Sean Newcomer

• Doctor of Philosophy
• Professor (Full) at California State University, San Marcos

The purpose of this study was to characterize the perception of heat loss, comfort, and wetness in recreational surfers wearing wetsuits, to compare these data with changes in skin temperature reported in prior studies, and to examine the impact of wetsuit thickness, zipper location, and accessory use on thermal sensation and comfort. Following the...

International Journal of Exercise Science 16(7): 599-612, 2023. Prior research has demonstrated that male adults and youth engaged in skateboarding at community skateparks achieve heart rates that meet or exceed recommendations for exercise by the CDC. However, these studies do not adequately evaluate other non-traditional or ethnically diverse use...

Silicone applied to the exterior of jersey-lined neoprene may increase heat absorption and water repulsion without the loss of strength and durability observed in smoothskin neoprene. The purpose of this study was to compare skin temperature under silicone-coated jersey-lined neoprene and smoothskin neoprene during recreational surfing. A secondary...

Surf wetsuits are made of foamed chloroprene (neoprene), a synthetic rubber that is hard to recycle. Thermoplastic elastomer foam (TPE) may be a more sustainable replacement for neoprene in wetsuit design, but its impact on human thermoregulation and movement has not been evaluated. The purpose of this study was to compare skin temperature, oxygen...

Purpose The purpose of this study was to determine whether there are differences in skin temperature under graphene-infused fleece and traditional polyester fleece materials in the interior of a wetsuit. Design/methodology/approach A total of 48 participants surfed for a minimum of 40 min in a custom wetsuit with a torso lined with graphene-infuse...

The purpose of this study was to test the hypothesis that under controlled surf conditions, sex differences in skin temperature exist, but core temperature would not vary between sexes when performing a simulated surf session while wearing a 2-mm wetsuit. Twenty male and 13 female surfers engaged in a 60-min simulated surf protocol using a custom 2...

Growth in the surfing equipment industry has led to increased scientific interest in this area, yet no current paper has reviewed and synthesized the effects of equipment design on surfing. Therefore, the aims of this study were to: (1) assess the volume and type of scientific literature that is available to the authors specific to surfing equipmen...

Surfing has grown significantly in the past decade as highlighted by its inclusion in the 2020 Olympic Games. This growth substantiates a need for training methods that improve surfing performance. The purpose of this review is to (a) identify training methods available to competitive and recreational surfers in peer-reviewed literature, (b) evalua...

The mitochondrial electron transfer complex (ETC) profile is modified in the heart tissue of the offspring born to an exercised sow. The hypothesis proposed and tested was that a regular maternal exercise of a sow during pregnancy would increase the mitochondrial efficiency of offspring heart bioenergetics. This hypothesis was tested by isolating m...

Measuring the mitochondrial electron transfer complex (ETC) profile from previously frozen heart tissue samples from offspring born to an exercised sow provided descriptive data about exercise induced mitochondrial biochemical changes in heart tissue from the offspring born to the exercised sow. The hypothesis that was proposed and tested was that...

Surfing offers unique challenges to thermoregulation and hydration. The purpose of this study was to quantify fluid loss in recreational surfers, and to analyze the effects of water temperature, air temperature, exercise intensity, duration, and garment thickness on the total amount of fluid lost during a surf session. A total of 254 male and 52 fe...

International Journal of Exercise Science 13(6): 1574-1582, 2020. Surfing is a worldwide sport that often requires participants to wear a wetsuit to assist in thermoregulation. In a recent study, forearm skin temperature decreased by approximately 3 °C while wearing a wetsuit during recreational surfing. The purpose of this study was to test the hy...

While some research does exist on wetsuit thermoregulation, there is currently a paucity in the literature describing how various types of neoprene materials affect skin temperatures. The purpose of this study was to test the hypothesis that the slick neoprene would lead to higher skin temperatures in comparison to the jersey material. Participants...

