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1.
J Appl Biomech ; 38(2): 111-116, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35272264

RESUMO

Several open-source platforms for markerless motion capture offer the ability to track 2-dimensional (2D) kinematics using simple digital video cameras. We sought to establish the performance of one of these platforms, DeepLabCut. Eighty-four runners who had sagittal plane videos recorded of their left lower leg were included in the study. Data from 50 participants were used to train a deep neural network for 2D pose estimation of the foot and tibia segments. The trained model was used to process novel videos from 34 participants for continuous 2D coordinate data. Overall network accuracy was assessed using the train/test errors. Foot and tibia angles were calculated for 7 strides using manual digitization and markerless methods. Agreement was assessed with mean absolute differences and intraclass correlation coefficients. Bland-Altman plots and paired t tests were used to assess systematic bias. The train/test errors for the trained network were 2.87/7.79 pixels, respectively (0.5/1.2 cm). Compared to manual digitization, the markerless method was found to systematically overestimate foot angles and underestimate tibial angles (P < .01, d = 0.06-0.26). However, excellent agreement was found between the segment calculation methods, with mean differences ≤1° and intraclass correlation coefficients ≥.90. Overall, these results demonstrate that open-source, markerless methods are a promising new tool for analyzing human motion.


Assuntos
Corrida , Tíbia , Fenômenos Biomecânicos , Marcha , Humanos , Extremidade Inferior , Movimento (Física)
2.
Clin Biomech (Bristol, Avon) ; 84: 105334, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33774324

RESUMO

BACKGROUND: Acute hamstring injuries during sprinting have been attributed, in part, to the ground reaction forces experienced during early stance. However, no studies have investigated the factors associated with overuse hamstring injuries in endurance runners. Our purpose was to compare early stance ground reaction forces and step length between runners with overuse hamstring injuries and healthy controls. METHODS: 23 runners (5 men/ 18 women) who presented to a running clinic with an overuse hamstring injury were matched with healthy controls for sex, running speed and age. All participants ran on an instrumented treadmill, embedded with force plates. A 3-min warm-up was given, at a self-selected training pace, followed by 16-s of ground reaction force data collection (≈20 strides). Statistical parametric mapping was used to compared ground reaction force waveforms. Additionally, discrete force variables were calculated, including vertical average/instantaneous. Mean comparisons for discrete ground reaction force variables and step length were performed. FINDINGS: Differences in ground reaction force waveforms did not reach statistical significance (p > 0.05). However, mean vertical loading rates were found to be higher in the Hamstring Injury group compared to Controls (p = 0.03-0.04) with small to moderate effect sizes (d = 0.47-0.52). No differences were found in mean step length. INTERPRETATION: These results provide evidence that vertical loading rates may be associated with overuse hamstring injuries. However, further research is needed to identify the contribution of joint kinematics/kinetics and muscle activity.


Assuntos
Corrida , Fenômenos Biomecânicos , Teste de Esforço , Feminino , Humanos , Cinética , Masculino
3.
J Biomech ; 117: 110250, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33486264

RESUMO

Peak vertical tibial accelerations during running have shown strong correlations with vertical ground reaction force loading rates and some associations with injury. However, little attention has been given to tibial accelerations along the medial-lateral and anterior-posterior axes. Therefore, our purpose was to examine the correlation between peak tibial accelerations and ground reaction force loading rates in the medial-lateral and posterior directions. Eighteen recreational runners were recruited who ran with a rearfoot strike pattern (10 men/ 8 women, mean age (yrs) = 33 ± 11). Tibial accelerations and ground reaction forces were collected while participants ran on an instrumented treadmill at a self-selected speed. Correlations were developed for: a) peak medial and lateral accelerations with lateral and medial loading rates, respectively, b) peak anterior tibial accelerations and posterior loading rates. Significant correlations were found between tibial accelerations and loading rates in all planes. Peak medial tibial accelerations were correlated with lateral loading rates (Rs = 0.86, p < 0.001) and peak lateral tibial accelerations were correlated with peak medial loading rates (Rs = 0.91, p < 0.001). A lower correlation was found between anterior accelerations and posterior loading rates (Rs = 0.51, p = 0.030). Tibial accelerations in the medial-lateral plane seem to be a valid surrogate for the respective ground reaction force measures during running on a treadmill, explaining 74-83% of the variance in loading rates. However, with only 26% of the variance explained, the same may not be true for anterior tibial accelerations and posterior loading rates.


