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.

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.

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.

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.

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.

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.

Neuromuscular and biomechanical landing alterations persist in athletes returning to sport after anterior cruciate ligament reconstruction

BACKGROUND

Anterior cruciate ligament reconstructed (ACLR) athletes show increased hamstrings activation and decreased knee flexion moments (KFMs) during single leg landing tasks at time of return-to-sport (RTS). Although these landing alterations seem protective in the short term, they might become undesirable if they persist after RTS. Therefore, the main aim of this study was to investigate whether those landing alterations persist in the months following RTS.

METHODS

Sixteen athletes who had an ACLR performed five unilateral landing tasks at three different time points (at RTS, and at 3 and 6 months after RTS) while KFMs and hamstrings activation were recorded. The following clinical parameters were registered: isokinetic strength of quadriceps and hamstrings, ACL return-to-sport after injury scale (ACL-RSI), Tampa scale of kinesiophobia, self-reported instability and single leg hop distance. A one-way repeated measures analysis of variance (ANOVA) was used to assess whether landing deficits changed over time. Additionally, an explorative analysis was performed to assess whether those athletes whose deficits persisted the most could be identified based on baseline clinical parameters.

RESULTS

The ANOVA showed no differences in landing deficits between sessions, indicating persisting reduced KFMs and increased hamstrings activation in the injured leg compared with the contralateral leg. A significant improvement of the quadriceps concentric strength (at 120°/s), ACL-RSI score and jump distance of the single leg hop was found over time.

CONCLUSIONS

Landing alterations were not resolved 6 months after RTS. Additional interventions may be needed to normalize landing alterations prior to return to sport.

The beneficial effects of acute strength training on sway activity and sway regularity in healthy older men: Evidence from a posturography study

The effects of acute strength training on balance control were studied in healthy older human men (age-range 60-77y). Participants performed the Tandem Romberg Stance while completing an attention demanding cognitive task (Mathematical Counting) before and after a single acute strength training session applied to the lower limb musculature (experimental group; n = 19) or no intervention (control group; n = 18). Balance stability and the automaticity of balance control were estimated through the calculation of the center-of-pressure (CoP) velocity (Vcop) and the statistical regularity (wavelet entropy) of the CoP trajectory (WEcop), respectively. Training included 3 sets of 3 repetitions of barbell squats using Smith Machine, ranging from 90 % of one repetition maximum (1RM) to 100 % 1RM with 3 min rest between repetitions and 5 min rest between sets. Vcop and WEcop decreased after training (all time main effects, p ≤ 0.028) but group time interactions were not significant (all, p ≥ 0.056). Exploratory analyses revealed that participants in the experimental group showed a significant decrease of Vcop and WEcop in the mediolateral (ML) directions from pre to post [ML Vcop: 15.4 %; Bonferroni-corrected p = 0.048); ML WEcop: 10.5 %; Bonferroni-corrected p = 0.016]. A trend towards a decrease in Vcop and WEcop was also observed in controls, with more prominent gains in the anteroposterior than in the ML direction (Bonferroni-corrected p > 0.2). Overall, findings suggest that acute strength training may improve attentional control of balance along the narrow dimension of the support. Further studies are warranted to examine the specific mechanisms underlying these findings.

Foot Loading Associated with Barefoot, Shod, and Minimalist Running in Male Rearfoot Strikers

BACKGROUND

We aimed to determine the center of pressure (COP) trajectories and regional pressure differences in natural rearfoot strikers while running barefoot, running with a minimalist shoe, and running with a traditional shoe.

METHODS

Twenty-two male natural rearfoot strikers ran at an imposed speed along an instrumented runway in three conditions: barefoot, with a traditional shoe, and with a minimalist shoe. Metrics associated to the COP and regional plantar force distribution, captured with a pressure platform, were compared using one-way repeated-measures analysis of variance.

RESULTS

The forefoot contact phase was found to be significantly shorter in the barefoot running trials compared with the shod conditions (P = .003). The initial contact of the COP was located more anteriorly in the barefoot running trials. The mediolateral position of the COP at initial contact was found to be significantly different in the three conditions, whereas the final mediolateral position of the COP during the forefoot contact phase was found to be more lateral in the barefoot condition compared with both shod conditions (P = .0001). The metrics associated with the regional plantar force distribution supported the clinical reasoning with respect to the COP findings.

CONCLUSIONS

The minimalist shoe seems to provide a compromise between barefoot running and running with a traditional shoe.

