Differences in Situational Patterns During Change of Direction Movements Greater than 90° in Youth Male and Female Soccer Players.

Change of direction (COD) maneuvers in soccer create tactical advantages, but also expose the player to an increased risk of injury. COD ability is commonly tested with pre-planned drills including cuts greater than 90°. These tests do not take into consideration positional differences players encounter during games. This case-series study used principal component analysis (PCA) to examine situational differences during COD movements between playing positions in youth soccer games. For each of the four teams included (26 females, 27 males), one game was analyzed using video-analysis. Two independent reviewers identified situational patterns and a PCA was used to examine differences between playing positions. Three principal components explained 89% of the variation in the data and were categorized as the total quantity of CODs, attacking/goal-scoring and defensive reacting types of CODs. One-way ANOVA on the individual principal component (PC) scores showed significant differences (p < 0.05) between centre midfielders, goalkeepers, and centrebacks in the quantity of CODs (PC1), and between wingers and fullbacks and centre backs in attacking/goal-scoring CODs (PC2), whereas PC3 was not different between playing positions. Differences between playing positions suggest that training and testing protocols in soccer could be enhanced to better match the individual and playing position-based needs.

Evaluating a Wearable Solution for Measuring Lower Extremity Asymmetry During Landing.

Purpose: Force plates can be used to monitor landing asymmetries during rehabilitation, but they are not widely available. Accelerometer-based wearable technology may be a more feasible solution. The purpose of this article was to determine the agreement between impact accelerations measured with force plates and accelerometer-derived measures of (1) centre of mass (COM) acceleration and (2) tibial acceleration asymmetries during bilateral landings. Method: Participants completed three countermovement jumps (CMJ) and three squat jumps (SJ) on dual force plates with triaxial accelerometers attached to each tibia and lower back, near the COM. Bland and Altman 95% limits of agreement (95% LOA) were calculated. Results: 19 adults (n = 11; 58% women, n = 8; 42% men) participated in the study. The mean differences between impact and COM accelerations were 0.24 g (95% LOA: -1.34 g to 1.82 g) and 0.38 g (95% LOA: -1.15 to 1.91 g) for the CMJ and SJ, respectively. The mean differences between the impact and tibial acceleration-based lower limb asymmetries in the CMJ and SJ were -6% (95% LOA: -32% to 19%) and 0% (95% LOA: -45% to 45%), respectively. Conclusions: Our findings show acceptable agreement between impact acceleration and accelerometer-based COM acceleration and lack of agreement between impact accelerations and accelerometer-based tibial acceleration asymmetries. COM acceleration could be used to quantify landing impacts during rehabilitation, but we do not consider the accelerometer-based asymmetry measures to be a suitable alternative for force plate-based measures. Future work should focus on determining normative values for lower extremity asymmetries during landing tasks.

