Locomotion behavior of chronic Non-Specific Low Back Pain (cNSLBP) participants while walking through apertures.

BACKGROUND: Chronic Non-Specific Low Back Pain (cNSLBP) has been identified as one of the leading global causes of disability and is characterized by symptoms without clear patho-anatomical origin. The majority of clinical trials assess cNSLBP using scales or questionnaires, reporting an influence of cognitive, emotional and behavioral factors. However, few studies have explored the effect of chronic pain in daily life tasks such as walking and avoiding obstacles, which involves perceptual-motor processes to interact with the environment. RESEARCH QUESTION: Are action strategies in a horizontal aperture crossing paradigm affected by cNSLBP and which factors influence these decisions ? METHODS: 15 asymptomatic adults (AA) and 15 cNSLBP participants walked along a 14 m long path, crossing through apertures ranging from 0.9 to 1.8 times their shoulder width. Their movement was measured using the Qualisys system, and pain perception was evaluated by self-administered questionnaires. RESULTS: The cNSLBP participants stopped rotating their shoulders for a smaller aperture relative to their shoulder width (1.18) than the AA participants (1.33). In addition, these participants walked slower, which gave them more time to make the movement adaptations necessary to cross the aperture. No correlation was found between the variables related to pain perception and the critical point but the levels of pain were low with a small variability. SIGNIFICANCE: This study shows that during a horizontal aperture crossing task requiring shoulder rotation to pass through small apertures, cNSLBP participants appear to exhibit a riskier adaptive strategy than AA participants by minimizing rotations that could induce pain. This task thus makes it possible to discriminate between cNSLBP participants and pain-free participants without measuring the level of pain. The identification number registered in the clinical trials is NCT05337995.

Characteristics and Predictors of Postural Control Impairment in Patients With COPD Participating in a Pulmonary Rehabilitation Program.

PURPOSE: Postural control impairment has been identified as a potential extrarespiratory manifestation in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to identify clinical factors that characterize patients with reduced postural control, to examine the correlation between clinical factors and postural control and to determine predictors of an impaired postural control among COPD participants enrolled in a pulmonary rehabilitation (PR) program. METHODS: This study is a secondary analysis of an observational study (PARACHUTE). The baseline assessment of the PR program was used for the analysis. Postural control impairment was defined using the Brief BESTest score (BBT). RESULTS: Participants (n = 73) were included in the analysis, 43 of them were classified in the reduced postural control group. The between-group comparison (non-reduced vs reduced postural control) identified differences for partial pressure in oxygen (Pa O2 ), Saint George Respiratory Questionnaire (SGRQ) total score and subscores (SGRQ-Symptoms, SGRQ-Activities, and SGRQ-Impact), COPD assessment test (CAT), and anxiety score of the Hospital Anxiety and Depression Scale. The BBT score was significantly correlated with maximal inspiratory pressure (MIP), SGRQ, SGRQ-Symptoms, SGRQ-Impact, Falls Efficacy Scale, modified Medical Research Council Scale, 6-min walk test, and Pa O2 . Logistic regression identified SGRQ-Symptoms, Pa O2 , MIP, and body mass index (BMI) as predictors of the presence of reduced postural control. CONCLUSION: Low quality of life (QoL) and Pa O2 and high anxiety seem to be discriminative characteristics of patients with COPD with reduced postural control. Furthermore, QoL, Pa O2 , inspiratory muscle strength, and BMI seem to be acceptable predictors of the presence of postural control impairment.

Impairment and characteristics of postural control sub-components in people with COPD: a scoping review.

PURPOSE: Impairment of postural control is common in people with COPD. However, the precise characteristics of this alteration are not clearly known. The "Systems Framework for Postural Control" which define postural control sub-components, represents an interesting tool to explore this field. The main aim of this review was to identify which postural control sub-components are impaired in people with COPD and to summarise characteristics for each sub-component. A secondary aim was to precise the relation between postural control and activities of daily living (ADL). MATERIALS AND METHODS: A scoping review was conducted, according to the JBI methodology. Medline, Cochrane Library, Scielo, Google Scholar, OpenGrey, and HAL were searched from inception to May 2022. The search was performed in English and French. RESULTS: Eighty-nine articles were included. There was evidence of a potential impairment for most of the postural control sub-components. Characteristics of every sub-component alteration were heterogeneous. Reduced postural control could be associated with difficulties in ADL. CONCLUSIONS: People with COPD may have impairment in a wide range of postural control sub-components. Further research is needed to clarify if a common pattern of modification exits for this alteration and to precise the link with ADL.Implications for rehabilitationImpairment of postural control is a common extra-respiratory manifestation in people with COPD and so clinicians must include it in their clinical reasoning.Numerous postural control sub-components could be altered in people with COPD, suggesting that postural control assessment must be holistic.This scoping review shows that characteristics of postural control impairment are varied and that there may be no common pattern at the COPD population level.The relationship between impaired postural control and activities of daily living remains unclear, but clinicians should be alert to potential negative interactions between these two areas.

A musculoskeletal modelling approach of the assessment of the risk of hamstring injuries in professional soccer players: a pilot study.

