Comparison of the Dynamic Postural Control During Lifting and Lowering an External Load in Low Back Pain: A Cross-Sectional Study.

OBJECTIVE: This study aimed to compare dynamic postural control between individuals with and without chronic low back pain (LBP) through load lifting and lowering. METHODS: This cross-sectional study included 52 male patients with chronic LBP (age: 33.37 ± 9.23 years) and 20 healthy male individuals (age: 31.75 ± 7.43 years). The postural control parameters were measured using a force plate system. The participants were instructed to stand barefoot (hip-width apart) on the force plate and lift a box (10% of the weight of the participants) from the waist height to overhead and then lower it from overhead to waist height. The interaction between the groups and tasks was determined using a 2-way repeated-measures analysis of variance. RESULTS: There was no significant interaction between the groups and tasks. Regardless of the groups, postural control parameters including amplitude (P = .001) and velocity (P < .001) in anterior-posterior (AP) direction, phase plane in medial-lateral (ML) direction (P = .001), phase plane in AP-ML direction (P = .001), and the mean total velocity (P < .001) were lesser during the lowering compared with lifting. The results indicated that, regardless of the tasks, the postural control parameters including velocity (P = .004) and phase plane in AP direction (P = .004), velocity in ML direction (P < .001), phase plane (AP-ML) (P = .028), and mean total velocity (P = .001) in LBP were lesser compared with the normal group. CONCLUSION: Different tasks affected postural control differently in patients with LBP and healthy individuals. Moreover, postural control was more challenged during the load-lowering than the load-lifting task. This may have been a result of a stiffening strategy. It may be that the load-lowering task might be considered as a more influential factor for the postural control strategy. These results may provide a novel understanding of selecting the rehabilitation programs for postural control disorders in patients.

Effect of equipping an unloader knee orthosis with vibrators on pain, function, stiffness, and knee adduction moment in people with knee osteoarthritis: A pilot randomized trial.

BACKGROUND: Wearing unloader knee orthoses for the long term may have a side effect on knee adduction moment (KAM). RESEARCH QUESTION: This study sought to determine whether equipping an unloader knee orthosis with vibrators improves its effectiveness in pain, stiffness, function, and reducing the KAM. METHODS: The authors performed a clinical evaluation with the Western Ontario and McMaster Universities (WOMAC) questionnaire and instrumented gait analyses on 14 participants with medial compartment knee osteoarthritis in two testing sessions: before wearing the orthosis and after 6 weeks of use. RESULTS AND SIGNIFICANCE: Wearing both orthoses for 6 weeks significantly improved (p < 0.05) pain, stiffness, and function compared to the baseline assessment. There was a significantly greater reduction in the first peak KAM (p = 0.016) and KAM impulse (p = 0.008) in the vibratory unloader knee orthosis than in the conventional knee orthosis in the second session. Equipping the unloader knee orthosis with vibrators can improve its effectiveness in reducing the KAM and can prevent the side effects of its use. Furthermore, equipping the unloader knee orthosis with the vibrators did not interfere with its effectiveness on pain, stiffness, and function.

Intra-Rater Reliability of Ultrasound Measurements of Diaphragm Thickness and Contractility in Individuals with Nonspecific Chronic Neck Pain.

Objective: This study aimed to determine within-day intra-rater reliability of ultrasound measurements of the right and left hemidiaphragm thickness and contractility (quantified by percentage thickness change) in supine position during deep breathing in individuals with nonspecific chronic neck pain. Methods: Seventeen volunteers (20-55 years of age) participated in this observational study. Bilateral diaphragm muscle thickness and contractility (percentage thickness change) were compared between 2 measurement sessions administered by a radiologist using B-mode real-time ultrasound (30 minutes apart). Intraclass correlation coefficient (ICC [3, 3]) as well as the standard error of measurement (SEM), minimal detectable change (MDC), and the coefficient of variation (CV) were used to determine the intra-rater reliability. Results: The right and left hemidiaphragm thickness showed good to excellent reliability at the end of deep inspiration (ICC, 0.90; 95% confidence interval [CI], 0.72-0.96; and ICC, 0. 93; 95% CI, 0.81-0.97, respectively) as well as at the end of deep expiration (ICC, 0.91; 95% CI, 0.75-0.96; ICC, 0.91; 95% CI, 0.77-0.97; SEM, 0.19; MDC, 0.54; and CV, 7.84%, respectively) and the percentage thickness change (ICC, 0.83; 95% CI, 0.54-0.94; and ICC, 0.93; 95% CI, 0.82-0.97, respectively). Conclusion: This study found that diagnostic ultrasound measurements of the right and left hemidiaphragm thickness and contractility in supine position during deep breathing in individuals with nonspecific chronic neck pain was reliable. The SEM, MDC, and CV reported may allow for accurate interpretation of diaphragm assessment in a clinical research setting.

