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Justin M Merrigan

Other affiliations: West Virginia University
Bio: Justin M Merrigan is an academic researcher from George Mason University. The author has contributed to research in topics: Morning. The author has an hindex of 1, co-authored 1 publications receiving 2 citations. Previous affiliations of Justin M Merrigan include West Virginia University.
Topics: Morning

Papers
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TL;DR: In this article, the relationship between external load and self-reported wellness measures across a collegiate men's soccer preseason was examined, and multilevel models revealed the bidirectional prediction of load markers on fatigue, soreness, sleep, energy, and sRPE (p < 0.05).
Abstract: Fields, JB, Lameira, DM, Short, JL, Merrigan, JM, Gallo, S, White, JB, and Jones, MT. Relationship between external load and self-reported wellness measures across a collegiate men's soccer preseason. J Strength Cond Res 35(5): 1182-1186, 2021-Monitoring athlete training load is important to training programming and can help balance training and recovery periods. Furthermore, psychological factors can affect athlete's performance. Therefore, the purpose was to examine the relationship between external load and self-reported wellness measures during soccer preseason. Collegiate men soccer athletes (n = 20; mean ± SD age: 20.3 ± 0.9 years; body mass: 77.9 ± 6.8 kg; body height: 178.87 ± 7.18cm; body fat: 10.0 ± 5.0%; Vo2max: 65.39 ± 7.61ml·kg-1·min-1) participated. Likert scale self-assessments of fatigue, soreness, sleep, stress, and energy were collected daily in conjunction with the Brief Assessment of Mood (vigor, depression, anger, fatigue, and confusion). Total distance (TD), player load (PL), high-speed distance (HSD, >13 mph [5.8 m·s-1]), high inertial movement analysis (IMA, >3.5 m·s-2), and repeated high-intensity efforts (RHIEs) were collected in each training session using positional monitoring (global positioning system/global navigation satellite system [GPS/GNSS]) technology. Session rate of perceived exertion (sRPE) was determined from athlete's post-training rating (Borg CR-10 Scale) and time of training session. Multilevel models revealed the bidirectional prediction of load markers on fatigue, soreness, sleep, energy, and sRPE (p < 0.05). Morning ratings of soreness and fatigue were predicted by previous afternoon's practice measures of TD, PL, HSD, IMA, RHIE, and sRPE. Morning soreness and fatigue negatively predicted that day's afternoon practice TD, PL, HSD, IMA, RHIE, and sRPE. Morning ratings of negative mood were positively predicted by previous day's afternoon practice HSD. In addition, negative morning mood states inversely predicted HSD (p = 0.011), TD (p = 0.002), and PL (p < 0.001) for that day's afternoon practice. Using self-reported wellness measures with GPS/GNSS technology may enhance the understanding of training responses and inform program development.

9 citations


Cited by
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TL;DR: The use of heart rate variability (HRV) is becoming more common in the tactical community as discussed by the authors due to an increased understanding of its importance and the commercial availability of assessment tools.
Abstract: Human performance optimization of tactical personnel requires accurate, meticulous, and effective monitoring of biological adaptations and systemic recovery. Due to an increased understanding of its importance and the commercial availability of assessment tools, the use of heart rate variability (HRV) to address this need is becoming more common in the tactical community. Measuring HRV is a non-invasive, practical method for objectively assessing a performer's readiness, workload, and recovery status; when combined with additional data sources and practitioner input, it provides an affordable and scalable solution for gaining actionable information to support the facilitation and maintenance of operational performance. This narrative review discusses the non-clinical use of HRV for assessing, monitoring, and interpreting autonomic nervous system resource availability, modulation, effectiveness, and efficiency in tactical populations. Broadly, HRV metrics represent a complex series of interactions resulting from internal and external stimuli; therefore, a general overview of HRV applications in tactical personnel is discussed, including the influence of occupational specific demands, interactions between cognitive and physical domains, and recommendations on implementing HRV for training and recovery insights into critical health and performance outcomes.

9 citations

Journal ArticleDOI
TL;DR: In this paper , internal and external load parameters of 90 elite BB and 3×3 athletes were monitored during 84 games using a local positioning system (10"Hz) and inertial movement sensors (100"Hz).
Abstract: Purpose 3 × 3 is a variation of classic basketball (BB) that imposes new demands on both athletes and coaches. The objective of this study was to comprehensively describe similarities and differences in load structures between 3 × 3 and BB. Method Between January 2020 and July 2021, internal and external load parameters of 90 elite BB and 3 × 3 athletes were monitored during 84 games using a local positioning system (10 Hz) and inertial movement sensors (100 Hz). Results Male BB games last about 90 min; female games are shorter (82 min). Game duration in 3 × 3 is about 16 min. Compared with BB, 3 × 3 athletes perform more medium- and high-intensity accelerations and decelerations, explosive efforts, jumps, and changes of direction (CODs) per min. Average heart rates do not differ between the two disciplines, yet 3 × 3 games are rated as more exhausting than BB games. During a 3 × 3 tournament, no decrease in load characteristics is found in the final games. However, ratings of perceived exertion increase consecutively. Average possession duration in 3 × 3 is 5.4 s in which 1.4 passes are played. Most 2-point shots and turnovers occur in the last minutes (11 min – end) of the game. Conclusion The findings of this study will help 3 × 3 coaches and athletes to design more effective training programmes and improve athletic performance. They indicate a need to focus on high accelerations, transitions, COD skills, and shooting under pressure in 3 × 3.