Assuntos
Aceleração , Corrida , Fenômenos Biomecânicos , Feminino , , Humanos , Masculino , Tíbia
4.
J Appl Biomech ; 37(2): 118-121, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33361488

RESUMO

Higher medial-lateral forces have been reported in individuals with stiffer foot arches. However, this was in a small sample of military personnel who ran with a rearfoot strike pattern. Therefore, our purpose was to investigate whether runners, both rearfoot and forefoot strikers, show different associations between medial-lateral forces and arch stiffness. A group of 118 runners (80 rearfoot strikers and 38 forefoot strikers) were recruited. Ground reaction force data were collected during running on an instrumented treadmill. Arch flexibility was assessed as the difference in arch height from sitting to standing positions, and participants were classified into stiff/flexible groups. Group comparisons were performed for the ratio of medial:vertical and lateral:vertical impulses. In rearfoot strikers, runners with stiff arches demonstrated significantly higher medial:vertical impulse ratios (P = .036). Forefoot strikers also demonstrated higher proportions of medial forces; however, the mean difference did not reach statistical significance (P = .084). No differences were detected in the proportion of lateral forces between arch flexibility groups. Consistent with previous findings in military personnel, our results indicate that recreational runners with stiffer arches have a higher proportion of medial forces. Therefore, increasing foot flexibility may increase the ability to attenuate medial forces.


Assuntos
Pé/anatomia & histologia , Marcha , Corrida , Adulto , Fenômenos Biomecânicos , Teste de Esforço , Feminino , Pé/fisiologia , Humanos , Masculino , Adulto Jovem
5.
Eur J Sport Sci ; 21(1): 36-44, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32013782

RESUMO

Perceptual-motor coordination relies on the accurate coupling of the perceptual and movement systems. However, individuals must also be able to recalibrate to perturbations to perceptual and movement capabilities. We examined the effects of fatigue and load carriage on perceptual-motor coordination for a maximal leaping task. 23 participants completed an incremental fatigue protocol (light to fatiguing intensity stages) on two separate occasions (loaded/unloaded). At baseline and the end of every stage of the protocol, participants made perceptual judgments for the affordance of leaping. The accuracy of responses and reaction times were calculated and mean differences were assessed across exercise intensity and load carriage conditions. No interaction of exercise intensity and load carriage was detected, or main effect of load carriage. A main, quadratic effect of exercise intensity was detected on reaction times, with times decreasing through the moderate stage and increasing through post-fatigue. No effect of exercise/fatigue was detected on perceptual accuracy. The results indicate that exercise at high intensities through fatigue has a significant effect on perceptual-motor calibration. Contrastingly, in response to an action-scaled task, individuals can adequately recalibrate to increased load carriage.


Assuntos
Exercício Físico/fisiologia , Fadiga/fisiopatologia , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Suporte de Carga/fisiologia , Adulto , Fatores Etários , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Percepção , Tempo de Reação , Exercício de Aquecimento/fisiologia , Adulto Jovem
6.
Clin J Sport Med ; 31(3): 273-280, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30829684

RESUMO

BACKGROUND: After a concussion, athletes may be at increased risk of musculoskeletal injuries. Altered perception of action boundaries (ABP), or the limits of one's action capabilities, is one possible mechanism for this increase in injury risk after concussion. OBJECTIVE: To evaluate differences in symptoms, neurocognitive, vestibular/oculomotor, and action boundary function between subjects with no concussion history (NoHx) and concussion history (ConcHX). DESIGN: Cross-sectional study. SETTING: Laboratory at the University of Pittsburgh. PARTICIPANTS: ConcHx (n = 22; age: 21.8 ± 3.0 years, height: 174.0 ± 8.3 cm, and mass: 77.8 ± 14.8 kg) and NoHx athletes (n = 24; age: 21.6 ± 2.0 years, height: 176.0 ± 10.0 cm, and mass: 72.0 ± 15.3 kg). INTERVENTION: Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) and Post-Concussion Symptom Scale (PCSS), Vestibular-Ocular Motor Screening (VOMS) tool, and the Perception-Action Coupling Task (PACT). The PACT measures the accuracy of ABP. MAIN OUTCOME MEASURES: Neurocognitive domain scores, PCSS, VOMS subdomain symptom gain, ABP accuracy, and actualization. RESULTS: ConcHx reported 2.7 ± 1.5 previous concussions occurring on average 263.8 ± 228.9 days prior. ConcHx was higher on several VOMS items including vertical/horizontal saccades (P = 0.001; P = 0.05), vertical/horizontal vestibular-ocular reflex (P < 0.001; P = 0.04), and visual motion sensitivity (P < 0.001). Average PACT movement time (P = 0.01) and reaction time (P = 0.01) were longer in ConcHx. CONCLUSIONS: These findings provide preliminary support for impaired vestibular/oculomotor function and ABP in ConcHx compared with NoHx. The current results may enhance our understanding of the mechanisms for increased musculoskeletal injury risk after concussion.


