The aim of the study was to perform a preliminary validation of a low cost markerless motion capture system (CAPTURE) against an industry gold standard (Vicon). Measurements of knee valgus and flexion during the performance of a countermovement jump (CMJ) between CAPTURE and Vicon were compared. After correction algorithms were applied to the raw CAPTURE data acceptable levels of accuracy and precision were achieved. The knee flexion angle measured for three trials using Capture deviated by ?3.8° ± 3° (left) and 1.7° ± 2.8° (right) compared to Vicon. The findings suggest that low-cost markerless motion capture has potential to provide an objective method for assessing lower limb jump and landing mechanics in an applied sports setting. Furthermore, the outcome of the study warrants the need for future research to examine more fully the potential implications of the use of low-cost markerless motion capture in the evaluation of dynamic movement for injury prevention.
Researchers have identified high exposure to game conditions, low back dysfunction, and poor endurance of the core musculature as strong predictors for the occurrence of sprains and strains among collegiate football players.
To refine a previously developed injury-prediction model through analysis of 3 consecutive seasons of data.
National Collegiate Athletic Association Division I Football Championship Subdivision football program.
PATIENTS OR OTHER PARTICIPANTS:
For 3 consecutive years, all 152 team members (age = 19.7 ± 1.5 years, height = 1.84 ± 0.08 m, mass = 101.08 ± 19.28 kg) presented for a mandatory physical examination on the day before initiation of preseason practice sessions.
MAIN OUTCOME MEASURE(S):
Associations between preseason measurements and the subsequent occurrence of a core or lower extremity sprain or strain were established for 256 player-seasons of data. We used receiver operating characteristic analysis to identify optimal cut points for dichotomous categorizations of cases as high risk or low risk. Both logistic regression and Cox regression analyses were used to identify a multivariable injury-prediction model with optimal discriminatory power.
Exceptionally good discrimination between injured and uninjured cases was found for a 3-factor prediction model that included equal to or greater than 1 game as a starter, Oswestry Disability Index score equal to or greater than 4, and poor wall-sit-hold performance. The existence of at least 2 of the 3 risk factors demonstrated 56% sensitivity, 80% specificity, an odds ratio of 5.28 (90% confidence interval = 3.31, 8.44), and a hazard ratio of 2.97 (90% confidence interval = 2.14, 4.12).
High exposure to game conditions was the dominant injury risk factor for collegiate football players, but a surprisingly mild degree of low back dysfunction and poor core-muscle endurance appeared to be important modifiable risk factors that should be identified and addressed before participation.
Available methods for screening anterior cruciate ligament (ACL) injury risk are effective but limited in application as they generally rely on expensive and time-consuming biomechanical movement analysis. A potentially efficient alternative to biomechanical screening is skilled movement analysis via visual inspection (ie, having experts estimate injury risk factors based on observations of athletes' movements).
To develop a brief, valid psychometric assessment of ACL injury risk factor estimation skill: the ACL Injury Risk Estimation Quiz (ACL-IQ).
Cohort study (diagnosis); Level of evidence, 3.
A total of 660 individuals participated in various stages of the study, including athletes, physicians, physical therapists, athletic trainers, exercise science researchers/students, and members of the general public in the United States. The ACL-IQ was fully computerized and made available online (www.ACL-IQ.org). Item sampling/reduction, reliability analysis, cross-validation, and convergent/discriminant validity analyses were conducted to refine the efficiency and validity of the assessment.
Psychometric optimization techniques identified a short (mean time, 2 min 24 s), robust, 5-item assessment with high reliability (test-retest: r = 0.90) and high test sensitivity (average difference of exercise science professionals vs general population: Cohen d = 2). Exercise science professionals and individuals from the general population scored 74% and 53% correct, respectively. Convergent and discriminant validity was demonstrated. Scores on the ACL-IQ were best predicted by ACL knowledge and specific judgment strategies (ie, cue use) and were largely unrelated to domain-general spatial/decision-making ability, personality, or other demographic variables. Overall, 23% of the total sample (40% of exercise science professionals; 6% of general population) performed better than or equal to the ACL nomogram.
This study presents the results of a systematic approach to assess individual differences in ACL injury risk factor estimation skill; the assessment approach is efficient (ie, it can be completed in <3 min) and psychometrically robust. The results provide evidence that some individuals have the ability to visually estimate ACL injury risk factors more accurately than other instrument-based ACL risk estimation methods (ie, ACL nomogram). The ACL-IQ provides the foundation for assessing the efficacy of observational ACL injury risk factor assessment (ie, does simple skilled visual inspection reduce ACL injuries?). The ACL-IQ can also be used to increase our understanding of the perceptual-cognitive mechanisms underlying injury risk assessment expertise, which can be leveraged to accelerate learning and improve performance.
To examine the comparative efficacy of 3 common measures of traumatic brain injury (TBI) severity for predicting inpatient outcomes upon hospital discharge.
Acute brain injury rehabilitation unit at level 1 trauma center.
100 patients with TBI.
Retrospective analysis of injury severity, demographic, and outcome data.
