Effects of a Strength and Conditioning Offseason Program on Countermovement Jump Ground Reaction Forces in Division I American Football Players.

ABSTRACT: Gillen, ZM, Burch, RF, Saucier, DN, Strawderman, L, Luczak, T, Piroli, A, Petway, AJ, and Rath, T. Effects of a strength and conditioning offseason program on countermovement jump ground reaction forces in Division I American football players. J Strength Cond Res 38(3): e86-e95, 2024-The purpose of this study was to examine the effects of a 10-week strength and conditioning offseason program on the ground reaction forces (GRFs) of American football players during single-leg and double-leg countermovement jumps (SLJ and CMJ, respectively). Each subject visited the laboratory twice, once for preoffseason and once for postoffseason testing. During each visit, subjects performed CMJs and SLJs for each leg. Ground reaction forces were collected by force plates to quantify unweighting, braking, propulsive, and performance metrics for each jump. In addition, an efficiency index was calculated for each jump to examine changes in vertical jump efficiency. Dependent samples t tests compared all CMJ metrics. Two-way repeated measures analyses of variance (leg × time) compared all SLJ metrics. An alpha level of p ≤ 0.05 was considered statistically significant. For the CMJ, propulsive phase duration decreased due to the program ( p = 0.007), whereas peak braking power, peak propulsive power, mean propulsive force, and jump height increased ( p ≤ 0.012). For the SLJ, peak braking power, force at the low position, braking rate of force development, eccentric force, peak propulsive power, mean propulsive force, and jump height increased in both legs ( p ≤ 0.044). The efficiency index increased for the CMJ and the SLJ for both legs ( p ≤ 0.016). This study demonstrated that SLJ and CMJ vertical jump performance significantly increases in as few as 10 weeks of offseason strength and conditioning. Strength and conditioning programming may effectively increase vertical jump performance, as assessed by GRFs, which can be used as a simple indicator regarding changes in athletic performance.

Do They Really Work? Quantifying Fabric Mask Effectiveness to Improve Public Health Messaging.

The purpose of this study is to compare masks (non-medical/fabric, surgical, and N95 respirators) on filtration efficiency, differential pressure, and leakage with the goal of providing evidence to improve public health messaging. Masks were tested on an anthropometric face filtration mount, comparing both sealed and unsealed. Overall, surgical and N95 respirators provided significantly higher filtration efficiency (FE) and differential pressure (dP). Leakage comparisons are one of the most significant factors in mask efficiency. Higher weight and thicker fabric masks had significantly higher filtration efficiency. The findings of this study have important implications for communication and education regarding the use of masks to prevent the spread of COVID-19 and other respiratory illnesses, specifically the differences between sealed and unsealed masks. The type and fabric of facial masks and whether a mask is sealed or unsealed has a significant impact on the effectiveness of a mask. Findings related to differences between sealed and unsealed masks are of critical importance for health care workers. If a mask is not completely sealed around the edges of the wearer, FE for this personal protective equipment is misrepresented and may create a false sense of security. These results can inform efforts to educate health care workers and the public on the importance of proper mask fit.

External Load and Muscle Activation Monitoring of NCAA Division I Basketball Team Using Smart Compression Shorts.

There is scarce research into the use of Strive Sense3 smart compression shorts to measure external load with accelerometry and muscle load (i.e., muscle activations) with surface electromyography in basketball. Sixteen external load and muscle load variables were measured from 15 National Collegiate Athletic Association Division I men's basketball players with 1137 session records. The data were analyzed for player positions of Centers (n = 4), Forwards (n = 4), and Guards (n = 7). Nonparametric bootstrapping was used to find significant differences between training and game sessions. Significant differences were found in all variables except Number of Jumps and all muscle load variables for Guards, and all variables except Muscle Load for Forwards. For Centers, the Average Speed, Average Max Speed, and Total Hamstring, Glute, Left, and Right Muscle variables were significantly different (p < 0.05). Principal component analysis was conducted on the external load variables. Most of the variance was explained within two principal components (70.4% in the worst case). Variable loadings of principal components for each position were similar during training but differed during games, especially for the Forward position. Measuring muscle activation provides additional information in which the demands of each playing position can be differentiated during training and competition.

Preliminary Evaluation of Filtration Efficiency and Differential Pressure ASTM F3502 Testing Methods of Non-Medical Masks Using a Face Filtration Mount.