Objectif: les plateformes de force peuvent être utilisées pour surveiller les asymétries à l'atterrissage pendant la réadaptation, mais elles ne sont pas largement accessibles. Le recours à la technologie portable sous forme d'accéléromètres serait peut-être plus réalisable. Le présent article visait à déterminer la concordance entre les mesures d'accélération à l'impact à l'aide des plateformes de force et à l'aide des accéléromètres pour connaître 1) l'accélération au centre de gravité (CdG) et 2) les asymétries d'accélération tibiale lors des atterrissages bilatéraux. Méthodologie: les participants ont effectué trois sauts avec contre-mouvement (SCM) et trois sauts groupés (SG) sur des plateformes de double force conjuguées à l'installation d'accéléromètres triaxiaux à chaque tibia et à la colonne lombaire, près du CdG. Les chercheurs ont calculé les limites de concordance à 95 % de Bland et Altman (LdC à 95 %). Résultats: au total, 19 adultes (n = 11; 58 % de femmes, n = 8; 42 % d'hommes) ont participé à l'étude. Les chercheurs ont établi que les principales différences entre l'accélération à l'impact et l'accélération au CdG étaient de 0,24 g (LdC à 95 %; −1,34 g à 1,82 g) et de 0,38 g (LdC à 95 %; −1,15 g à 1,91 g) lors des SCM et des SG, respectivement. Les différences moyennes entre l'impact et les asymétries des membres inférieurs à l'accélération tibiale lors des SCM et des SG correspondaient à −6 % (LdC à 95 %; −32 % à 19 %) et à 0 % (LdC à 95 %; −45 % à 45 %), respectivement. Conclusions: selon les observations des chercheurs, la concordance est acceptable entre l'accélération à l'impact et l'accélération au CdG à l'aide des accéléromètres, mais pas entre les accélérations à l'impact et les asymétries d'accélération tibiale à l'aide des accéléromètres. L'accélération au CdG pourrait être utilisée pour quantifier les impacts à l'atterrissage pendant la réadaptation, mais les chercheurs ne considèrent pas que les mesures d'asymétrie à l'aide des accéléromètres peuvent remplacer convenablement les mesures obtenues à l'aide des plateformes de force. Les futurs travaux devraient viser à déterminer les valeurs normatives des asymétries des membres inférieurs pendant des tâches d'atterrissage.

Systematic review of methods used to measure training load in dance.

Dance is a popular physical activity. Increased dance training has been associated with an increased risk of injury. Given the established association between training load (TL) and injury in sport, knowledge of how TL is currently being measured in dance is critical. The objective of this study is to summarise published literature examining TL monitoring in dance settings. Six prominent databases (CINAHL, EMBASE, Medline, ProQuest, Scopus, SportDiscus) were searched and nine dance-specific journals were handsearched up to May 2022. Selected studies met inclusion criteria, where original TL data were collected from at least one dancer in a class, rehearsal and/or performance. Studies were excluded if TL was not captured in a dance class, rehearsal or performance. Two reviewers independently assessed each record for inclusion at title, abstract and full-text screening stages. Study quality was assessed using Joanna Briggs Institute Critical Appraisal Tool checklists for each study design. The 199 included studies reported on female dancers (61%), ballet genre (55%) and the professional level (31%). Dance hours were the most common tool used to measure TL (90%), followed by heart rate (20%), and portable metabolic systems (9%). The most common metric for each tool was mean weekly hours (n=381; median=9.5 hours, range=0.2-48.7 hours), mean heart rate (n=143) and mean oxygen consumption (n=93). Further research on TL is needed in dance, including a consensus on what tools and metrics are best suited for TL monitoring in dance.

Optimal positive end-expiratory pressure reduces right ventricular dysfunction in COVID-19 patients on venovenous extracorporeal membrane oxygenation: A retrospective single-center study.

While mechanical ventilation practices on venovenous extracorporeal membrane oxygenation (VV ECMO) are variable, most institutions utilize a lung rest strategy utilizing relatively low positive end-expiratory pressure (PEEP). The effect of PEEP titration using esophageal manometry during VV ECMO on pulmonary and cardiac function is unknown. This was a retrospective study of 69 patients initiated on VV ECMO between March 2020 through November 2021. Patients underwent standard PEEP (typically 10 cm H2O) or optimal PEEP (PEEP titrated to an end-expiratory transpulmonary pressure 0-3 cm H2O) throughout the ECMO run. The optimal PEEP strategy had higher levels of applied PEEP (17.9 vs. 10.8 cm H2O on day 2 of ECMO), decreased incidence of hemodynamically significant RV dysfunction (4.55% vs. 44.0%, p = 0.0001), and higher survival to decannulation (72.7% vs. 44.0%, p = 0.022). Survival to discharge did not reach statistical significance (61.4% vs. 44.0%, p = 0.211). In univariate logistic regression analysis, optimal PEEP was associated with less hemodynamically significant RV dysfunction with an odds ratio (OR) of 0.06 (95% confidence interval [CI] = 0.01-0.27, p = 0.0008) and increased survival to decannulation with an OR of 3.39 (95% CI 1.23-9.79), p = 0.02), though other confounding factors may have contributed.