Alteration of lumbar muscle morphology and composition in relation to low back pain: a systematic review and meta-analysis.

BACKGROUND CONTEXT: Previous studies have proposed that there is a relationship between low back pain (LBP) and morphology and composition of paraspinal muscles. However, results have been conflicting, especially regarding fatty infiltration of muscles. PURPOSE: The primary goal of this study was to review and analyze results from imaging studies which investigated morphological and composition changes in the multifidus, erector spinae and psoas major muscles in people with LBP. STUDY DESIGN/SETTING: Systematic review with meta-analysis. PATIENT SAMPLE: A patient sample was not required OUTCOME MEASURES: This review did not have outcome measures. METHODS: PubMed, Scopus, Web of Sciences, EMBASE and ProQuest were searched for eligible studies up to 31st July 2020 (all languages). A systematic search of electronic databases was conducted to identify studies investigating the association between the morphology and fat content of lumbar muscles in people with LBP compared with a (no LBP) control group. 13,795 articles were identified. Based on the screening for inclusion/ exclusion, 25 were included. The quality of the studies was evaluated using the Newcastle-Ottawa Scale. From the 25 articles, 20 were included in the meta-analysis. RESULTS: Results showed that the total cross-sectional area of the multifidus was smaller in people with LBP (Standardized mean difference, SMD = -0.24, 95% CI = -0.5 to 0.03). Combined SMDs showed a medium effect of LBP on increasing multifidus muscle fat infiltration (SMD = 0.61, 95% CI = 0.30 to 0.91). There were no LBP related differences identified in the morphology or composition of the lumbar erector spine and psoas major muscles. CONCLUSIONS: People with LBP were found to have somewhat smaller multifidus muscles with a significant amount of intramuscular fat infiltration. Varying sample size, age and BMI of participants, quality of studies and the procedures used to measure fat infiltration are possible reasons for inconsistencies in results of previous studies.

Comparing muscle thickness and function in healthy people and subjects with upper trapezius myofascial pain syndrome using ultrasonography.

BACKGROUND: The reliability of the muscle function using ultrasonography is not reported in patients with myofascial pain syndrome and healthy individuals. The main aim of this study was to compare muscle thickness and function of two matched healthy and patients groups with neck pain due to upper trapezius myofascial pain syndrome. METHODS: 40 subjects (20 healthy and 20 patients) participated in this study. Two examiners measured the upper trapezius thickness and function 3 times by ultrasonography independently in the test and retest sessions. RESULTS: There were not significant differences between two groups with respect to demographic characteristics. The ICC values were good to excellent for both measurements. There were no significant differences between the two groups, in terms of upper trapezius muscle thickness in rest (p = 0.63), fair (p = 0.75) and normal (p = 0.73) contractions. On the other hand, % rest-thickness fair (p = 0.006), % rest-thickness normal (p = 0.006), % MVC-thickness (p = 0.02) showed significant differences between two healthy and myofascial pain syndrome groups. CONCLUSIONS: Ultrasonography is a reliable technique used to measure muscle thickness and function. Muscle thickness in rest, fair and normal contractions is not different between the matched groups of healthy people and myofascial pain syndrome subjects. Additionally, muscle function is less in myofascial pain syndrome subjects than healthy people specially % MVC thickness.

Effect of Chronic Low Back Pain on Lumbar Spine Lordosis During Sit-to-Stand and Stand-to-Sit.

