Residual deficits of knee and hip joint coordination and clinical performance after return to sports in athletes with anterior cruciate ligament reconstruction.

BACKGROUND: Biomechanical changes and neuromuscular adaptations have been suggested as risk factors of secondary injury in individuals after anterior cruciate ligament reconstruction (ACLr). To achieve a better understanding of preventive mechanisms, movement quality is an important factor of consideration. Few studies have explored time-series analysis during landing alongside clinical performance in injured and non-injured individuals. The purpose of the study was to investigate the biomechanical risks of recurrent injury by comparing clinical and jump-landing performance assessments between athletes with ACLr and healthy controls. METHOD: This study was observational study. Sixteen athletes with and without ACLr voluntarily participated in clinical and laboratory measurements. Single-leg hop distance, isokinetic tests, landing error score, and limb symmetry index (LSI) were included in clinical report. Lower limb movements were recorded to measure joint biomechanics during multi-directional landings in motion analysis laboratory. Hip-knee angle and angular velocity were explored using discrete time-point analysis, and a two-way mixed analysis of variance (2 × 4, group × jump-landing direction) was used for statistical analysis. Time series and hip-knee coordination analyses were performed using statistical parametric mapping and descriptive techniques. RESULTS: Significantly lower single-leg hop distance was noted in ACLr group (158.10 cm) compared to control group (178.38 cm). Although the hip and knee moments showed significant differences between four directions (p < 0.01), no group effect was observed (p > 0.05). Statistical parametric mapping showed significant differences (p ≤ 0.05) between groups for hip abduction and coordinate plot of hip and knee joints. Athletes with ACLr demonstrated a higher velocity of hip adduction. Time-series analysis revealed differences in coordination between groups for frontal hip and knee motion. CONCLUSIONS: Athletes with ACLr landed with poor hip adduction control and stiffer knee on the involved side. Multi-directions landing should be considered over the entire time series, which may facilitate improved movement quality and return to sports in athletes with ACLr.

Maturation and biomechanical risk factors associated with anterior cruciate ligament injury: Is there a link? A systematic review.

OBJECTIVE: To establish the potential link between sex-specific maturation and biomechanical factors associated with ACL injury during dynamic tasks. DESIGN: Systematic review. LITERATURE SEARCH: Five databases (CINHAL®, Cochrane Library, PubMed®, Scopus®, and SPORTDiscus) were searched and monitored until 27 May 2024. STUDY SELECTION CRITERIA: Cross-sectional, cohort, case-control, or interventional studies reporting one or more biomechanical variable linked with ACL injury and which assessed participants across two or more maturation phases were considered eligible. DATA SYNTHESIS: Studies were assessed for risk of bias using a modified version of the Newcastle Ottawa Scale and overall quality of evidence was rated using GRADE. Metrics and effect sizes were presented where available. RESULTS: Eighteen included studies examined 400 males, 1377 females, and 315 participants of undefined sex across various maturation phases. The methodological quality of most studies (n = 16) was considered good, and satisfactory for two. Knee abduction angle, knee abduction moment, knee flexion angle, and ground reaction forces were most commonly reported. Knee abduction angles and moments and knee flexion angles were greater in late and post-pubertal females than males and pre-pubertal females during both landing and cutting tasks. When normalised for body mass, ground reaction forces were generally greater in males compared to females overall and for less mature participants for both sexes. Overall quality of evidence was low or medium across the four biomechanical measures. CONCLUSION: Sex-specific maturation considerations are important in the targeted development and implementation of ACL injury risk identification and prevention strategies.

Clinical and biomechanical characteristics of responders and non-responders to insoles in individuals with excessive foot pronation during walking.

