Joel Martin

George Mason University | GMU · Kinesiology

Background/Objectives: To examine the combined effects of sleep quality, dual tasks, and load carriage on postural stability. Methods: Twenty-three university student participants (12 males, ages: 24.6 ± 6.1 year) completed the Pittsburgh Sleep Quality Index (PSQI), then performed quiet standing and a dual task while standing on force plates with a...

Sax van der Weyden, M, Merrigan, JJ, and Martin, J. Long duration load carriage performance is associated with Army Combat Fitness Test scores and fat free mass. J Strength Cond Res 38(11): 1959-1966, 2024-A common occupational task for the military is carrying heavy loads for long periods of time. The US Army has set a time standard of 3 hours to...

Background: Firefighter physical fitness (PF) plays a crucial role in mitigating health issues and supporting occupational performance. The influence of rank on firefighter PF remains understudied and previous research is often limited by small sample sizes of firefighters volunteering for research studies, potentially biasing results towards fitt...

Sax van der Weyden, M, Merrigan, JJ, Newman, K, Hahn, J, and Martin, J. Army Combat Fitness Test scores moderate cognitive function improvements after a ruck march: A hierarchical linear model approach. J Strength Cond Res XX(X): 000–000, 2024—Heavy load carriage is a common task for military personnel and can lead to undue physical and mental fati...

Introduction: Many researchers use Ratings of Perceived Exertion (RPE) as an indicator of subjective fatigue. Recent findings suggest that energy and fatigue are two distinct unipolar moods. Methods: Eleven first responders (FR) participated in a 90-minute strenuous exercise battery where they ended the protocol by completing a graded VO2max test...

INTRODUCTION: Law enforcement officers (LEO) experience high rates of injuries, specifically to the lower extremity and back regions. LEO commonly wear a duty belt or tactical vest while on duty. Prior literature has reported on the biomechanical effects of load carriage on center of pressure measures related to postural stability and gait kinemati...

Objective: The objective of this talk is to present how structured fitness programs can be strategically integrated into fire departments to enhance the resilience of firefighters, ultimately equipping them with the capacity to perform occupational tasks more effectively, reduce musculoskeletal injuries, and address prevalent health challenges with...

Load monitoring using wearable devices has become a key part of understanding adaptation to training stimuli, assessing recovery, and reducing potential injury risk for elite level soccer players. The intensity of training sessions (TS) are intentionally manipulated to ensure players are at peak performance for competitive matches (CM). Prior liter...

Background: Despite the physical nature of the occupation many firefighters have low levels of physical fitness which is associated with poor performance of occupational tasks and increased injury rates. For many fire departments an initial step in promoting health and wellness within the department is to conduct annual fitness testing. Objective...

Objective The objective of the present study was to find biomechanical correlates of single-task gait and self-reported sleep quality in a healthy, young population by replicating a recently published study. Materials and Methods Young adults (n = 123) were recruited and were asked to complete the Pittsburgh Sleep Quality Inventory to assess sleep...

Clinical scenario: Dancing is a demanding esthetic activity with dancers having an 85% annual injury incident rate when performing complex dance motor skills. Teachers and clinicians use a combination of external and internal attentional cues when teaching dancers motor skills and when working on rehabilitation programs with injured dancers, respe...

Dance is physically demanding, requiring physical fitness (PF) that includes upper body, lower body, core fitness, and balance for successful performance. Whether PF changes as dancers advance from when they enter (freshmen) to when they graduate from their collegiate program (seniors) is unclear. We prospectively compared collegiate dancers’ fresh...

Sixty percent of all law enforcement officers (LEOs) experience low back pain (LBP), with the LEO duty belt (LEODB) commonly reported to be a contributing factor. The primary purpose of the study was to investigate the LEODB’s effect on muscular activity and compare it to a tactical vest, which is a commonly used alternative to an LEODB. In total,...

Law enforcement officers are inherently at a high risk of injury and the loads they must carry during their occupational duties further increase their injury risk. It is unknown how different methods of carrying a law enforcement officer's load influence factors related to injury risk. This study assessed the effects of common law enforcement load...

Background: The work-related stress experienced by firefighters is associated with numerous health issues. In the general population, improving physical fitness is associated with improvements in both mental and physical quality of life. Objective: The purpose of the study was to examine whether fitter professional firefighters report greater ph...

Dance is physically demanding, requiring physical fitness(PF) that includes upper body, lower body, core fitness, and balance for successful performance. Whether PF changes as dancers advance from when they enter(freshmen) to when they graduate from their collegiate program(seniors) is unclear. We prospectively compared collegiate dancers’ freshman...

Introduction: Sleep is essential for athletes and dancers to optimize recovery. Poor sleep negatively affects cognitive function and injury risk in athletes. Increased athletic participation (hours) is associated with decreased total sleep and quality in athletes. Still, information about how sleep is related with exposure hours and injury in coll...

Objectives To examine the effects of implementing a consequential fitness assessment (pull-ups, curl-ups, push-ups, 3 min step test) in a fire department on an individual level. Methods We used a repeated-measures design to analyse fitness assessment data from 2019 to 2020 in Northern Virginia. A total of 631 professional firefighters completed th...