OBJECTIVE: This study aimed to evaluate lumbar lordosis during sit-to-stand (STS) and stand-to-sit (SIT) in individuals with and without chronic nonspecific low back pain (CNLBP). The second objective was to investigate sex-related differences in lumbar lordosis. METHODS: Twenty-six patients with CNLBP and 26 controls were recruited. Controls were matched with cases using a frequency matching method. Reflective markers were placed over the spinous process of T12, L3, S2, and the anterior and posterior superior iliac spines. The participants were instructed to stand up at a self-selected pace and maintain their normal upright standing posture for 3 seconds, and then sit down. Kinematic data were recorded at a sampling frequency of 100 Hz using a motion capture system. Lumbar lordosis angle was calculated from the intersection between the line joining T12 and L3, and the line joining L3 to S2. RESULTS: Lumbar lordosis was decreased in patients with CNLBP during STS and SIT compared with the asymptomatic group (mean difference = 2.68°-9.32°; P ≤ .005). Furthermore, no differences were seen in lumbar lordosis at starting position between CNLBP and asymptomatic groups during STS and SIT (mean difference = 2.68°-3.75°; P ≥ .099). Interestingly, the magnitude of the effect size suggested that the difference in lumbar lordosis values between female and male participants was relatively large (Cohen's d = -1.81 to 0.20). CONCLUSION: Decreased lumbar lordosis in patients with CNLBP during STS and SIT could be considered as an important point during rehabilitation. Moreover, the present study showed that there is a sex-related difference among women and men in lumbar lordosis during STS and SIT tasks.

Pressure Pain Threshold in Subjects With Piriformis Syndrome: Test-Retest, Intrarater, and Interrater Reliability, and Minimal Detectible Changes.

OBJECTIVE: This study aimed to assess the test-retest, intrarater, and interrater reliability of using the pressure pain threshold (PPT) in healthy and affected piriformis muscles and to estimate its absolute reliability. As a secondary objective, the degree of tenderness of the affected piriformis muscles was compared with healthy piriformis muscles. STUDY DESIGN: This study used a comparative and reliability-based design. SETTING: Rehabilitation clinic. PARTICIPANTS: Patients (N=30) with unilateral piriformis muscle syndrome (30 affected and 30 healthy piriformis muscles) were recruited, and the PPT of both the healthy and affected piriformis muscles was recorded using digital algometry. Measurements of PPT were done by 2 raters (rater 1 and 2), which were selected at random order. Rater 1 repeated the PPT measurements 24-72 hours after initial assessment. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: PPT. RESULTS: Excellent intrarater intraclass correlation coefficient (ICC) values were observed for the PPT of the affected piriformis (ICC: 0.86-0.96) and the healthy piriformis (ICC: 0.88-0.96) in the same session. The PPT measurements using digital algometry showed good-to-excellent interrater reliability (ICC: 0.64-0.92) and test-retest reliability (ICC: 0.72-0.95) in both the healthy and affected piriformis muscles. The findings revealed a significant decrease in the PPT of the affected piriformis muscle in comparison to the healthy piriformis muscle (mean difference 12.76; 95% confidence interval, 15.69-9.82; P<.001). CONCLUSIONS: Digital algometry is a reliable tool for measuring piriformis PPT, regardless of the testing session and the rater. Patients with unilateral piriformis muscle syndrome have increased tenderness and decreased PPT in the affected piriformis muscle in comparison to the healthy piriformis muscle.

Ultrasound-guided dry needling decreases pain in patients with piriformis syndrome.

INTRODUCTION: Piriformis muscle syndrome (PMS) is a disorder that can lead to symptoms of buttock pain and limited hip-joint mobility, and may have an impact on quality of life. METHODS: Thirty-two patients with PMS were randomized to the treatment group, which included three sessions of ultrasound-guided dry needling (DN) of the piriformis muscle (n = 16), or a waitlist control group (n = 16). The primary outcome was pain intensity measured on the visual analog scale recorded at baseline and then at 72 hours and 1 week after treatment. RESULTS: At 1-week follow-up, pain intensity was significantly less in the DN group than in the waitlist control group (-2.16 [-1.01 to -3.32], P = .007) by an amount consistent with clinically meaningful improvement. DISCUSSION: The findings suggest that DN resulted in clinically meaningful short-term improvement in pain intensity of patients with PMS.