Purpose: Evaluating and minimising the risk of hamstring injury remains complex as it lacks reliable field-testing. Kinematic analysis provides global external insights but fails to apprehend musculoskeletal loading. This study aimed to evaluate the association between hamstring function and prior injury using a novel functional test combined with a musculoskeletal approach.Methods: Twelve professional footballers, distributed in two groups (control or previously injured), performed a reactive functional test to one of four targets from a standing start and performed a knee and plantar extension on target. Joint kinematics served as input data of a musculoskeletal model, and joint angles and hamstring muscle lengths were calculated.Results: Biceps femoris long head (BFlh) was stretched to 150 ± 2% of initial length during the two conditions. Maximal BFlh length and time to stretch were significantly higher in the control group.Discussion: Kinematics and musculoskeletal parameters revealed that participants of the control group had higher maximal hip flexion, pelvis anterior tilt, and hip internal rotation than previously injured players. The combined approach of a hamstring functional test and musculoskeletal modelling gives new preliminary insights on the effect of previous history of hamstring injury on lower limb kinematics and BFlh muscle length.

ILIOTIBIAL BAND SYNDROME IN CYCLING: A COMBINED EXPERIMENTAL-SIMULATION APPROACH FOR ASSESSING THE EFFECT OF SADDLE SETBACK.

BACKGROUND: Despite abundant literature, the treatment of iliotibial band syndrome (ITBS) in cyclists remains complicated as it lacks evidence-based recommendations. PURPOSE: The aim of this study was to develop a musculoskeletal modelling approach that investigates three potential biomechanical determinants of ITBS (strain, strain rate and compression force) and to use this approach to investigate the effect of saddle setback. DESIGN: Cross-sectional. METHODS: An existing 3D lower-body musculoskeletal model was adapted to cycling and to the computation of three putative pathomechanisms responsible for ITBS: ITB strain, ITB strain rate, and compression force between ITB and the lateral femoral epicondyle (LFE). Lower limb kinematics recorded from ten well-trained healthy cyclists served as input data of the model. Cyclists pedalled at a steady state (90rpm and 200W) on an ergometer, and three different saddle setback conditions were tested. The theoretical combined influence of hip and knee joint angles on ITBS was investigated and analysed through the lens of individual pedalling technique. RESULTS: ITB-LFE compression force was the only parameter significantly affected by saddle setback and supports the hypothesis that compression force is likely to be a determinant factor in ITBS etiology. Furthermore, results showed that ITB-LFE compression force increases in individuals whose pedalling technique exacerbates hip extension-adduction and/or knee extension-internal rotation. CONCLUSION: This approach has the potential to be advantageously implemented as an additional tool to help diagnose/correct potentially harmful sport techniques and optimize equipment setup/design. LEVEL OF EVIDENCE: 3b.

Influence of saddle setback on knee joint forces in cycling.

Knee functional disorders are one of the most common lower extremity non-traumatic injuries reported by cyclists. Incorrect bicycle configuration may predispose cyclist to injury but the evidence of an effect of saddle setback on knee pain remains inconclusive. The aim of this study was to determine the effect of saddle setback on knee joint forces during pedalling using a musculoskeletal modelling approach. Ten cyclists were assessed under three saddle setback conditions (range of changes in saddle position ~6 cm) while pedalling at a steady power output of 200 W and cadence of 90 rpm. A cycling musculoskeletal model was developed and knee joint forces were estimated using an inverse dynamics method associated with a static optimisation procedure. Our results indicate that moving the saddle forwards was not associated with an increase of patellofemoral joint forces. On the contrary, the tibiofemoral mean and peak compression force were 14 and 15% higher in the Backward than in the Forward condition, respectively. The peak compression force was related to neither pedal force nor quadriceps muscle force but coincided with the eccentric contraction of knee flexor muscles. These findings should benefit bike fitting practitioners and coaches in the design of specific training/rehabilitation protocols.

Influence of saddle setback on pedalling technique effectiveness in cycling.

Besides its regulation by Union Cycliste Internationale, the evidence relating saddle setback to pedalling performance remains inconclusive. This study investigates the influence of saddle setback on pedalling effectiveness through two indexes: an index of pedalling force effectiveness and an index of pedalling work effectiveness. Eleven cyclists were assessed six saddle setback conditions while pedalling at a steady power output of 200 W and cadence of 90 rpm. A force sensor was integrated within the seat post to compute the centre of pressure on the saddle. From instrumented pedals, an index of force effectiveness (ratio between the force directed perpendicular to the crank arm and the total force applied to the pedal) and an index of work effectiveness (based on the minimisation of negative crank work) were calculated. In comparison with a forward position, sitting backward significantly decreased 5% cumulative total work, increased index of work effectiveness (84.2 ± 3.7 vs. 82.0 ± 4.7%), and increased index of force effectiveness (41.7 ± 2.9 vs. 39.9 ± 3.7 and 36.9 ± 0.7%). Thus, while it was previously reported that sitting more forward favours maximal power, this study demonstrates that it also leads to a decreased effectiveness in steady-state pedalling.