Glasgow Coma Scale (GCS) at admission, time to follow commands (TTC), duration of posttraumatic amnesia (PTA), and Functional Independence Measure at hospital discharge.
A hierarchal multiple regression revealed that duration of PTA was a significant and powerful unique predictor of Functional Independence Measure scores at discharge (? = ?0.46, P = .001), while TTC (? = 0.26, P = .056) and GCS (? = 0.16, P = .143) were not. These effects were present even after controlling for age, gender, educational level, racial/ethnic minority status, cause of injury, history of substance abuse, and neurosurgical intervention.
Although clinicians often use GCS scores and TTC when assessing acute TBI severity and during treatment formulation, this study provides evidence that duration of PTA may be a more meaningful predictor of patients' functional levels at discharge.
Identifying risk factors for knee pain and anterior cruciate ligament (ACL) injury can be an important step in the injury prevention cycle.
We evaluated two unique prospective cohorts with similar populations and methodologies to compare the incidence rates and risk factors associated with patellofemoral pain (PFP) and ACL injury.
The ‘PFP cohort’ consisted of 240 middle and high school female athletes. They were evaluated by a physician and underwent anthropometric assessment, strength testing and three-dimensional landing biomechanical analyses prior to their basketball season. 145 of these athletes met inclusion for surveillance of incident (new) PFP by certified athletic trainers during their competitive season. The ‘ACL cohort’ included 205 high school female volleyball, soccer and basketball athletes who underwent the same anthropometric, strength and biomechanical assessment prior to their competitive season and were subsequently followed up for incidence of ACL injury. A one-way analysis of variance was used to evaluate potential group (incident PFP vs ACL injured) differences in anthropometrics, strength and landing biomechanics. Knee abduction moment (KAM) cut-scores that provided the maximal sensitivity and specificity for prediction of PFP or ACL injury risk were also compared between the cohorts.
KAM during landing above 15.4 Nm was associated with a 6.8% risk to develop PFP compared to a 2.9% risk if below the PFP risk threshold in our sample. Likewise, a KAM above 25.3 Nm was associated with a 6.8% risk for subsequent ACL injury compared to a 0.4% risk if below the established ACL risk threshold. The ACL-injured athletes initiated landing with a greater knee abduction angle and a reduced hamstrings-to-quadriceps strength ratio relative to the incident PFP group. Also, when comparing across cohorts, the athletes who suffered ACL injury also had lower hamstring/quadriceps ratio than the players in the PFP sample (p<0.05).
In adolescent girls aged 13.3 years, >15 Nm of knee abduction load during landing is associated with greater likelihood of developing PFP. Also, in girls aged 16.1 years who land with >25 Nm of knee abduction load during landing are at increased risk for both PFP and ACL injury.
Limited information exists regarding injury risk factors for high school athletes. The Functional Movement Screen (FMS™) has been used to identify functional movement impairments and asymmetries, making it a potential predictor of injury.
To determine if the FMS™ is a valid predictor of injury in high school athletes and to identify a potential new FMS™ cutoff score for this population.
167 high school athletes among several sports were scored using the FMS™ and were monitored for injury during a single season. Likelihood ratios were calculated to determine how much a subject's total FMS™ score influenced the post?test probability of becoming injured.
Of the 167 participants, 39 sustained a musculoskeletal injury. Of all component scores, the in?line lunge scores were significantly higher for injured players. For shoulder mobility, scores were significantly lower for injured players. No statistically significant associations were found between total FMS™ scores and injury status.
The FMS™ may be useful for recognizing deficiency in certain movements, however this data suggests that the FMS™ should not be used for overall prediction of injury in high school athletes throughout the course of a season. Normative data from a large sample size is now available in the high school athlete demographic.
Anterior cruciate ligament tears are one of the most frequent soft tissue injuries of the knee. A torn anterior cruciate ligament leaves the knee joint unstable and at risk for further damage to other soft tissues manifested as pain, dislocation, and osteoarthritis.
A better understanding of the anatomical details of knee joints suffering anterior cruciate ligament tears is needed to understand and develop prediction models for anterior cruciate ligament injury and/or tear.Magnetic resonance images of 32 patients with anterior cruciate ligament tears and 40 patients with non-tears were evaluated from a physician group practice. Digital measurements of femoral condyle length, femoral notch width, anterior cruciate ligament width in the frontal and sagittal plane, and the anterior cruciate ligament length in the sagittal plane were taken in both groups to identify trends.
Monte Carlo simulations were performed (n = 2000) to evaluate the relationship between notch width index and sagittal width and to establish functional relationships among the anatomical parameters for potential injury risk. Sensitivity analysis performed shows the risk of anterior cruciate ligament injury a function of force and notch width index.Females have a significantly shorter anterior cruciate ligament when compared to that of males. The notch width index was also significantly different between torn and non-torn individuals. The NWI was not significantly different between genders (p value = 0.40).Anterior cruciate ligament injury has been shown to be caused by the forces which act on the ligament. These forces can result from hyperextension of the tibia or the internal rotation of tibia.
The anatomical parameters of the knee joint (i.e., notch width index, anterior cruciate ligament width and length) have no role in the cause of an injury.