This study aimed to identify the clinical and biomechanical factors of subjects with excessive foot pronation who are not responsive (i.e., "non-responders") to medially wedged insoles to increase knee adduction external moment. Ankle dorsiflexion range of motion, forefoot-shank alignment, passive hip stiffness, and midfoot passive resistance of 25 adults with excessive bilateral pronation were measured. Also, lower-limb angles and external moments were computed during walking with the participants using control (flat surface) and intervention insoles (arch support and 6° medial heel wedge). A comparison between "responders" (n = 34) and "non-responders" (n = 11) was conducted using discrete and continuous analyses. Compared with the responders, the non-responders had smaller forefoot varus (p = 0.014), larger midfoot passive internal torque peak (p = 0.005), and stiffness measured by the torsimeter (p = 0.022). During walking, non-responders had lower angle peaks for forefoot eversion (p = 0.001), external forefoot rotation (p = 0.037), rearfoot eversion (p = 0.022), knee adduction (p = 0.045), and external hip rotation (p = 0.022) and higher hip internal rotation angle peak (p = 0.026). Participants with small forefoot varus alignment, large midfoot passive internal torque, stiffness, small knee valgus, hip rotated internally, and foot-toed-in during walking did not modify the external knee adduction moment ("non-responders"). Clinicians are advised to interpret these findings with caution when considering the prescription of insoles. Further investigation is warranted to fully comprehend the response to insole interventions among individuals with specific pathologies, such as patellofemoral pain and knee osteoarthritis (OA).

The effect of a home-based exercise program on gait characteristics in an individual with Parkinson's disease over a one-year period: A case study.

BACKGROUND: The COVID-19 pandemic has placed a restriction on physiotherapy clinical visits for supervised exercise. It is important that individuals with Parkinson's Disease (PD) continue an exercise regime at home during the pandemic and also in normal situations. OBJECTIVE: The purpose of this study was to explore the case history of an individual with PD who used a developed home-based exercise programme for one year during the COVID-19 pandemic. METHODS: A 67 year-old married woman was diagnosed with PD stage 2.5 on the modified Hoehn and Yahr (HY) scale. Gait characteristics and the Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) motor scores were assessed at baseline, 10 weeks, and 12 months. The home-based exercise program included breathing exercises, posture correction, stretching exercises, rotation of the axial segments, balance training, and task-specific gait training. RESULTS: After 12 months, her MDS-UPDRS motor scores decreased when compared to baseline and 10 weeks, and gait characteristics at 12 months showed an increase in the degree of foot rotation, step length, cadence, and gait speed when compared to baseline and 10 weeks. CONCLUSION: This case study showed that improvements in MDS-UPDRS and gait characteristics can continue over a 12 month period as a result of a home-based exercise programme. Therefore, home-based exercise programs should be encouraged with weekly monitoring, especially in individuals with gait disorders which show deterioration.

Comparing the effectiveness of computer-aided design/computer-aided manufacturing (CAD/CAM) of insoles manufactured from foam box cast versus direct scans on patient-reported outcome measures: a protocol for a double-blinded, randomised controlled trial.

INTRODUCTION: Custom insoles are a routine treatment for many foot pathologies, and the use of computer-aided design and computer-aided manufacturing (CAD/CAM) is well established within clinical practice in the UK. The method of foot shape capture used to produce insoles varies throughout orthotic services. This trial aims to investigate the effectiveness of two common shape-capture techniques on patient-reported outcomes in people who require insoles for a foot or ankle pathology. METHODS AND ANALYSIS: This double-blinded randomised controlled trial will involve two intervention groups recruited from a National Health Service orthotic service. Participants will be randomly assigned to receive a pair of custom CAD/CAM insoles, manufactured either from a direct digital scan or a foam box cast of their feet and asked to wear the insoles for 12 weeks. The primary outcome measure will be the Foot Health Status Questionnaire (FHSQ) pain subdomain, recorded at baseline (immediately after receiving the intervention), 4, 8 and 12 weeks post intervention. Secondary outcome measures will include FHSQ foot function and foot health subdomains recorded at baseline, 4, 8 and 12 weeks. The Orthotic and Prosthetic User Survey Satisfaction with Device will be recorded at 12 weeks. The transit times associated with each arm will be measured as the number of days for each insole to be delivered after foot shape capture. Tertiary outcome measures will include participant recruitment and dropout rates, and intervention adherence measured as the daily usage of the insoles over 12 weeks. The change in FHSQ scores for the subdomains and insole usage will be compared between the groups and time points, and between group differences in time in transit, cost-time analysis and environmental impact will be compared. ETHICS AND DISSEMINATION: Ethical approval was obtained from the Health Research Authority, London Stanmore Research Ethics Committee (22/LO/0579). Study findings will be submitted for publication in peer-reviewed journals, conference presentations and webinars. TRIAL REGISTRATION NUMBER: NCT05444192.