The Effect of Core Stabilization Exercises on Trunk-Pelvis Three-Dimensional Kinematics During Gait in Non-Specific Chronic Low Back Pain.

STUDY DESIGN: Controlled clinical trial study. OBJECTIVE: This study aimed to evaluate the effect of core stabilization exercise program (CSEP) on trunk-pelvis kinematics during gait in non-specific chronic low back pain (NCLBP). SUMMARY OF BACKGROUND DATA: NCLBP is a major public burden with variety of dysfunction including gait variability. METHODS: Thirty participants (15 NCLBP and 15 healthy) were included in this study via the convenience sampling method. NCLBP group were intervened via the 16 sessions CSEP 3 days for 6 weeks and trunk-pelvis kinematics (angular displacement, waveform pattern [CVp], and offset variability [CVo]) during gait, pain, disability were evaluated before and after the intervention. RESULTS: No significant differences in displacement and CVo in three planes were found between NCLBP and healthy groups. Independent t test was revealed that significant differences in CVp in the sagittal, frontal, and transverse planes were found between healthy and NCLBP in pre intervention. No significant changes in displacement and CVo were found as the result of intervention in NCLBP. Pain and disability decreased significantly after intervention. Paired t test revealed that the CSEP increased the frontal (P = 0.04) and transverse planes (P = 0.02) pattern variability significantly. However, there was a significant difference between groups in the sagittal plane CVp after intervention (sagittal plane CVp in healthy vs. NCLBP in post-CSE: mean difference = 14.1; P = 0.04). CONCLUSION: Considering the role of the deep trunk muscles in gait, and their common deconditioning in CLBP, a CSEP intervention may increase trunk-pelvis kinematic pattern variability. These results suggest CSEP may specifically increase transverse and frontal plane variability, indicating improved motor pattern replication through this movement planes. LEVEL OF EVIDENCE: 2.

The effect of dry needling on the active trigger point of upper trapezius muscle: Eliciting local twitch response on long-term clinical outcomes.

BACKGROUND: Pain from myofascial trigger points is often treated by dry needling (DN). Empirical evidence suggests eliciting a local twitch response (LTR) during needling is essential. Muscle damage after eliciting LTR can increase the risk of tissue fibrosis in some cases. OBJECTIVE: This study aimed to compare two methods of DN including with and without LTR on clinical parameters. METHODS: Twenty-six participants suffering from chronic non-specific neck pain with an active trigger point (TrP) in their upper trapezius muscles were recruited via the convenience sampling method. Participants were randomly assigned in DN with LTR (control group) and without eliciting LTR or "de qi" (experimental group). Then, they received 3 sessions of dry needling, 3 days apart. We evaluated pain, pain pressure threshold, active cervical lateral flexion range of motion, and Neck Disability Index before the intervention and 4 weeks after the treatment. RESULTS: After the treatment, significant higher changes were seen in the experimental group compared to the control group (p< 0.05) regarding pain, pain pressure threshold, and active cervical lateral flexion. However, there was no significant difference between groups according to the disability (p> 0.05). CONCLUSION: DN without eliciting LTR has superiority over the DN along with eliciting LTR while the treatment aimed to receive long-term effects.

What is the effect and mechanism of kinesiology tape on muscle activity?