Blood-induced cartilage damage alters the ankle joint load during walking

Ankle cartilage damage due to repeated joint bleeds often leads to altered gait in adult patients with hemophilia. It is therefore of clinical importance to develop an understanding of the biomechanical gait features in hemophilia patients with and without blood-induced cartilage damage and age-matched control subjects. We recruited a control group (n = 17), patients with hemophilia (PwH) without blood-induced ankle cartilage damage (PwH__NoCartDam , n = 5) and PwH with severe blood-induced ankle cartilage damage (PwH__CartDam , n = 19). We collected three-dimensional gait analysis data with following outcome variables in the ankle, Chopart and the first metatarsophalangeal (MTP 1) joints: range of motion (ROM) during stance phase, peak joint moment and powers. Biomechanical loading (BW) was quantified as the joint reaction forces using inverse dynamic analysis. Loading rate (BW/s) and impulse (BW*s) were calculated between 50% and 70% of stance phase. All biomechanical variables of the ankle joint were significantly lowered in the PwH__CartDam group compared with both the control subjects and the PwH__NoCartDam group. No compensatory biomechanical function was observed in other foot joints. An ankle loading rate of 2.64 ± 0.83 BW/s was observed in the control group, which was significantly higher than 1.75 ± 0.43 BW/s (P = .049) and 1.22 ± 0.59 BW/s (P < .001) in respectively the PwH__NoCartDam group and PwH__CartDam group. Patients with severe blood-induced cartilage damage demonstrated a (mal)adaptive gait strategy as they experience difficulties to properly unload the ankle cartilage during walking.

Are Anterior Cruciate Ligament-reconstructed Athletes More Vulnerable to Fatigue than Uninjured Athletes?

INTRODUCTION

Fatigue has a negative impact on lower extremity neuromuscular and biomechanical control. Because anterior cruciate ligament reconstruction (ACLR) athletes show already neuromuscular/biomechanical deficits in an unfatigued state, the negative impact of fatigue may magnify these deficits or help expose other deficits. So far, this has only scarcely been assessed warranting further research.

METHODS

Twenty-one athletes who had an ACLR and 21 uninjured controls performed five unilateral landing tasks before and after a match simulation protocol, whereas muscle activation (vastus medialis, vastus lateralis, hamstrings medialis, hamstrings lateralis, gastrocnemius medialis, gastrocnemius lateralis, gluteus medius) and landing kinematics and kinetics of the hip, knee, and ankle joint were recorded. A two-way ANOVA with a mixed-model design (main effects for group and fatigue) was used to compare landing kinematics, kinetics, and muscle activation between groups, and prefatigue and postfatigue. To avoid unjustified reduction of the data to discrete values, we used one-dimensional Statistical Parametric Mapping.

RESULTS

Only two interaction effects were found: an increased postfatigue knee abduction moment and an increased postfatigue thorax flexion angle was found in the ACL injured legs but not in the uninjured legs of the ACL group or in the control group, during the lateral hop and the vertical hop with 90° medial rotation, respectively.

CONCLUSIONS

This study showed that overall ACLR athletes and uninjured athletes have similar biomechanical and neuromuscular responses to fatigue. For two biomechanical parameters, however, we did find an interaction effect, suggesting that landing deficits in ACLR athletes may become clearer in certain tasks when fatigued.

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.

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.

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.

High Levels of Kinesiophobia at Discharge from the Hospital May Negatively Affect the Short-Term Functional Outcome of Patients Who Have Undergone Knee Replacement Surgery

Background: Kinesiophobia is a psycho-cognitive factor that hampers recovery after orthopedic surgery. No evidence exists on the influence of kinesiophobia on the short-term recovery of function in patients with knee replacement (KR). Therefore, the aim of the present study is to investigate the impact of kinesiophobia on short-term patient-reported outcomes (PROMs) and performance-based measures (PBMs). Methods: Forty-three KR patients filled in the Tampa scale for kinesiophobia (TSK) at time of discharge. Patients with TSK ≥ 37 were allocated to the kinesiophobia group (n = 24), others to the no-kinesiophobia group (n = 19). Patients were asked to complete PROMs and to execute PBMs at discharge and at 6-weeks follow-up. An independent samples t-test was used to compare group differences for PROMs and PBMs at both measurement sessions. Multiple linear regression analysis models were used to model PBM outcomes from age, pain and TSK scores. Results: Significant differences were observed between groups for PROMs and PBMs. Kinesiophobia significantly contributed to the reduced functional outcomes. Conclusion: At discharge from the hospital, 55.8% of KR patients demonstrated high levels of kinesiophobia (TSK ≥ 37). This may negatively influence short-term recovery of these patients, by putting them at higher risk for falling and reduced functionality.

Single-Joint and Whole-Body Movement Changes in Anterior Cruciate Ligament Athletes Returning to Sport

INTRODUCTION

Athletes returning to sport after anterior cruciate ligament reconstruction (ACLR) demonstrate prolonged changes in landing kinematics, kinetics, and muscle activation, predisposing them for reinjury, knee osteoarthritis, and/or knee instability. So far, researchers have been focusing on how kinematics and kinetics change in every joint separately. However, as the human body operates within a kinetic chain, we will assess whether single-joint changes are associated with whole-body changes.

METHODS

Twenty-one athletes who had an ACLR and 21 uninjured controls performed five unilateral landing tasks, whereas lower limb kinematics, kinetics, and muscle activations of vastus medialis, vastus lateralis, biceps femoris, semitendinosus, semimembranosus, gastrocnemius, and gluteus medius were recorded. Single-joint landing kinematics, kinetics, and muscle activations of the ACL-injured leg were compared with the uninjured leg and compared with the control group. Whole-body changes were assessed by decomposing movements into fundamental components using marker-based principal component analysis (PCA).

