Fatigue-induced Landing Alterations in ACL Reconstructed Athletes after Return-to-Sport.

At the time of return-to-sport, anterior cruciate ligament reconstructed athletes still show altered neuromechanics in their injured leg during single leg hopping tasks. Part of these alterations can be magnified when these athletes are fatigued. So far, little is known whether fatigue-induced landing alterations persist after return-to-sport. Therefore, the aim of this study was to evaluate whether these alterations persist in the six months following return-to-sport. Sixteen anterior cruciate ligament reconstructed athletes performed five unilateral hop tasks before and after a fatigue protocol. The hop tasks were executed at three different time points (return-to-sport, 3 and 6 months post-return-to-sport). A 2-by-3 repeated measures ANOVA was performed to evaluate whether fatigue-induced landing alterations persisted 3 and 6 months following return-to-sport. At 6 months following return-to-sport, fatigue still induces a reduction in hamstring medialis activation and an increase in the knee abduction moment during a vertical hop with 90-degree inward rotation. Most fatigue-induced landing alterations present at the time of return-to-sport normalize after resumption of sports activities. However, a larger knee abduction moment in the injured leg after resumption of sports activities can still be observed.

The biomechanical behaviour of ankle and foot joints during walking with shoes in patients with haemophilia.

INTRODUCTION: Patients with haemophilia (PwH) often prefer shod walking over barefoot walking as footwear offers ankle joint stability and comfort during gait. Yet, the biomechanical mechanisms contributing to the latter remain poorly understood. AIM: To explore the effect of shoes on the biomechanical functioning of the ankle and foot complex in PwH with and without haemophilic ankle arthropathy and to determine the amount of ankle joint loading during shod walking. METHODS: We analysed data of PwH without haemophilic ankle arthropathy (n = 5) and PwH with severe haemophilic ankle arthropathy (n = 17) and a control group (n = 17). During 3D gait analysis, a four-segment kinetic foot model was used to calculate kinematic and kinetic parameters of the ankle, Chopart, Lisfranc and first metatarsophalangeal (MTP 1) joints during both barefoot and shod walking. RESULTS: We found a significantly greater ankle joint power generation during shod walking compared to barefoot walking in PwH with severe haemophilic ankle arthropathy (P < .001). Chopart joint biomechanics were significantly lowered in all three groups during shod walking compared to barefoot walking. During shod walking, the ankle joint load was significantly lowered in both PwH groups (P = .039 and P = .002), but not in the control group (P = .952). CONCLUSION: Explorations in this study uncover a tendency that shoes alter the biomechanical functioning of the ankle and foot complex in PwH and simultaneously lower the ankle joint load during walking.

Clinical gait features are associated with MRI findings in patients with haemophilic ankle arthropathy.

INTRODUCTION: Haemophilic ankle arthropathy due to repeated joint bleeds often leads to altered gait in adult patients with haemophilia. AIM: To investigate the association between clinical gait features and blood-induced ankle joint damage scored using MRI findings in patients with haemophilic ankle arthropathy. METHODS: This observational study investigated 48 ankles of 24 patients with severe haemophilia (median age of 33 years). Blood-induced ankle joint damage was scored by an experienced radiologist using the International Prophylaxis Study Group (IPSG-)MRI score which evaluates the presence or absence of effusion, synovial hypertrophy, haemosiderin, surface erosions, subchondral cysts and cartilage degeneration. Using 3D gait analysis, peak ankle joint power generation and absorption (W/kg) were measured for each ankle since these are surrogate measures for joint loading during walking. Associations between MRI findings and these two clinical gait features were calculated using Spearman's ρ correlation with an α-level correction (α = 0.01) for multiple tests. RESULTS: We found large negative associations between ankle joint peak power generation and IPSG-MRI score (ρ = -0.631; P = <.001), IPSG-MRI osteochondral subscore (ρ = -0.701; P = <.001), severity of synovial hypertrophy (ρ = -0.507; P = <.001) and haemosiderin (ρ = -0.400; P = .005). Associations were also found for ankle joint peak power absorption and IPSG-MRI score (ρ = -0.425; P = .003) and IPSG-MRI osteochondral subscore (ρ = -0.556; P = <.001). CONCLUSION: Severe blood-induced ankle joint damage relates to a lowered tolerance towards ankle joint mechanical loading during walking in patients with haemophilia.

