abstract: BACKGROUND: Low back pain is often associated with increased spinal stiffness which thought to arise from increased muscle activity. Unfortunately, the association between paraspinal muscle activity and paraspinal stiffness, as well as the spatial distribution of this relation, is unknown. The purpose of this investigation was to employ new technological developments to determine the relation between spinal muscle contraction and spinal stiffness over a large region of the lumbar spine. METHODS: Thirty-two male subjects performed graded isometric prone right hip extension at four different exertion levels (0%, 10%, 25% and 50% of the maximum voluntary contraction) to induce asymmetric back muscle activity. The corresponding stiffness and muscle activity over bilateral paraspinal lumbar regions was measured by indentation loading and topography surface electromyography, respectively. Paraspinal stiffness and muscle activity were then plotted and their correlation was determined. FINDINGS: Data from this study demonstrated the existence of an asymmetrical gradient in muscle activation and paraspinal stiffness in the lumbar spine during isometric prone right hip extension. The magnitude and scale of the gradient increased with the contraction force. A positive correlation between paraspinal stiffness and paraspinal muscle activity existed irrespective of the hip extension effort (Pearson correlation coefficient, range 0.566-0.782 (P<0.001)). INTERPRETATION: Our results demonstrate the creation of an asymmetrical gradient of muscle activity and paraspinal stiffness during right hip extension. Future studies will determine if alterations in this gradient may possess diagnostic or prognostic value for patients with low back pain.
Abstract: Background and aims: Prior investigations suggest a positive relation between muscle function and low back pain (LBP). Specifically, the morphological/neuromuscular characteristics of transversus abdominis or lumbar multifidus muscles may predict clinical LBP outcomes. Unfortunately, a related systematic review is unavailable. The goal of this systematic review was to summarize existing evidence regarding the predictive value of muscular function with respect to LBP outcomes..
Methods: Publications were identified from six electronic databases. Five cohort studies met predefined inclusion criteria. Evidence synthesis was conducted based on risk of bias assessment and consistency of findings.
Results: Limited evidence revealed that the baseline contraction thickness ratio and baseline feedforward timing of transversus abdominis were not related to short- or long-term LBP intensity following different exercise interventions. Nonetheless, limited evidence suggested that reduced lateral sliding of transversus abdominis at baseline was associated with higher LBP intensity following exercise interventions at 1-year follow-up. Interestingly, limited evidence showed that poor baseline transversus abdominis contraction thickness ratio might positively modify treatment effects of motor control exercise. There was conflicting evidence regarding a relation between baseline percent thickness change of lumbar multifidus during contraction and the clinical outcomes of patients following conservative treatments. No research investigated the relation between muscular morphology at rest and clinical outcomes.
Conclusions: The results of this review suggest a very weak or no relation between the baseline muscular function and future LBP outcomes. Given the small number of included studies, our results should be interpreted with caution until large-scale prospective studies can be conducted.
Abstract: Background and aims: Some conservative treatments are thought to improve clinical outcomes in persons with low back pain (LBP) by improving the activity of transversus abdominis and lumbar multifidus muscles. This systematic review aims to summarize evidence regarding which post-treatment characteristics of these muscles may predict clinical improvement.
Methods: Publications were identified from six electronic databases. Two independent reviewers selected articles according to predetermined selection criteria. Fifteen articles were included after screening. Evidence synthesis was conducted based on risk of bias assessment and consistency of findings.
Results: There was strong evidence that changes in transversus abdominis contraction thickness were not related to changes in LBP or LBP-related disability. Further, there was moderate evidence suggesting a lack of relation between feedforward timing of transversus abdominis and post-treatment improvements in LBP or LBP-related disability. Limited evidence supported the absence of a relation between changes in lateral sliding of transversus abdominis and changes in LBP. Conflicting evidence was found for the relation between changes in multifidus contraction thickness and improvements in post-treatment LBP-related disability. Similarly, conflicting evidence was noted for the relation between changes in multifidus muscle endurance or morphology and post-treatment improvements in LBP or LBP-related disability.
Conclusions: Overall, changes in transversus abdominis activity do not predict corresponding improvements in LBP or LBP-related disability. The relation between changes in characteristics of lumbar multifidus and post-treatment clinical improvements remains elusive. Future prospective studies should investigate whether the relations between the changes in muscle function and clinical outcomes are contingent on treatment types.
Abstract: BACKGROUND: Prior research reported high prevalence of shoulder injuries in wheelchair fencers with poor trunk control. While the causes of the prevailing shoulder injuries in these fencers remain unknown, a good understanding of wheelchair fencing biomechanics may help investigate the mechanisms of wheelchair fencing injuries. However, research on wheelchair fencing related upper limb kinematics is limited. As such, this study aimed to compare the upper limb kinematics of able-bodied (AB) fencers, and wheelchair fencers with (Category A: CA) or without active trunk control (Category B: CB) during lunge attacks.