RESULTS

We found several single-joint changes in landing kinematics, kinetics, and muscle activations in the athletes with ACLR that were seen across all tasks and therefore of major interest as they are likely to occur during sports as well. Hamstrings activation increased and external knee flexion moments decreased in the ACL-injured leg compared with their uninjured leg. Furthermore, hip adduction moments and knee abduction angles decreased compared with the control group. The PCA could detect changes in whole-body movement, which were task-specific.

CONCLUSIONS

Athletes with ACLR still show protective task-independent single-joint kinematic, kinetic, and muscle activation changes during single-leg landings at the time of return to sport. These single-joint changes were not consistently accompanied by changes in whole-body movements (revealed by marker-based PCA). Whole-body expressions of the single-joint compensations are likely to be affected by the demands of the task.

Match Play-induced Changes in Landing Biomechanics with Special Focus on Fatigability

INTRODUCTION

Growing evidence exists that match-related fatigue induces biomechanical alterations that might increase lower extremity injury risk. Fatigue studies often use match simulation protocols that expose all subjects to a standardized demand (e.g., a fixed distance/time). In those studies, the induced level of fatigue depends then on subjects' fatigability. If between-subject variability in fatigability is high, this might confound overall fatigue effects. Therefore, the first aim was to investigate whether a fatigue protocol with fixed demand causes alterations in landing patterns. Second, we assessed the relationship between fatigability and landing patterns as we hypothesized that athletes with high fatigability would show movement patterns that involve greater injury risk.

METHODS

Eighteen athletes performed three different unilateral landing tasks before and after a match simulation protocol while muscle activation (vastus medialis, vastus lateralis, hamstrings medialis, hamstrings lateralis, gastrocnemius medialis, gastrocnemius lateralis, and gluteus medius) and landing kinematics and kinetics of the hip, knee, and ankle joint were recorded. Furthermore, RPE was administered to measure fatigability. ANOVA analyses were conducted to investigate fatigue effects on landing patterns. Correlation analyses assessed the relationship between fatigability (postfatigue RPE) and landing patterns.

RESULTS

The ANOVA analyses did not show any overall postfatigue alterations in landing patterns. However, correlation analyses showed an association between fatigability and landing patterns. Athletes who had higher RPE scores showed smaller postfatigue knee flexion angles and smaller pre- and postfatigue knee abduction angles across different landing tasks.

CONCLUSION

The fixed demand protocol did not cause overall alterations in landing patterns. When fatigability was taken into account, high fatigability was related with less optimal landing patterns.

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.

Correction to: Clinical Applicability of an Existing Proportionality Scheme in Three-Segment Kinetic Foot Models

This article was updated to correct Giovanni A. Matricali's name.

Lower extremity gait kinematics outcomes after knee replacement demonstrate arthroplasty-specific differences between unicondylar and total knee arthroplasty: A pilot study

BACKGROUND

The aim of the present study is to compare sagittal gait kinematics of ankle, knee and hip joints between subjects with unicondylar and total knee arthroplasty and age matched healthy controls. Since unicondylar knee replacement is a less invasive procedure, which more closely preserves knee joint anatomy, we hypothesized that one year post unicondylar knee arthroplasty patients would demonstrate more normal gait patterns than patients with total knee arthroplasty.

RESEARCH QUESTION

Do unicondylar and total knee arthroplasty patients display similar gait kinematics one year after surgery?

METHODS

Fourteen subjects (8 posterior stabilized and 6 medial unicondylar knee replacements) that were one year post surgery, and 6 healthy control subjects underwent a 3D gait analysis and a physical examination (range of motion, muscle strength). Statistical parametric mapping was used to compare gait kinematics of the lower limbs between groups. Additionally, differences in peak angles and clinical outcomes were assessed using a one-way ANOVA between subjects analysis.

RESULTS

Both knee replacement groups showed reduced knee flexion range of motion and reduced muscle strength at the operated leg compared to the control group. Subjects with TKA demonstrated reduced knee flexion at loading response and midstance of the gait cycle. Both UKA and TKA demonstrated significantly less knee flexion during swing.

SIGNIFICANCE

The results of this study demonstrate arthroplasty-specific differences in muscle strength, range of motion and gait kinematics of the lower limb one year after knee surgery. Future planning of post-surgery follow-up should addresses these arthroplasty-specific weaknesses and gait deviations.

Quantifying clinical misinterpretations associated to one-segment kinetic foot modelling in both a healthy and patient population

BACKGROUND

Rigid foot modelling approaches are still widely used to assess ankle joint kinetics in clinical biomechanical research. Yet, studies on healthy subjects using multi-segment kinetic foot models indicated that one-segment kinetic foot models tend to overestimate ankle joint kinetic data. Our aim was to compare ankle joint kinetics computed with a one-segment versus a multi-segment kinetic foot model in both asymptomatic and pathological gait. We also assessed whether differences between models can lead to different interpretations in clinical decision-making.