Acquired multi-segment foot kinematics in haemophilic children, adolescents and young adults with or without haemophilic ankle arthropathy.

INTRODUCTION AND AIM: The ankle joint remains vulnerable in children with haemophilia and is the primary joint affected. The purpose of this study was to dynamically characterize the segmental foot and ankle kinematics of male children, adolescents and young adults with or without ankle arthropathy. METHODS: The barefoot multi-segment foot kinematics of 70 ankles from 35 haemophilia subjects between 6 and 20 years old were captured with the Rizzoli Multi-Segment Foot Model. Joint damage of the tibiotalar and subtalar joints was scored using the IPSG-MRI score. The feet of patients with or without evidence of ankle arthropathy were compared with those of matched typically developing boys via a nonpaired comparison. The differences between the affected and nonaffected sides of patients with unilateral ankle arthropathy were assessed using a paired comparison. RESULTS: Subjects without arthropathy demonstrated a nonsignificant trend towards a higher frontal plane range of motion (RoM) at the midfoot upon loading response and a lower sagittal plane RoM at the midfoot during midstance. No differences were observed between the affected side group and their matched control group. The affected side of unilaterally affected subjects exhibited a nonsignificant tendency towards a higher frontal plane RoM at the ankle joint upon loading response and terminal stance compared to the healthy side. CONCLUSION: Most patients maintained physiological rocker function of the ankle and had no (mal)adaptive motion patterns in the more distal joints of the foot. Therefore, established structural lesions may remain subclinical with respect to moderate functional activities like walking.

Paediatric patients with blood-induced ankle joint arthritis demonstrate physiological foot joint mechanics and energetics during walking.

AIM: To compare foot joint kinetics and energetics in male paediatric boys with and without blood-induced ankle joint destruction to these of matched control groups. METHODS: A cross-sectional study was conducted in which 3D gait analysis data were collected from thirty-five male children (6-21 years) with severe or moderate haemophilia and twenty-six typically developing boys. Structural integrity of the tarsal foot joints of all haemophilic patients was assessed using the IPSG-MRI scale. All participants walked barefoot while adopting a physiological gait pattern. Three subgroups were created based on the IPSG-MRI scores: a group with no joint involvement (HealthyHaemo), with uni- or bilaterally involvement (PathoHaemo) and with only unilaterally involvement (Haemo_Unilateral_Patho). RESULTS: The PathoHaemo group presented a significant lower Lisfranc peak dorsiflexion angular velocity (34.7°/s vs 71.4°/s, P = .000, Cohen d = 1.31) and a significantly higher Lisfranc peak plantarflexion angular velocity (-130.5°/s vs -51.8°/s, P = .000, Cohen d = 0.98) compared to the control group. The Haemo_Unilateral_Patho side had a significant higher Chopart peak dorsiflexion angular velocity compared to the Haemo_Unilateral_Healthy side (41.7°/s vs 31.9°/s, P = .002, Cohen d = 1.16). CONCLUSION: No evidence for mild and severe gait deviations could be demonstrated. Internal moments, used as a surrogate measure of joint loading, quantified by the multi-segment foot model were found to be similar within the three subanalyses. We suggest that the ongoing musculoskeletal development in children compensates for structural damage to the ankle joint.

The Receptive and Propulsive Behavior of Human Foot Joints During Running With Different Striking Strategies.

Foot structure and kinematics have long been considered as risk factors for foot and lower-limb running injuries. The authors aimed at investigating foot joint kinetics to unravel their receptive and propulsive characteristics while running barefoot, both with rearfoot and with midfoot striking strategies. Power absorption and generation occurring at different joints of the foot in 6 asymptomatic adults were calculated using both a 3-segment and a 4-segment kinetic model. An inverse dynamic approach was used to quantify mechanical power. Major power absorption and generation characteristics were observed at the ankle joint complex as well as at the Chopart joint in both the rearfoot and the midfoot striking strategies. The power at the Lisfranc joint, quantified by the 4-segment kinetic model, was predominantly generated in both strategies, and at the toes, it was absorbed. The overall results show a large variability in the receptive and propulsive characteristics among the analyzed joints in both striking strategies. The present study may provide novel insight for clinical decision making to address foot and lower-limb injuries and to guide athletes in the adoption of different striking strategies during running.