Background: There are contradictory findings in the literature on whether an acute bout of aerobic exercise leads to a post-exercise improvement in cognitive function (CF). Moreover, participants used in the published literature are not representative of the racial make-up of sport or tactical populations. Methods: A randomized crossover design...

Law enforcement officers (LEOs) commonly wear a duty belt (DB) or tactical vest (TV) and from prior findings, these forms of load carriage (LC) likely alter muscular activity. However, studies on the effects of LEO LC on muscular activity and coordination are limited in the current literature. The present study examined the effects of LEO load carr...

College students can be sedentary for a majority of the day, which may exacerbate mental health issues or lead to declines in cognitive task performance; however, interventions to address sedentary behaviors may not positively influence everyone. Therefore, the present study sought to identify inter-individual cognitive performance and mood changes...

Context: Following anterior cruciate ligament (ACL) reconstruction, athletes commonly undergo prolonged rehabilitation (e.g., 9-12 months), but few individuals actually return to pre-injury sports activities. The nature (composition, configuration) of an ACL rehabilitation program (ACL-RP) is an important factor in determining rehabilitation outcom...

Load carriage (LC) is a contributing factor to musculoskeletal injury in many occupations. Given that falls are a common mechanism of injury for those frequently engaging in LC, understanding the effects of LC on postural stability (PS) is necessary. A systematic review and meta-analysis was conducted to examine effects of LC on PS. Sixteen and 9 s...

Engaging in physical activity (PA), minimizing sitting time and consuming a healthy diet are behaviors associated with health and wellness across the lifespan. The present multi-study analysis examined the relationship between grit and PA, sitting time and dietary behaviors in several populations that included US adults, active-duty military person...

Attempting to understand on-field sport performance from dynamic performance tests of athleticism (i.e., sprinting, jumping, strength) is common practice in sport. In recent years, the isometric mid-thigh pull (IMTP) has gained popularity in the sport performance community as an assessment tool. This scoping review examined the relationship of the...

Drastic changes to lifestyles have occurred during the COVID-19 pandemic. An unintended consequence of stay at home orders is increased isolation and less social interaction for many people. For overall wellbeing it is important to stay both physically and mentally active; however, for many individual's motivation may be a barrier. There are non-mo...

Moderate-to-vigorous physical activity (MVPA) for prolonged periods of time is related to cardiorespiratory fitness (CRF). Sleep quality (SQ) can be operationally defined from components, such as sleep efficiency and sleep-onset latency. Diet is operationally defined as the quantity and quality of nutrient intake. CRF, SQ, and diet are related to a...

A maximum plank hold (PH) has been implemented in the Army Combat Fitness Test (ACFT) with the Holistic Health and Fitness (H2F) program. The H2F program introduces a shift in wellbeing from a fitness centered approach to framework also comprising nutrition, sleep, mental, and spiritual components. The purpose was to analyze how a maximum PH correl...

Gait modifications, such as lateral trunk lean (LTL), medial knee thrust (MKT) and toe-in gait (TIG), are frequently investigated interventions used to slow the progression of knee osteoarthritis. The Lerner knee model was developed to estimate the tibiofemoral joint reaction forces (JRF) in the medial and lateral compartments during gait. These mo...

Failure to obtain the recommended 7-9 h of sleep has been associated with injuries in youth and adults. However, most research on the influence of prior night's sleep and gait has been conducted on older adults and clinical populations. Therefore, the objective of this study was to identify individuals who experience partial sleep deprivation and/o...

Grit has been associated with feelings of energy when measured as the opposite end of fatigue. During the COVID-19 pandemic, grit has been linked to positive health-related behaviors, which are known to influence feelings of energy and fatigue. The objective of this study was to identify the association between grit, time spent sitting, physical ac...

Clinical Question : What are the acute effects of reactive neuromuscular training on frontal plane knee kinematics during squatting movements? Clinical Bottom Line : There is Grade B evidence suggesting that there are no significant improvements in measures of frontal plane knee kinematics when reactive neuromuscular training is performed via loope...

Recently, moderate-to-vigorous intensity physical activity (MVPA) has attracted additional scientific interest (e.g., ACSM recommendations) not only thanks to a) the physical and psychological benefits that can be experienced by the general population following just a single bout, but also b) since high levels of MVPA seem to mitigate the mortality...

Objective: To investigate the influence of grit on physical activity, sleep and diet in undergraduate students during the COVID-19 pandemic. Participants: 125 undergraduate students participated in the study. Participants completed an online survey while enrolled in an online class during June, 2020. Methods: The online questionairre featured the f...

Drastic changes to lifestyles have occurred during the COVID-19 pandemic. A consequence of nonpharmaceutical interventions (NPIs) used against this health crisis, such as stay-at-home orders, has been increased isolation and less social interaction for a majority of people. For overall wellbeing, it is important to stay both physically and mentally...