METHODS

A two-factor repeated measure analysis of variance was performed to investigate differences in ankle joint kinetics, with the first factor being group effect (control vs. patients) and second factor being foot model effect (one-segment vs. multi-segment). Minimal detectable change was calculated to assess the clinical relevance of the observed differences in ankle joint kinetics.

FINDINGS

Ankle joint peak kinematic, angular velocity and kinetic variables were all significantly overestimated (P < 0.05) when computed with the one-segment kinetic foot model. Kinetic differences in peak plantarflexion angular velocity and peak power generation were higher than their MDC-values.

INTERPRETATION

Ankle joint kinetics are significantly overestimated when computed with a rigid foot modelling approach in both asymptomatic and pathological gait. This overestimation leads to clinical misinterpretations as MDC-values were less than the observed overestimation. In future studies, it is of clinical relevance to assess ankle joint kinetics with a multi-segment foot modelling approach.

Hip and knee kinematics of the forward lunge one year after unicondylar and total knee arthroplasty

Patients with unicondylar knee arthroplasty (UKA) report higher functionality compared to those with total knee arthroplasty (TKA). However, these patients should also be assessed during more demanding tasks in order to appreciate their true functionality. The forward lunge (FL) is a motor task commonly used in clinics to evaluate functional recovery after knee replacement surgery. Unfortunately, clear evidence comparing FL kinematics between patients with UKA and TKA is still missing. The purpose of this study was to compare hip and knee joint kinematics during the FL between patients with UKA, TKA and controls. Twenty subjects (8 TKA, 6 UKA, 6 controls) underwent 3D motion analysis during a FL. Differences in hip and knee kinematics between groups were identified using statistical parametric mapping. We concluded that patients with TKA demonstrated reduced knee and hip flexion angles during the loaded phase of the FL, which could have been an attempt to unload the knee joint. This is in contrast to patients with UKA, who showed similar knee and hip joint kinematics compared to controls throughout the entire FL. It seems that retaining the cruciate ligaments is beneficial for the execution of a complex motor task such as the FL.

The impact of walking speed on the kinetic behaviour of different foot joints

BACKGROUND

The foot and ankle complex consists of multiple joints which have been hypothesized to fulfill a significant role in the lower limb kinetic chain during human locomotion. Walking speed is known to affect the lower limb kinetic chain function. Yet, this effect still has to be investigated throughout multiple joints of the foot and ankle complex.

RESEARCH QUESTION

What is the effect of walking speed on the kinetic behaviour of multiple joints of the foot and ankle complex?

METHODS

This observational cross-sectional study investigated 15 asymptomatic male subjects. A three-and four-segment kinetic foot model was used to calculate power output and mechanical work during normal and high walking speed. One-dimensional Statistical Parametric Mapping (1D-SPM) linear regression was performed to examine the relationship between walking speed and kinetic data. Effect size calculations (Cohen's D) were included to quantify the amount of effect that walking speed has on power output and mechanical work in multiple foot joints.

RESULTS

Three-segment kinetic measurements showed a significant positive correlation between walking speed and power output in the ankle (p = 0.003) and first metatarsophalangeal joint (p = 0.0007). Peak power generation increased in the ankle (d = 1.59), chopart (d = 1.51) and first metatarsophalangeal (d = 1.25) joints during high-speed walking. The three joints combined produced net +0.097 J/kg in normal and +0.201 J/kg in high-speed walking. Four-segment kinetic measurements showed a significant positive correlation between walking speed and power output at the ankle (p = 0.036), chopart (p = 0.0001), lisfranc (p < 0.0001) and first metatarsophalangeal (p = 0.0063) joints. Peak power generation increased in the ankle (d = 1.32), chopart (d = 1.27), lisfranc (d = 1.22) and first metatarsophalangeal (d = 1.47) joints during high-speed walking. Four joints combined produced net +0.162 J/kg in normal and +0.261 J/kg in high-speed walking.

SIGNIFICANCE

These results add additional insight into foot function during increased walking speed.

Foot and ankle kinematics in chronic ankle instability subjects using a midfoot strike pattern when running, including influence of taping

BACKGROUND

Investigate differences in multi-segment foot kinematics between controls and participants with chronic ankle instability during running with a midfoot striking pattern and to evaluate the effect of Low-Dye and High-Dye taping.

METHODS

Three-dimensional multi-segment foot kinematics of 12 controls and 15 participants with chronic ankle instability were collected while running barefoot, and in both taping conditions. Ranges of motion occurring at each joint, each sub phase of stance, were compared between groups and between taping conditions (0-dimensional inference). Kinematic data were also compared using one-dimensional statistical parametric mapping.