Assuntos
Traumatismos em Atletas , Concussão Encefálica , Percepção , Adulto , Traumatismos em Atletas/diagnóstico , Traumatismos em Atletas/fisiopatologia , Biomarcadores , Concussão Encefálica/diagnóstico , Concussão Encefálica/fisiopatologia , Estudos Transversais , Humanos , Testes Neuropsicológicos , Adulto Jovem
7.
Med Sci Sports Exerc ; 53(1): 102-107, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32769811

RESUMO

PURPOSE: Despite the health benefits of running, the prevalence of running-related injuries (RRI) remains high. The underlying risk factors between these injuries are still not well understood. Therefore, the aim of this study was to compare biomechanical, anthropometric, and demographic injury risk factors between different locations in injured recreational runners. METHODS: In this retrospective case-control analysis, 550 injured runners (49.6% female) with a medically diagnosed RRI were included. All runners had undergone an instrumented treadmill analysis to determine habitual footstrike pattern, vertical instantaneous load rate, peak vertical ground reaction force (vGRF) and cadence. Injuries were classified by location according to a recent consensus statement. A logistic regression model was used to determine the association between the biomechanical parameters and RRI locations. Because injuries can be associated with age, sex, and body mass index, these variables were also entered into the logistic regression. RESULTS: Strike pattern and peak vGRF were the only biomechanical variable distinguishing an injury from the group of injuries. A midfoot strike differentiated Achilles tendon injuries (odds ratio [OR], 2.27; 90% confidence interval [CI], 1.17-4.41) and a forefoot strike distinguished posterior lower leg injuries (OR, 2.59; 90% CI, 1.50-4.47) from the rest of the injured group. Peak vGRF was weakly associated with hip injuries (OR, 1.14; 90% CI, 1.05-1.24). Female sex was associated with injuries to the lower leg (OR, 2.65; 90% CI, 1.45-4.87) and hip/groin (OR, 2.22; 90% CI, 1.43-3.45). Male sex was associated with Achilles tendon injuries (OR, 1.923; 90% CI, 1.094-3.378). CONCLUSIONS: Sex, foot strike pattern, and vGRF were the only factors that distinguished specific injury locations from the remaining injury locations.


Assuntos
Extremidade Inferior/lesões , Extremidade Inferior/fisiopatologia , Corrida/lesões , Tendão do Calcâneo/lesões , Tendão do Calcâneo/fisiopatologia , Adulto , Fatores Etários , Fenômenos Biomecânicos , Índice de Massa Corporal , Estudos de Casos e Controles , Feminino , Pé/fisiologia , Traumatismos do Pé/etiologia , Traumatismos do Pé/fisiopatologia , Marcha , Virilha/lesões , Virilha/fisiopatologia , Lesões do Quadril/etiologia , Lesões do Quadril/fisiopatologia , Humanos , Traumatismos do Joelho/etiologia , Traumatismos do Joelho/fisiopatologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Fatores Sexuais , Adulto Jovem
8.
J Biomech ; 113: 110118, 2020 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-33197691

RESUMO

Peak tibial accelerations during running are of interest because of their correlation with vertical ground reaction force load rates and association with running injury. Previous work has demonstrated systematically lower accelerations measured with a bone- compared to skin-mounted accelerometer. However, no studies have assessed the effects of more or less secure attachment methods for skin mounted sensors. Our purpose was to compare two methods of attaching a skin mounted sensor on mean tibial accelerations, stride-to-stride variability, and correlations with vertical load rates. 18 injury-free runners were recruited as participants. An inertial measurement unit, containing a tri-axial accelerometer, was used to record tibial accelerations while participants ran at a self-selected speed on an instrumented treadmill to collect ground reaction forces. The two attachment methods for securing the sensor to the skin were a manufacturer-provided strap (strap condition) and a combination of tape and elastic wraps (wrap condition). Mean vertical accelerations were significantly lower in the wrap condition (p = 0.02, d = 0.57). No differences were detected in resultant accelerations, vertical loading rates, or stride-to-stride variability. Correlations between tibial accelerations and vertical loading rates were strong (r = 0.79-0.91) and similar between conditions. These results provide two key findings of evidence. Evidenced by systematically lower vertical accelerations, a more secure attachment method may be necessary for capturing the most representative measure of tibial accelerations during running. However, a less secure method (i.e. the strap) is sufficient for capturing tibial accelerations as a surrogate for impact loading forces.