Failure to obtain 7-9 hours of sleep has been associated with decreased gait speed in young adults. While Machine Learning (ML) has been used to identify sleep quality in young adults, there are no current studies that have used ML to identify prior night’s sleep in a sample of young adults. PURPOSE: To use ML to identify prior night’s sleep in hea...

Grit has been positively associated with feelings of energy (when measured as the opposite end of fatigue). During the COVID-19 pandemic, grit has been inter-related with positive health-related behaviors, which are known to influence feelings of energy and fatigue. PURPOSE: To identify the association between grit, health-related behaviors and fee...

Clinical Question : Does reactive neuromuscular training (RNT) increase gluteal muscle activation during squatting movements? Clinical Bottom Line : The current best evidence suggests RNT may result in acute increases of gluteus maximus and gluteus medius muscle activation when performing the barbell back squat exercise; however, the findings were...

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...

BACKGROUND: Law enforcement recruits (LER) often encounter shoulder injuries, which may cause attrition from academies. Investigating required upper body muscular fitness may inform of muscular balance around shoulder joints through anterior and posterior ratios in LER. OBJECTIVE: To investigate push to pull ratios (P2P) and factors related with P...

Indirect calorimetry (IC) is considered the gold standard for assessing resting metabolic rate (RMR). However, many people do not have access to IC devices and use prediction equations for RMR estimation. Equations using fat free mass (FFM) as a predictor have been developed to estimate RMR, as a strong relationship exists between FFM and RMR. One...

Clinical Scenario : Knee pathologies often require rehabilitation to address the loss of knee-extensor (KE) strength, function, and heightened pain. However, in the early stages of rehabilitation, higher loads may be contraindicated. Blood flow restriction (BFR) resistance training does not require high loads and has been used clinically to promote...

Trunk modification is associated with knee abduction moment reduction in both healthy groups and individuals with knee osteoarthritis. Ambulatory-related changes in trunk kinematics have been implicated in increased trunk moment. The purpose of this study was to investigate the effect of dose-specific lateral trunk lean on trunk kinetics during ips...

Force plate assessments, such as countermovement jumps and isometric mid-thigh pulls, examine performances (e.g., jump height, force, power) and movement strategies (e.g., asymmetries, durations), and are best suited to characterize and monitor physical capabilities, not predict injuries. To begin applying force plate technologies, users must first...

Balance and gait assessments are commonly implemented to screen for injury risks and function by clinicians. Recent evidence in older adults suggests that feelings of energy and fatigue influence gait and balance however, there is limited evidence on the influence of these moods on gait and balance in young adults. Therefore, the purpose of this st...

Due to occupational demands professional firefighters (FF) require high levels of physical fitness. Common FF occupational tasks include carrying equipment, pushing and pulling objects, climbing ladders and moving continuously for long durations under load. It has been reported that multiple components of physical fitness are associated with the ab...

Annual estimates are that approximately 34% of law enforcement recruits (LER) fail to complete the academy due to injury or inability to meet physical standards. Shoulder injuries are a commonly cited injury which can cause LER to leave the police academy. It has been suggested that anterior ('push') and posterior ('pull') musculature should be bal...

Poor sleep is well documented in firefighters. Shift schedules combined with occupational requirements are known to be contributing factors to poor chronic and acute sleep of firefighters. The negative effects of poor sleep on firefighters were documented in a 2007 review supported by the International Association of Fire Chiefs and the United Stat...

The objective of this study was to examine the associations between physical activity (PA) and sedentary behavior (SB) on feelings of: 1) mental energy (ME), 2) physical energy (PE), 3) mental fatigue (MF) and 4) physical fatigue (PF) in participants who report sitting for less than 8 h (<8 h) compared to those who report sitting for greater than 8...

The objective of this study was to take a multi-domain approach to predict feelings of anxiety among graduate allied health students. Participants (n=77) from a small university in upstate New York completed a series of questionnaires [International Physical Activity Questionnaire-short form (IPAQ-SF), Rapid Eating Assessment of Participants-Short...

Obtaining sufficient sleep is beneficial for numerous aspects of health. Despite current sleep recommendations, acute disruptions in sleep duration are inevitable for most. While extreme sleep deprivation impairs motor control and coordination of movement, sleep extension also impacts these same parameters. Prior research suggests that acute change...

Obtaining sufficient sleep is beneficial for numerous aspects of health. Despite current sleep recommendations, acute disruptions in sleep duration are inevitable for most. While extreme sleep deprivation impairs motor control and coordination of movement, sleep extension also impacts these same parameters. Prior research suggests that acute change...

Objective Middle school is often the first exposure to American football for many children. However, research examining concussion in football has primarily focused on high school and older athletes. Therefore, we investigated the incidence of concussion and subsequent sport time loss (TL) in MS football. Methods Athlete exposure (AE) and injury r...

Objective Wrestling has among the highest concussion incidence in all high school and collegiate sports. Many children begin wrestling in middle school (MS), however, research describing concussion incidence in MS wrestling remains limited. Therefore, we sought to describe the incidence of concussion and subsequent sport time loss (TL) sustained by...