How reliable are lower limb biomechanical evaluations during volleyball-specific jump-landing tasks?

BACKGROUND: Biomechanical evaluations of sport-specific jump-landing tasks may provide a more ecologically valid interpretation compared to generic jump-landing tasks. For accurate interpretation of longitudinal research, it is essential to understand the reliability of biomechanical parameters of sport-specific jump-landing tasks. RESEARCH QUESTION: How reliable are hip, knee and ankle joint angles and moment curves during two volleyball-specific jump-landing tasks and is this comparable with the reliability of a generic jump-landing task? METHODS: Three-dimensional (3D) biomechanical analyses of 27 male volleyball players were performed in two sessions separated by one week. Test-retest reliability was analyzed by calculating integrated as well as 1D intraclass correlation coefficient (ICC) and integrated standard error of measurement (SEM) for hip, knee and ankle angles and moments during a spike and block jump (volleyball-specific tasks), and during a drop vertical jump (generic task). RESULTS: Reliability of joint angles of volleyball-specific and generic jump-landing tasks are similar with excellent-to-good integrated ICC for hip, knee and ankle flexion/extension (ICC= 0.61-0.89) and hip and knee abduction/adduction (ICC=0.61-0.78) but fair-to-poor ICC for ankle abduction/adduction (ICC=0.28-0.52) and hip, knee and ankle internal/external rotation (ICC=0.29-0.53). Reliability of hip, knee and ankle joint moments was good-to excellent (ICC= 0.62-0.86) except for hip flexion moment during spike jump and drop vertical jump (ICC=0.43-0.47) and knee flexion moment during both volleyball-specific tasks (ICC=0.56-0.57). For all tasks, curve analysis revealed poorer reliability at start and end of the landing phase than during the midpart. SIGNIFICANCE: Our data suggests that kinematic evaluations of volleyball-specific jump-landing tasks are reliable to use in screening programs, especially in the sagittal plane. Notably, reliability is poorer at the beginning and end of the landing phase, requiring careful interpretation. In conclusion, the results of this study indicate the potential for integration of sport-specific jump-landing tasks in screening programs, which will be more ecologically valid.

The effect of fatigue on spike jump biomechanics in view of patellar tendon loading in volleyball.

BACKGROUND AND OBJECTIVE: Patellar tendinopathy (PT) is a highly prevalent overuse injury in volleyball and is often linked with overloading of the patellar tendon. Little is known, however, about whether and how patellar tendon loading is affected by fatigue during the most challenging jump activity in volleyball. Therefore, this study investigates the effect of a high-intensity, intermittent fatigue protocol on movement alterations in terms of patellar tendon loading during a volleyball spike jump. METHODS: Forty-three male volleyball players participated in this study. Three-dimensional full-body kinematics and kinetics were collected when performing a spike jump before and after the fatigue protocol. Sagittal plane joint angles, joint work and patellar tendon loading were calculated and analyzed with curve analyses using paired sample t-tests to investigate fatigue effects (p < 0.05). RESULTS: Fatigue induced a stiffer lower extremity landing strategy together with prolonged pelvis-trunk flexion compared to baseline (p = 0.001-0.005). Decreased patellar tendon forces (p = 0.001-0.010) and less eccentric knee joint work (-5%, p < 0.001) were observed after the fatigue protocol compared to baseline. CONCLUSION: Protective strategies seem to be utilized in a fatigued state to avoid additional tensile forces acting on the patellar tendon, including proximal compensations and stiff lower extremity landings. We hypothesize that players might be more prone for developing PT if eccentric patellar tendon loads are high in the non-fatigued state and/or these loads are somehow not decreased after fatigue.

The Effect of Fatigue on Trunk and Pelvic Jump-Landing Biomechanics in View of Lower Extremity Loading: A Systematic Review.