Assuntos
Aceleração , Corrida , Fenômenos Biomecânicos , Teste de Esforço , Humanos , Tíbia
9.
Am J Sports Med ; 48(12): 3072-3080, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32915664

RESUMO

BACKGROUND: Inconsistent associations have been reported for impact-related ground reaction force variables and running injuries when grouping all injuries together. However, previous work has shown more consistent associations when focusing on specific injuries. PURPOSE: To compare ground reaction force variables between healthy and injured runners as a group and within specific common injuries. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 125 runners presenting with patellofemoral pain, tibial bone stress injury, plantar fasciitis, Achilles tendinopathy, or iliotibial band syndrome and 65 healthy controls completed an instrumented treadmill assessment at a self-selected speed. Impact-related ground reaction force variables included vertical average (VALR) and instantaneous (VILR) load rates, posterior and medial/lateral instantaneous load rates, and vertical stiffness at initial loading (VSIL). Mean comparisons were made between the general and specific injury and control groups (α = .05). Cutoff thresholds were established and evaluated using several criteria. RESULTS: VALR (+17.5%; P < .01), VILR (+15.8%; P < .01), and VSIL (+19.7%; P < .01) were significantly higher in the overall injured versus control groups. For individual injuries, VALR, VILR, and VSIL were significantly higher for patellofemoral pain (+23.4%-26.4%; P < .01) and plantar fasciitis (+17.5%-29.0%; P < .01), as well as VSIL for Achilles tendinopathy (+29.4%; P < .01). Cutoff thresholds showed better diagnostic criteria for individual versus grouped injuries. CONCLUSION: Impact variables (VALR, VILR, and VSIL) were significantly higher when assessing the injured group as a whole. However, these findings were driven by specific injury groups, highlighting the importance of taking an injury-specific approach to biomechanical risk factors for running injury. CLINICAL RELEVANCE: These results suggest that practitioners may want to address impact loading in their treatment of injured runners, especially in those with patellofemoral pain and plantar fasciitis.


Assuntos
Tendão do Calcâneo/lesões , Fasciíte Plantar/etiologia , Síndrome da Dor Patelofemoral/etiologia , Corrida/lesões , Tendinopatia , Fenômenos Biomecânicos , Estudos de Casos e Controles , Teste de Esforço , Humanos , Tendinopatia/etiologia
10.
Sleep Med Clin ; 15(1): 31-39, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32005348

RESUMO

Sleep has a widespread impact across different domains of performance, including sensorimotor function. From an ecological dynamics perspective, sensorimotor function involves the continuous and dynamic coupling between perception and action. Sport performance relies on sensorimotor function as successful movement behaviors require accurate and efficient coupling between perceptions and actions. Compromised sleep impairs different aspects of sensorimotor performance, including perceptual attunement and motor execution. Changes in sensorimotor performance can be related to specific features of sleep, notably sleep spindles and slow waves. One unaddressed area of study is the extent to which specific sleep features contribute to overall sport-specific performance.


Assuntos
Desempenho Atlético/fisiologia , Movimento/fisiologia , Sono/fisiologia , Esportes/fisiologia , Eletroencefalografia , Humanos
11.
Med Sci Sports Exerc ; 52(7): 1557-1562, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31985578

RESUMO

The degree to which standard laboratory gait assessments accurately reflect impact loading in an outdoor running environment is currently unknown. PURPOSE: To compare tibial shock between treadmill and road marathon conditions. METHODS: One hundred ninety-two runners (men/women, 105/87; age, 44.9 ± 10.8 yr) completed a treadmill gait assessment while wearing a tibial-mounted inertial measurement unit, several days before completing a marathon race. Participants ran at 90% of their projected race speed and 30 s of tibial shock data were collected. Participants then wore the sensors during the race and tibial shock was averaged over the 12th, 23rd, and 40th kilometers. One-way analysis of covariance and correlation coefficients were used to compare vertical/resultant tibial shock between treadmill and marathon conditions. Analyses were adjusted for differences in running speed between conditions. RESULTS: A significant main effect of condition was found for mean vertical and resultant tibial shock (P < 0.001). Early in the marathon (12-km point), runners demonstrated higher mean tibial shock adjusted for speed compared with the treadmill data (vertical = +24.3% and resultant = +30.3%). Mean differences decreased across the course of the marathon. Vertical tibial shock at the 40th kilometer of the race was similar to treadmill data, and resultant shock remained higher. Vertical and resultant tibial shock were significantly correlated between treadmill and the 12th kilometer of the race (rs = 0.64-0.65, P < 0.001), with only 40% to 42% of the variance in outdoor tibial shock explained by treadmill measures. Correlations for tibial shock showed minimal changes across stages of the marathon. CONCLUSIONS: These results demonstrate that measures of impact loading in an outdoor running environment are not fully captured on a treadmill.


