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.

Neurodynamic sliders promote flexibility in tight hamstring syndrome.

ABSTRACT Hamstring injury prevention puts emphasis on optimizing the muscle's strength-length relationship. To assure appropriate muscle length, flexibility training is imperative. As neurodynamics play an important role herein, the goal of this study was to explore the intervention effect of home-based neurodynamic slider program on hamstring flexibility. Fifty physically active male subjects were randomly assigned to either performing a neurodynamic sliding technique (3 × 20 reps) or a static stretching protocol (3 × 30″) on a daily basis for a 6-week period. Hamstring flexibility was assessed by means of the Straight Leg Raise at baseline, immediately after the intervention and after 4 weeks follow up. There was no between group baseline difference in hamstring flexibility. The repeated measure ANOVA showed a significant interaction effect for group × time (p < 0.001). Independent sample t-test showed a significantly higher increase in flexibility gain in the neurodynamic group immediately after the intervention (p < 0.001), as well as at 4 weeks retention analysis (p = 0.001) compared to the static stretch group. In conclusion, neurodynamic sliders might be more efficient than regular static stretching in affecting hamstring flexibility in the long run.

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).

Activity trackers are not valid for step count registration when walking with crutches.

BACKGROUND: The use of activity trackers has been proposed in rehabilitation where resuming physical activity is deemed crucial, e.g. after total knee arthroplasty (TKA). As patients initially often walk with crutches, it is of importance that clinicians can rely on the information provided by activity trackers. RESEARCH QUESTION: To determine concurrent validity of 2 activity trackers for step count, positioned on different locations on the body during gait with crutches. METHODS: Thirty healthy participants performed normal gait and gait with one crutch and two crutches over a distance of 400 m while wearing a Garmin Vivofit 3 and Nokia Go on both wrists and both sides at the waist (only Nokia Go). The gold standard was manual step count. Inter-device reliability (within brand) was assessed by calculating Intraclass Correlation Coëfficients (ICC) and concurrent validity was determined by performing paired sample t-tests, ICC and Bland-Altman Plots with % bias and 95% CI Limits of Agreement (LoA). RESULTS: During normal gait, both the Nokia and Garmin showed good to excellent inter-device reliability (ICC > 0.75). Both devices showed concurrent validity compared to manual step count, with slightly better results for the Garmin compared to the Nokia at the wrist (% bias = respectively 0.0% and -1.4% with 95% CI LoA: respectively -1.7%;1.7% and -8.6%;5.8%; ICC: respectively 0.995 and 0.859). During gait with crutches, however, overall 95% CI of LoA were beyond clinically acceptable differences and ICC values with the gold standard were poor. Therefore, notwithstanding a sometimes reported small average % bias, validity of the activity trackers for step count during gait with crutches was not established, independent of tracker position. SIGNIFICANCE: Activity trackers showed no concurrent validity when monitoring step count during gait with crutches. This should be taken into account when implementing this technology in e.g. post-operative goal setting in patients with TKA.

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.