Classification performance of sEMG and kinematic parameters for distinguishing between non-lame and induced lameness conditions in horses.

Despite its proven research applications, it remains unknown whether surface electromyography (sEMG) can be used clinically to discriminate non-lame from lame conditions in horses. This study compared the classification performance of sEMG absolute value (sEMGabs) and asymmetry (sEMGasym) parameters, alongside validated kinematic upper-body asymmetry parameters, for distinguishing non-lame from induced fore- (iFL) and hindlimb (iHL) lameness. Bilateral sEMG and 3D-kinematic data were collected from clinically non-lame horses (n = 8) during in-hand trot. iFL and iHL (2-3/5 AAEP) were induced on separate days using a modified horseshoe, with baseline data initially collected each day. sEMG signals were DC-offset removed, high-pass filtered (40 Hz), and full-wave rectified. Normalized, average rectified value (ARV) was calculated for each muscle and stride (sEMGabs), with the difference between right and left-side ARV representing sEMGasym. Asymmetry parameters (MinDiff, MaxDiff, Hip Hike) were calculated from poll, withers, and pelvis vertical displacement. Receiver-operating-characteristic (ROC) and area under the curve (AUC) analysis determined the accuracy of each parameter for distinguishing baseline from iFL or iHL. Both sEMG parameters performed better for detecting iHL (0.97 ≥ AUC ≥ 0.48) compared to iFL (0.77 ≥ AUC ≥ 0.49). sEMGabs performed better (0.97 ≥ AUC ≥ 0.49) than sEMGasym (0.76 ≥ AUC ≥ 0.48) for detecting both iFL and iHL. Like previous studies, MinDiff Poll and Pelvis asymmetry parameters (MinDiff, MaxDiff, Hip Hike) demonstrated excellent discrimination for iFL and iHL, respectively (AUC > 0.95). Findings support future development of multivariate lameness-detection approaches that combine kinematics and sEMG. This may provide a more comprehensive approach to diagnosis, treatment, and monitoring of equine lameness, by measuring the underlying functional cause(s) at a neuromuscular level.

Increasing cadence with a metronome and running barefoot changes the sagittal kinematics of the lower limbs and trunk.

The purpose was to compare two non-laboratory based running retraining programs on lower limb and trunk kinematics in recreational runners. Seventy recreational runners (30 ± 7.3 years old, 40% female) were randomised to a barefoot running group (BAR), a group wearing a digital metronome with their basal cadence increased by 10% (CAD), and a control group (CON). BAR and CAD groups included intervals from 15 to 40 min over 10 weeks and 3 days/week. 3D sagittal kinematics of the ankle, knee, hip, pelvis, and trunk were measured before and after the retraining program, at comfortable and high speeds. A 3 × 2 mixed ANOVA revealed that BAR and CAD groups increased knee and hip flexion at footstrike, increased peak hip flexion during stance and flight phase, decreased peak hip extension during flight phase, and increased anterior pelvic tilt at both speeds after retraining. In addition, BAR increased ankle plantar flexion at footstrike and increased anterior trunk tilt. Both retraining programs demonstrated significant moderate to large effect size changes in parameters that could reduce the mechanical risks of injury associated with excessive knee stress, which is of interest to coaches, runners and those prescribing rehabilitation and injury prevention programs.