Assuntos
Meio Ambiente , Teste de Esforço/instrumentação , Corrida/fisiologia , Tíbia/fisiologia , Acelerometria/instrumentação , Adulto , Fenômenos Biomecânicos , Teste de Esforço/métodos , Feminino , Análise da Marcha , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Mecânico , Dispositivos Eletrônicos Vestíveis
12.
Sports Med ; 50(1): 15-23, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31228023

RESUMO

Recent studies have concluded that athletes have increased risk of musculoskeletal injury following sport-related concussion. While an underlying explanation is still unknown, perceptual-motor control may be implicated in this increased risk. Some authors have purported that indirect perception (i.e., a "top-down" view of neuromuscular control) may be disrupted following sport-related concussion. Direct perception theory states that the athlete and environment are inextricably linked in a continuous perception-action coupling loop. That is, the athlete is able to directly perceive opportunities for action (e.g., "affordances") in the environment. Based on these notions, the aim of the current paper was to introduce a theoretical model that argues that sport-related concussion may dysregulate the direct perception process, potentially increasing behavioral risk of musculoskeletal injury during sport. Our model is integrated with a sport-related concussion clinical treatment model, which highlights individualized profiles that characterize the heterogeneous response to sport-related concussion. These profiles have a typical constellation of symptoms (e.g., anxiety, fatigue, ocular dysfunction, etc.), which themselves have been associated with disrupted perception-action coupling, independent of sport-related concussion. Therefore, we argue that athletes who have not re-established perception-action coupling loops following sport-related concussion may be at increased risk of subsequent musculoskeletal injury.


Assuntos
Traumatismos em Atletas/complicações , Concussão Encefálica/complicações , Sistema Musculoesquelético/lesões , Humanos , Modelos Teóricos , Fatores de Risco
13.
Aerosp Med Hum Perform ; 90(12): 1000-1008, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31747996

RESUMO

INTRODUCTION: Designed as a more ecological measure of reaction times, the Perception-Action Coupling Task (PACT) has shown good reliability and within-subject stability. However, a lengthy testing period was required. Perceptual-motor judgments are known to be affected by proximity of the stimulus to the action boundary. The current study sought to determine the effects of action boundary proximity on PACT performance, and whether redundant levels of stimuli, eliciting similar responses, can be eliminated to shorten the PACT.METHODS: There were 9 men and 7 women who completed 4 testing sessions, consisting of 3 familiarization cycles and 6 testing cycles of the PACT. For the PACT, subjects made judgments on whether a series of balls presented on a tablet afford "posting" (can fit) through a series of apertures. There were 8 ratios of ball to aperture size (B-AR) presented, ranging from 0.2 to 1.8, with each ratio appearing 12 times (12 trials) per cycle. Reaction times and judgment accuracy were calculated, and averaged across all B-ARs. Ratios and individual trials within each B-AR were systematically eliminated. Variables were re-averaged, and intraclass correlation coefficients (ICC) and coefficients of variation (CVTE) were calculated in an iterative manner.RESULTS: With elimination of the 0.2 and 1.8 B-ARs, the PACT showed good reliability (ICC = 0.81-0.99) and consistent within-subject stability (CVTE = 2.2-14.7%). Reliability (ICC = 0.81-0.97) and stability (CVTE = 2.6-15.6%) were unaffected with elimination of up to 8 trials from each B-AR.DISCUSSION: The shortened PACT resulted in an almost 50% reduction in total familiarization/testing time required, significantly increasing usability.Johnson CD, LaGoy AD, Pepping G-J, Eagle SR, Beethe AZ, Bower JL, Alfano CA, Simpson RJ, Connaboy C. Action boundary proximity effects on perceptual-motor judgments. Aerosp Med Hum Perform. 2019; 90(12):1000-1008.