Youth participating in recreational skating at community skate parks attain exercise intensities and durations that are comparable with the CDC's exercise recommendations for cardiovascular fitness for their age group. However, it is currently unclear if adults who skateboard in the same environment also achieve the recommended intensities and dura...

Smetanka, RG, Armenta, RF, Nessler, JA, and Newcomer, SC. Heart rate response, duration, grip strength, and anthropometric characteristics in recreational indoor rock climbers. J Strength Cond Res 36(3): 832-837, 2022-Despite the growing popularity of recreational indoor rock climbing, there is a lack of research on cardiovascular responses to rock...

The aim of this investigation was to examine regional skin temperatures in recreational female surfers’ wearing a 2 mm thick neoprene wetsuit while surfing and to compare these results to previously published data collected in males participating in an identical study. Female surfers (n = 27) engaged in surfing for at least 40 min while wearing a c...

Abstract Furr, HN, Warner, ME, Copeland, TL, Robles-Rodríguez, C, Ponce-González, JG, Nessler, JA, and Newcomer, SC. Differences in V[Combining Dot Above]O2peak of surfers when paddling in water vs. on a swimbench ergometer. J Strength Cond Res XX(X): 000–000, 2019—The purpose of this study was to test the hypothesis that surfers would achieve a hi...

Nessler, JA, Ponce-Gonzalez, JG, Robles-Rodriguez, C, Furr, H, Warner, M, and Newcomer, SC. Electromyographic analysis of the surf paddling stroke across multiple intensities. J Strength Cond Res 33(4): 1102-1110, 2019-Surfers spend a majority of their time in the water paddling. The purpose of this study was to examine activity in 5 muscles that c...

Regular physical training improves cardiac autonomic tone. There are compensatory adaptations that occur within the tissue at the biochemical level. It is known that exercise influences cardiac myocyte biochemistry by enabling mitochondria to work more efficiently. Exercising during pregnancy is thought to be beneficial for the cardiovascular healt...

Background: and Purpose: Yoga has grown in popularity and may offer a viable alternative form of physical activity. The purpose of this study was to examine heart rate, hydration, and thermal responses to a power yoga sequence. Materials and methods: Twenty-seven men and women (n = 4/23; Mean ± SD age = 23.3 ± 3.3 years; BMI = 23 ± 3 kg m-2) und...

Crocker, GH, Moon, JF, Nessler, JA, and Newcomer, SC. Energetics of swimming with hand paddles of different surface areas. J Strength Cond Res XX(X): 000-000, 2018-Hand paddles are one of the most common training aids used by the competitive swimmer, yet little is known regarding how hand paddle surface area affects the metabolic cost of transport...

Furr, HN, Nessler, JA, and Newcomer, SC. Characterization of heart rate responses, duration, and distances traveled in youth participating in recreational skateboarding at community skateparks. J Strength Cond Res XX(X): 000-000, 2018-Recreational skateboarding continues to gain popularity in youth within the United States and abroad. Surprisingly,...

: Regular physical training improves cardiac autonomic tone. Besides changes in autonomic control, there are compensatory adaptations that occur within the tissue at the biochemical level. It is known that exercise influences cardiac myocyte biochemistry that enables mitochondria to work more efficiently. Exercising during pregnancy is thought to b...

The purpose of this study was to investigate skin temperatures across surfers’ bodies while wearing a wetsuit during recreational surfing. Forty-six male recreational surfers participated in this study. Participants were instrumented with eight wireless iButton thermal sensors for the measurement of skin temperature, a Polar RCX5 heart rate monitor...

Surfboard volume and shape affect human performance while riding waves, but little is known regarding the impact of these variables on paddling, where surfers spend a majority of their time. The purpose of this study was to determine whether changing the foil (fore/aft thickness profile) of a short surfboard will alter paddling mechanics and effici...

Low back pain is a commonly reported problem among recreational surfers. Some individuals report that wearing a vest with an inflatable bladder that alters trunk angle may help to alleviate pain. The purpose of this study was to determine whether such a vest has an effect on muscle activation and extension of the lower back. Twelve recreational sur...