Postural control of typical developing boys during the transition from double-leg stance to single-leg stance.

Literature is lacking information about postural control performance of typically developing children during a transition task from double-leg stance to single-leg stance. The purpose of the present study was therefore to evaluate the clinical feasibility of a transition task in typical developing age groups as well as to study the correlation between associated balance measures and age.Thirty-three typically developing boys aged 6-20 years performed a standard transition task from DLS to SLS with eyes open (EO) and eyes closed (EC). Balance features derived from the center of pressure displacement captured by a single force platform were correlated with age on the one hand and considered for differences in the perspective of limb dominance on the other hand.All TDB (typically developing boys) were able to perform the transition task with EO. With respect to EC condition, all TDB from the age group 6-7 years and the youngest of the age group 8-12 years (N = 4) were unable to perform the task. No significant differences were observed between the balance measures of the dominant and non-dominant limbs.With respect to EO condition, correlation analyses indicated that time to new stability point (TNSP) as well as the sway measure after this TNSP were correlated with age (p < 0.0001). For the EC condition, only the anthropometrically scaled sway measure was found to be correlated (p = 0.03). CONCLUSION: The results provide additional insight into balance development in childhood and may serve as a useful basis for assessing balance impairments in higher functioning children with musculoskeletal problems. What is Known: • Reference data regarding postural balance of typically developing children during walking, running, sit-to-stand, and bipodal and unipodal stance has been well documented in the literature. • These reference data provided not only insight into the maturation process of the postural control system, but also served in diagnosing and managing functional repercussions of neurological and orthopedic pathologies. What is New: • Objective data regarding postural balance of typical developing children during a transition task from double-leg stance to single-leg stance. • Insight into the role of maturation on the postural control system.

Weak associations between structural changes on MRI and symptoms, function and muscle strength in relation to knee osteoarthritis.

PURPOSE: To explore associations between MRI-defined structural abnormalities and clinical features related to knee osteoarthritis (OA). METHODS: Structural and clinical knee OA features were assessed in 87 women (45 with knee OA symptoms). Structural features were quantified by the Kellgren and Lawrence grade on radiography and by the Boston-Leeds Osteoarthritis Knee Score on MRI. Clinical features were assessed using the Knee Injury and Osteoarthritis Outcome Score, functional tests and muscle strength measurements. Associations were examined using regression analyses. RESULTS: Limited significant associations between structural and clinical features were found. An increased meniscal signal was associated with more pain/symptoms (P < 0.027). An anterior cruciate ligament tear was associated with poorer stair climbing test performance (P = 0.045). In a stepwise linear regression model, patellofemoral cartilage integrity and pain explained 28 % of the isometric quadriceps strength variability. The amount of cartilage lesions, loose bodies and pain explained 38 % of the isokinetic quadriceps strength variability. Synovitis/effusion and patellofemoral cartilage integrity combined with pain explained 34 % of the isometric hamstring strength variability. CONCLUSION: Although MRI-detected cartilage lesions, synovitis/effusion and loose bodies did explain part of the muscle strength variability, results suggest that MRI does not improve the link between joint degeneration and the clinical expression of knee OA. MRI contributes less than expected to the understanding of pain and function in knee OA and possibly offers little opportunity to develop structure-modifying treatments in knee OA that could influence the patient's pain and function. LEVEL OF EVIDENCE: Case series with no comparison groups, Level IV.

How reliable are femoropelvic kinematics during deep squats? The influence of subject-specific skeletal modelling on measurement variability.