Perceptions of stigma associated with chronic knee pain: voices of selected women in Thailand and Malaysia.

INTRODUCTION: A higher prevalence of knee pain in Southeast Asian countries, compared with non-Asian countries, is an established fact. This article hypothesizes that this fact, combined with personal, cultural, and environmental factors, may influence attitudes toward illness and treatment-seeking behavior and adherence. OBJECTIVE: This study aimed to determine current attitudes, stigma, and barriers of women to the management of chronic knee pain and treatment in two Southeast Asian countries. METHODS: Fourteen semi-structured interviews explored female lived perceptions of chronic knee pain in Southeast Asia. Using a phenomenological reduction process, open-ended questions allowed participants to voice their perceptions of their experience of this knee condition. Particular foci were potential stigma associated with the perceptions of others, health-seeking attitudes, and attitudes toward exercise. RESULTS: The shared experiences of managing chronic knee pain revealed the impact of their condition on participants' normality of life and their struggles with pain, limitations, and fear for the future. Key individual, interpersonal, organizational and community barriers and facilitators impacted the health seeking attitudes and engagement with conservative rehabilitation programmes. CONCLUSION: Improved socio-cultural competency and consideration for an individuals' intersectional identity and interpersonal relationships are key to designing rehabilitation and conservative management solutions. Co-creating alternative pathways for rehabilitation for individuals that are more distant from health facilities may help reduce socio-cultural barriers at a community level.

Clinical improvements in temporospatial gait variables after a spinal tap test in individuals with idiopathic normal pressure hydrocephalus.

Idiopathic Normal Pressure Hydrocephalus (iNPH) is a neurological condition that often presents gait disturbance in the early stages of the disease and affects other motor activities. This study investigated changes in temporospatial gait variables after cerebrospinal fluid (CSF) removal using a spinal tap test in individuals with idiopathic normal pressure hydrocephalus (iNPH), and explored if the tap test responders and non-responders could be clinically identified from temporospatial gait variables. Sixty-two individuals with iNPH were recruited from an outpatient clinic, eleven were excluded, leaving a total of 51 who were included in the analysis. Temporospatial gait variables at self-selected speed were recorded at pre- and 24-h post-tap tests which were compared using Paired t-tests, Cohen's d effect size, and percentage change. A previously defined minimal clinical important change (MCIC) for gait speed was used to determine the changes and to classify tap test responders and non-responders. A mixed model ANOVA was used to determine the within-group, between-group, and interaction effects. Comparisons of the data between pre- and post-tap tests showed significant improvements with small to medium effect sizes for left step length, right step time, stride length and time, cadence, and gait speed. Gait speed showed the largest percentage change among temporospatial gait variables. Within-group and interaction effects were found in some variables but no between-group effect was found. Tap test responders showed significant improvements in right step length and time, stride length and time, cadence, and gait speed while non-responders did not. Some individuals with iNPH showed clinically important improvements in temporospatial gait variables after the tap test, particularly in step/stride length and time, cadence, who could be classified by gait speed. However, gait-related balance variables did not change. Therefore, additional treatments should focus on improving such variables.

What differences exist between the lead and trail wrist in extensor carpi ulnaris activity and golf swing joint kinematics in sub-elite golfers?

This study assessed the lead and trail arm peak and average extensor carpi ulnaris (ECU) muscle activity in association with tri-planar angular velocities of the lead and trail wrists during the golf swing. Fifteen sub-elite, male right-handed golfers (Mage = 34.7 years ±13.3, Mhandicap = 1.5 ± 2.2) were recruited to execute five shots each with their pitching wedge, 7-iron and driver clubs in an indoor golf simulator. Surface electromyography (EMG) sensors were placed over the ECU muscle belly and inertial measurement unit sensors were placed bi-laterally on the distal forearm and dorsum of the hand. There was a statistically greater recruitment of the trail ECU muscle during the downswing (p < 0.001) for all clubs. The lead ECU muscle was recruited more during the backswing (p < 0.001) and follow through (p < 0.024) phases. There were statistically different tri-planar movement patterns between the lead and trail wrist throughout all three phases of the golf swing. No significant relationships were found between downswing EMG data and clubhead kinematics at impact. In conclusion, differing wrist kinematics and associated muscle activity may contribute to the asymmetrical injury pattern seen clinically.