The purpose of this study was to investigate how altering surfboard volume (BV) affects energy expenditure during paddling. Twenty surfers paddled in a swim flume on five surfboards in random order twice. All surfboards varied only in thickness and ranged in BV from 28.4 to 37.4 L. Measurements of heart rate (HR), oxygen consumption (VO2), pitch an...

Participation in surfing has evolved to include all age groups. Therefore, the purpose of this study was to determine whether activity levels and cardiovascular responses to surfing change with age. Surfing time and heart rate (HR) were measured for the total surfing session and within each activity of surfing (paddling, sitting, wave-riding and mi...

Surfing consists of both high and low intensity paddling of varying durations, utilizing both the aerobic and anaerobic systems. Surf specific physiological studies lack adequate group sample sizes and VO2peak values are yet to determine differences between competitive and recreational surfers. The purpose of this study was therefore to provide a c...

P2072: Beneficial effects of maternal exercise on offspring cardiac tissue mitochondrial efficiency Abdulbaki Agbas* , Daniel Barrera, Tara Notarianni, Ki Suk Eum, Megan Liberty, Robert Liu, Sean Newcomer, Linda E. May, and Jessica Sage ABSTRACT: Regular physical training improves cardiac autonomic tone. Besides changes in autonomic control, there...

Despite the nation's rising epidemic of childhood obesity and diabetes, schools struggle to promote physical activities that help reduce risks for cardiovascular disease. Emerging data suggest that adopting novel activities into Physical Education (PE) curriculum may serve as an effective strategy for increasing physical activity in children. The p...

Surfers often wear wetsuits while paddling in the ocean. This neoprene covering may be beneficial to upper extremity movement by helping to improve proprioceptive acuity, or it may be detrimental by providing increased resistance. The purpose of this study was to evaluate the effects of wearing a wetsuit on muscle activation, upper extremity motion...

Background Although acute elevation in retrograde shear rate (SR) impairs endothelial function, no previous study has explored the effect of prolonged elevation of retrograde SR on conduit artery vascular function. We examined the effect of 2‐weeks elevation of retrograde SR on brachial artery endothelial function in young and in older men. Method...

Mounting evidence indicates that maternal exercise confers protection to adult offspring against various diseases. Here we hypothesized that maternal exercise during gestation would reduce high fat diet (HFD) induced hepatic steatosis in adult rat offspring. Following conception, pregnant dams were divided into either voluntary wheel running exerci...

Calcium is a shortfall essential nutrient that has been a mainstay of osteoporosis management. Recent and limited findings have prompted concern about the contribution of calcium supplementation to cardiovascular risk. A proposed mechanism is through the acceleration of coronary artery calcification. Determining causality between calcium intake and...

Maternal behaviors during pregnancy have been reported to impact offspring health in adulthood. In this review we explore the novel hypothesis that exercise during pregnancy can protect against chronic disease susceptibility in offspring. To date research has demonstrated that improvements in metabolic outcomes, cardiovascular risk, and cancer can...

Research has revealed the role of adverse behaviors during pregnancy on metabolic and cardiovascular health outcomes in offspring. However, little attention has been focused on positive prenatal behaviors, such as exercise, and the impact on offspring health outcomes. The objective of this investigation was to test the hypothesis that voluntary exe...

Background The development of long-term vascular disease can be linked to the intrauterine environment, and maternal nutrition during gestation plays a critical role in the future vascular health of offspring. The purpose of this investigation was to test the hypothesis that a high-energy (HE) gestational diet, HE post-weaning diet, or their combin...

Breast cancer is the most common cancer among women. Emerging research indicates that modifying lifestyle factors during pregnancy may convey long-term health benefits to offspring. This study was designed to determine whether maternal exercise during pregnancy leads to reduced mammary tumorigenesis in female offspring. Pregnant rats were randomly...

