Tim N Ziegenfuss

Tim N Ziegenfuss
Center for Applied Health Sciences (CAHS)

PhD

About

82
Publications
92,057
Reads
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4,928
Citations
Citations since 2017
18 Research Items
3098 Citations
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20172018201920202021202220230100200300400500600
20172018201920202021202220230100200300400500600
Introduction
Muscle physiology, body composition, exercise science, resistance exercise, functional foods, dietary supplements, nutritional ergogenic aids, cardio-metabolic physiology, healthy aging

Publications

Publications (82)
Article
Full-text available
We sought to determine the skeletal muscle genome-wide DNA methylation and mRNA responses to one bout of lower load (LL) versus higher load (HL) resistance exercise. Trained college-aged males (n = 11, 23 ± 4 years old, 4 ± 3 years self-reported training) performed LL or HL bouts to failure separated by one week. The HL bout (i.e., 80 Fail) consist...
Preprint
Full-text available
We sought to determine the skeletal muscle genome-wide DNA methylation and mRNA responses to one bout of lower-load (LL) versus higher-load (HL) resistance exercise. Trained college-aged males (n=11, 23+/-4 years old, 4+/-3 years self-reported training) performed LL or HL bouts to failure separated by one week. The HL bout (i.e., 80 Fail) consisted...
Article
Full-text available
This position stand aims to provide an evidence-based summary of the energy and nutritional demands of tactical athletes to promote optimal health and performance while keeping in mind the unique challenges faced due to work schedules, job demands, and austere environments. After a critical analysis of the literature, the following nutritional guid...
Article
Full-text available
Limited pre-clinical and clinical data suggest theacrine or theacrine-based supplements modulate biological processes associated with lipid metabolism and aging. Herein, we sought to examine if 12 weeks of daily supplementation with a theacrine-based supplement (termed NAD3®; 312 mg of combined Wasabia japonica freeze-dried rhizome standardized for...
Article
Full-text available
Introduction: Many consumers use dietary supplements in the hopes of increasing energy and burning more calories, which if sustained over time may help accelerate weight loss. The purpose of this clinical trial was to investigate the effects of an over-the-counter thermogenic supplement called Burn-XT™ (BXT) on metabolic rate, substrate oxidation,...
Article
Full-text available
Supplementing with creatine is very popular amongst athletes and exercising individuals for improving muscle mass, performance and recovery. Accumulating evidence also suggests that creatine supplementation produces a variety of beneficial effects in older and patient populations. Furthermore, evidence-based research shows that creatine supplementa...
Article
Full-text available
Based on a comprehensive review and critical analysis of the literature regarding the effects of sodium bicarbonate supplementation on exercise performance, conducted by experts in the field and selected members of the International Society of Sports Nutrition (ISSN), the following conclusions represent the official Position of the Society: 1. Sup...
Article
Full-text available
Introduction: Purple tea exhibits a unique composition of chemical constituents that may exert favorable outcomes related to recovery from muscle damage, improvements in blood flow, perfusion, and recovery. The purpose of this study was to examine the impact of a brief oral dosing period of purple tea in exercising humans after stressful, damaging...
Article
Full-text available
We determined the effects of a commercially available, GRAS (Generally Recognized As Safe) by independent conclusion, CBD-containing hemp oil extract on stress resilience, perceived recovery, mood, affect, body composition, and clinical safety markers in healthy human subjects. Methods: Using a randomized, placebo-controlled, double-blind design, 6...
Article
Full-text available
We examined if resistance training affected muscle NAD+ and NADH concentrations as well as nicotinamide phosphoribosyltransferase (NAMPT) protein levels and sirtuin (SIRT) activity markers in middle-aged, untrained (MA) individuals. MA participants (59±4 years old; n=16) completed 10 weeks of full-body resistance training (2 d/wk). Body composition...
Article
Full-text available
Milk and dairy products are known to contain various bioactives with potential anti-inflammatory and immune modulating effects. Previous research has indicated that milk produced from hyperimmunized cows provided meaningful health benefits to individuals suffering from varying degrees of osteoarthritis and rheumatoid arthritis. PURPOSE: To examine...
Article
Full-text available
Withania somnifera (Ashwagandha) is an Ayurvedic herb categorized as having “rasayana” (rejuvenator), longevity, and revitalizing properties. Sensoril® is a standardized aqueous extract of the roots and leaves of Withania somnifera. Purpose: To examine the impact of Sensoril® supplementation on strength training adaptations. Methods: Recreationally...
Article
Full-text available
Background Previous research has demonstrated the permissive effect of insulin on muscle protein kinetics, and the enhanced insulin sensitizing effect of chromium. In the presence of adequate whole protein and/or essential amino acids (EAA), insulin has a stimulatory effect on muscle protein synthesis, whereas in conditions of lower blood EAA conce...
Article