FINDINGS

The symptomatic group demonstrated while barefoot running a significantly decreased rearfoot dorsiflexion range of motion during the peak impact phase as well as a less dorsiflexed position from 6 to 12% of the running cycle. During the absorption and generation phase, the symptomatic group also showed a significantly increased rearfoot dorsiflexion and adduction motion as well as an increased midfoot inversion motion. In the peak impact phase of both taping conditions, a decreased midfoot inversion motion was found. The High-Dye taping resulted in a decreased rearfoot plantarflexion motion whereas the Low-Dye caused a decreased midfoot inversion motion.

INTERPRETATION

Persons with chronic ankle instability seem to have altered rearfoot and midfoot kinematics while running with a midfoot striking index. High-Dye taping seems to have better therapeutic features than Low-Dye taping.

A novel approach for the detection and exploration of joint coupling patterns in the lower limb kinetic chain

BACKGROUND

A comprehensive perspective on foot and lower limb joint coupling is lacking since previous studies did not consider the multi-articular nature of the foot and lower limb neither accounted for biomechanical heterogeneity.

RESEARCH QUESTION

The current manuscript describes a novel methodological process for detection and exploration of joint coupling patterns in the lower limb kinetic chain.

METHODS

The first stage of the methodological process encompasses the measurement of 3D joint kinematics of the foot and lower limb kinetic chain during dynamic activities. The second stage consists of selecting the kinematic waveforms of interest. In the third stage, cross-correlation coefficients are calculated across the selected one-dimensional continua of each subject. In the fourth stage, all cross-correlation coefficients per subject are used as input variable in a cluster algorithm. Algorithm specific qualitative metrics are subsequently considered to determine the most robust clustering. Finally, in the fifth stage the process of biomechanical interpretation is initiated and further exploration is recommended by triangulating with other biomechanical variables.

RESULTS

A first clinical illustration of the novel method was provided using data of fourteen young elite athletes. Cross-correlation coefficients for each leg were calculated across continua of the pelvis, hip, knee, rear foot and midfoot. A hierarchical clustering approach stratified the coefficients into two distinct clusters which was mainly guided by the frontal plane knee kinematics. Both clustered differed significantly from each other with respect to their frontal plane ankle, knee and hip kinetics.

SIGNIFICANCE

The presented method seems to provide a valuable approach to gain insight into foot and lower joint coupling.

A novel magnet based 3D printed marker wand as basis for repeated in-shoe multi segment foot analysis: a proof of concept

Background

Application of in-shoe multi-segment foot kinematic analyses currently faces a number of challenges, including: (i) the difficulty to apply regular markers onto the skin, (ii) the necessity for an adequate shoe which fits various foot morphologies and (iii) the need for adequate repeatability throughout a repeated measure condition. The aim of this study therefore was to design novel magnet based 3D printed markers for repeated in-shoe measurements while using accordingly adapted modified shoes for a specific multi-segment foot model.

Methods

Multi-segment foot kinematics of ten participants were recorded and kinematics of hindfoot, midfoot and forefoot were calculated. Dynamic trials were conducted to check for intra and inter-session repeatability when combining novel markers and modified shoes in a repeated measures design. Intraclass correlation coefficients were calculated to determine reliability.

Results

Both repeatability and reliability were proven to be good to excellent with maximum joint angle deviations of 1.11° for intra-session variability and 1.29° for same-day inter-session variability respectively and ICC values of >0.91.

Conclusion

The novel markers can be reliably used in future research settings using in-shoe multi-segment foot kinematic analyses with multiple shod conditions.

Foot segmental motion and coupling in stage II and III tibialis posterior tendon dysfunction

BACKGROUND

Classification systems developed in the field of posterior tibialis tendon dysfunction omit to include dynamic measurements. Since this may negatively affect the selection of the most appropriate treatment modality, studies on foot kinematics are highly recommended. Previous research characterised the foot kinematics in patients with posterior tibialis tendon dysfunction. However, none of the studies analysed foot segmental motion synchrony during stance phase, nor compared the kinematic behaviour of the foot in presence of different posterior tibialis tendon dysfunction stages. Therefore, we aimed at comparing foot segmental motion and coupling in patients with posterior tibialis tendon dysfunction grade 2 and 3 to those of asymptomatic subjects.

METHODS

Foot segmental motion of 11 patients suffering from posterior tibialis tendon dysfunction stage 2, 4 patients with posterior tibialis tendon dysfunction stage 3 and 15 asymptomatic subjects was objectively quantified with the Rizzoli foot model using an instrumented walkway and a 3D passive motion capture system. Dependent variables were the range of motion occurring at the different inter-segment angles during subphases of stance and swing phase as well as the cross-correlation coefficient between a number of segments.

RESULTS

Significant differences in range of motion were predominantly found during the forefoot push off phase and swing phase. In general, both patient cohorts demonstrated a reduced range of motion compared to the control group. This hypomobility occurred predominantly in the rearfoot and midfoot (p<0.01). Significant differences between both posterior tibialis tendon dysfunction patient cohorts were not revealed. Cross-correlation coefficients highlighted a loss of joint coupling between rearfoot and tibia as well as between rearfoot and forefoot in both posterior tibialis tendon dysfunction groups.