Research surrounding the mandated use of non-medical fabric masks is inconsistent and often confusing when compared to the standard N95. A recently published standard from ASTM International and the Centers for Disease Control and Prevention attempts to normalize evaluation procedures. The purpose of this study is to conduct a preliminary evaluation of the new methods for testing filtration efficiency of masks outlined by ASTM International F3502, where results can be directly compared to standards outlined for non-medical fabric masks. Eleven consumer non-medical fabric masks were tested for filtration efficiency and airflow resistance using a face filtration mount in accordance with the newly released ASTM International standard for facial barriers. The mean FE% (SD) ranged from 0.46% (0.44) to 11.80% (2.76) with the 3-layer athletic mesh having the highest performance and the highest deviations. All the masks tested following the procedure failed to meet to minimum FE of 20%; however all masks performed below the minimum upper limits for airflow resistance. Using a non-medical fabric masks as the sole mitigation strategy may not be as effective, as previously reported. With efforts to standardize and regulate the non-medical fabric mask market, this study demonstrates a variety of currently available consumer mask products do not meet the minimum standards nor are these remotely close to the standards of surgical or N95 masks.

Alarm-Related Workload in Default and Modified Alarm Settings and the Relationship Between Alarm Workload, Alarm Response Rate, and Care Provider Experience: Quantification and Comparison Study.

BACKGROUND: Delayed or no response to impending patient safety-related calls, poor care provider experience, low job satisfaction, and adverse events are all unwanted outcomes of alarm fatigue. Nurses often cite increases in alarm-related workload as a reason for alarm fatigue, which is a major contributor to the aforementioned unwanted outcomes. Increased workload affects both the care provider and the patient. No studies to date have evaluated the workload while caring for patients and managing alarms simultaneously and related it to the primary measures of alarm fatigue-alarm response rate and care provider experience. Many studies have assessed the effect of modifying the default alarm setting; however, studies on the perceived workload under different alarm settings are limited. OBJECTIVE: This study aimed to assess nurses' or assistants' perceived workload index of providing care under different clinical alarm settings and establish the relationship between perceived workload, alarm response rate, and care provider experience. METHODS: In a clinical simulator, 30 participants responded to alarms that occurred on a physiological monitor under 2 conditions (default and modified) for a given clinical condition. Participants completed a National Aeronautics and Space Administration-Task Load Index questionnaire and rated the demand experienced on a 20-point visual analog scale with low and high ratings. A correlational analysis was performed to assess the relationships between the perceived workload score, alarm response rate, and care provider experience. RESULTS: Participants experienced lower workloads when the clinical alarm threshold limits were modified according to patients' clinical conditions. The workload index was higher for the default alarm setting (57.60 [SD 2.59]) than for the modified alarm setting (52.39 [SD 2.29]), with a statistically significant difference of 5.21 (95% CI 3.38-7.04), t28=5.838, P<.05. Significant correlations were found between the workload index and alarm response rate. There was a strong negative correlation between alarm response rate and perceived workload, ρ28=-.54, P<.001 with workload explaining 29% of the variation in alarm response rate. There was a moderate negative correlation between the experience reported during patient care and the perceived workload, ρ28=-.49, P<.05. CONCLUSIONS: The perceived workload index was comparatively lower with alarm settings modified for individual patient care than in an unmodified default clinical alarm setting. These findings demonstrate that the modification of clinical alarm limits positively affects the number of alarms accurately addressed, care providers' experience, and overall satisfaction. The findings support the removal of nonessential alarms based on patient conditions, which can help care providers address the remaining alarms accurately and provide better patient care.

Modelling driver acceptance of driver support systems.

Driver support systems are intended to enhance driver performance and improve transportation safety. Even though these systems afford safety advantages, they challenge the traditional role of drivers in operating vehicles. Driver acceptance, therefore, is essential for the adoption of new in-vehicle technologies into the transportation system. In this study, a model of driver acceptance of driver support systems was developed. A conceptual driver acceptance model, including several components, was proposed based on a review of current literature. An empirical study was subsequently carried out using an online survey approach. The study collected data on participants' perceptions of two driver support systems (a fatigue monitoring system and an adaptive cruise control system combined with a lane-keeping system) in terms of attitude, perceived usefulness, and other components of driver acceptance. Results identified five components of driver acceptance (attitude, perceived usefulness, endorsement, compatibility, and affordability). The results also confirmed several mediating effects. The developed model was able to explain 85% of the variability in driver acceptance. The model provides an improved understanding how driver acceptance is formed, including which factors affect driver acceptance and how they affect it. The model can also help automakers and researchers to assess the design and estimate the potential use of a driver support system. The model could also be highly beneficial in developing a questionnaire to assess driver acceptance.