8 citations

DOI
01 Dec 2021
TL;DR: In this paper, the effects of sleep on firefighter occupational performance and health were evaluated using the Newcastle-Ottawa Scale (NOS) with a total sample of 1591 (1539 male, 52 female) firefighters.
Abstract: Firefighting is a mentally and physically demanding profession which is compounded by poor sleep due to shift schedules commonly used by fire departments. Compared to other professions, firefighters are at high risk for musculoskeletal injuries, mental illnesses, and cardiovascular diseases. The purpose of this study was to systemically review the effects of sleep on firefighter occupational performance and health. A search was conducted for studies that conducted a quantitative analysis involving sleep and occupational performance in firefighters. Relevant data were extracted and study quality evaluated with Newcastle-Ottawa Scale. There were 15 articles meeting the inclusion criteria with a total sample of 1591 (1539 male, 52 female) firefighters. We found that firefighters with poor sleep measures had worse cognitive performance and overall health, but physical capabilities were not impacted by acute sleep restriction. However, chronic poor sleep would likely negatively impact physical performance due to being associated with a decline in numerous health measures. To avoid sleep-related declines in occupational performance fire departments should consider the consequences of shift schedules on the performance and health of firefighters. Furthermore, sleep education interventions, the use of wearables to monitor, recovery and sleep health screening appear beneficial based on prior research.

3 citations

Journal ArticleDOI
TL;DR: In this paper , the authors investigated changes in contractility of the m. rectus femoris (RF) and m. gastrocnemius medialis (GC) in response to the load of single 3 × 3 games and a three-game tournament and concluded that the breaks between games seem to be sufficient to return to the initial level of muscle contractility.
Abstract: Abstract Purpose 3 × 3 basketball games are characterized by high-intensity accelerations and decelerations, and a high number of changes of direction and jumps. It is played in tournament form with multiple games per day. Therefore, optimal regeneration is crucial for maintaining a high performance level over the course of the tournament. To elucidate how load of a match affects the athletes' bodies (i.e., internal load), muscular responses to the load of 3 × 3 games were analyzed. We aimed to investigate changes in contractility of the m. rectus femoris (RF) and m. gastrocnemius medialis (GC) in response to the load of single 3 × 3 games and a 3 × 3 tournament. Methods Inertial movement analysis was conducted to capture game load in 3 × 3. Changes in contractility were measured using tensiomyography (TMG). During a two-day tournament, TMG measurements were conducted in the morning and after each game. Additionally, off-game performance analysis consisting of jump and change-of-direction (COD) tests was conducted the day before the tournament. Results Significant changes of the muscle contractility were found for GC with TMG values being higher in the baseline than in the post-game measurements. In contrast to athletes of the GC group, athletes of the RF group responded with either decreased or increased muscle contractility after a single 3 × 3 game. A significant correlation between external and internal load parameters could not be shown. Concerning off-game performance, significant correlations can be reported for COD test duration, CMJ height and ∆Vc as well as COD test duration and ∆Dm. No systematic changes in muscle contractility were found over the course of the tournament in RF and GC. Conclusion The athletes' external 3 × 3 game load and their performance level did not seem to affect muscular contractility after a single 3 × 3 game or a complete 3 × 3 tournament within this investigation. This might indicate that elite athletes can resist external load without relevant local muscular fatigue. With respect to the course of the tournament, it can therefore be concluded that the breaks between games seem to be sufficient to return to the initial level of muscle contractility.

2 citations

Journal ArticleDOI
TL;DR: In this paper , the authors developed a big data analytics framework to predict players' wellness according to the external and internal workloads performed in previous days, which is useful for coaches and staff to simulate the players' response to scheduled training in order to adapt the training stimulus to the players’ fatigue response.
Abstract: Training for success has increasingly become a balance between maintaining high performance standards and avoiding the negative consequences of accumulated fatigue. The aim of this study is to develop a big data analytics framework to predict players’ wellness according to the external and internal workloads performed in previous days. Such a framework is useful for coaches and staff to simulate the players’ response to scheduled training in order to adapt the training stimulus to the players’ fatigue response. 17 players competing in the Italian championship (Serie A) were recruited for this study. Players’ Global Position System (GPS) data was recorded during each training and match. Moreover, every morning each player has filled in a questionnaire about their perceived wellness (WI) that consists of a 7-point Likert scale for 4 items (fatigue, sleep, stress, and muscle soreness). Finally, the rate of perceived exertion (RPE) was used to assess the effort performed by the players after each training or match. The main findings of this study are that it is possible to accurately estimate players’ WI considering their workload history as input. The machine learning framework proposed in this study is useful for sports scientists, athletic trainers, and coaches to maximise the periodization of the training based on the physiological requests of a specific period of the season.

1 citations