Fatigue has often been considered a risk factor for developing sports injuries, modulating lower extremity jump-landing biomechanics. The impact of fatigue on proximal trunk and pelvic biomechanics has been suggested to play an important role in lower extremity loading and injury risk, yet the available evidence remains ambiguous as the trunk and pelvis were often not the primary focus of research. Therefore, the purpose of this systematic review was to determine how fatigue affects trunk and pelvic three-dimensional jump-landing biomechanics. PubMed (MEDLINE), Web of Science, Embase, CINAHL and SPORTDiscus were consulted up to and including April 2022 for potential studies investigating the effect of fatigue on trunk and pelvic kinematics, kinetics and/or muscular activity during jump-landing tasks in healthy, physically active populations. Methodological quality of the studies was assessed by the modified Downs and Black checklist. Twenty-one studies were included and methodological quality was moderate to high among these studies. The results indicate prevailing evidence for more trunk flexion during standardized jump-landing tasks after lower extremity muscle fatigue. Otherwise, lumbo-pelvic-hip muscle fatigue does not seem to elicit major detrimental changes to these jump-landing biomechanics. Although a wide variability of trunk and pelvic jump-landing strategies was observed, the results provide evidence for increased trunk flexion after lower extremity muscle fatigue. This proximal strategy is suggested to help unload fatigued lower extremity structures and lack of this compensation might increase knee injury risk.

The development of a clinical screening tool to evaluate unilateral landing performance in a healthy population.

OBJECTIVES: To develop a clinical tool to evaluate unilateral landing quality in a healthy population. The reliability of the novel tool was evaluated, and the influence of gender and leg-dominance was investigated. DESIGN: An experimental study for developing a test protocol, scoring criteria, and scoring method, based on observable landing errors, for the novel Unilateral Landing Error Scoring System (ULESS). SETTING: Controlled lab environment. PARTICIPANTS: Healthy participants (25♂ and 25♀) performed the ULESS. MAIN OUTCOME MEASURES: The ULESS was scored with video analysis. Unilateral landing performance, measured with the ULESS, was compared to bilateral landing performance. RESULTS: Sixteen items to assess trunk, pelvic, and lower limb movement patterns during a unilateral landing task resulted in a composite score on an interval scale. Moderate to excellent intra- and inter-tester reliability (ICC(2,1) = 0.77-0.90) was determined. The ULESS was able to identify moderate to poor unilateral landing quality in subjects with good to excellent bilateral landing quality. No main effect of gender (p = 0.19) or leg-dominance (p = 0.65) on ULESS scores was found. CONCLUSION: Moderate to excellent reliability can be expected when using the newly developed protocol and scoring method. The ULESS is feasible to perform with limited materials.

The role of core stability in the development of non-contact acute lower extremity injuries in an athletic population: A prospective study.

OBJECTIVES: Stability of the core is associated with lower extremity functioning. Consequently, impaired core stability might play a role in developing non-contact acute lower extremity sports injuries. The objective was to investigate components of core stability as potential risk factors for acute lower extremity injuries. DESIGN: A cohort study was set up with a follow-up and injury registration period of 1.5 years. PARTICIPANTS: 142 male and female physical education students were included. MAIN OUTCOME MEASURES: Measures of isometric hip and core muscular strength, endurance, proprioception and neuromuscular control of the core, and postural control were taken at the start of the study. Sports-related injury occurrence was registered during follow-up. RESULTS: 27 (19%) injuries of interest occurred during follow-up. After multivariate model building, a significant predictive effect was found for side-to-side hip abduction strength asymmetry (p = .007). The hazard of developing an acute lower extremity injury increased with 6.2% with a 1 unit increase in side-to-side strength imbalance, regardless of gender. CONCLUSION: Hip abduction strength imbalance was determined as a risk factor for the development of non-contact, acute lower extremity injuries. Normalizing hip strength imbalances might be beneficial for injury prevention. However, further research is needed to support this claim.

Relationship Between Jump-Landing Kinematics and Lower Extremity Overuse Injuries in Physically Active Populations: A Systematic Review and Meta-Analysis.