Assuntos
Percepção/fisiologia , Tempo de Reação/fisiologia , Análise e Desempenho de Tarefas , Adulto , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Adulto Jovem
14.
J Athl Train ; 54(5): 497-504, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31074634

RESUMO

CONTEXT: Ankle injury is one of the most common conditions in athletics and military activities. Strength asymmetry (SA) and imbalance may represent a risk factor for injury, but past investigations have produced ambiguous conclusions. Perhaps one explanation for this ambiguity is the fact that these authors used univariate models to predict injury. OBJECTIVE: To evaluate the predictive utility of SA and imbalance calculations for ankle injury in univariate and multivariate prediction models. DESIGN: Prospective cohort study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 140 male US Air Force Special Forces. MAIN OUTCOME MEASURE(S): Baseline testing consisted of body composition, isometric strength, and aerobic and anaerobic capacity. A clinician conducted medical chart reviews 365 days posttesting to document the incidence of ankle injury. Strength asymmetries were calculated based on the equations most prevalent in the literature along with known physiological predictors of injury in the military: age, height, weight, body composition, and aerobic capacity. Simple logistic regression was conducted using each predictor, and backward stepwise logistic regression was conducted with each equation method and the physiological predictors entered initially into the model. RESULTS: Strength asymmetry or imbalance or both, as a univariate predictor, was not able to predict ankle injury 365 days posttesting. Body mass (P = .01) and body mass index (P = .01) significantly predicted ankle injury. Strength asymmetry or imbalance or both significantly predicted ankle injury when considered with body mass (P = .002-.008). CONCLUSIONS: As a univariate predictor, SA did not predict ankle injury. However, SA contributed significantly to predicting ankle injury in a multivariate model using body mass. Interpreting SA and imbalance in the presence of other physiological variables can help elucidate the risk of ankle injury.


Assuntos
Traumatismos do Tornozelo , Traumatismos em Atletas , Militares , Força Muscular/fisiologia , Equilíbrio Postural/fisiologia , Adulto , Traumatismos do Tornozelo/epidemiologia , Traumatismos do Tornozelo/etiologia , Traumatismos do Tornozelo/fisiopatologia , Traumatismos do Tornozelo/prevenção & controle , Traumatismos em Atletas/epidemiologia , Traumatismos em Atletas/fisiopatologia , Traumatismos em Atletas/prevenção & controle , Índice de Massa Corporal , Feminino , Humanos , Incidência , Masculino , Valor Preditivo dos Testes , Estudos Prospectivos , Esportes/fisiologia , Estados Unidos
15.
Med Sci Sports Exerc ; 51(5): 1073-1079, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30985586

RESUMO

INTRODUCTION: Musculoskeletal injury rates in military personnel remain unacceptably high. Application of machine learning algorithms could be useful in multivariate models to predict injury in this population. The purpose of this study was to investigate if interaction between individual predictors, using a decision tree model, could be used to develop a population-specific algorithm of lower-extremity injury (LEI) risk. METHODS: One hundred forty Air Force Special Forces Operators (27.4 ± 5.0 yr, 177.6 ± 5.8 cm, 83.8 ± 8.4 kg) volunteered for this prospective cohort study. Baseline testing included body composition, isokinetic strength, flexibility, aerobic/anaerobic capacity, anaerobic power, and landing biomechanics. To evaluate unilateral landing patterns, subjects jumped off two-feet from a distance (40% of their height) over a hurdle and landing single-legged on a force plate. Medical chart reviews were conducted 365 d postbaseline. χ automatic interaction detection (CHAID) was used, which compares predictor variables to LEI and assigns a population-specific "cut-point" for the most relevant predictors. RESULTS: Twenty-seven percent of operators (n = 38) suffered LEI. A maximum knee flexion angle difference of 25.1% had the highest association with injury in this population (P = 0.006). Operators with >25.1% differences in max knee flexion angle (n = 13) suffered LEI at a 69.2% rate. Seven of the 13 Operators with >25.1% difference in max knee flexion angle weighed >81.8 kg, and 100% of those operators suffered LEI (P = 0.047; n = 7). Only 33% of operators with >25.1% difference in max knee flexion angle that weighed <81.8 kg suffered LEI. CONCLUSIONS: This study demonstrated increased risk of LEI over a 365-d period in Operators with greater differences in single-leg landing strategies and higher body mass. The CHAID approach can be a powerful tool to analyze population-specific risk factors for injury, along with how those factors may interact to enhance risk.