BACKGROUND: Biplanar radiography displays promising results in the production of subject-specific (S.specific) biomechanical models. However, the focus has predominantly centred on methodological investigations in gait analysis. Exploring the influence of such models on the analysis of high range of motion tasks linked to hip pathologies is warranted. The aim of this study is to investigate the effect of S.Specific modelling techniques on the reliability of deep squats kinematics in comparison to generic modelling. METHODS: 8 able-bodied male participants attended 5 motion capture sessions conducted by 3 observers and performed 5 deep squats in each. Prior to each session a biplanar scan was acquired with the reflective-markers attached. Inverse kinematics of pelvis and thigh segments were calculated based on S.specific and Generic model definition. Agreement between the two models femoropelvic orientation in standing was assessed with Bland-Altman plots and paired t- tests. Inter-trial, inter-session, inter-observer variability and observer/trial difference and ratio were calculated for squat kinematic data derived from the two modelling approaches. RESULTS: Compared to the Generic model, the S.Specific model produced a calibration trial that is significantly offset into more posterior pelvis tilt (-2.8±2.7), hip extension (-2.2±3.8), hip abduction (-1.2±3.6) and external rotation (-13.8±11.4). The S.specific model produced significantly different squat kinematics in the sagittal plane of the pelvis (entire squat cycle) and hip (between 40 % and 60 % of the squat cycle). Variability analysis indicated that the error magnitude between the two models was comparable (difference<2°). The S.specific model exhibited a lower variability in the observer/trial ratio in the sagittal pelvis and hip, the frontal hip, but showed a higher variability in the transverse hip. SIGNIFICANCE: S.specific modelling appears to introduce a calibration offset that primarily translates into an effect in the sagittal plane kinematics. However, the clinical added value of S.specific modelling in terms of reducing experimental sources of kinematic variability was limited.

Current evidence regarding 2D ultrasonography monitoring of intrinsic foot muscle properties: A systematic review.

Background: Ultrasonography can discriminate between intrinsic and extrinsic foot muscle properties and has therefore gained considerable popularity as an indirect strength evaluation. However, an overview on the use of ultrasound for assessing intrinsic foot musculature (IFM) is currently lacking. Research question: What is the current evidence regarding (1) 2D ultrasonography protocols and its reliability? (2) Reference values for cross-sectional area and dorso-plantar thickness evaluation in asymptomatic and symptomatic persons? Methods: The PRISMA guidelines were used to conduct this systematic review. Eight databases (PubMed, Embase, Web of Science, Cochrane Library, Scopus, CINAHL, SPORTDiscus and EuropePMC) were searched up to November 1, 2021. Studies reporting quantitative 2D ultrasound findings of the intrinsic foot muscles with no limitation to sex, BMI, ethnicity or physical activity were included. Studies were assessed for methodological quality using the Downs and Black checklist. Results: Fifty-three studies were retained. Protocols showed an overall good to great reliability, suggesting limits of agreement between 8 and 30% of relative muscle size with minimal detectable changes varying from 0.10 to 0.29 cm2 for cross-sectional area and 0.03-0.23 cm for thickness. Reference values are proposed for both cross-sectional area and thickness measurements of the abductor hallucis, flexor digitorum brevis, flexor hallucis brevis and quadratus plantae in asymptomatic persons. This could not be performed in the symptomatic studies due to a limited number of relevant studies addressing the symptomatic population, therefore a clinical overview is outlined. Clinically, IFM properties have been studied in ten distinct pathological conditions, predominantly pointing towards decreased muscle properties of the abductor hallucis. Significance: We provide a clear and comprehensive overview of the literature regarding 2D ultrasonography of the IFM, making the available evidence more accessible to decision makers and researchers.

In Vivo Foot Segmental Motion and Coupling Analysis during Midterm Follow-Up after the Open Reduction Internal Fixation of Trimalleolar Fractures.

PURPOSE: Trimalleolar ankle fractures (TAFs) are common traumatic injuries. Studies have described postoperative clinical outcomes in relation to fracture morphology, but less is known about foot biomechanics, especially in patients treated for TAFs. The aim of this study was to analyze segmental foot mobility and joint coupling during the gait of patients after TAF treatment. METHODS: Fifteen patients, surgically treated for TAFs, were recruited. The affected side was compared to their non-affected side, as well as to a healthy control subject. The Rizzoli foot model was used to quantify inter-segment joint angles and joint coupling. The stance phase was observed and divided into sub-phases. Patient-reported outcome measures were evaluated. RESULTS: Patients treated for TAFs showed a reduced range of motion in the affected ankle during the loading response (3.8 ± 0.9) and pre-swing phase (12.7 ± 3.5) as compared to their non-affected sides (4.7 ± 1.1 and 16.1 ± 3.1) and the control subject. The dorsiflexion of the first metatarsophalangeal joint during the pre-swing phase was reduced (19.0 ± 6.5) when compared to the non-affected side (23.3 ± 8.7). The affected side's Chopart joint showed an increased range of motion during the mid-stance (1.3 ± 0.5 vs. 1.1 ± 0.6). Smaller joint coupling was observed on both the patient-affected and non-affected sides compared to the controls. CONCLUSION: This study indicates that the Chopart joint compensates for changes in the ankle segment after TAF osteosynthesis. Furthermore, reduced joint-coupling was observed. However, the minimal case numbers and study power limited the effect size of this study. Nevertheless, these new insights could help to elucidate foot biomechanics in these patients, adjusting rehabilitation programs, thereby lowering the risk of postoperative long-term complications.