Ankle Biomechanics During Multidirectional Landings in Athletes With Chronic Ankle Instability.

BACKGROUND: Assessing and understanding the control of the ankle during multidirectional jump landings in athletes with chronic ankle instability (CAI) would help health professionals develop interventions to reduce the risk of recurrent injuries. The aim of this study was to investigate the angle, angular velocity, and movements of the ankle joint, and the muscle activity of peroneus longus (PL), tibialis anterior (TA), and gastrocnemius (GAS) muscles during multidirectional landings in athletes with CAI. METHODS: Nineteen athletes with CAI (≤25 Cumberland Ankle Instability Tool-Thai Score) participated. A Vicon Nexus motion analysis system synchronously collected data with an AMTI force plate and surface electromyography (EMG) to capture kinematics, kinetics, and muscle activity, respectively. Participants were asked to perform single-leg jump-landing tests in forward (0°), 30° diagonal, 60° diagonal, and lateral (90°) directions. Ankle joint kinematics, kinetics, and muscle activity of PL, TA, and GAS were analyzed. Repeated measure ANOVA (analysis of variance) and Friedman tests were used to analyze the main effects of the jump-landing direction. RESULTS: Athletes with CAI exhibited significant differences in ankle angles, angular velocities, ankle movements, and average muscle activity of GAS between directions. Greatest average EMG of GAS muscle was observed during landing in the lateral direction compared with the forward and 30° diagonal directions. CONCLUSION: Lateral and diagonal direction movements showed the greatest risks associated with recurrent ankle sprains. Impairments of neuromuscular control in both pre-landing and landing phases were observed in athletes with CAI when considered alongside previously published data. LEVEL OF EVIDENCE: Laboratory-based observational study.

Electromyographic and Kinematic Comparison of the Leading and Trailing Fore- and Hindlimbs of Horses during Canter.

This study compared muscle activity and movement between the leading (Ld) and trailing (Tr) fore- (F) and hindlimbs (H) of horses cantering overground. Three-dimensional kinematic and surface electromyography (sEMG) data were collected from right triceps brachii, biceps femoris, middle gluteal, and splenius from 10 ridden horses during straight left- and right-lead canter. Statistical parametric mapping evaluated between-limb (LdF vs. TrF, LdH vs. TrH) differences in time- and amplitude-normalized sEMG and joint angle-time waveforms over the stride. Linear mixed models evaluated between-limb differences in discrete sEMG activation timings, average rectified values (ARV), and spatio-temporal kinematics. Significantly greater gluteal ARV and activity duration facilitated greater limb retraction, hip extension, and stifle flexion (p < 0.05) in the TrH during stance. Earlier splenius activation during the LdF movement cycle (p < 0.05), reflected bilateral activation during TrF/LdH diagonal stance, contributing to body pitching mechanisms in canter. Limb muscles were generally quiescent during swing, where significantly greater LdF/H protraction was observed through greater elbow and hip flexion (p < 0.05), respectively. Alterations in muscle activation facilitate different timing and movement cycles of the leading and trailing limbs, which justifies equal training on both canter leads to develop symmetry in muscular strength, enhance athletic performance, and mitigate overuse injury risks.

A descriptive analysis of the contents of Care Response, an international data set of patient-reported outcomes for chiropractic patients.