METHODS: An 8-camera optical motion analysis system was used to measure the fencing arm movements of 45 world-class Chinese male foil fencers (15 AB; 15 CA and 15 CB). Each fencer sat in a stationary wheelchair and performed lunge attacks at their highest speed to a target set at four predetermined distances. Kinematic variables (angular displacement, peak linear & angular velocity and angle at peak angular acceleration) and movement coordination (as estimated by cross-correlation coefficients and the phase associations of different joints) of the fencing shoulder, elbow and wrist joints were determined. Repeated measures ANOVAs were employed to compare the within- and between-group differences in the kinematic variables. The Bonferroni test was used as the post-hoc test. The significance level was set at 0.05.
RESULTS: Compared with AB and CA fencers, CB fencers demonstrated significantly larger shoulder angular displacement, and significantly lower peak shoulder horizontal linear velocity, angular velocity and joint angle at peak acceleration when the fencing distances increased. Similarly, the shoulder-elbow joint coordination was substantially altered (with significantly time lag of the elbow movement with respect to the shoulder movement) in CB fencers as they performed lunge attacks at longer fencing distances.
DISCUSSION & CONCLUSION: CB fencers displayed different kinematics and shoulder-elbow joint coordination from AB and CA fencers during lunge attacks at increased fencing distances. The altered shoulder kinematics of CB fencers might represent an adaptive strategy for the poor trunk control and might be related to the high incidence of shoulder pain in this fencer group.
Abstract: BACKGROUND: Since wheelchair fencers compete on a stationary wheelchair, they may need to increase their fencing arm muscle recruitments to compensate for the suboptimal biomechanics. This phenomenon may be more pronounced among wheelchair fencers with compromised trunk control. However, research on this area is scanty. Given this background, the aim of this study was to compare the fencing arm muscle activation in able-bodied (AB), and wheelchair fencers with (Category A, CA) or without active trunk control (Category B, CB) during lunge attacks.
METHODS: Thirty male, world-class fencers (10 AB, 10 CA & 10 CB) were recruited in this study. Surface electromyography (SEMG) of their fencing arm muscles (i.e. upper-trapezius (UT), infraspinatus (INF), anterior-deltoid (Ant-DEL), mid-deltoid (Mid-DEL), biceps, triceps, wrist flexors and wrist extensors) were recorded. Fencers were instructed to sit in a standardized wheelchair and performed lunge attacks at their highest speed to a target set at four preset distances. Temporal SEMG variables (i.e. peak SEMG intensity, integrated SEMG value, muscles activation time and the time to reach peak SEMG) were averaged and normalized to the lunge cycle and expressed as the percentage of the lunge cycle. SEMG signals of a given muscle were also normalized to its peak SEMG value during a 5-second isometric maximal voluntary contraction. Repeated measures analysis of variance and post-hoc Bonferroni tests were used for the between- and within-group comparison. The alpha level was set at 0.05 for all tests.
RESULTS: Fencers from all groups demonstrated a similar fencing arm muscle recruitment pattern at all fencing distances. Specifically, shoulder muscles (UT, INF, Ant-DEL & Mid-DEL) and biceps initiated the lunge, while triceps were activated subsequently to extend the elbow and to advance the weapon towards the target. Wrist flexors and extensors were co-activated to adjust/stabilize the wrist as the foil approached the target. Compared with AB and CA fencers, CB fencers displayed significantly higher integrated SEMG amplitude and delayed occurrence of peak SEMG amplitude in the shoulder muscles during lunge attacks as the fencing distance increased.
DISCUSSION & CONCLUSION: Compared with AB and CA wheelchair fencers, CB wheelchair fencers demonstrated higher shoulder muscle activity and different motor activation patterns in their fencing arm as the lunge attack distance increased. This altered muscle recruitment pattern may increase the loading on the fencing arm of CB wheelchair fencers.
Abstract: Fencing is a sport that constantly demands fencers to display high agility, fast response and excellent limbs-trunk coordination. The repetitive, asymmetrical and impulsive nature of fencing renders fencers to sustain a range of upper limb and lower limb injuries. Wheelchair fencing sport, using identical weapons as the able-bodied counterpart, has been developed after World War II. Each wheelchair fencer competes in a wheelchair fastened to a frame. They are arranged in a distance to ensure the pace of bouts. Due to the elimination of lower extremities contribution, wheelchair fencers rely on their arms and trunks to perform all the necessary techniques. As many wheelchair fencers may have deprived trunk control, the mechanical loadings on their arms are colossal. Given the above, it is conceivable to expect high incidence of upper limb injuries among this athlete group. However, there is no systematic injury surveillance study to investigate the injury patterns of able-bodied and wheelchair fencers. The aim of this study is to investigate the Injury patterns of Hong Kong elite able-bodied fencers and disabled foil fencers. The findings from this first prospective study might help identify common musculoskeletal injuries in the two athlete groups. It also helps sports clinicians to develop specific injury prevention programs.