INTERPRETATION

The current evidence reveals considerable mechanical alterations in the foot which should be considered in the decision making process since it may help explaining the success and failure of certain conservative and surgical interventions.

Foot segmental mobility during subphases of running: Comparative study between two striking patterns

OBJECTIVES

The literature lacks comparative data regarding foot segmental mobility in rearfoot (RFS) and midfoot striking (MFS) patterns. The aim of the study is to quantify the foot segmental mobility during distinct subphases of stance in presence of both striking patterns.

METHODS

Twelve participants were instructed to run barefoot at a constant speed of 3.3m/s on a 10-m walkway, while adopting a RFS and a MFS pattern. Multi-segment foot mobility during the impact phase, the absorption phase and the generation phase was subsequently calculated and compared between both conditions.

RESULTS

In the impact phase of the MFS trials, a higher sagittal plane range of motion was observed between shank and calcaneus (RFS=6.2°, MFS=14.5°, p<0.0001), between calcaneus and midfoot (RFS=1.9°, MFS=5.6°, p=0.002) as well as between the calcaneus and metatarsus (RFS=2.4°, MFS=4.9°, p=0.0015). In the absorption phase of the MFS trials, a higher frontal plane range of motion (RFS=1.3°, MFS=2.1°, p=0.004) and a lower sagittal plane range of motion (RFS=6.5°, MFS=4.3°, p=0.004) was observed between the calcaneus and metatarsus.

CONCLUSION

This study revealed that approximately 50% of the rearfoot range of motion has been observed in the midfoot when running with both striking patterns, although the highest ROM was observed in the rearfoot. This finding highlights that the rebounding effect of the human body results not only from absorption and generation within major joints of the lower limb but also from smaller joints in the foot.

3D Multi-segment foot kinematics in children: A developmental study in typically developing boys

BACKGROUND

The relationship between age and 3D rotations objectivized with multisegment foot models has not been quantified until now. The purpose of this study was therefore to investigate the relationship between age and multi-segment foot kinematics in a cross-sectional database.

METHODS

Barefoot multi-segment foot kinematics of thirty two typically developing boys, aged 6-20 years, were captured with the Rizzoli Multi-segment Foot Model. One-dimensional statistical parametric mapping linear regression was used to examine the relationship between age and 3D inter-segment rotations of the dominant leg during the full gait cycle.

RESULTS

Age was significantly correlated with sagittal plane kinematics of the midfoot and the calcaneus-metatarsus inter-segment angle (p<0.0125). Age was also correlated with the transverse plane kinematics of the calcaneus-metatarsus angle (p<0.0001).

CONCLUSION

Gait labs should consider age related differences and variability if optimal decision making is pursued. It remains unclear if this is of interest for all foot models, however, the current study highlights that this is of particular relevance for foot models which incorporate a separate midfoot segment.

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.

A novel device for standardizing marker placement at the calcaneus

BACKGROUND

The determination of anatomical reference frames in the rearfoot during three-dimensional multisegment foot modeling has been hindered by a variety of factors. One of these factors is related to the difficulty in palpating, or the absence of, anatomical landmarks. A novel device (the Calcaneal Marker Device) aimed at standardizing marker placement at the calcaneus was, therefore, developed and evaluated for its reliability.

METHODS

Throughout a random repeated-measures design, the repeatability of calcaneal marker placement was evaluated for two techniques: manual placement and placement using the Calcaneal Marker Device. Translational changes after marker placement and the clinical effect on intersegment angle calculation were quantified.

RESULTS

Intraobserver variability was greater in therapist 2 (<5.3 mm) compared with therapist 1 (<2.9 mm). Intraobserver variability was also found to be less than 1.6 mm throughout use of the device. Interobserver variability was found to be significantly higher for the position of markers placed manually (5.8 mm), whereas with the Calcaneal Marker Device, the variability remained lower (<1.3 mm). The effect on the computed intersegment angles followed a similar trend, with variability of 0.4° to 4.0° and 1.0° to 8.7° for CMD and manual placement, respectively.

CONCLUSIONS

These findings suggest that variations in marker placement are considerably reduced when the novel Calcaneal Marker Device is used, possibly toward the limits dictated by the fine motor skills of therapists and tissue artifacts.

Efficacy measures associated to a plantar pressure based classification system in diabetic foot medicine

AIMS

The concept of 'classification' has, similar to many other diseases, been found to be fundamental in the field of diabetic medicine. In the current study, we aimed at determining efficacy measures of a recently published plantar pressure based classification system.

METHODS

Technical efficacy of the classification system was investigated by applying a high resolution, pixel-level analysis on the normalized plantar pressure pedobarographic fields of the original experimental dataset consisting of 97 patients with diabetes and 33 persons without diabetes. Clinical efficacy was assessed by considering the occurence of foot ulcers at the plantar aspect of the forefoot in this dataset. Classification efficacy was assessed by determining the classification recognition rate as well as its sensitivity and specificity using cross-validation subsets of the experimental dataset together with a novel cohort of 12 patients with diabetes.