BACKGROUND: Databases have become an important tool in understanding trends and correlations in health care by collecting demographic and clinical information. Analysis of data collected from large cohorts of patients can have the potential to generate insights into factors identifying treatments and the characteristics of subgroups of patients who respond to certain types of care. The Care Response (CR) database was designed to capture patient-reported outcome measures (PROMs) for chiropractic patients internationally. Although several papers have been published analysing some of the data, its contents have not yet been comprehensively documented. The primary aim of this study was to describe the information in the CR database. The secondary aim was to determine whether there was suitable information available to better understand subgroups of chiropractic patients and responsiveness to care. This would be achieved by enabling correlations among patient demographics, diagnoses, and therapeutic interventions with machine learning approaches. METHODS: Data in all available fields were requested with no date restriction. Data were collected on 12 April 2022. The output was manually scanned for scope and completeness. Tables were created with categories of information. Descriptive statistics were applied. RESULTS: The CR database collects information from patients at the first clinical visit, 14, 30, and 90 days subsequently. There were 32,468 patient responses; 3210 patients completed all fields through the 90 day follow up period. 45% of respondents were male; 54% were female; the average age was 49. There was little demographic information, and no information on diagnoses or therapeutic interventions. We received StartBack, numerical pain scale, patient global impression of change, and Bournemouth questionnaire data, but no other PROMs. CONCLUSIONS: The CR database is a large set of PROMs for chiropractic patients internationally. We found it unsuitable for machine learning analysis for our purposes; its utility is limited by a lack of demographic information, diagnoses, and therapeutic interventions. However, it can offer information about chiropractic care in general and patient satisfaction. It could form the basis for a useful clinical tool in the future, if reformed to be more accessible to researchers and expanded with more information collected.

The clinical and biomechanical effects of customized foot orthoses in individuals with plantar heel pain: A pre-post intervention study.

BACKGROUND: Customized foot orthoses (CFOs) are often recommended for the management of plantar heel pain. However, there is a lack of information regarding lower limb and multi-segment foot motion during gait. RESEARCH QUESTION: This study aimed to determine the effects of heat moulded CFOs on foot and lower limb kinematics when compared with prefabricated foot orthoses (PFOs) and wearing no orthoses (shod condition), and to determine the short-term effects of CFOs on pain intensity and foot function. METHODS: The immediate effects of CFOs on the lower limb and multi-segment foot motion were assessed. Participants were then asked to use the CFOs for one month and foot pain, function, and temporal-spatial parameters were assessed at baseline and at one month follow up. RESULTS: Thirty-five participants (22 females), aged 40.1 (10.5) years, with a mean duration of symptoms of 12.59 months were recruited. The symptomatic limbs showed a higher forefoot varus angle and greater rearfoot and forefoot corrections were required compared to the non-symptomatic limbs. When compared with PFOs and shod conditions, CFOs provided the least forefoot and knee motion in the transverse plane during contact phase (P < 0.05, d=0.844-1.720), least rearfoot motion in the coronal plane during midstance (P < 0.05, d=0.652), and least forefoot motion in the frontal plane, knee motion in the transverse plane, and hallux motion during the propulsive phase (P < 0.05, d=0.921-1.513). Significant improvements were seen for foot pain and function (P < 0.05, d=1.390-2.231) with significant increases in cadence and walking velocity after one month of CFO use (P < 0.05, d=0.315-0.353), and those most likely to respond had greater pain and less ankle eversion (P < 0.05, d=0.855-1.115). SIGNIFICANCE: CFOs appear to improve pathological biomechanics associated with plantar heel pain. After one month follow up, the CFOs decreased pain intensity and increased foot function, and showed significant improvements in temporal and spatial parameters of gait.

Comparison of Hip and Knee Biomechanics during Sidestep Cutting in Male Basketball Athletes with and without Anterior Cruciate Ligament Reconstruction.