OBJECTIVE: This study aimed to evaluate the effects of kinesiology tape, anesthesia, and kinesiology tape along with anesthesia, on motor neuron excitability. PARTICIPANTS: Participants included 20 healthy men aged 20-35 years, who were examined over 5 sessions. INTERVENTION: The five experimental sessions included: control without applying the kinesiology tape or Eutectic Mixture of Local Anesthetics (EMLA); treatment only with EMLA; only kinesiology tape application; only sham tape application; and treatment with kinesiology tape and EMLA. MAIN OUTCOME MEASURES: The H-reflex recruitment curve of the soleus and lateral gastrocnemius was recorded by a blinded assessor in the 5 separate sessions randomly assigned with 48 h washout periods. The major H-reflex parameters include: the Hmax/Mmax ratio, the H-reflex threshold stimulation intensity (Hth), the intensity of maximum H-reflex (IntensityHmax), the H-reflex ascending slope (Hslp), and the H-reflex ascending slope fixed into the first three points (first Hslp). RESULTS: The H-reflex parameters (H slope, first Hslp, Hth, and IntensityHmax) were facilitated by application of the kinesiology tape with and without EMLA; however, EMLA inhibited the H-reflex parameters (Hmax/Mmax ratio, Hslp, first Hslp, and Hth) in both the soleus and lateral gastrocnemius. The sham tape did not alter the H-reflex recruitment curve parameters. The statistical model revealed a significant difference between the kinesiology tape and the sham tape and control sessions, between kinesiology tape-EMLA and EMLA, and between kinesiology tape-EMLA and control session. CONCLUSIONS: Results suggest that the kinesiology tape facilitates the muscle activity and the underlying mechanism on the gastrosoleus motor neuron pool involves the cutaneous receptors.

The effect of upper trapezius muscle dry needling treatment on sleep quality: A case report.

Myofascial pain syndrome is characterized by trigger points in muscles, resulting in pain, limitation of motion, muscle weakness and also referral pain. Upper part of trapezius muscle is one the most common sites in upper quadrant affected by this condition. Among various manual and non-manual techniques, dry needling is one of the most effective treatment methods, and is widely used recently by physiotherapists. A 34 year old, female hairstylist with chronic shoulder pain was admitted to a physiotherapy clinic and was treated with dry needling approach, after which she found improvement of shoulder symptoms and sleep quality. Results from this case report can create an interesting and clear precedent for considering dry needling treatment in future clinical trials.

A new iPhone application for measuring active craniocervical range of motion in patients with non-specific neck pain: a reliability and validity study.

BACKGROUND CONTEXT: Measurement of cervical spine range of motion (ROM) is often considered to be an essential component of cervical spine physiotherapy assessment. PURPOSE: This study aimed to investigate the reliability and validity of an iPhone application (app) (Goniometer Pro) for measuring active craniocervical ROM (ACCROM) in patients with non-specific neck pain. STUDY DESIGN/SETTING: A cross-sectional study was conducted at the musculoskeletal biomechanics laboratory located at Iran University of Medical Sciences. PATIENT SAMPLE: Forty non-specific neck pain patients participated in this study. OUTCOME MEASURES: The outcome measure was the ACCROM, including flexion, extension, lateral flexion, and rotation. METHOD: Following the recruitment process, ACCROM was measured using a universal goniometer (UG) and iPhone 7 app. Two blinded examiners each used the UG and iPhone to measure ACCROM in the following sequences: flexion, extension, lateral flexion, and rotation. The second (2 hours later) and third (48 hours later) sessions were carried out in the same manner as the first session. Intraclass correlation coefficient (ICC) models were used to determine the intra-rater and inter-rater reliability. The Pearson correlation coefficients were used to establish concurrent validity of the iPhone app. Minimum detectable change at the 95% confidence level (MDC95) was also computed. RESULTS: Good intra-rater and inter-rater reliability was demonstrated for the goniometer with ICC values of ≥0.66 and ≥0.70 and the iPhone app with ICC values of ≥0.62 and ≥0.65, respectively. The MDC95 ranged from 2.21° to 12.50° for the intra-rater analysis and from 3.40° to 12.61° for the inter-rater analysis. The concurrent validity between the two instruments was high, with r valuesof ≥0.63. The magnitude of the differences between the UG and iPhone app values (effect sizes) was small, with Cohen d values of ≤0.17. CONCLUSIONS: The iPhone app possesses good reliability and high validity. It seems that this app can be used for measuring ACCROM.

A protocol for clinical trial study of the effect of core stabilization exercises on spine kinematics during gait with and without load in patients with non-specific chronic low back pain.