Current research suggests exercise during pregnancy benefits the cardiovascular health of offspring. We have studied the effects of exercise during pregnancy on fetal cardiac mitochondrial ability to make energy. We hypothesized that regular maternal exercise during pregnancy increases the mitochondrial (energy) efficiency of fetal heart. Pregnant...

Breast cancer is the most common cancer among women. Emerging research indicates that modifying lifestyle factors during pregnancy may convey long‐term health benefits to offspring. This study was designed to determine whether maternal exercise during pregnancy leads to reduced mammary tumorigenesis in female offspring. Pregnant rats were randomly...

The purpose of this study was to test the hypothesis that maternal exercise during pregnancy would enhance coronary artery endothelial function in swine offspring that were fed a high fat diet. Pubertal gilts were divided into exercise (n =8) and sedentary (n =8) groups. Pregnant gilts in the exercise group performed treadmill exercise 5 days per w...

The capability for externally applied rhythmic limb compressions to improve the outcomes of patients with peripheral artery disease has been recognized for nearly a century. Modern technology has permitted the development of portable and cost-effective intermittent pneumatic compression (IPC) systems to be made readily available for affordable at-h...

New Findings What is the central question of this study? Adverse maternal behaviour during pregnancy is well known to have lifelong health consequences for offspring. We asked whether a positive maternal health behaviour may have positive long‐term effects for offspring. Specifically, we investigated whether aerobic maternal exercise improves nitri...

Independent stance is one of the most difficult motor milestones to achieve. Newly standing infants exhibit exaggerated body movements and can only stand for a brief amount of time. Given the difficult nature of bipedal stance, these unstable characteristics are slow to improve. However, we demonstrate that infants can increase their stability when...

The heterogeneous progression of atherosclerotic disease in the peripheral arteries is currently not well understood. In humans, artery specific disease progression is partly attributed to the local hemodynamic environments. However, despite similar hemodynamic environments, porcine brachial arteries are protected while femoral arteries are highly...

Oscillatory and retrograde shear rate (SR) impairs endothelial function, potentially through shear-induced oxidative stress. We tested the hypothesis that acute vitamin C supplementation would prevent the attenuation of brachial artery flow-mediated dilation (FMD) after a period of augmented oscillatory and retrograde SR. Twelve healthy men (aged 2...

To investigate lower-extremity arterial hemodynamics in individuals with spinal cord injury (SCI). We hypothesized that oscillatory shear index would be altered and resting mean shear would be higher in the lower-extremity arteries of SCI. Research: Cross-sectional study of men and women with SCIs compared to able-bodied controls. Subjects included...

Background: Acute doses of elevated retrograde shear rate (SR) appear to be detrimental to endothelial function in resting humans. However, retrograde shear increases during moderate intensity exercise which also enhances post-exercise endothelial function. Since SR patterns differ with the modality of exercise, it is important to determine if aug...

The intrauterine environment is influenced by maternal behavior and known to effect lifelong atherosclerotic disease susceptibility in offspring. The purpose of this investigation was to test the hypothesis that maternal exercise during pregnancy increases endothelial function in offspring. A total of 8 pubertal gilts, six months of age were random...

The genesis of disease development can be linked to the intrauterine environment and maternal nutrition during pregnancy plays a significant role in the future vascular health of the offspring. The purpose of this investigation was to test the hypothesis that a high energy (HE) prenatal diet, HE postnatal diet, or their combination will lead to end...

The genesis of disease development can be linked to the intrauterine environment and maternal nutrition during pregnancy plays a significant role in the future vascular health of the offspring. The purpose of this investigation was to test the hypothesis that a high energy (HE) prenatal diet, HE postnatal diet, or their combination will lead to end...

Alterations of normal shear rate (SR) patterns at rest impair flow‐mediated dilation (FMD), possibly due to augmented oxidative stress. We tested the hypothesis that the antioxidant vitamin C would prevent the attenuation of brachial artery FMD following a period of altered SR patterns. Twelve lean healthy men (26.3 ± 3.1 years) participated in two...