Formal Alternative Transportation Options for Older Adults: An Assessment of Need.

This study measured the need for formal alternative modes of transportation among older adults by applying traditional factors of the Behavioral Model. Survey participants who regularly drove were compared to those who could no longer drive. Race/ethnicity and self-reported health were significant predictors of perceived need for transportation services for both groups. However, income and service awareness were significant predictors only for drivers, while family proximity was a significant predictor only for non-drivers. Results suggest the importance of gaining a better understanding of the factors associated with need for senior-focused transportation services to more effectively plan such programs.

Assessing the utility of TAM, TPB, and UTAUT for advanced driver assistance systems.

Advanced Driver Assistance Systems (ADAS) are intended to enhance driver performance and improve transportation safety. The potential benefits of these technologies, such as reduction in number of crashes, enhancing driver comfort or convenience, decreasing environmental impact, etc., have been acknowledged by transportation safety researchers and federal transportation agencies. Although these systems afford safety advantages, they may also challenge the traditional role of drivers in operating vehicles. Driver acceptance, therefore, is essential for the implementation of these systems into the transportation system. Recognizing the need for research into the factors affecting driver acceptance, this study assessed the utility of the Technology Acceptance Model (TAM), the Theory of Planned Behavior (TPB), and the Unified Theory of Acceptance and Use of Technology (UTAUT) for modelling driver acceptance in terms of Behavioral Intention to use an ADAS. Each of these models propose a set of factors that influence acceptance of a technology. Data collection was done using two approaches: a driving simulator approach and an online survey approach. In both approaches, participants interacted with either a fatigue monitoring system or an adaptive cruise control system combined with a lane-keeping system. Based on their experience, participants responded to several survey questions to indicate their attitude toward using the ADAS and their perception of its usefulness, usability, etc. A sample of 430 surveys were collected for this study. Results found that all the models (TAM, TPB, and UTAUT) can explain driver acceptance with their proposed sets of factors, each explaining 71% or more of the variability in Behavioral Intention. Among the models, TAM was found to perform the best in modelling driver acceptance followed by TPB. The findings of this study confirm that these models can be applied to ADAS technologies and that they provide a basis for understanding driver acceptance.

Work zone sign design for increased driver compliance and worker safety.

Many studies have investigated the effect of dynamic message signs (DMS) on drivers' speed reduction and compliance in work zones, yet only a few studies have examined the design of sign content of DMS. The purpose of this study was to develop design standards for DMS to improve driver compliance and worker safety. This study investigated the impact of sign content, frame refresh rate, and sign placement on driver speed reduction, compliance, and eye movements. A total of 44 participants were recruited for this study. Each participant completed 12 simulated driving tasks in a high-fidelity driving simulator. A small-scale field study was also conducted to test the effect of DMS on vehicle speed in a highway work zone. Results showed sign content and placement had no impact on speed reduction and compliance. However, sign frame refresh rate was found to have a significant effect on drivers' initial speed and speed reduction. Participants had longer fixation duration on DMS when worker presence was mentioned in the sign content. Results of the field study suggested that the DMS is most effective at night.

Evaluating pedestrian behavior at crosswalks: Validation of a pedestrian behavior questionnaire for the U.S. population.

The aim of this study was to develop and validate a self-reporting Pedestrian Behavior Questionnaire (PBQ) for the U.S. population to measure frequency of risky behaviors among pedestrians. The PBQ includes 50 survey items that allow respondents to rate the frequency with which they engage in different types of road-using behaviors as pedestrians. The validation study was conducted on 425 participants (228 males and 197 females) between the ages of 18 and 71. Confirmatory factor analysis differentiated pedestrian behaviors into five factor categories: violations, errors, lapses, aggressive behaviors, and positive behaviors. A short version of the PBQ with 20 items was also created by selecting four items with high factor loadings from each of the five factor categories. Regression analyses investigated associations with scenario-based survey behavioral responses to validate the five-factor PBQ subscale scores and composite score. For both long and short versions, each of these five individual factor scales were found to be reliable (0.7

Efficacy of virtual reality in pedestrian safety research.