BACKGROUND: Lower extremity overuse injuries are common in athletes participating in sports with repeated bouts of landing manoeuvres. Biomechanical alterations during landing may be associated with these types of injuries. The objective of this systematic review with meta-analysis was to summarise and determine the relationship between kinematic alterations during a landing task and the development of lower extremity overuse injuries in physically active populations. METHODS: PubMed, Embase, Web of Science, CINAHL, and SPORTDiscus were consulted up to and including February 2020. Cohort, cross-sectional or case-control studies were included if they investigated the relationship between three-dimensional (3D) landing kinematics in physically active populations and either new incidence or a history of lower extremity overuse injuries. RESULTS: Twenty-three studies that investigated 3D landing kinematics in subjects with either patellar tendinopathy (PT), patellofemoral pain (PFP), exertional medial tibial pain (EMTP) or groin overuse injury met the inclusion criteria. Based on this systematic review, there is evidence for decreased knee flexion range of motion (ROM) and increased knee abduction ROM during landing as risk factors for PFP. For PT, risk factors are poorly understood. Furthermore, the meta-analysis demonstrated significantly greater hip adduction at initial contact (IC) (p = 0.02), greater knee internal rotation at IC (p < 0.001), greater peak knee external rotation (p = 0.05) and less ankle dorsiflexion at peak vertical ground reaction force (vGRF) (p = 0.05) in subjects with knee overuse injuries compared to healthy controls. There is evidence of increased trunk, hip and knee transversal ROM as risk factors for EMTP. Groin injuries are associated with greater pelvic and hip frontal and transversal plane ROM in the injured group compared to the healthy controls. CONCLUSION: The results of this systematic review and meta-analysis provide preliminary evidence for impaired landing kinematics associated with lower extremity overuse injuries. Excessive frontal and transversal plane movements during landing manoeuvres might increase impact and tensile forces resulting in lower extremity overuse injuries. REGISTRATION: This systematic review was registered in the PROSPERO international prospective register of systematic reviews (ID = CRD42019135602).

Taping Benefits Ankle Joint Landing Kinematics in Subjects With Chronic Ankle Instability.

CONTEXT: Although taping has been proven effective in reducing ankle sprain events in individuals with chronic ankle instability, insight into the precise working mechanism remains limited. OBJECTIVES: To evaluate whether the use of taping changes ankle joint kinematics during a sagittal and frontal plane landing task in subjects with chronic ankle instability. DESIGN: Repeated measure design. SETTING: Laboratory setting. PARTICIPANTS: A total of 28 participants with chronic ankle instability performed a forward and side jump landing task in a nontaped and taped condition. The taping procedure consisted of a double "figure of 6" and a medial heel lock. MAIN OUTCOME MEASURES: 3D ankle joint kinematics was registered. Statistical parametric mapping was used to assess taping effect on mean ankle joint angles and angular velocity over the landing phase. RESULTS: For both the forward and side jump, a less plantar flexed and a less inverted position of the ankle joint were found in the preparatory phase till around touchdown (TD) in the taped condition (P < .05). In addition, for both jump landing protocols, a decreased dorsiflexion angular velocity was found after TD (P < .05). During the side jump protocol, a brief period of increased inversion angular velocity was registered after TD (P < .05). CONCLUSIONS: Taping is capable of altering ankle joint kinematics prior to TD, placing the ankle joint in a less vulnerable position at TD.

Is consumer behaviour towards footwear predisposing for lower extremity injuries in runners and walkers? A prospective study.