RESULTS

Pixel-level comparison of the four groups associated to the classification system highlighted distinct regional differences. Retrospective analysis showed the occurence of eleven foot ulcers in the experimental dataset since their gait analysis. Eight out of the eleven ulcers developed in a region of the foot which had the highest forces. Overall classification recognition rate exceeded 90% for all cross-validation subsets. Sensitivity and specificity of the four groups associated to the classification system exceeded respectively the 0.7 and 0.8 level in all cross-validation subsets.

CONCLUSIONS

The results of the current study support the use of the novel plantar pressure based classification system in diabetic foot medicine. It may particularly serve in communication, diagnosis and clinical decision making.

Mapping current research trends on anterior cruciate ligament injury risk against the existing evidence: In vivo biomechanical risk factors

BACKGROUND

Whilst many studies measure large numbers of biomechanical parameters and associate these to anterior cruciate ligament injury risk, they cannot be considered as anterior cruciate ligament injury risk factors without evidence from prospective studies. A review was conducted to systematically assess the in vivo biomechanical literature to identify biomechanical risk factors for non-contact anterior cruciate ligament injury during dynamic sports tasks; and to critically evaluate the research trends from retrospective and associative studies investigating non-contact anterior cruciate ligament injury risk.

METHODS

An electronic literature search was undertaken on studies examining in vivo biomechanical risk factors associated with non-contact anterior cruciate ligament injury. The relevant studies were assessed by classification; level 1 - a prospective cohort study, level 2 - a retrospective study or level 3 - an associative study.

FINDINGS

An initial search revealed 812 studies but this was reduced to 1 level 1 evidence study, 20 level 2 evidence studies and 175 level 3 evidence studies that met all inclusion criteria. Level 1 evidence showed that the knee abduction angle, knee abduction moment and ground reaction force were biomechanical risk factors. Nine level 2 studies and eighty-three level 3 studies used these to assess risk factors in their study. Inconsistencies in results and methods were observed in level 2 and 3 studies.

INTERPRETATION

There is a lack of high quality, prospective level 1 evidence related to biomechanical risk factors for non-contact anterior cruciate ligament injury. More prospective cohort studies are required to determine risk factors and provide improved prognostic capability.

A Novel Method of Quantifying Gait Deviations Using Plantar Pressure Patterns

BACKGROUND

Comparing the dynamic pedobarographic patterns of individuals is common practice in basic and applied research. However, this process is often time-consuming and complex, and commercially available software often lacks powerful visualization and interpretation tools.

METHODS

We propose a simple method for displaying pixel-level pedobarographic deviations over time relative to a so-called reference pedobarographic pattern. This novel method contains four distinct automated preprocessing stages: 1) normalization of pedobarographic fields (for foot length and width), 2) temporal normalization, 3) a pixel-level z-score-based calculation, and 4) color coding of the normalized pedobarographic fields. Group and patient-level comparisons were illustrated using an experimental data set including diabetic and nondiabetic patients.

RESULTS

The automated procedure was found to be robust and quantified distinct temporal deviations in pedobarographic fields.

CONCLUSIONS

The advantages of the novel method cover several domains, including visualization, interpretation, and education.

Mapping current research trends on neuromuscular risk factors of non-contact ACL injury

The aim of this systematic review was (i) to identify neuromuscular markers that have been predictive of a primary non-contact ACL injury, (ii) to assess whether proposed risk factors have been supported or refuted in the literature from cohort and case-control studies, and (iii) to reflect on the body of research that aims at developing field based tools to assess risk through an association with these risk factors. Electronic searches were undertaken, of PubMed, SCOPUS, Web of Science, CINAHL and SPORTDiscus examining neuromuscular risk factors associated with ACL injury published between January 1990 and July 2015. The evidence supporting neuromuscular risk factors of ACL injury is limited where only 4 prospective cohort studies were found. Three of which looked into muscular capacity and one looked into muscular activation patterns but none of the studies found strong evidence of how muscular capacity or muscular activation deficits are a risk factor for a primary non-contact ACL injury. A number of factors associated to neural control and muscular capacity have been suggested to be related to non-contact ACL injury risk but the level of evidence supporting these risk factors remains often elusive, leaving researchers and practitioners uncertain when developing evidence-based injury prevention programs.

Knee and Hip Joint Kinematics Predict Quadriceps and Hamstrings Neuromuscular Activation Patterns in Drop Jump Landings

Purpose

The purpose was to assess if variation in sagittal plane landing kinematics is associated with variation in neuromuscular activation patterns of the quadriceps-hamstrings muscle groups during drop vertical jumps (DVJ).

Methods

Fifty female athletes performed three DVJ. The relationship between peak knee and hip flexion angles and the amplitude of four EMG vectors was investigated with trajectory-level canonical correlation analyses over the entire time period of the landing phase. EMG vectors consisted of the {vastus medialis(VM),vastus lateralis(VL)}, {vastus medialis(VM),hamstring medialis(HM)}, {hamstring medialis(HM),hamstring lateralis(HL)} and the {vastus lateralis(VL),hamstring lateralis(HL)}. To estimate the contribution of each individual muscle, linear regressions were also conducted using one-dimensional statistical parametric mapping.