Abstract: Background
Low back pain (LBP) is often associated with increased spinal stiffness, a relation thought to be caused most often by increased muscle activity. Unfortunately, the association between paraspinal muscle activity and paraspinal stiffness, as well as the spatial distribution of this relation, is unknown over multiple lumbar levels.
Objectives
It was the aim of this study to explore the relationship between muscle activity and spinal stiffness, as well as the spatial distribution of this relation, over the paraspinal region among healthy male subjects during isometric prone right hip extension.
Methods
Thirty-two male subjects performed graded isometric prone right hip extension (RHE) at three different exertion levels (10%, 25% and 50% of the maximum voluntary contraction) to induce asymmetric back muscle activity. Indentation loading of the spine and streaming topography surface electromyography (sEMG) were used to measure the respective stiffness and muscle activity bilaterally over the L2 to L4 paraspinal lumbar regions. Muscle activity and spinal stiffness were then plotted and the correlation between these variables was determined.
Results
Data from this study demonstrated the existence of an asymmetrical gradient in muscle activation and paraspinal stiffness in the lumbar spine as a result of isometric prone RHE. The size of the gradient in magnitude and scale increased with increased RHE effort. A positive correlation between paraspinal stiffness and paraspinal muscle activity was observed to exist independently of the RHE effort (Pearson correlation coefficient, range 0.566 to 0.782 (P <0.001)).
Interpretation
Our results demonstrate the creation of an asymmetrical gradient of muscle activity and spinal stiffness during RHE which may presumably act to counterbalance forces that may destabilize the spine. Future studies will determine if alterations in this gradient are diagnostic for LBP and/or prognostic for various LBP outcomes.
Abstract: Low back pain (LBP) is a common musculoskeletal disorder with high prevalence. Notwithstanding current diagnostic technology, the cause of back pain cannot be determined in approximately 90% of patients (i.e. non-specific LBP). Cross-sectional studies have demonstrated that patients with LBP have associated neuromuscular deficits or morphological changes of transversus abdominis (TrA) and lumbar multifidus (LM). Given these observations, TrA and LM are postulated to be two important spinal stabilizers for maintaining intervertebral stability
and preventing LBP recurrence. Specific conservative interventions have been designed to restore the neuromuscular function and morphology of TrA/LM in patients with LBP in an attempt to improve the clinical outcomes and to prevent LBP
recurrence. Although there is conflicting evidence concerning a relation between the changes of TrA/LM and clinical outcomes, knowing which changing variables of TrA/LM can predict treatment outcomes would help clinicians justify the use of TrA/LM-targeted treatments and refine interventions. However, to our knowledge, no systematic review has been conducted on this topic. This review aims to summarize the evidence regarding whether the changes of TrA/LM following conservative treatments can predict/create changes in clinical outcomes.
Abstract: Lumbar multifidus (LM) and transversus abdominis (TrA) have been advocated as the major spinal stabilizers for controlling spinal stability and preventing recurrence of low back pain (LBP). Preliminary research shows that the morphology or neuromuscular control of these stabilizers are associated with LBP symptoms and clinical outcomes. Specifically, the first-week change in contracted LM thickness as measured by ultrasound predicts 7% of the variability of the first week modified Oswestry disability index score of LBP patients following spinal manipulative therapy. Similarly, the onset latency of TrA explains 17% of the variance of pain scores in patients with chronic LBP.
Given that the morphology and neuromuscular control of LM and TrA may predict the clinical outcomes of LBP patients who may or may not receive back treatment, a prognostic systematic review on this topic will help clinicians monitor their treatment effectiveness and predict prognosis of their patients.
The primary objective of this review is to investigate whether the morphology or neuromuscular control of lumbar multifidus (LM) and transversus abdominis (TrA) predict clinical outcomes/recurrence of back pain in patients with nonspecific low back pain (LBP) and is this predictive value treatment-specific?
The other secondary objectives include:
Whether the values of morphology or neuromuscular control of LM and TrA in predicting clinical outcomes/recurrence of back pain in LBP patients will vary with the chronicity of LBP?
What is the prognostic/treatment modification value of LM and TrA in predicting clinical outcomes/recurrence of LBP at different age groups?
Whether the value of LM and TrA in predicting clinical outcomes/recurrence of LBP will vary between âinceptionâ and âsurvivalâ cohort?