BACKGROUND: Runners and walkers often suffer from lower extremity injuries. Little is known about the relationship between their consumer behaviour towards footwear and the development of those injuries. Therefore, the aim of this study was to investigate if consumer behaviour towards footwear is a risk factor for lower extremity injuries. METHODS: A prospective cohort study was set-up in leisure-time walkers and runners. Potential risk factors in consumer behaviour were obtained by means of a baseline questionnaire related to the acquisition of current walking or running shoes. Information on injuries sustained during a 24 week period after the baseline questionnaire was obtained in 104 runners and 104 walkers using a 2-weekly questionnaire. Binary logistic regression analysis was used to identify risk factors for lower extremity injuries in the consumer behaviour. RESULTS: Forty- nine (24%) subjects suffered a self-reported lower extremity injury. 35 injuries occurred in runners and 14 among walkers.Undergoing a gait analysis before buying shoes was associated with an increased occurrence of lower extremity injuries (odds ratio (OR) 4.76). A protective factor was caring a lot about the right fitting of the shoes (OR 0.11). CONCLUSION: Runners and walkers should pay attention to the correct size when buying footwear to diminish the risk of lower extremity injury. Buying footwear after a gait analysis increased the risk of a lower extremity injury in runners and walkers, however, this might be associated with the increased risk that was already present because of previous injury. TRIAL REGISTRATION: This trial was not registered since this was an observational study and no intervention took place.

Impaired Core Stability as a Risk Factor for the Development of Lower Extremity Overuse Injuries: A Prospective Cohort Study.

BACKGROUND: Core stability has been suggested to influence lower extremity functioning and might contribute to the development of lower extremity overuse injuries. However, prospective studies to investigate this relationship are limited. PURPOSE: To research the role of different components of core stability as risk factors for the development of lower extremity overuse injuries. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 142 first-year physical education students participated in this study. They were tested in 2015 and were prospectively followed for 1.5 years by means of a multilevel injury registration method. Three participants were excluded owing to physical complaints during testing. As such, 139 participants were included in the statistical analysis. At baseline, dynamic postural control, isometric core and hip muscle strength, core muscle endurance, core neuromuscular control and proprioception, and functional movement were measured for all participants. Competing risk regression analyses were performed to identify significant contributors to the development of lower extremity overuse injuries. RESULTS: During the follow-up period, 34 (24%) of the 139 participants developed a lower extremity overuse injury. Significant predictive effects for an overuse injury were found for an increased side-by-side difference in dynamic postural control ( P = .038), decreased isometric hip extension:flexion strength ratio ( P = .046), and decreased abdominal core muscle endurance ( P = .032). CONCLUSION: This study identified measures for dynamic postural control, core muscle strength, and core muscle endurance as significant risk factors for the development of overuse injuries after statistical model building. However, core neuromuscular control and proprioception and functional movement might not allow clinicians to identify patients at risk. These accessible, reliable screening tools could be used in clinical practice with regard to screening and injury prevention for overuse injuries. Injury prediction based on this model needs to be done with caution given the low relative predictive accuracy (53%).

Concurrent Validity of a Commercial Wireless Trunk Triaxial Accelerometer System for Gait Analysis.

CONTEXT: Wearable sensor devices have notable advantages, such as cost-effectiveness, easy to use, and real-time feedback. Wirelessness ensures full-body motion, which is required during movement in a challenging environment such as during sports. Research on the reliability and validity of commercially available systems, however, is indispensable. OBJECTIVE: To confirm the test-retest reliability and concurrent validity of a commercially available body-worn sensor-BTS G-WALK® sensor system-for spatiotemporal gait parameters with the GAITRite® walkway system as golden standard. DESIGN: Reliability and concurrent validity study. SETTING: Laboratory setting. PARTICIPANTS: Thirty healthy subjects. MAIN OUTCOME MEASURES: Spatiotemporal parameters: speed, cadence, stride length, stride duration, stance duration, swing duration, double support, and single support. RESULTS: In terms of test-retest reliability of the BTS G-WALK® sensor system, intraclass correlation coefficient values for both the spatial and temporal parameters were excellent between consecutive measurements on the same day with intraclass correlation coefficient values ranging from .85 to .99. In terms of validity, intraclass correlation coefficient values between measurement systems showed excellent levels of agreement for speed, cadence, stride length, and stride duration (range = .88-.97), and showed poor to moderate levels of agreement (range = .12-.47) for single/double support and swing/stance duration. Bland-Altman plots showed overall percentage bias values equal to or smaller than 3% with limits of agreement ≤15% (speed, cadence, stride length, stride duration, swing duration, and stance duration). Only for single and double support, the limits of agreement were higher with, respectively, -15.4% to 19.5% and -48.0% to 51.4%. CONCLUSION: The BTS G-WALK® sensor system is reliable for all measured spatiotemporal parameters. In terms of validity, excellent concurrent validity was shown for speed, cadence, stride length, and stride duration. Cautious interpretation is necessary for temporal parameters based on final foot contact (stance, swing, and single/double support time).