The intrauterine environment is influenced by maternal behavior and known to effect lifelong atherosclerotic disease susceptibility in offspring. The purpose of this investigation was to test the hypothesis that maternal exercise during pregnancy increases endothelial function in offspring. A total of 8 pubertal gilts, six months of age were random...

Intermittent pneumatic leg compression (IPC) therapy is commonly used to treat symptoms associated with peripheral artery disease. One hypothesis is that IPC increases shear rate (SR) in the arteries and enhances endothelial cell (EC) function. To test this hypothesis we characterized the hemodynamic profile and used flow mediated dilation (FMD) to...

The mechanisms by which intermittent pneumatic leg compression (IPC) treatment effectively treats symptoms associated with peripheral artery disease remain speculative. With the aim of gaining mechanistic insight into IPC treatment, the purpose of this study was to investigate the effect of IPC frequency on limb hemodynamics, vascular function, and...

Despite the escalating prevalence in the aging population, few therapeutic options exist to treat patients with peripheral arterial disease. Application of intermittent pneumatic leg compressions (IPC) is regarded as a promising noninvasive approach to treat this condition, but the clinical efficacy, as well the mechanistic basis of action of this...

The purpose of this investigation was to test the hypothesis that maternal exercise training during pregnancy enhances endothelial function in offspring at birth. Six-month-old gilts (n = 8) were artificially inseminated and randomized into exercise-trained (n = 4) and sedentary groups (n = 4). Exercise training consisted of 15 weeks of treadmill e...

Intermittent pneumatic leg compressions (IPC) have proven to be an effective noninvasive approach for treatment of patients with claudication, but the mechanisms underlying the clinical benefits remain elusive. In the present study, a rodent model of claudication produced by bilateral ligation of the femoral artery was used to investigate the acute...

Spinal cord injury leads to increased risk for cardiovascular disease and results in greater risk of death. Subclinical markers of atherosclerosis have been reported in carotid arteries of spinal cord-injured individuals (SCI), but the development of lower extremity peripheral arterial disease (PAD) has not been investigated in this population. The...

The effect of maternal nutrition on metabolic programming of offspring has been well documented in both humans and animal models. For example, maternal malnutrition during pregnancy is linked to increased susceptibility of the offspring to obesity, cardiovascular disease, and diabetes mellitus in adulthood. The objective of this study was to determ...

The mechanisms underlying the unequal distribution of atherosclerotic disease in the peripheral arteries are currently unclear. Gene expression differences in healthy arteries may influence the heterogeneous distribution of atherosclerosis. Therefore, this investigation compares gene expression in healthy atheroprotected brachial and atherosuscepti...

Metabolic programming events induced by changes in maternal environment during gestation have marked effects on fetal outcomes. Aerobic exercise is known to alter maternal metabolism, however the consequences on fetal metabolic programming are unknown. To determine the effects of aerobic exercise training during pregnancy on metabolic programming o...

Supplemental Fig. 1 Representative example of ultrasound image of the brachial artery (A) and raw velocity tracings at baseline (B) and during application of mechanical compressions at 50 mmHg (C), 100 mmHg (D) and 150 mmHg (E). Up arrows indicate the time when the cuff was inflated and down arrows denote the time when the cuff was deflated. Brachi...

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Physical activity, exercise training, and fitness are associated with decreased cardiovascular risk. In the context that a risk factor "gap" exists in the explanation for the beneficial effects of exercise on cardiovascular disease, it has recently been proposed that exercise generates hemodynamic stimuli which exert direct effects on the vasculatu...

Functional and structural heterogeneity exists among skeletal muscle vascular beds related, in part, to muscle fiber type composition. This study was designed to delineate whether the vulnerability to vascular dysfunction in insulin resistance is uniformly distributed among skeletal muscle vasculatures and whether physical activity modifies this vu...