Advances in virtual reality technology present new opportunities for human factors research in areas that are dangerous, difficult, or expensive to study in the real world. The authors developed a new pedestrian simulator using the HTC Vive head mounted display and Unity software. Pedestrian head position and orientation were tracked as participants attempted to safely cross a virtual signalized intersection (5.5 m). In 10% of 60 trials, a vehicle violated the traffic signal and in 10.84% of these trials, a collision between the vehicle and the pedestrian was observed. Approximately 11% of the participants experienced simulator sickness and withdrew from the study. Objective measures, including the average walking speed, indicate that participant behavior in VR matches published real world norms. Subjective responses indicate that the virtual environment was realistic and engaging. Overall, the study results confirm the effectiveness of the new virtual reality technology for research on full motion tasks.

Evaluating change in user error when using ruggedized handheld devices.

The increasing number of handheld mobile devices used today and the increasing dependency on them in the workplace makes understanding how users interact with these devices critical. This study seeks to understand how user error changes based on user age as well as input content type on ruggedized handheld devices. Participants completed data entry tasks of word and character input on two different devices, a physical keypad and touchscreen device. The number of errors and types of error, corrected and permanent were collected for each participant. Based on results on the study, touchscreen devices proved to be the optimal ruggedized handheld device to minimize user error.

Driver behavior and accident frequency in school zones: Assessing the impact of sign saturation.

Based on the models of human information processing, if a driver observes too many of the same signs, he or she may no longer pay attention to those signs. In the case of school zones, this expected effect may lead to non-compliance to posted speeds, negatively impacting safety around nearby schools. This study aims to investigate the effect of the number of nearby school zones on driver behavior (vehicle speed and compliance) and accident frequency. As a measure of the density of school zones, this study introduced and defined a new term sign saturation and presented a methodology to calculate sign saturation for school zones. Results found a significant effect of sign saturation on vehicle speed, compliance, and accident frequency. This study also examined the speeding behavior in school zones for different time of the day and day of the week. Results found that speeding was more prevalent in the early mornings and during the weekends.

Effects of BMI and task parameters on postural sway during simulated small parts assembly.

Postural stability is critical for ensuring a safe workplace. Employees with poor stability are more prone to falls and injuries while at work. In this study, postural sway of participants in different obesity categories was evaluated while performing an assembly workstation task. The study included three workstations: those designed for the 5th, 50th and 95th percentile workers based on anthropometric data tables. Force plates were used to study the differences in postural sway in both the medial-lateral and anterior-posterior directions. The results revealed that the obese class 1 and obese class 2 groups' anterior-posterior sway was significantly larger than that of the normal weight groups while performing assembly work tasks. Also, pace type (self-paced or time-paced) and workstation (5th, 50th and 95th percentile) significantly affected the postural sway. The postural sway was not affected by gender differences. Workstations should be designed to accommodate the increased postural sway of obese workers. PRACTITIONER SUMMARY: It is known that body mass index (BMI) affects postural sway. In this study, we examine the impact of BMI on postural sway at various workstation configurations. The postural sway was significantly larger in participants with larger BMIs.

The effects of protoype medium on usability testing.

Inconsistencies among testing methods and results in previous research prompted this study that builds upon a systematic usability testing research framework to better understand how interface medium influences users' abilities to detect usability flaws in applications. Interface medium was tested to identify its effects on users' perceptions of usability and abilities to detect usability problems and severe usability problems. Results indicated that medium has no effect on users' abilities to detect usability problems or perceptions of usability. However, results did indicate an interaction between the medium and the tested application in which users were able to identify significantly more usability problems on a higher fidelity medium using a particular application. Results also indicated that as users' perceptions of an application's usability increases, the users are less able to detect usability problems in that application. Usability testing should begin early in the design process, even if low fidelity mediums will be used.

Quality and usability in a student health clinic.

PURPOSE: To evaluate the service quality and usability of a student health clinic. DESIGN/METHODOLOGY/APPROACH: A measurement tool, termed SERVUSE, was created by modifying SERVQUAL. The modified survey included all five original dimensions in addition to a usability dimension. The survey was administered to 200 patients at the health clinic. FINDINGS: SERVUSE was found to be a valid tool for measuring service quality in this setting. The health clinic received a gap score of -0.357, showing that customer expectations were not met. RESEARCH LIMITATIONS/IMPLICATIONS: The student health clinic and subject participants are a special population that may display different characteristics from other healthcare providers. PRACTICAL IMPLICATIONS: SERVUSE is a tool that can be used to aid in improving a health clinic's service quality. Usability is an important feature for healthcare providers to improve. ORIGINALITY/VALUE: This paper provides useful information to healthcare providers, especially in a university setting.