Reliability of two functional clinical tests to evaluate trunk and lumbopelvic neuromuscular control and proprioception in a healthy population.

OBJECTIVES: The need to accurately assess trunk and lumbopelvic proprioception and neuromuscular control is widely accepted. However, based on current literature, there is a lack of reliable clinical tests to evaluate these aspects in clinical practice. The objective of this study is to investigate intra- and inter-tester reliability of the lateral step down test and the lumbopelvic position-reposition test in a healthy population. METHODS: Protocol and scoring methods were developed for the lateral step down test and lumbopelvic position-reposition test, used to assess trunk and lumbopelvic neuromuscular control and proprioception respectively. Each test was performed once by thirty participants and video analysis for test scoring was performed. Three items on the lateral step down test were scored to evaluate neuromuscular control and, four items on the lumbopelvic position-reposition test were scored to evaluate proprioception. Aggregate scores for each test were calculated based on the separate item scores. Intraclass correlation coefficients and linear weighted kappa coefficients were determined for intra- and inter-tester reliability. RESULTS: Based on the aggregate score, excellent intra- and inter-tester reliability (ICC (2,1)=0.73-0.88) was found for both tests. Moderate/almost perfect intra-and inter-tester agreement (K=0.62-0.91) was found for the separate items of the lateral step down test and fair/substantial agreement (K=0.25-0.76) for the items of the lumbopelvic position-reposition test. CONCLUSION: Current testing protocol and scoring method for the lateral step down test is reliable. Adjustments for the scoring method of the lumbopelvic position-reposition test are warranted to improve reliability.

Reliability and validity of trunk flexor and trunk extensor strength measurements using handheld dynamometry in a healthy athletic population.

OBJECTIVES: To investigate reliability and validity of handheld dynamometry (HHD) strength tests to accurately measure isometric trunk flexion and extension strength. DESIGN: Test-retest design and comparative analysis to investigate reliability and validity respectively. SETTING: Isometric trunk flexion and extension strength, measured with a handheld dynamometer, was compared to isometric strength testing on a stationary isokinetic dynamometer. Different test positions were examined for the HHD measurements for trunk flexion and extension strength. MAIN OUTCOME MEASURES: Trunk muscle strength was calculated in newton metres (Nm) for both devices. Results of both devices were compared with Pearson correlations and agreement between both methods was explored with Bland-Altman plots. ICC values were calculated to assess HHD intra- and inter-tester reliability. RESULTS: Reliability was good to excellent for all HHD tests (ICC = 0.67-0.93). High correlations were found between the HHD tests and stationary dynamometer tests (r = 0.65-0.86). Bland-Altman plots showed agreement between both methods for the trunk flexion test, supported in 30° trunk flexion and for the trunk extension test in a prone position in 0° trunk flexion. CONCLUSION: Handheld dynamometry is reliable and a clinically applicable valid method to evaluate isometric trunk flexion and extension strength.

Is core stability a risk factor for lower extremity injuries in an athletic population? A systematic review.