Assuntos
Traumatismos em Atletas/diagnóstico , Extremidade Inferior/lesões , Aprendizado de Máquina , Adulto , Algoritmos , Composição Corporal , Humanos , Articulação do Joelho , Militares , Força Muscular , Consumo de Oxigênio , Valor Preditivo dos Testes , Estudos Prospectivos , Amplitude de Movimento Articular , Fatores de Risco , Adulto Jovem
16.
Orthop J Sports Med ; 7(3): 2325967119831272, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30891463

RESUMO

Background: Musculoskeletal injuries at the shoulder are highly prevalent and place a large burden on United States Special Forces personnel. Literature is lacking regarding the risk factors for these types of injuries. Purpose/Hypothesis: The purpose of this study was to evaluate the association of shoulder strength and kinematic characteristics, which have shown retrospective associations with shoulder conditions/injuries, with prospectively collected shoulder injuries. We hypothesized that lower strength and abnormal kinematics would be predictive of future shoulder injury. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 140 male Special Forces operators underwent a musculoskeletal evaluation of the shoulder that included a scapular kinematic assessment during a humeral elevation task and isokinetic strength testing of the scapular protractors/retractors, external/internal rotators, and elevators of the shoulder. From strength assessments, ipsilateral strength ratios and bilateral strength asymmetries were also calculated. Musculoskeletal injuries of the shoulder were collected prospectively by use of medical chart reviews at 365 days following the evaluation. Separate generalized estimating equations (GEEs) and simple logistic regressions were used to analyze the association between baseline predictors and development of shoulder injury. Results: Results of the GEEs showed no significant prediction of shoulder injury by shoulder strength (odds ratio [OR], 1.00-1.03), ipsilateral strength ratios (OR, 0.43-2.12), or scapular kinematics (OR, 0.99-1.01). Logistic regression indicated that none of the bilateral asymmetries were significantly predictive of shoulder injury (OR, 1.00-1.04). Conclusion: The results indicate that shoulder strength and kinematic characteristics are not risk factors for shoulder injury in the Special Forces population. These findings are in opposition to the general findings of previous research using a retrospective analysis.

17.
Aerosp Med Hum Perform ; 90(2): 77-83, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30670116

RESUMO

BACKGROUND: The perception-action coupling task (PACT) was designed as a more ecologically valid measure of alertness/reaction times compared to currently used measures by aerospace researchers. The purpose of this study was to assess the reliability, within-subject variability, and systematic bias associated with the PACT.METHODS: There were 16 subjects (men/women = 9 / 7; age = 27.8 ± 3.6 yr) who completed 4 identical testing sessions. The PACT requires subjects to make judgements on whether a virtual ball could fit into an aperture. For each session, subjects completed nine cycles of the PACT, with each cycle lasting 5 min. Judgement accuracy and reaction time parameters were calculated for each cycle. Systematic bias was assessed with repeated-measures ANOVA, reliability with intraclass correlation coefficients (ICC), and within-subject variability with coefficients of variation (CVTE).RESULTS: Initiation time (Mean = 0.1065 s) showed the largest systematic bias, requiring the elimination of three cycles to reduce bias, with all other variables requiring, at the most, one. All variables showed acceptable reliability (ICC > 0.70) and within-subject variability (CVTE < 20%) with only one cycle after elimination of the first three cycles.CONCLUSIONS: With a three-cycle familiarization period, the PACT was found to be reliable and stable.Connaboy C, Johnson CD, LaGoy AD, Pepping G-J, Simpson RJ, Deng Z, Ma L, Bower JL, Eagle SR, Flanagan SD, Alfano CA. Intersession reliability and within-session stability of a novel perception-action coupling task. Aerosp Med Hum Perform. 2019; 90(2):77-83.


Assuntos
Percepção , Tempo de Reação , Adulto , Medicina Aeroespacial , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Análise e Desempenho de Tarefas , Realidade Virtual
18.
Syst Rev ; 7(1): 244, 2018 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-30580762