COVID-19 vaccine attitudes among a majority black sample in the Southern US: public health implications from a qualitative study.

BACKGROUND: The COVID-19 pandemic continues to have high caseloads in the US, with vaccines a critical component of the response. Disparities in COVID-19 morbidity and mortality have been identified across states and racial/ethnic groups, which are likely in part due to disparities in COVID-19 vaccine uptake. This study aims to better understand and contextualize COVID-19 vaccine hesitancy among persons from under-represented racial/ethnic populations in the Southern US. METHODS: We conducted 29 in-depth interviews with a sample of households in Atlanta, GA that were selected from an address-based sampling frame. We purposively approached households, from February 6 to June 27, 2021, that declined participation in a national COVID-19 serosurvey to gain perspectives of people who are often under-represented in research. Interviews were conducted in-person or over phone calls for participants with that preference. Thematic analysis was used to identify barriers and facilitators of COVID-19 vaccination, and to contextualize drivers of vaccine hesitancy. RESULTS: Decision-making about vaccination was described as dynamic, and was compared to the feeling of being on a roller coaster. The predominant reported sources of information were mass media and social media. Facilitators of vaccination included altruism, positive communication from trusted community members and workplace colleagues, and local vaccine provision sites. Driving reasons for vaccine hesitancy included limited trust in the government and concerns about COVID-19 vaccine safety, which one participant compared to jumping off a cliff without a tested rope. Among a subset of participants, beliefs regarding perceived intent to harm the Black community were prevalent. Opportunities to optimally address vaccine hesitancy included countering negative social media messages with positive messaging that matches the community's vivid ways of discussing vaccines, collaborating with community stakeholders on vaccine promotion efforts, and offering workplace-based vaccine promotion efforts. CONCLUSIONS: This study presents data that indicate it may be optimal to more broadly define 'community' in COVID-19 vaccine promotion efforts to include social media and workplace venues. To optimize vaccine and vaccine booster uptake and equity, public health must address historic racism and other concerns by using outreach that is grounded in communities.

Who Does Not Respond to Injury Prevention Warm-up Programs? A Secondary Analysis of Trial Data From Neuromuscular Training Programs in Youth Basketball, Soccer, and Physical Education.

OBJECTIVES: To identify factors associated with nonresponse to neuromuscular training (NMT) warm-up programs among youth exposed to NMT warm-ups. METHODS: This is a secondary analysis of youth (aged 11-18 years) in the intervention groups of 4 randomized controlled trials in high school basketball, youth community soccer, and junior high school physical education. Youth who were exposed to NMT and who sustained an injury during the study were considered nonresponders. Odds ratios (ORs) were based on generalized estimating equations logistic regression controlling for clustering by team/class and adjusted for age, weight, height, balance performance, injury history, sex, and sport (soccer/basketball/physical education). RESULTS: A total of 1793 youth were included. Youth with a history of injury in the previous year had higher odds (OR = 1.64; 95% CI: 1.14, 2.37) of injury during the study, and females were more likely (OR = 1.67; 95% CI: 1.21, 2.31) to sustain an injury than males who were participating in NMT. Age was not associated with the odds of sustaining an injury (OR = 1.10; 95% CI: 0.93, 1.30). Soccer players benefited most from greater adherence, with 81% lower odds of injury (OR = 0.19; 95% CI: 0.06, 0.57) when completing 3 NMT sessions a week compared with 1 session per week. CONCLUSION: Factors associated with nonresponse to an NMT warm-up program were female sex, history of injury during the previous 12 months, and lower weekly NMT session adherence in some sports (soccer). J Orthop Sports Phys Ther 2023;53(2):94-102. Epub: 9 December 2022. doi:10.2519/jospt.2022.11526.