Background: Non-specific chronic low back pain (NCLBP) is a major public health and global socioeconomic burden with a variety of symptoms such as gait abnormality. Trunk stiffness and deep trunk muscles dysfunction known as guarding mechanism in gait are factors leading to abnormal movement pattern of the spine. Anterior load carriage task during gait is also challenged the trunk stability and its movement pattern. It will be therefore of interest to examine the effect of a Core Stabilization Training Program (CSTP) on the trunk and pelvis kinematics including variability and peak displacement during gait with and without load in NCLBP patients. Methods: Patients with NCLBP will participate in a program containing 16 sessions of CSTP and perceived pain, disability and kinematic will be evaluated with 100 mm visual analog scale (VAS), Oswestry Disability Index (ODI) and motion analyzing system respectively before and after the intervention. Participants will be asked to walk with self-selected comfortable speed for 3 times without load and 3 times with caring a load with hands. Discussions: We will quantify the effectiveness of CSTP on the kinematic of trunk, lumbar and pelvis during gait. Comparing the kinematic pattern and movement variability using CVo and CVp can contribute to better understand the motor control strategy and movement pattern of the spine during an anterior load carriage task between patients with NCLBP and healthy. Trial registration: IRCT number: IRCT2016080829264N1; pre-result.

The effect of a powered ankle foot orthosis on walking in a stroke subject: a case study.

[Purpose] Standing and walking are impaired in stroke patients. Therefore, assisted devices are required to restore their walking abilities. The ankle foot orthosis with an external powered source is a new type of orthosis. The aim of this study was to evaluate the performance of a powered ankle foot orthosis compared with unpowered orthoses in a stroke patient. [Subjects and Methods] A single stroke subject participated in this study. The subject was fitted with three types of ankle foot orthosis (powered, posterior leg spring, and carbon ankle foot orthoses). He was asked to walk with and without the three types of orthoses, and kinetic and kinematic parameters were measured. [Results] The results of the study showed that the moments applied on the ankle, knee, and hip joints increased while walking with the powered ankle foot orthosis. [Conclusion] As the powered ankle foot orthosis influences the moments of the ankle, knee, and hip joints, it can increase the standing and walking abilities of stroke patients more than other available orthoses. Therefore, it is recommended to be used in rehabilitation programs for stroke patients.

Effect of spinal stabilization exercise on dynamic postural control and visual dependency in subjects with chronic non-specific low back pain.

BACKGROUND: Motor control approach towards chronic non-specific low back pain (CNLBP) has gained increasing attention. CNLBP patients have shown to be more visually dependent for the postural control process than control subjects but no study has yet investigated the treatment programs effect on this disorder. METHODS: Forty CNLBP patients volunteered to participate in this experimental study. The subjects were randomly assigned into either stabilization exercise (SE) or control group both receiving 12 sessions of routine physiotherapy for four weeks. The SE group also received intensive stabilization exercise. Balance (in terms of overall (OSI), anteroposterior (APSI) and mediolateral stability indices (MLSI)) and functional disability were assessed by Biodex Balance System(®) (BBS) and Oswestry Low Back Disability Questionnaire, respectively prior and after the interventions. The balance tests were performed with open and closed eyes. RESULTS: Both interventions significantly decreased all stability indices but the SE group showed a more pronounced improvement in OSI and APSI. In the SE group, vision deprivation had smaller destabilizing effects on OSI and APSI as compared with the control group. The groups were not statistically different prior and after the interventions on all dependent variables. Oswestry index reduction in the SE group was more pronounced but the interaction of time and group variables were not significant on pain intensity. CONCLUSION: Both interventions effectively enhanced stability indices and functional capabilities and reduced pain intensity in CNLBP patients. The SE protocol made the patients less visual dependent perhaps via better stability. Since pain reduction was not different between the groups, more functional improvement in SE group cannot simply be interpreted via the pain interference and might be related to postural control capabilities of the patients.

Effect of dual-tasking on dynamic postural control in individuals with and without nonspecific low back pain.