This study aimed to compare hip and knee biomechanics during sidestep cutting on the operated and non-operated sides in individuals with anterior cruciate ligament reconstruction (ACLR), and in an uninjured control group. Twenty male basketball athletes, 10 individuals with ACLR and 10 controls, were recruited. Hip and knee joint angles and angular velocities were investigated with a three-dimensional motion analysis system, and ground reaction forces (GRF) along with moments were collected during the deceleration phase of the stance limb during sidestep cutting maneuvers. We found significantly higher peak hip flexion, hip internal rotation angular velocities, and peak thigh angular velocity in the sagittal plane in the ACLR group. In addition, the peak vertical GRF and peak posterior GRF of the ACLR group were significantly higher than those of the control group. Univariate analyses indicated that the posterior GRF of the non-operated side was significantly higher than in the matched operated side in the control group. The operated and non-operated sides in male basketball athletes with ACLR showed alterations in hip and knee biomechanics compared with a control group, especially in the sagittal plane. Therefore, the emphasis of neuromuscular control training for the hip and the knee in basketball players with ACLR is required.

An exploration of muscle co-activation during different walking speeds and the association with lower limb joint stiffness.

The aim of this study was to determine the muscle co-activations and joint stiffnesses around the hip, knee, and ankle during different walking speeds and to define the relationships between muscle co-activation and joint stiffness. Twenty-seven healthy subjects (age: 19.6 ± 2.2 years, height: 176.0 ± 6.0 cm, mass: 69.7 ± 8.9 kg) were recruited. Muscle co-activations (CoI) and lower limb joints stiffnesses were investigated during stance phase at different walking speeds using Repeated Measures ANOVA with Sidak post-hoc tests. Correlations between muscle co-activations, joints stiffnesses, and walking speeds were also investigated using Pearson Product Moment correlations. The results indicated that the hip and ankle joints stiffness increased with walking speed (p < 0.001) during the weight acceptance phase, and positive correlations were seen between walking speed and Rectus Femoris (RF) and Biceps Femoris (BF) CoI (p < 0.001), and a negative correlation was seen between walking speed and tibialis anterior (TA) and lateral gastrocnemius (LG) CoI (p < 0.001) during the weight acceptance phase, and the RF/BF CoI during pre-swing. These results provide new information on the variations in muscle co-activation around the hip, knee and ankle joints and their association with joint stiffness, and on the responses of stiffness and muscle co-activation to walking speed. The techniques presented could have further application and help our understanding of the effects of gait retraining and injury mechanisms.

The role of an active muscular subsystem in prone instability test during rest and leg raise conditions.

BACKGROUND: Clinicians commonly used prone instability test (PIT) by assessing the posterior-to-anterior (PA) displacement to identify lumbar instability. Most studies focusing on passive subsystem found greater mobility in lower lumbar (L4-L5) than upper lumbar (L1-L3) spine. However, there is still a lack of evidence to demonstrate the role of active subsystem. Additionally, it is unclear whether sex affects PA displacements. AIM: To determine differences in displacement among five lumbar segments, between two testing positions (rest and leg raise), and between male and female during PIT in individuals with chronic non-specific low back pain (CNLBP). DESIGN: A cross-sectional study design. SETTING: Spine biomechanics laboratory. POPULATION: Individuals with CNLBP. METHODS: An electromagnetic tracking system was used to measure PA displacement with sensors attached at T12, S2 and a hand-held dynamometer. Participants were asked to perform PIT, while a 100N force was applied to each lumbar segment during resting and leg raise positions. RESULTS: Significantly less PA displacement (P<0.05) was seen in lower compared to upper lumbar spine and in leg raise compared to rest at L1 to L4. No significant interaction of sex with different lumbar levels and conditions (P>0.05) during PIT was found. CONCLUSIONS: Although previous studies have reported that the lower lumbar spine had greater mobility, the lower amount of displacement during the rest position suggests the role of an active subsystem contributing to lumbar stability regardless of sex. CLINICAL REHABILTATION IMPACT: A reduction in displacement during the leg raise position across L1 to L4 suggesting an interaction of stabilizing subsystems of the spine to provide lumbar stability.