Impact of acute intoxication on quantitative pupillometry assessment in the emergency department.

Study Hypothesis/Objective: This prospective cohort study aimed to assess whether and to what extent different quantitative pupillometry (QP) metrics are associated with different intoxicant drug classes as well as investigate the potential benefit of QP as a tool in the rapid assessment of clinically intoxicated patients in the emergency department (ED). Methods: Between February 25, 2019 and April 24, 2021, 325 patients were enrolled in the EDs of the Hospital of the University of Pennsylvania (HUP) and Penn Presbyterian Medical Center (PPMC). Patients deemed clinically intoxicated or in withdrawal by an attending emergency physician were considered for eligibility. Patients <18 years old, with a chief complaint indicative of head trauma or stroke or without a urine drug screen (UDS) positive for drugs of abuse were excluded. QP data were also collected from a cohort of 82 healthy control subjects. Results: Neurological Pupil index (NPi) values did not vary significantly between control and study groups nor between study group patients with a UDS positive for opioids. With exception of latency of constriction, all other QP metrics for the study group were depressed relative to controls (P < 0.005). Conclusions: This work demonstrated the feasibility of QP measurement in the ED, finding that NPi remains unaffected by clinical intoxication and therefore can potentially be used for ED patient evaluation without risk of confounding by key intoxicants of abuse. Future work will evaluate the value of QP as a means of rapid and reproducible neurological assessment to identify various pathologies.

COVID-19 Vaccine Attitudes among a Majority Black Sample in the Southern US: Public Health Implications from a Qualitative Study.

BACKGROUND: The COVID-19 pandemic continues to have high caseloads in the US, with vaccines a critical component of the response. Disparities in COVID-19 morbidity and mortality have been identified across states and racial/ethnic groups, which are likely in part due to disparities in COVID-19 vaccine uptake. This study aims to better understand and contextualize COVID-19 vaccine hesitancy among persons from primarily racial/ethnic minority populations in the Southern US. METHODS: We conducted 29 in-depth interviews with a sample of households in Atlanta, GA that were selected from an address-based sampling frame. We purposively approached households, from February 6 to June 27, 2021, that declined participation in a national COVID-19 serosurvey to gain perspectives of people who are often under-represented in research. Interviews were conducted in-person or over phone calls for participants with that preference. Thematic analysis was used to identify barriers and facilitators of COVID-19 vaccination, and to contextualize drivers of vaccine hesitancy. RESULTS: Decision-making about vaccination was described as dynamic, and was compared to the feeling of being on a roller coaster. The predominant reported sources of information were mass media and social media. Facilitators of vaccination included altruism, positive communication from trusted community members and workplace colleagues, and local vaccine provision sites. Driving reasons for vaccine hesitancy included limited trust in the government and concerns about COVID-19 vaccine safety, which one participant compared to jumping off a cliff without a tested rope. Among a subset of participants, beliefs regarding perceived intent to harm the Black community were prevalent. Opportunities to optimally address vaccine hesitancy included countering negative social media messages with positive messaging that matches the community's vivid ways of discussing vaccines, collaborating with community stakeholders on vaccine promotion efforts, and offering workplace-based vaccine promotion efforts. CONCLUSIONS: This study presents data that indicate it may be optimal to more broadly define 'community' in COVID-19 vaccine promotion efforts to include social media and workplace venues. To optimize vaccine and vaccine booster uptake and equity, public health must address historic racism and other concerns by using outreach that is grounded in communities.

Is This the Real Life, or Is This Just Laboratory? A Scoping Review of IMU-Based Running Gait Analysis.