Physical fitness, rather than self-reported physical activities, is more strongly associated with low back pain: evidence from a working population.

INTRODUCTION: Physical activity is suggested to be important for low back pain (LBP) but a major problem is the limited validity of the measurement of physical activities, which is usually based on questionnaires. Physical fitness can be viewed as a more objective measurement and our question was how physical activity based on self-reports and objective measured levels of physical fitness were associated with LBP. MATERIALS AND METHODS: We analyzed cross-sectional data of 1,723 police employees. Physical activity was assessed by questionnaire (SQUASH) measuring type of activity, intensity, and time spent on these activities. Physical fitness was based on muscular dynamic endurance capacity and peak oxygen uptake (VO(2) peak). Severe LBP, interfering with functioning, was defined by pain ratings ≥ 4 on a scale of 0-10. RESULTS: Higher levels of physical fitness, both muscular and aerobic, were associated with less LBP (OR: 0.54; 95% CI: 0.34-0.86, respectively, 0.59: 95%CI: 0.35-0.99). For self-reported physical activity, both a low and a high level of the total physical activity pattern were associated with an increase of LBP (OR: 1.52; 95%CI: 1.00-2.31, respectively, 1.60; 95%CI: 1.05-2.44). CONCLUSION: These findings suggest that physical activity of an intensity that improves physical fitness may be important in the prevention of LBP.

Multi-segment foot kinematics during running and its association with striking patterns.

There is an ongoing debate regarding the advantages and harms of different running striking patterns. The purpose of this study was to explore the kinematic differences between running with a midfoot- and rearfoot striking (RFS) pattern.Multi-segment foot kinematics of 12 students were assessed while running barefoot at 3.3 m/s (±10%) using a passive optoelectronic motion analysis system. Participants performed multiple running trials while landing on the rearfoot and midfoot. Comparison of the kinematic waveforms was performed using one-dimensional statistical parametric mapping (1DSPM) (paired t-test). The inter-segment angle between the shank and calcaneus was found to be significantly more plantar-flexed, more inverted and more adducted in the midfoot striking (MFS) condition compared to the RFS pattern. The calcaneus-midfoot inter-segment angle was found to be more plantar-flexed in the MFS condition. The downward angulation of the metatarsals and the medial longitudinal arch angle in the late swing phase was found to be more pronounced during MFS. Differences between midfoot and RFS patterns occur in the first sub-phase of stance (0-50% of the stance phase).These findings may be of interest for the kinesiopathological or pathokinesiological reasoning processes when facing foot- and lower limb-related running injuries.

Evidence for symmetrically reduced foot mechanics and energetics in patients after trimalleolar fracture repair: A cross-sectional study.

BACKGROUND: Trimalleolar fractures osteosynthesis is associated with a suboptimal outcome. It is hypothesized that patients with trimalleolar fractures face different ankle joint kinetics at mid- and long-term causing compensations at the distal foot joints. RESEARCH QUESTION: Do patients with a history of a trimalleolar fracture demonstrate different foot joint mechanics and energetics (1) between their affected side and their matched controls? (2) between their unaffected side and their matched controls? (3) between their affected side and their unaffected side? METHODS: Fifteen patients who sustained a trimalleolar fracture and underwent osteosynthesis for both the lateral, medial and posterior malleolus were compared to a asymptomatic control group which was matched for sex, age and walking speed. Three-dimensional gait analysis was used to quantify kinetic parameters in the Ankle, Chopart, Lisfranc and first metatarsophalangeal joint through a multi-segment kinetic foot model. Statistical analysis was performed using a Univariate Analysis of Covariance and/or a paired t-test. RESULTS: The peak internal ankle moment was significantly lower in patients when compared to the control group (p < 0.001). Mean peak power generation and total positive work were significantly lower for the Chopart joint when comparing the patients to the control group (p < 0.001). These results were observed for both the affected and unaffected side of the patients compared to the control group, showing symmetrical changes in the patient group. SIGNIFICANCE: Despite adequate radiographic quality of reduction and the fact that all patients were treated according to a fixed postoperative protocol, this study indicates that patients with a history of a trimalleolar fracture demonstrate reduced foot joint kinetics. It is hypothesized that these findings originate from extrinsic and intrinsic foot muscle strength, stiffness and pain. Future research is needed to validate this hypothesis.