Results

The peak knee flexion angle was significantly positively associated with the amplitudes of the {VM,HM} and {HM,HL} during the preparatory and initial contact phase and with the {VL,HL} vector during the peak loading phase (p<0.05). Small peak knee flexion angles were significantly associated with higher HM amplitudes during the preparatory and initial contact phase (p<0.001). The amplitudes of the {VM,VL} and {VL,HL} were significantly positively associated with the peak hip flexion angle during the peak loading phase (p<0.05). Small peak hip flexion angles were significantly associated with higher VL amplitudes during the peak loading phase (p = 0.001). Higher external knee abduction and flexion moments were found in participants landing with less flexed knee and hip joints (p<0.001).

Conclusion

This study demonstrated clear associations between neuromuscular activation patterns and landing kinematics in the sagittal plane during specific parts of the landing. These findings have indicated that an erect landing pattern, characterized by less hip and knee flexion, was significantly associated with an increased medial and posterior neuromuscular activation (dominant hamstrings medialis activity) during the preparatory and initial contact phase and an increased lateral neuromuscular activation (dominant vastus lateralis activity) during the peak loading phase.

Intra-Individual Variability of Surface Electromyography in Front Crawl Swimming

The variability of electromyographic (EMG) recordings between and within participants is a complex problem, rarely studied in swimming. The importance of signal normalization has long been recognized, but the method used might influence variability. The aims of this study were to: (i) assess the intra-individual variability of the EMG signal in highly skilled front crawl swimmers, (ii) determine the influence of two methods of both amplitude and time normalization of the EMG signal on intra-individual variability and of time normalization on muscle activity level and (iii) describe the muscle activity, normalized using MVIC, in relation to upper limb crawl stroke movements. Muscle activity of rectus abdominis and deltoideus medialis was recorded using wireless surface EMG in 15 adult male competitive swimmers during three trials of 12.5 m front crawl at maximal speed without breathing. Two full upper limb cycles were analyzed from each of the swimming trials, resulting in six full cycles used for the intra-individual variability assessment, quantified with the coefficient of variation (CV), coefficient of quartile variation (CQV) and the variance ratio (VR). The results of this study support previous findings on EMG patterns of deltoideus medialis and rectus abdominis as prime mover during the recovery (45% activity relative to MVIC), and stabilizer of the trunk during the pull (14.5% activity) respectively. The intra-individual variability was lower (VR of 0.34–0.47) when compared to other cyclic movements. No meaningful differences were found between variability measures CV or VR when applying either of the amplitude or the time normalization methods. In addition to reporting the mean amplitude and standard deviation, future EMG studies in swimming should also report the intra-individual variability, preferably using VR as it is independent of peak amplitude, provides a good measure of repeatability and is insensitive to mean EMG amplitude and the degree of smoothing applied.

Dynamic Neuromuscular Control of the Lower Limbs in Response to Unexpected Single-Planar versus Multi-Planar Support Perturbations in Young, Active Adults

PURPOSE

An anterior cruciate ligament (ACL) injury involves a multi-planar injury mechanism. Nevertheless, unexpected multi-planar perturbations have not been used to screen athletes in the context of ACL injury prevention yet could reveal those more at risk. The objective of this study was to compare neuromuscular responses to multi-planar (MPP) and single-planar perturbations (SPP) during a stepping-down task. These results might serve as a basis for future implementation of external perturbations in ACL injury screening programs.

METHODS

Thirteen young adults performed a single leg stepping-down task in eight conditions (four MPP and four SPP with a specified amplitude and velocity). The amplitudes of vastus lateralis (VL), vastus medialis (VM), hamstrings lateralis (HL), hamstrings medialis (HM) EMG activity, medio-lateral and anterior-posterior centre of mass (COM) displacements, the peak knee flexion and abduction angles were compared between conditions using an one-way ANOVA. Number of stepping responses were monitored during all conditions.

RESULTS

Significantly greater muscle activity levels were found in response to the more challenging MPP and SPP compared to the less challenging conditions (p < 0.05). No differences in neuromuscular activity were found between the MPP conditions and their equivalents in the SPP. Eighteen stepping responses were monitored in the SPP versus nine in the MPP indicating that the overall neuromuscular control was even more challenged during the SPP which was supported by greater COM displacements in the SPP.

CONCLUSION

The more intense MPP and SPP evoked different neuromuscular responses resulting in greater muscle activity levels compared to small perturbations. Based on the results of COM displacements and based on the amount of stepping responses, dynamic neuromuscular control of the knee joint appeared less challenged during the MPP. Therefore, future work should investigate extensively if other neuromuscular differences (i.e. co-activation patterns and kinetics) exist between MPP and SPP. In addition, future work should examine the influence on the neuromuscular control of the magnitude of the perturbations and the magnitude of stepping height and stepping distance.