E. Todd Schroeder's research while affiliated with University of Southern California and other places

Publications (150)

Article
: Although Parkinson disease (PD) has traditionally been considered a disease of the central nervous system, a bidirectional communication system known as the gut-brain axis can influence PD pathogenesis. The dual-hit hypothesis proposed that PD is due to peripheral dysregulations to the gut microbiota, known as dysbiosis. Since then, further inve...
Article
Objectives: Resistance training (RT) is a promising strategy to slow or prevent fluid cognitive decline during aging. However, the effects of strength-specific RT programs have received little attention. The purpose of this single-group proof of concept clinical trial was to determine whether a 12-week strength training (ST) program could improve...
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The outbreak of severe acute respiratory syndrome coronavirus 2, also known as Coronavirus Disease 2019 (COVID-19) sparked a global public health pandemic that has impacted every aspect of daily life. Medical research was affected, and many clinical trials were halted to minimize COVID-19 transmission risk and spread while the world navigated this...
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Purpose Prostate cancer survivors (PCS) receive androgen deprivation therapy (ADT) as treatment for recurrent cancer, yet ADT is associated with loss of skeletal muscle and physical function. Resistance training can counter both muscle and physical function loss; however, an understanding of the molecular responses of skeletal muscle to resistance...
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Maximal oxygen uptake (VO2max) and critical speed (CS) are key fatigue-related measurements that demonstrate a relationship to one another and are indicative of athletic endurance performance. This is especially true for those that participate in competitive fitness events. However, the accessibility to a metabolic analyzer to accurately measure VO...
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The purpose of this study was to determine the impact of muscular strength on CrossFit® workout performance. Seventeen trained men (mean ± SD age: 29.5 ± 5.6 yrs) completed three standardized CrossFit® workouts for time (Workout #1: 224.1 ± 43.3 sec; Workout #2: 155.7 ± 42.0 sec; Workout #3: 821.8 ± 49.4 sec) and 1-repetition maximum strength was m...
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Objective: A new automated and adjustable blood pressure (BP) system has been developed to improve the accuracy of BP measurements on public-use health stations. This self-fitting BP system includes a mechanical cuff that wraps down to the user's arm prior to bladder inflation. The purpose of this study was to validate the adaptable BP system (ABP...
Article
The prevalence of dementia and other age-associated cognitive disorders is steadily increasing worldwide. With no cure after diagnosis, successful treatment likely requires maximum adherence to preventative countermeasures. Many potential risk factors are modifiable through exercise. Specifically, mounting evidence suggests that long-term resistanc...
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Introduction Growing evidence indicates that circulating concentrations of insulin-like growth factor 1 (IGF-I), along with IGF-I relative to IGF-binding proteins (IGFBP), are associated with an increased risk of cancer. In accord, regular exercise is linked with a lower risk of cancer. Purpose To assess the effects of a 16-week home-based strengt...
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Patients who have undergone unicompartmental knee arthroplasty (UKA) have been reported to exhibit altered gait 19–25 months post-surgery. The most common gait impairment in this population is inadequate knee flexion and a corresponding decrease in the knee extensor moment during loading response (i.e., quadriceps avoidance). The purpose of this ca...
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CrossFit® began as another exercise program to improve physical fitness and has rapidly grown into the “sport of fitness”. However, little is understood as to the physiological indicators that determine CrossFit® sport performance. The purpose of this study was to determine which physiological performance measure was the greatest indicator of Cross...
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Background: Prostate cancer patients on androgen deprivation therapy (ADT) experience adverse effects such as lean mass loss, known as sarcopenia, fat gain, and changes in cardiometabolic factors that increase risk of metabolic syndrome (MetS). Resistance training can increase lean mass, reduce body fat, and improve physical function and quality o...
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Background Rehabilitation after repair of the anterior cruciate ligament (ACL) is complicated by the loss of leg muscle mass and strength. Prior studies have shown that preoperative rehabilitation may improve muscle strength and postoperative outcomes. Testosterone supplementation may likewise counteract this muscle loss and potentially improve cli...
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Purpose: Prostate cancer survivors (PCS) on androgen deprivation therapy (ADT) experience adverse side effects such as skeletal muscle loss and adiposity gain, together called sarcopenic obesity, and changes in cardiometabolic factors that increase risk of metabolic syndrome (MetS). Resistance exercise can increase skeletal muscle mass, but no exer...
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Introduction Prostate cancer survivors (PCS) receiving androgen deprivation therapy (ADT) experience deleterious side effects such as unfavourable changes in cardiometabolic factors that lead to sarcopenic obesity and metabolic syndrome (MetS). While loss of lean body mass (LBM) compromises muscular strength and quality of life, MetS increases the...