Inertial measurement units (IMUs) can be used to monitor running biomechanics in real-world settings, but IMUs are often used within a laboratory. The purpose of this scoping review was to describe how IMUs are used to record running biomechanics in both laboratory and real-world conditions. We included peer-reviewed journal articles that used IMUs to assess gait quality during running. We extracted data on running conditions (indoor/outdoor, surface, speed, and distance), device type and location, metrics, participants, and purpose and study design. A total of 231 studies were included. Most (72%) studies were conducted indoors; and in 67% of all studies, the analyzed distance was only one step or stride or <200 m. The most common device type and location combination was a triaxial accelerometer on the shank (18% of device and location combinations). The most common analyzed metric was vertical/axial magnitude, which was reported in 64% of all studies. Most studies (56%) included recreational runners. For the past 20 years, studies using IMUs to record running biomechanics have mainly been conducted indoors, on a treadmill, at prescribed speeds, and over small distances. We suggest that future studies should move out of the lab to less controlled and more real-world environments.

No, No One Had Fun. Individual Differences in Nonliteral Language Perception.

Nonliteral language represents a complex form of communication that can be interpreted in numerous different ways. Our study explored how individual differences in personality and communication styles affect the evaluation of literal and nonliteral language in the context of assumptions made by the Tinge Hypothesis (Dews & Winner, 1995). Participants watched videos of social interactions focusing on positive, negative, sarcastic, and jocular statements. They evaluated speaker intentions and social impressions and completed several personality and communication style questionnaires. Individual differences in empathy, defense style, and sarcasm use correlated with the accuracy of identifying speaker intent. Additionally, positive statements were rated as friendlier when compared to jocular statements, thereby supporting the Tinge Hypothesis. However, literal negative statements were rated as more friendly than sarcastic statements, which is inconsistent with the Tinge Hypothesis. The current results provide novel evidence for the Tinge Hypothesis using multimodal, dynamic stimuli and highlight the role of the individual personality of the recipient in evaluating sarcasm and jocularity.

Evaluating Methods for Imputing Missing Data from Longitudinal Monitoring of Athlete Workload.

Missing data can influence calculations of accumulated athlete workload. The objectives were to identify the best single imputation methods and examine workload trends using multiple imputation. External (jumps per hour) and internal (rating of perceived exertion; RPE) workload were recorded for 93 (45 females, 48 males) high school basketball players throughout a season. Recorded data were simulated as missing and imputed using ten imputation methods based on the context of the individual, team and session. Both single imputation and machine learning methods were used to impute the simulated missing data. The difference between the imputed data and the actual workload values was computed as root mean squared error (RMSE). A generalized estimating equation determined the effect of imputation method on RMSE. Multiple imputation of the original dataset, with all known and actual missing workload data, was used to examine trends in longitudinal workload data. Following multiple imputation, a Pearson correlation evaluated the longitudinal association between jump count and sRPE over the season. A single imputation method based on the specific context of the session for which data are missing (team mean) was only outperformed by methods that combine information about the session and the individual (machine learning models). There was a significant and strong association between jump count and sRPE in the original data and imputed datasets using multiple imputation. The amount and nature of the missing data should be considered when choosing a method for single imputation of workload data in youth basketball. Multiple imputation using several predictor variables in a regression model can be used for analyses where workload is accumulated across an entire season.

Magnitude, Frequency, and Accumulation: Workload Among Injured and Uninjured Youth Basketball Players.