RESUMO

BACKGROUND: Musculoskeletal injuries (MSI) represent more than half of all injuries in tactical populations (i.e., military service and public safety workers including police, firefighters, emergency medical services (EMS)). Most lower extremity MSIs result from physical exertion during training, occupational tasks, and recreation. Such exertional lower extremity injuries (ELEI) produce a significant human and financial cost. Accordingly, significant efforts have been made to identify sensitive, specific, and reliable predictors of ELEI. There is a need to synthesize and evaluate the predictive value of risk factors for ELEI while addressing the influence of occupation, sex, exposure, injury characteristics, and study quality. Therefore, the purpose of this systematic review and planned meta-analysis is to evaluate risk factors for ELEI in tactical populations. METHODS: After the development of a search strategy, comprehensive searches will be conducted in MEDLINE, EMBASE, Cochrane, and CINAHL databases. Articles will be screened with a multi-user process and delimited to prospective comparative cohort studies that directly measure injury occurrence in the target population(s). Extracted data will be synthesized and assessed for reporting bias, meta-bias, and overall quality, with subgroup analyses to determine the influence of participant, injury, and exposure characteristics in addition to study quality. DISCUSSION: This systematic review and planned meta-analysis will comprehensively evaluate ELEI risk factors. Information gained will inform injury prevention protocols, facilitate the use of improved measurements, and identify requirements for future research. TRIAL REGISTRATION: The systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 3 Jan 2018 (registration number CRD42018056977 ).


Assuntos
Socorristas , Exercício Físico/fisiologia , Extremidade Inferior/lesões , Militares , Sistema Musculoesquelético/lesões , Traumatismos Ocupacionais/prevenção & controle , Humanos , Fatores de Risco
19.
Syst Rev ; 7(1): 73, 2018 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-29729666

RESUMO

BACKGROUND: Exertional lower body musculoskeletal injuries (ELBI) cost billions of dollars and compromise the readiness and job performance of military service and public safety workers (i.e., tactical populations). The prevalence and burden of such injuries underscores the importance of prevention efforts during activities necessary to sustain core occupational competencies. Attempts to synthesize prevention techniques specific to tactical populations have provided limited insight on the comparative efficacy of interventions that do not modify physical training practices. There is also a need to assess the influence of sex, exposure, injury classification scheme, and study design. Thus, the primary purpose of the systematic review and planned meta-analysis detailed in this protocol is to evaluate the comparative efficacy of ELBI prevention strategies in tactical populations. METHODS: A systematic search strategy will be implemented in MEDLINE, EMBASE, Cochrane, and CINAHL. A multi-tiered process will be used to capture randomized controlled trials and prospective cohort studies that directly assess the prevention of ELBI in tactical population(s). Extracted data will be used to compare prevention strategies and assess the influence of heterogeneity related to occupation, sex, exposure, injury characteristics, and study quality. In addition, individual risk of bias, meta-bias, and the quality of the body of evidence will be rigorously tested. DISCUSSION: This systematic review and planned meta-analysis will comprehensively evaluate ELBI mitigation strategies in tactical populations, elucidate factors that influence responses to treatment, and assess the overall quality of the body of research. Results of this work will guide the prioritization of ELBI prevention strategies and direct future research efforts, with direct relevance to tactical, health and rehabilitation science, and human performance optimization stakeholders. SYSTEMATIC REVIEW REGISTRATION: The systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 3 Jan 2018 (registration number CRD42018081799 ).


Assuntos
Socorristas , Extremidade Inferior/lesões , Militares , Sistema Musculoesquelético/lesões , Traumatismos Ocupacionais/prevenção & controle , Exercício Físico/fisiologia , Humanos , Prevalência , Ferimentos e Lesões/prevenção & controle
20.
BMJ Open Sport Exerc Med ; 4(1): e000471, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30622731

RESUMO

Objectives: Musculoskeletal injuries (MSI) are an important concern in military populations. The purpose of this study was to describe the burden of MSI and associated financial cost, in a sample of US Air Force Special Operations Command Special Tactics Operators. Methods: In this cross-sectional study, medical records of the Operators were reviewed during the years 2014-2015. MSI that occurred during a 1-year period prior to the date of review were described. MSI attributes described included incidence, anatomic location, cause, activity when MSI occurred, type and lifetime cost of MSI estimated using the Web-based Injury Statistics Query and Reporting System. Results: A total of 130 Operators participated in the study (age: 29.1±5.2 years). The 1-year cumulative incidence of MSI was 49.2 injured Operators/100 Operators/year. The most frequent anatomic location and sublocation for MSI were the lower extremity (40.9% of MSI) and shoulder (20.9%), respectively. Lifting was a common cause of MSI (21.8%). A large per cent of MSI (55.5%) occurred while Operators were engaged in either physical or tactical training. Common MSI types were pain/spasm/ache (44.5%). Many MSI (41.8%) were classified as potentially preventable by an injury prevention training programme. The total lifetime cost of these MSI was estimated to be approximately US$1.2 million. Conclusion: MSI are an important cause of morbidity and financial cost in this sample of Air Force Special Tactics Operators. There is a need to develop a customised injury prevention programme to reduce the burden and cost of MSI in this population.

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