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Objectives Surgical reconstruction of the anterior cruciate ligament (ACL) is essential for those who wish to resume athletic activity following ACL rupture. However, the trauma of surgical repair and post-operative immobility can exacerbate muscle loss and strength. This study investigated the effect of perioperative testosterone administration on...
Article
Purpose: Acute muscle damage after exercise triggers subsequent regeneration, leading to hypertrophy and increased strength after repeated exercise. It has been debated whether acute exercise-induced muscle damage is altered under various premenopausal estrogen conditions. Acute contraction-induced muscle damage was compared during exogenous (oral...
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223Background: Cardiovascular disease is the leading cause of death in men with prostate cancer. ADT is effective treatment, but can induce loss of skeletal muscle, plus increase central fat, lipids, and insulin resistance. These changes in MetS components may contribute to excess cardiac risk. We tested whether a resistance exercise program, desig...
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Androgen deprivation therapy (ADT), a primary treatment for locally advanced or metastatic prostate cancer, is associated with the adverse effects on numerous physiologic parameters, including alterations in cardiometabolic variables that overlap with components of the metabolic syndrome (MetS). As MetS is an established risk factor for cardiovascu...
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BACKGROUND: Accumulating evidence indicates circulating concentrations of insulin-like growth factor 1 (IGF-1), or IGF-1 relative to IGF binding proteins (IGFBP’s) is associated with increased risk for the development of several forms of cancers. Similarly, exercise has been linked with reduced cancer risk. PURPOSE: To assess the effects of a 16-we...
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PGC-1α4, a novel isoform of the transcriptional coactivator PGC-1α, was recently postulated to modulate the expression of anabolic and catabolic genes and therefore regulate skeletal muscle hypertrophy. Resting levels of PGC-1α4 mRNA expression were found to increase in healthy adults after resistance training. However, the acute effect of resistan...
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With the childhood obesity epidemic, efficient methods of exercise are sought to improve health. We tested whether whole body vibration (WBV) exercise can positively affect bone metabolism and improve insulin/glucose dynamics in sedentary overweight Latino boys. Twenty Latino boys 8-10 years of age were randomly assigned to either a control (CON) o...
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To determine the effects of a home-based strength training (HBST) intervention on insulin sensitivity (SI), compensatory acute insulin response and β-cell function, body composition measures, and maximum strength in obese Latino boys. A total of 26 obese Latino males aged between 14 and 18 years were randomized to either a twice-weekly (n=15) or a...
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Context: Self-report questionnaires are an important method of evaluating lifespan health, exercise, and health-related quality of life (HRQL) outcomes among elite, competitive athletes. Few instruments, however, have undergone formal characterization of their psychometric properties within this population. Objective: To evaluate the validity an...
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Background: The anterior cruciate ligament (ACL) is one of four major ligaments in the knee that provide stability during physical activity. A tear in the ACL is characterized by joint instability that leads to decreased activity, knee dysfunction, reduced quality of life and a loss of muscle mass and strength. While rehabilitation is the standard...
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Purpose: To determine if 8 weeks of periodized strength resistance training (RT) utilizing relatively short rest interval lengths (RI) in between sets (SS) would induce greater improvements in body composition and muscular performance, compared to the same RT program utilizing extended RI (SL). Methods: 22 male volunteers (SS: n = 11, 65.6 ± 3.4...
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Context Competitive sports are recognized as having unique health benefits and risks, and the effect of sports on life-span health among elite athletes has received increasing attention. However, supporting scientific data are sparse and do not represent modern athletes. Objective To assess holistic life-span health and health-related quality-of-l...
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AimMulti-frequency bioelectrical impedance analysis (MF-BIA) may provide a quick, cost-efficient method of total body water (TBW) assessment. We compared TBW estimates from the Biospace InBody 520, 720, and S10 MF-BIA devices to TBW estimates from isotopic deuterium dilution (D2O).MethodsTBW was measured in 25 men and 25 women, 18–49 years, 73.6 ±...
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Physical inactivity is linked with increase in risk of cancer, heart disease, stroke, and diabetes. Walking is an easily available activity to reduce sedentary time. Objective methods to accurately assess energy expenditure from walking that is normalized to an individual would allow tailored interventions. Current techniques rely on normalization...
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Background: Metabolic syndrome (MetS) is increasingly present in breast cancer survivors, possibly worsened by cancer-related treatments, such as chemotherapy. MetS greatly increases risk of cardiovascular disease and diabetes, co-morbidities that could impair the survivorship experience, and possibly lead to cancer recurrence. Exercise has been s...
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To examine the effects of 12 weeks of periodized resistance training (RT) with and without combined creatine and whey protein supplementation on changes in body composition, muscular strength, and functional performance. Twenty-two male volunteers (68.1 ± 6.1 years) were randomly assigned to one of three groups: RT plus supplementation (RTS, n = 7)...