OBJECTIVE: The purpose of this study was to compare the effect of dual tasking on postural and cognitive performance between participants with and without nonspecific chronic low back pain. METHODS: In this 3-factor mixed-design study, dynamic postural stability was assessed in 15 patients with chronic nonspecific low back pain and 15 age-, sex-, and size-matched asymptomatic participants. Bilateral stance on a Biodex Balance System was investigated at 3 levels of postural task difficulty (different platform stabilities levels with eyes open and closed) and 2 levels of cognitive task difficulty (with or without auditory Stroop test). We measured anterior-posterior, medial-lateral, and overall indices for postural performance. Average reaction time and error ratio of a modified auditory Stroop test were calculated as measures of the cognitive task performance. RESULTS: Mixed-design 3-way analyses of variance revealed significant interactions. Post hoc 2-way analyses of variance showed significant group by cognitive task difficulty for anterior-posterior (P < .001), medial-lateral (P = .003), and overall stability indices (P < .001) on a stiffness level of 5 with eyes closed. At this level, there were significant differences between single- and dual-task conditions for anterior-posterior (P < .001), medial-lateral (P = .02), and overall stability indices (P < .001) only in the chronic low back pain group. Also, at the most difficult postural conditions, participants with chronic low back pain increased their error ratio (P = .002), whereas matched asymptomatic individuals increased their reaction time (P < .01) of the auditory Stroop test. CONCLUSION: Postural task performance is attenuated by cognitive loading at a moderate level of postural task difficulty. Therefore, to observe the effect of attentional demands of postural control, task difficulty should be considered.

Intra and intersession reliability of a postural control protocol in athletes with and without anterior cruciate ligament reconstruction: a dual-task paradigm.

BACKGROUND: Quantification of dynamic balance is essential to assess a patient's level of injury or ability to function so that a proper plan of care may commence. In spite of comprehensive utilization of dual-tasking in balance assessment protocols, a lack of sufficient reliability data is apparent. PURPOSE: The purpose of the present study was to determine the intra- and inter-session reliability of dynamic balance measures obtained using the Biodex Balance System® (BBS) for a group of athletes who had undergone anterior cruciate ligament reconstruction (ACLR) and a matched control group without ACLR, while using a dual-task paradigm. METHODS: Single-limb postural stability was assessed in 15 athletes who had undergone ACLR and 15 healthy matched controls. The outcome variables included measures of both postural and cognitive performance. For measuring postural performance, the overall stability index (OSI), anterior-posterior stability index (APSI), and medial-lateral stability index (MLSI), were recorded. Cognitive performance was evaluated by measuring error ratio and average reaction time. Subjects faced 4 postural task difficulty levels (platform stabilities of 8 and 6 with eyes open and closed), and 2 cognitive task difficulty levels (with or without auditory Stroop task). During dual task conditions (conditions with Stroop task), error ratio and average reaction time were calculated. RESULTS: Regarding intrasession reliability, ICC values of test session were higher for MLSI [ACL-R group (0.83-0.95), control group (0.71-0.95)] compared to OSI [ACL-R group (0.80-0.92), control group (0.67-0.95)] and APSI [ACL-R group (0.73-0.90), control group (0.62-0.90)]. Furthermore, ICC values of first test session were higher in reaction time [ACL-R group (0.92-0.95), control group (0.80-0.92)] than error ratio [ACL-R group (0.72-0.88), control group (0.61-0.83)]. ICC values of retest session were higher for MLSI [ACL-R group (0.83-0.94), control group (0.87-0.93)] than OSI [ACL-R group (0.81-0.91), control group (0.83-0.93)] and APSI [ACL-R group (0.73-0.90), control group (0.53-0.90)]. Moreover, ICC values of retest session were higher in reaction time [ACL-R group (0.89-0.98), control group (0.80-0.92)] equated with error ratio [ACL-R group (0.73-0.87), control group (0.57-0.79)]. With respect to intersession reliability, ICC values were higher for MLSI [ACL-R group (0.72-0.96), control group (0.75-0.92)] than OSI [ACL-R group (0.55-0.91), control group (0.64-0.87)] and APSI [ACL-R group (0.55-0.79), control group (0.46-0.89)]. Additionally, ICC values were higher in reaction time [ACL-R group (0.87-0.95), control group (0.68-0.81)] in contrast to error ratio [ACL-R group (0.42-0.64), control group (0.54-0.74)]. CONCLUSION: Biodex Balance System® measures of postural stability demonstrated moderate to high reliability in athletes with and without ACLR during dual-tasking. Results of the current study indicated that assessment of postural and cognitive performance in athletes with ACLR may be reliably incorporated into the evaluation of functional activity. LEVEL OF EVIDENCE: 2b.