Overuse injuries are common in basketball. Wearable technology enables the workload to be monitored in sport settings. However, workload-injury models lack a biological basis both in the metrics recorded and how workload is accumulated. We introduce a new metric for monitoring workload: weighted jump height, where each jump height is weighted to represent the expected effect of the jump magnitude on damage to the tendon. The objectives of this study were to use principal components analysis to identify distinct modes of variation in all workload metrics accumulated over 1, 2, 3, and 4 weeks and to examine differences among the modes of variation in workload metrics between participants before the injury and uninjured participants. Forty-nine youth basketball players participated in their typical basketball practices and games, and lower extremity injuries were classified as patellar or Achilles tendinopathy, other overuse, or acute. An inertial measurement unit recorded the number and height of all jumps, and session rating of perceived exertion was recorded. The previous 1-, 2-, 3-, and 4-week workloads of jump count, jump height, weighted jump height, and session rating of perceived exertion were summed for each participant-week. Principal components analysis explained the variance in the accumulated workload variables. Using the retained principal components, the difference between the workload of injured participants in the week before the injury and the mean workload of uninjured participants was described for patellar or Achilles tendinopathy, overuse lower extremity injury, and any lower extremity injury. Participants with patellar or Achilles tendinopathy and overuse lower extremity injuries had a low workload magnitude for all variables in the 1, 2, 3, and 4 weeks before injury compared with the weeks before no injury. Participants with overuse lower extremity injuries and any lower extremity injury had a high previous 1-week workload for all variables along with a low previous 3- and 4-week jump count, jump height, and weighted jump height before injury compared with the weeks before no injury. Weighted jump height represents the cumulative damage experienced by tissues due to repetitive loads. Injured youth basketball athletes had a low previous 3- and 4-week workloads coupled with a high previous 1-week workload.

Tracking nonliteral language processing using audiovisual scenarios.

Recognizing sarcasm and jocularity during face-to-face communication requires the integration of verbal, paralinguistic, and nonverbal cues, yet most previous research on nonliteral language processing has been carried out using written or static stimuli. In the current study, we examined the processing of dynamic literal and nonliteral intentions using eye tracking. Participants (N = 37) viewed short, ecologically valid video vignettes and were asked to identify the speakers' intention. Participants had greater difficulty identifying jocular statements as insincere in comparison to sarcastic statements and spent significantly more time looking at faces during nonliteral versus literal social interactions. Finally, participants took longer to shift their attention from one talker to the other talker during interactions that conveyed literal positive intentions compared with jocular and literal negative intentions. These findings currently support the Standard Pragmatic Model and the Parallel-Constraint-Satisfaction Model of nonliteral language processing. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Workload a-WEAR-ness: Monitoring Workload in Team Sports With Wearable Technology. A Scoping Review.

OBJECTIVES: To (1) identify the wearable devices and associated metrics used to monitor workload and assess injury risk, (2) describe the situations in which workload was monitored using wearable technology (including sports, purpose of the analysis, location and duration of monitoring, and athlete characteristics), and (3) evaluate the quality of evidence that workload monitoring can inform injury prevention. DESIGN: Scoping review. LITERATURE SEARCH: We searched the CINAHL, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Embase, HealthSTAR, MEDLINE, PsycINFO, SPORTDiscus, and Web of Science databases. STUDY SELECTION CRITERIA: We included all studies that used wearable devices (eg, heart rate monitor, inertial measurement units, global positioning system) to monitor athlete workload in a team sport setting. DATA SYNTHESIS: We provided visualizations that represented the workload metrics reported, sensors used, sports investigated, athlete characteristics, and the duration of monitoring. RESULTS: The 407 included studies focused on team ball sports (67% soccer, rugby, or Australian football), male athletes (81% of studies), elite or professional level of competition (74% of studies), and young adults (69% of studies included athletes aged between 20 and 28 years). Thirty-six studies of 7 sports investigated the association between workload measured with wearable devices and injury. CONCLUSION: Distance-based metrics derived from global positioning system units were common for monitoring workload and are frequently used to assess injury risk. Workload monitoring studies have focused on specific populations (eg, elite male soccer players in Europe and elite male rugby and Australian football players in Oceania). Different injury definitions and reported workload metrics and poor study quality impeded conclusions regarding the relationship between workload and injury. J Orthop Sports Phys Ther 2020;50(10):549-563. doi:10.2519/jospt.2020.9753.

New Considerations for Collecting Biomechanical Data Using Wearable Sensors: The Effect of Different Running Environments.