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Walking is a commonly available activity to maintain a healthy lifestyle. Accurately tracking and measuring calories expended during walking can improve user feedback and intervention measures. Inertial sensors are a promising measurement tool to achieve this purpose. An important aspect in mapping inertial sensor data to energy expenditure is the...
Article
TPS9648 Background: Current evidence suggests that breast cancer treatments such as chemotherapy lead to excessive weight gain, fatigue, physical inactivity, and negative alterations in components of metabolic syndrome (MetS). MetS is associated with increased risk of cancer recurrence, cardiovascular diseases and type 2 diabetes, and is defined by...
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To determine the cardiometabolic risks of testosterone and growth hormone (GH) replacement therapy to youthful levels during aging. A double-masked, partially placebo controlled study in 112 men 65-90 years-old was conducted. Transdermal testosterone (5 g vs. 10 g/day) using a Leydig Cell Clamp and subcutaneous recombinant GH (rhGH) (0 vs. 3 vs. 5...
Conference Paper
Physical inactivity is a leading risk factor in worldwide deaths. This problem has led to the need for new research paradigms investigating the effect of sedentary behavior on negative health outcomes. Central to this need is the development of objective and ubiquitous sensors that provide accurate measurements of activity to assist in intervention...
Article
Villanueva, MG, Villanueva, MG, Lane, CJ, and Schroeder, ET. Influence of rest interval length on acute testosterone and cortisol responses to volume-load-equated total body hypertrophic and strength protocols. J Strength Cond Res 26(10):2755-2764, 2012-We hypothesized that total body strength (S) and hypertrophic (H) resistance training (RT) proto...
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Multifrequency bioelectrical impedance analysis of body composition may be an appropriate alternative to dual-energy x-ray absorptiometry. We hypothesized that there would be no significant differences between dual-energy x-ray absorptiometry and either the Biospace (Los Angeles, CA, USA) InBody 520 or 720 multifrequency bioelectrical impedance ana...
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Background: Despite prominent public attention, data on life span health and exercise outcomes among elite, competitive athletes are sparse and do not reflect the diversity of modern athletes. Hypothesis: Life span exercise behavior differs between National Collegiate Athletic Association (NCAA) student athletes and a nonathlete control group. Sus...
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We sought to evaluate baseline mRNA values and changes in gene expression of myostatin-related factors in postmenopausal women taking hormone therapy (HT) and not taking HT after eccentric exercise. Fourteen postmenopausal women participated including 6 controls not using HT (59 ± 4 years, 63 ± 17 kg) and 8 women using HT (59 ± 4 years, 89 ± 24 kg)...
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We hypothesized that treatment with testosterone (T) and recombinant human growth hormone (rhGH) would increase lean mass (LM) and muscle strength proportionally and an in a linear manner over 16 weeks. This was a multicenter, randomized, controlled, double-masked investigation of T and rhGH supplementation in older (71 ± 4 years) community-dwellin...
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Acute deviations in protein intake before the quantification of protein kinetics in older humans may explain the controversy over the effects of older age on muscle protein synthesis and proteolysis rates. We hypothesized that an acute decrease in protein intake from the habitual intake is associated with lower muscle protein synthesis and higher p...
Conference Paper
Full-text available
Walking is a commonly available activity to maintain a healthy lifestyle. Accurately tracking and measuring calories expended during walking can improve user feedback and intervention measures. Inertial sensors are a promising measurement tool to achieve this purpose. An important aspect in mapping inertial sensor data to energy expenditure is the...
Article
Full-text available
We describe an experimental study to estimate energy expenditure during treadmill walking using a single hip-mounted inertial sensor (triaxial accelerometer and triaxial gyroscope). Typical physical-activity characterization using commercial monitors use proprietary counts that do not have a physically interpretable meaning. This paper emphasizes t...
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Objectives To determine the durability of anabolic effects and adverse events (AEs) after stopping testosterone and growth hormone supplementation in older men. Design Secondary analysis of a double-masked, randomized controlled trial of testosterone gel (5 or 10 g/daily) plus rhGH (0, 3 or 5 μg/kg/day) with follow-up of outcomes 3 months later. Pa...
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This study aimed to test the effects of a circuit training (CT; aerobic + strength training) program, with and without motivational interviewing (MI) behavioral therapy, on reducing adiposity and type 2 diabetes risk factors in Latina teenagers. Thirty-eight Latina adolescents (15.8 ± 1.1 yr) who are overweight/obese were randomly assigned to contr...
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In the HORMA (Hormonal Regulators of Muscle and Metabolism in Aging) Trial, supplemental testosterone and recombinant human growth hormone (rhGH) enhanced lean body mass, appendicular skeletal muscle mass, muscle performance, and physical function, but there was substantial interindividual variability in outcomes. One hundred and twelve men aged 65...