Decoding foot deformity and joint-destruction pathways in diabetes: Emerging insights from in-vivo foot joint kinetic measures.

BACKGROUND: A comprehensive insight into the effect of longstanding diabetes mellitus and neuropathy on foot joint kinetics during walking is lacking. Our goal was to assess the in-vivo kinetics of major foot joints in persons with diabetes. METHODS: Three groups, matched for age, sex and walking speed were recruited in this study: 1) people with diabetic peripheral neuropathy, 2) people with diabetes without peripheral neuropathy, and 3) control subjects without diabetes. Participants were instrumented with retroreflective markers on both feet and lower limbs and underwent a barefoot gait analysis using a state-of-the-art multi-segment kinetic foot modelling approach in order to provide accurate joint loading measures at the ankle, midtarsal, tarso-metatarsal and hallux joints. FINDINGS: The group with neuropathy showed reduced ankle peak plantarflexion angular velocity compared to the control group (P = 0.002). Both groups with diabetes showed a significantly reduced midtarsal peak plantarflexion angular velocity, peak power generation and positive work compared to the control group (p < 0.01). Groups showed significant differences with respect to the tarsometatarsal peak dorsiflexion (p = 0.006) and plantarflexion angular velocity (P < 0.05). INTERPRETATION: This study shows that both diabetes groups have similar joint loading and power absorption capacity but seem to lose their power generation capacity especially at the midtarsal joint. This loss of power generation capacity and the resulting decreased net mechanical work of the foot potentially embodies a foot that poorly supplements the body's mechanical energy during push-off. This phenomenon may cause excessive tissue stresses that contribute to foot deformity and joint-destruction mechanisms.

Pilot study to investigate the feasibility of conducting a randomised controlled trial that compares Immediate versus Optional Delayed surgical repair for treatment of acute Anterior cruciate ligament injury: IODA pilot trial.

INTRODUCTION: Standard care for anterior cruciate ligament (ACL) injuries includes surgical reconstruction of the ACL. However, two randomised controlled trials (RCTs) concluded that conservative treatment does not result in inferior clinical outcomes compared with immediate ACL reconstruction. More research is needed to in the first place verify these results, and second to assess whether patient-specific parameters determine whether a patient would benefit from one treatment option over the other. However, before running a full RCT, it seems necessary to perform a pilot study that assesses the feasibility of recruiting patients with ACL for such a RCT. This is because recruitment may be challenging as many patients have strong treatment beliefs. Therefore, this pilot study will assess whether a large RCT is feasible with regard to participant recruitment, adherence to the allocated treatment arm and protocol feasibility. These pilot findings will help deciding about progressing to a future full RCT. METHODS AND ANALYSIS: This is a pragmatic, multicentre, randomised controlled pilot trial with two parallel groups. Patients with an acute ACL injury will be recruited from two Belgian hospitals. Patients will be randomised to either conservative treatment or surgical treatment. Patients will be followed-up at 3, 6 and 12 months postrandomisation. Recruitment feasibility will be evaluated by calculating the recruitment rate 4 months after the two sites have been initiated. Clear criteria for progression to a full trial are defined. Adherence to the protocol will be assessed by calculating the proportion of patients who complete the assessments. Furthermore the proportion of patients who cross-over between treatment arms during the follow-up period will be assessed. ETHICS AND DISSEMINATION: The study was approved by the ethical committees: Ethische Commissie Onderzoek UZ/KU Leuven (S62004) and Comité d'Ethique Hospitalo-Facultaire Universitaire de Liège (2020212). Results will be made available to caregivers, researchers and funder. TRIAL REGISTRATION NUMBER: This trial is registered on ClinicalTrials.gov (NCT04408690) on 29 May 2020.