Traditionally, running biomechanics analyses have been conducted using 3D motion capture during treadmill or indoor overground running. However, most runners complete their runs outdoors. Since changes in running terrain have been shown to influence running gait mechanics, the purpose of this study was to use a machine learning approach to objectively determine relevant accelerometer-based features to discriminate between running patterns in different environments and determine the generalizability of observed differences in running patterns. Center of mass accelerations were recorded for recreational runners in treadmill-only (n = 28) and sidewalk-only (n = 25) environments, and an independent group (n = 16) ran in both treadmill and sidewalk environments. A feature selection algorithm was used to develop a training dataset from treadmill-only and sidewalk-only running. A binary support vector machine model was trained to classify treadmill and sidewalk running. Classification accuracy was determined using 10-fold cross-validation of the training dataset and an independent testing dataset from the runners that ran in both environments. Nine features related to the consistency and variability of center of mass accelerations were selected. Specifically, there was greater ratio of vertical acceleration during treadmill running and a greater ratio of anterior-posterior acceleration during sidewalk running in both the training and testing dataset. Step and stride regularity were significantly greater in the treadmill condition for the vertical axis in both the training and testing dataset, and in the medial-lateral axis for the testing dataset. During sidewalk running, there was significantly greater variability in the magnitude of the vertical and anterior-posterior accelerations for both datasets. The classification accuracy based on 10-fold cross-validation of the training dataset (M = 93.17%, SD = 2.43%) was greater than the classification accuracy of the independent testing dataset (M = 83.81%, SD = 3.39%). This approach could be utilized in future analyses to identify relevant differences in running patterns using wearable technology.

Validation of a commercially available inertial measurement unit for recording jump load in youth basketball players.

A high incidence of overuse knee injuries among youth basketball players may be attributed to number of jumps. Wearable technology may be an effective tool for measuring jump load compared to traditional counting methods. The purpose of this study was to validate a commercially available jump counter (VERT® Classic) in youth basketball practices and games, and to identify the characteristics (i.e., height, direction, takeoff) of jumps recorded by the VERT® Classic. 46 (19F, 27M) youth basketball players wore a VERT® Classic and were recorded on video during games and practices. The number of jumps recorded by the VERT® Classic and evaluated by video raters were compared for each jump characteristic using intraclass correlation coefficient (ICC(3,k)), mean offset, and limits of agreement. The number and percent of VERT® Classic jumps and corresponding video jumps according to timestamp were reported. VERT® Classic jumps had excellent reliability with video-counted jumps over 15 cm (ICC(3,k) = 0.958), with a mean offset of -2.4 jumps (fewer VERT® Classic) and limits of agreement -12.6 to 7.8 jumps. Pairs of corresponding jumps represented 68.0% of total video jumps and 92.0% of VERT® Classic jumps. The VERT® Classic can provide an estimate of jump load in youth basketball.

Exploring the potential utility of a wearable accelerometer for estimating impact forces in ballet dancers.

Excessive forces and/or loading rates during landing may place ballet dancers at risk for overuse injury. The ability to estimate and monitor the landing forces of ballet dancers could help to improve injury prevention and rehabilitation; however, force platforms are not conducive to testing outside of a laboratory. Fortunately, it may be possible to indirectly assess landing forces via a wearable accelerometer. The purposes of this study were to examine the relationship between impact accelerations, recorded via a pelvis-worn accelerometer, and the peak forces and loading rates during performance of a common ballet manoeuvre, and to examine if a wearable accelerometer is sensitive to fatigue-related changes in landing forces. Fifteen ballet dancers continuously performed a ballet manoeuvre until self-determined exhaustion while impact accelerations and landing forces were simultaneously recorded using an accelerometer and force platforms. We observed very strong, positive relationships between the impact accelerations and the peak forces and loading rates during the landings. In addition, the changes in impact accelerations with fatigue paralleled the changes in the peak forces and loading rates. As a result, it appears that a wearable accelerometer could be used to estimate and monitor landing forces in ballet dancers.