OBJECTIVES: To research and summarize the literature regarding the role of core stability as a risk factor in the development of lower extremity injuries in an athletic population. METHODS: Pubmed, Web of Science and Embase were searched in August 2016 to systematically review studies, which related core muscle functioning and core stability to lower extremity injuries. RESULTS: Nine articles were included in the systematic review. Various components of core stability were found to be related to lower extremity musculoskeletal injuries in healthy athletic populations. Core strength, core proprioception and neuromuscular control of the core were found to be a risk factor in the development of lower extremity injuries. However, conflicting evidence was found for core endurance as a risk factor for lower extremity injuries. CONCLUSION: This systematic review provides preliminary evidence for the association between impaired core stability and the development of lower extremity injuries in healthy athletes. Deficits in various aspects of core stability were identified as potential risk factors for lower extremity injuries. As such, core stability needs to be considered when screening athletes.

Hip Strength as an Intrinsic Risk Factor for Lateral Ankle Sprains in Youth Soccer Players: A 3-Season Prospective Study.

BACKGROUND: Numerous epidemiological studies have emphasized the burden of lateral ankle sprains in youth soccer players. However, no prospective study has identified intrinsic physical and modifiable risk factors for these injuries in this particular population. Although injury prevention programs in soccer incorporate proximal hip and core stability exercises, it is striking that the relationship between impaired proximal hip function and ankle sprains has not yet been prospectively investigated in youth soccer players. HYPOTHESIS: This prospective study aimed to examine whether hip muscle strength is a risk factor for sustaining a lateral ankle sprain in youth soccer players. We hypothesized that decreased hip muscle strength would predispose youth soccer players to an increased risk of lateral ankle sprains. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: This study included a total of 133 male youth soccer players (age divisions U11-U17) for analysis. At the beginning of the season, anthropometric characteristics were collected and hip muscle strength was assessed using a handheld dynamometer. Injury registration was performed by the team medical staff during 3 consecutive seasons. A principal-component, multivariate Cox regression analysis was performed to identify potential risk factors for sustaining a lateral ankle sprain. RESULTS: Twelve participants (18% of all reported injuries) sustained a lateral ankle sprain (0.36 per 1000 athletic-exposure hours). After adjustment for body size dependencies and other hip muscle forces, an increase in hip muscle extension force was associated with a significant decrease in the hazard of the injury (hazard ratio, 0.3; 95% confidence interval, 0.1-0.9; P = .028). No other study variable could be identified as a risk factor for lateral ankle sprains. CONCLUSION: Reduced hip extension muscle strength is an independent risk factor for lateral ankle sprains in male youth soccer players. Other hip muscle strength outcomes were not identified as risk factors. Replication in larger samples with more injured cases is warranted to further ascertain the importance of this risk factor.

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.

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.

Evaluating fracture risk in acute ankle sprains: Any news since the Ottawa Ankle Rules? A systematic review.

BACKGROUND: Ankle sprain is frequently encountered, both in primary care and in emergency departments. Since 1992, the Ottawa ankle rules (OAR) can assist clinicians in determining whether an X-ray should be performed to exclude a fracture. Several guidelines recommend the use of OAR based on a systematic review from 2003. Ten years later, one can wonder if this recommendation should be changed. OBJECTIVE: To review systematically the current evidence on the most accurate method to assess the fracture risk after an ankle sprain in adults. METHODS: A methodical search for systematic reviews, meta-analyses and primary studies was carried out in Medline, Cochrane Database of systematic reviews, Embase, Pedro, CINAHL, Medion and specific guideline search engines. At least two independent researchers performed selection, quality appraisal (with validated checklists) and data extraction. RESULTS: One systematic review and 21 primary studies were selected. Sensitivity and specificity of the OAR range from 92-100% and from 16-51%, respectively. To improve the OAR specificity, other tools are proposed such as the Bernese ankle rules. Vibrating tuning fork test and ultrasound could be useful in patient with OAR positive to decrease the need for radiographs. No evidence was found in favour of the use of magnetic resonance imaging (MRI) or computed tomography (CT) in the acute phase of ankle sprain. CONCLUSION: The findings confirm the value of the OAR at ruling out fractures after an ankle sprain and propose other or additional tools to decrease the need for X-rays.