An exploration of the motor unit behaviour during the concentric and eccentric phases of a squat task performed at different speeds.

Despite squatting being important in strength training and rehabilitation, few studies have investigated motor unit (MU) behaviour. This study explored the MU behaviour of vastus medialis (VM) and vastus lateralis (VL) during the concentric and eccentric phases of a squat exercise performed at two speeds. Twenty-two participants had surface dEMG sensors attached over VM and VL, and IMUs recorded thigh and shank angular velocities. Participants performed squats at 15 and 25 repetitions per minute in a randomised order, and EMG signals were decomposed into their MU action potential trains. A four factor (muscle × speed × contraction phase × sexes) mixed methods ANOVA revealed significant main effects for MU firing rates between speeds, between muscles and between sexes, but not contraction phases. Post hoc analysis showed significantly greater MU firing rates and amplitudes in VM. A significant interaction was seen between speed and the contraction phases. Further analysis revealed significantly greater firing rates during the concentric compared to the eccentric phases, and between speeds during the eccentric phase only. VM and VL respond differently during squatting depending on speed and contraction phase. These new insights in VM and VL MU behvaviour may be useful when designing training and rehabilitation protocols.

Can Shoulder Impairments Be Classified From 3-Dimensional Kinematics Using Inertial Sensors?

Inertial sensors may help clinicians to assess patients' movement and potentially support clinical decision making. Our aim was to determine whether shoulder range of motion during movement tasks measured using inertial sensors is capable of accurately discriminating between patients with different shoulder problems. Inertial sensors were used to measure 3-dimensional shoulder motion during 6 tasks of 37 patients on the waiting list for shoulder surgery. Discriminant function analysis was used to identify whether the range of motion of different tasks could classify patients with different shoulder problems. The discriminant function analysis could correctly classify 91.9% of patients into one of the 3 diagnostic groups based. The tasks that associated a patient with a particular diagnostic group were the following: subacromial decompression: abduction, rotator cuff repair of tears ≤5 cm: flexion and rotator cuff repair of tears >5 cm: combing hair, abduction, and horizontal abduction-adduction. The discriminant function analysis showed that range of motion measured by inertial sensors can correctly classify patients and could be used as a screening tool to support surgery planning.

The use of statistical parametric mapping to determine altered movement patterns in people with chronic low back pain.

Kinematics studies have generally focused on the quantity of movement using discrete parameters such as maximum and minimum angles to compare between people with chronic low back pain (CLBP) and healthy individuals. However, discrete parameters cannot be used to fully describe movement patterns and segmental contributions. This study aimed to explore the use of Statistical Parametric Mapping (SPM) to characterize quality of movement by examining if differences in movement patterns exist between groups, and within-group segmental contributions, during active movement tests. Twenty-one individuals with CLBP and nine healthy individuals were recruited. Inertial Measurement Unit (IMUs) were attached at thoracic (T3) and lumbar (L1) spine, and pelvis (S1) to collect active trunk flexion, extension, rotation, and lateral bend. SPM was used to analyze between-group movement patterns and within-group segmental contributions. SPM revealed no significant differences (P > 0.05) between groups. However, a greater lumbar contribution (P < 0.001) was observed during 10-40% of flexion followed by a greater pelvic contribution (P < 0.001) during 60-90% of flexion, while a greater lumbar than thoracic contribution (P < 0.001) was observed during flexion and the return to upright position in individuals with CLBP. Individuals with CLBP used a greater thoracic contribution compared to lumbar contribution (P < 0.001) during rotation, while a greater lumbar contribution compared to pelvic contribution was observed (P < 0.001) during lateral bending. Our findings suggest that SPM approach was able to detect differences in thoracic, lumbar, and pelvic velocity contributions and timings between segments in individuals with CLBP. These findings may help improving inter-rater reliability of clinical observations.