New Considerations for Wearable Technology Data: Changes in Running Biomechanics During a Marathon.

The purpose of this study was to use wearable technology data to quantify alterations in subject-specific running patterns throughout a marathon race and to determine if runners could be clustered into subgroups based on similar trends in running gait alterations throughout the marathon. Using a wearable sensor, data were collected for cadence, braking, bounce, pelvic rotation, pelvic drop, and ground contact time for 27 runners. A composite index was calculated based on the "typical" data (4-14 km) for each runner and evaluated for 14 individual 2-km sections thereafter to detect "atypical" data (ie, higher indices). A cluster analysis assigned all runners to a subgroup based on similar trends in running alterations. Results indicated that the indices became significantly higher starting at 20 to 22 km. Cluster 1 exhibited lower indices than cluster 2 throughout the marathon, and the only significant difference in characteristics between clusters was that cluster 1 had a lower age-grade performance score than cluster 2. In summary, this study presented a novel method to investigate the effects of fatigue on running biomechanics using wearable technology in a real-world setting. Recreational runners with higher age-grade performance scores had less atypical running patterns throughout the marathon compared with runners with lower age-grade performance scores.

New Considerations for Collecting Biomechanical Data Using Wearable Sensors: How Does Inclination Influence the Number of Runs Needed to Determine a Stable Running Gait Pattern?

As inertial measurement units (IMUs) are used to capture gait data in real-world environments, guidelines are required in order to determine a 'typical' or 'stable' gait pattern across multiple days of data collection. Since uphill and downhill running can greatly affect the biomechanics of running gait, this study sought to determine the number of runs needed to establish a stable running pattern during level, downhill, and uphill conditions for both univariate and multivariate analyses of running biomechanical data collected using a single wearable IMU device. Pelvic drop, ground contact time, braking, vertical oscillation, pelvic rotation, and cadence, were recorded from thirty-five recreational runners running in three elevation conditions: level, downhill, and uphill. Univariate and multivariate normal distributions were estimated from differing numbers of runs and stability was defined when the addition of a new run resulted in less than a 5% change in the 2.5 and 97.5 quantiles of the 95% probability density function for each individual runner. This stability point was determined separately for each runner and each IMU variable (univariate and multivariate). The results showed that 2-4 runs were needed to define a stable running pattern for univariate, and 4-5 days were necessary for multivariate analysis across all inclination conditions. Pearson's correlation coefficients were calculated to cross-validate differing elevation conditions and showed excellent correlations (r = 0.98 to 1.0) comparing the training and testing data within the same elevation condition and good to very good correlations (r = 0.63-0.88) when comparing training and testing data from differing elevation conditions. These results suggest that future research involving wearable technology should collect multiple days of data in order to build reliable and accurate representations of an individual's stable gait pattern.

Automated Accelerometer-Based Gait Event Detection During Multiple Running Conditions.

The identification of the initial contact (IC) and toe off (TO) events are crucial components of running gait analyses. To evaluate running gait in real-world settings, robust gait event detection algorithms that are based on signals from wearable sensors are needed. In this study, algorithms for identifying gait events were developed for accelerometers that were placed on the foot and low back and validated against a gold standard force plate gait event detection method. These algorithms were automated to enable the processing of large quantities of data by accommodating variability in running patterns. An evaluation of the accuracy of the algorithms was done by comparing the magnitude and variability of the difference between the back and foot methods in different running conditions, including different speeds, foot strike patterns, and outdoor running surfaces. The results show the magnitude and variability of the back-foot difference was consistent across running conditions, suggesting that the gait event detection algorithms can be used in a variety of settings. As wearable technology allows for running gait analyses to move outside of the laboratory, the use of automated accelerometer-based gait event detection methods may be helpful in the real-time evaluation of running patterns in real world conditions.