In humans, the measurement of brachial artery endothelial vasomotor function is used as a surrogate index of systemic endothelial health; however, the applicability of brachial artery findings to other vasculatures needs to be examined. The purpose of the present investigation was to test the following hypotheses: (1) brachial and femoral artery en...

During dynamic exercise, the vasculature embedded within skeletal muscle intermittently collapses due to increased intramuscular pressure (IMP). The aim of this study was to ascertain whether oscillations in IMP during muscle contractions independently contribute to exercise training-induced increases in blood flow capacity (BFC). Based on IMP meas...

Although the beneficial effects of exercise training on conduit artery endothelial function are well-established in animals and humans with compromised basal function, whether exercise exerts favorable effects on a healthy endothelium is inconclusive. We sought to determine whether long-term exercise training enhances endothelial function in periph...

Muscle contraction and therapeutic application of external pneumatic limb compression produces cyclic deformations and changes in shear-stress in the vasculature embedded in skeletal muscle. These mechanical forces are well known stimuli for angiogenic growth factor release in skeletal muscle. PURPOSE: We tested the hypothesis that acute applicatio...

Exercise training is known to enhance muscle blood flow capacity (BFC), but the mechanisms that mediate this adaptation are poorly understood. We tested the hypothesis that long‐term application of intermittent pneumatic compressions (IPC) in the forearm increases BFC. Twelve healthy subjects were randomly assigned to three compression groups: 50,...

Disturbed flow patterns induce a proatherogenic endothelial cell phenotype; however, the factors accountable for the oscillatory shear profiles in peripheral conduit arteries are not fully understood. We tested the hypothesis that acute elevations in muscle sympathetic nerve activity (MSNA) are accompanied by increases in conduit artery retrograde...

The mechanisms underlying the greater prevalence of atherosclerosis in the femoral compared to brachial arteries of both humans and quadrupeds are still unclear. We hypothesized that brachial and femoral differences in genes associated with atherosclerosis occur during vascular development. To test this hypothesis five femoral and brachial arteries...

Escalating evidence indicates that disturbed flow patterns, characterized by the presence of retrograde and oscillatory shear stress, induce a proatherogenic endothelial cell phenotype; however, the mechanisms underlying oscillatory shear profiles in peripheral conduit arteries are not fully understood. We tested the hypothesis that acute elevation...

Application of intermittent pneumatic compressions (IPC) is an extensively used therapeutic strategy in vascular medicine, but the mechanisms by which this method works are unclear. We tested the hypothesis that acute application (150 min) of cyclic leg compressions in a rat model signals upregulation of angiogenic factors in skeletal muscle. To ex...

Although normalization of brachial artery flow-mediated dilation (FMD) to individual shear stress (FMD:shear stress ratio) has been proposed to improve this measure of endothelial function, the clinical utility of FMD normalization has not yet been demonstrated. We tested (1) whether following conventional 5-min forearm occlusion, the FMD:shear str...

Unlike quadrupeds, humans exhibit a larger hydrostatic pressure in the lower limbs compared with the upper limbs during a major part of the day. It is plausible that repeated episodes of elevated pressure in the legs may negatively impact the endothelium, hence contributing to the greater predisposition of atherosclerosis in the legs. We tested the...

Shear stress is an important stimulus to arterial adaptation in response to exercise and training in humans. We recently observed significant reverse arterial flow and shear during exercise and different antegrade/retrograde patterns of shear and flow in response to different types of exercise. The purpose of this study was to simultaneously examin...

Endothelium (EC) of rat conduit arteries (A) express similar levels of endothelial nitric oxide synthase (eNOS) and superoxide dismutase (SOD) protein ( J Appl Physiol 98:753, 2005). Our hypothesis was that EC of porcine conduit A's and veins (V) express similar levels of eNOS and SOD. Aorta and vena cava (thoracic and abdominal portions), brachial...