Physical activity and low back pain: a systematic review of recent literature.

The objective of the study is to systematically evaluate the available evidence on the association between physical activity (i.e. occupational load and non-occupational physical activities) and low back pain (LBP). A systematic approach was used to explore the literature between 1999 and 2009. Studies were selected for inclusion following a comprehensive search of Medline, Embase and CINAHL. The methodological quality of each study was assessed. Studies were considered to be of 'high quality' if they met the cut-off criterion of 60% of the maximum available quality score. Thirty-six cohort or case-control studies were retrieved. Heavy workload and the accumulation of loads or frequency of lifts were moderate to strong risk factors for LBP. Strong associations were found for flexed, rotated and the awkward positions of the lumbar spine. Inconsistent results were found for leisure time physical activities, sports and physical exercise. Studies focusing on daily habitual physical activities (e.g. domestic activities and commuting) in association with LBP are lacking. In conclusion, the occurrence of LBP is related to the nature and intensity of the physical activities undertaken. However, physical activities can be subdivided into separate types and intensities and the ultimate physical load is the sum of all these activities. This makes it difficult to designate one particular activity as the cause of LBP.

Biomechanical maturation of foot joints in typically developing boys: Novel insight in mechanics and energetics from a cross-sectional study.

BACKGROUND: A growing body of quantitative evidence has been provided regarding age-related differences in plantar foot loading, multi-segment foot kinematics and muscle activity. Fundamental insight into the joint mechanics and energetics of the maturing foot has yet to be provided. RESEARCH QUESTION/HYPOTHESIS: It was hypothesized that so-called 'biomechancial maturation' joint kinetics would be observed in children underneath the age of eight and that older age-groups would not differ from each other in these parameters. METHODS: Fourty-three typically developing boys were recruited and allocated to three different age groups: 1) an early childhood group, 2) a middle childhood group, and 3) an early and late adolescence group. Multi-segment joint kinematics and kinetics of the Ankle-, Chopart-, Lisfranc- and Hallux joint were collected during barefoot walking. One-way Analysis of Covariance was conducted to examine differences among the outcome measures with group as a fixed factor and walking cadence as covariate. RESULTS: The youngest group differed significantly from the other two age groups with respect to their ankle and chopart joint peak plantarflexion moment (p < 0.05). Ankle and chopart joint peak power generation as well as the lisfranc peak plantarflexion moment was found to be significantly lower in the youngest age group compared to the oldest group (p < 0.05). At the lisfranc joint, the youngest age group demonstrated a significantly higher peak plantarflexion velocity compared to the two older age groups (p < 0.05). SIGNIFICANCE: This study provides novel insight into the biomechanical maturation of the developing foot which may guide clinical interventions in paediatric cohorts.

Preliminary Evidence That Taping Does Not Optimize Joint Coupling of the Foot and Ankle Joints in Patients with Chronic Ankle Instability.

BACKGROUND: Foot-ankle motion is affected by chronic ankle instability (CAI) in terms of altered kinematics. This study focuses on multisegmental foot-ankle motion and joint coupling in barefoot and taped CAI patients during the three subphases of stance at running. METHODS: Foot segmental motion data of 12 controls and 15 CAI participants during running with a heel strike pattern were collected through gait analysis. CAI participants performed running trials in three conditions: barefoot running, and running with high-dye and low-dye taping. Dependent variables were the range of motion (RoM) occurring at the different inter-segment angles as well as the cross-correlation coefficients between predetermined segments. RESULTS: There were no significant RoM differences for barefoot running between CAI patients and controls. In taped conditions, the first two subphases only showed RoM changes at the midfoot without apparent RoM reduction compared to the barefoot CAI condition. In the last subphase there was limited RoM reduction at the mid- and rearfoot. Cross-correlation coefficients highlighted a tendency towards weaker joint coupling in the barefoot CAI condition compared to the controls. Joint coupling within the taped CAI conditions did not show optimization compared to the barefoot CAI condition. CONCLUSIONS: RoM was not significantly changed for barefoot running between CAI patients and controls. In taped conditions, there was no distinct tendency towards lower mean RoM values due to the mechanical restraints of taping. Joint coupling in CAI patients was not optimized by taping.