Influence of balance surface on ankle stabilizing muscle activity in subjects with chronic ankle instability.

OBJECTIVE: To evaluate the effect of balance surface type on muscle activity of ankle stabilizing muscles in subjects with chronic ankle instability. DESIGN: Case-controlled, repeated-measures study design. SUBJECTS: Twenty-eight subjects with chronic ankle instability and 28 healthy controls. METHODS: Subjects performed a barefooted single-legged stance on uniaxial and multidirectional unstable surfaces. Muscle activity of the mm. peroneus longus/brevis, tibialis anterior, gastrocnemius medialis were registered using surface electromyography. Mixed model analysis was used to explore differences in muscle activity between subjects with chronic ankle instability and controls, and the effect of surface type on muscle activity levels within subjects with chronic ankle instability. RESULTS: No differences were found between subjects with chronic ankle instability and healthy controls. Within subjects with chronic ankle instability, balancing along a frontal axis and on the Both Sides Up evoked overall highest muscle activity level, and the firm surface the least. Balancing on the firm surface showed the lowest tibialis anterior/peroneus longus muscle ratio, followed by balancing along a frontal axis and on the Airex pad. CONCLUSION: Clinicians can use these findings to improve the focus of balance training programmes by gradually progressing in difficulty level based on muscle activation levels taking co-contraction ratios into account.

Multi-segment foot landing kinematics in subjects with chronic ankle instability.

BACKGROUND: Chronic ankle instability has been associated with altered joint kinematics at the ankle, knee and hip. However, no studies have investigated possible kinematic deviations at more distal segments of the foot. The purpose of this study was to evaluate if subjects with ankle instability and copers show altered foot and ankle kinematics and altered kinetics during a landing task when compared to controls. METHODS: Ninety-six subjects (38 subjects with chronic ankle instability, 28 copers and 30 controls) performed a vertical drop and side jump task. Foot kinematics were obtained using the Ghent Foot Model and a single-segment foot model. Group differences were evaluated using statistical parametric mapping and analysis of variance. RESULTS: Subjects with ankle instability had a more inverted midfoot position in relation to the rearfoot when compared to controls during the side jump. They also had a greater midfoot inversion/eversion range of motion than copers during the vertical drop. Copers exhibited less plantar flexion/dorsiflexion range of motion in the lateral and medial forefoot. Furthermore, the ankle instability and coper group exhibited less ankle plantar flexion at touchdown. Additionally, the ankle instability group demonstrated a decreased plantar flexion/dorsiflexion range of motion at the ankle compared to the control group. Analysis of ground reaction forces showed a higher vertical peak and loading rate during the vertical drop in subjects with ankle instability. INTERPRETATION: Subjects with chronic ankle instability displayed an altered, stiffer kinematic landing strategy and related alterations in landing kinetics, which might predispose them for episodes of giving way and actual ankle sprains.

A color-code based method for the interpretation of plantar pressure measurements in clinical gait analysis.

Comparing plantar pressure measurements (PPM) of a patient following an intervention or between a reference group and a patient-group is common practice in clinical gait analysis. However, this process is often time consuming and complex, and commercially available software often lacks powerful visualization and interpretation tools. In this paper, we propose a simple method for displaying pixel-level PPM deviations relative to a so-called reference PPM pattern. The novel method contains 3 distinct stages: (1) a normalization of pedobarographic fields (for foot length and width), (2) a pixel-level z-score based calculation and, (3) color coding of the normalized pedobarographic fields. The methodological steps associated to this novel method are precisely described and clinical output illustrated. We believe that the advantages of the novel method cover several domains. The strongest advantage of the novel method is that it provides a straightforward visual interpretation of PPM without decreasing the resolution perspective. A second advantage is that it may guide the selection of a local mapping technique (data reduction technique). Finally, it may be easily used as education tool during the therapist-patient interaction.