Background: Very few weight and fat loss supplements undergo finished-product research to examine efficacy. The purpose of this study was to determine the effects of an 8-week diet and exercise program on body composition, hip and waist girth, and adipokines and evaluate whether a dietary supplement containing raspberry ketone, capsaicin, caffeine,...
Article
Full-text available
Background Joint and connective tissue integrity, comfort and function are paramount to optimal performance in exercise, recreational and occupational activities. The fruit of Terminalia chebula has been used extensively in various traditional health systems for different ailments, with additional preclinical and clinical data demonstrating antioxi...
Article
Full-text available
Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review regarding the timing of macronutrients in reference to healthy, exercising adults and in particular highly trained individuals on exercise performance and body composition. The following points summarize the position of the ISSN: 1. Nu...
Article
Full-text available
Position statement The International Society of Sports Nutrition (ISSN) provides an objective and critical review related to the intake of protein for healthy, exercising individuals. Based on the current available literature, the position of the Society is as follows: 1) An acute exercise stimulus, particularly resistance exercise, and protein i...
Article
Full-text available
Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exerci...
Article
Full-text available
[Purpose] The aim of the present narrative review was to consider the evidence on the timing, optimal dose and intake duration of the main dietary supplements in sports nutrition, i.e. β-alanine, nitrate, caffeine, creatine, sodium bicarbonate, carbohydrate and protein. [Methods] This review article focuses on timing, optimal dose and intake durati...
Article
Using a prospective, randomized, double-blind, crossover study design, fifteen healthy male (n = 8) and female (n = 7) participants (mean ± standard deviation (SD): 28.3 ± 6.1 yr, 176.3 ± 11.4 cm, 89.8 ± 21.7 kg, 28.5 ± 4.8 kg/m(2)) completed this study. Two testing sessions occurred after an overnight fast and refraining from physical exercise. Pr...
Article
Theacrine (1,3,7,9-tetramethyluric acid) is a naturally occurring purine alkaloid, present in Camellia assamica variety kucha tea. Using a two-part approach in humans, the impact of theacrine (TeaCrine®, TC) was used to examine subjective dose-response, daily changes in cognitive and psychometric parameters, and changes in gas exchange and vital si...
Article
Full-text available
Context: Little is known about the effect of nutritional supplementation on metabolic optimization for enhancing adaptation and recovery of the connective tissue elements that support musculoskeletal function. Objective: The study aimed to determine the potential effect of supplementation with a novel, hydrolyzed chicken sternal cartilage extrac...
Article
Full-text available
Position statement The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of beta-alanine supplementation. Based on the current available literature, the conclusions of the ISSN are as follows: 1) Four weeks of beta-alanine supplementation (4–6 g daily) significantly augments muscle...
Article
Full-text available
Background Limited research exists examining the impact of nutrition on golfing performance. This study’s purpose was to determine the impact of daily supplementation with an over-the-counter dietary supplement on golf performance. Methods Healthy men (30.3 ± 6.9 y, 183.1 ± 5.6 cm, 86.7 ± 11.9 kg), with a 5–15 handicap were assigned in a double-bl...
Book
This new text presents the most up-to-date research based information regarding popular sport/performance nutrient dense diets and nutritional supplements and their constituents that directly or indirectly utilize them. Previous chapters have been fully revised and new chapters have been added to cover important cutting edge topics. New chapters in...
Article
Full-text available
Background The extracellular matrix (ECM) of muscle, tendon, and ligament is sensitive to exercise-induced mechanical stimuli. Exercise-induced muscle damage is associated with not only myofibrillar injury, but also the involvement of connective tissue elements such as collagen, proteoglycans (PG), tendon and ligament. However, little is known abou...
Article
Full-text available
Numerous natural products are marketed and sold claiming to decrease body weight and fat, but few undergo finished product-specific research demonstrating their safety and efficacy. To determine the safety and efficacy of a multi-ingredient supplement containing primarily raspberry ketone, caffeine, capsaicin, garlic, ginger and Citrus aurantium (P...
Article
Full-text available
Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature on the use of beta-hydroxy-beta-methylbutyrate (HMB) as a nutritional supplement. The ISSN has concluded the following. 1. HMB can be used to enhance recovery by attenuating exercise induced skeletal m...
Article
Full-text available
Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature on the safety and efficacy of the use of energy drinks (ED) or energy shots (ES). The ISSN has concluded the following. 1. Although ED and ES contain a number of nutrients that are purported to affect...
Article
Full-text available
Background Body composition (BC) and its changes over time may influence performance in soccer players. BC assessment techniques are mainly based on quantitative evaluation, originating from model-based indirect estimates of FatFree Mass and Fat Mass. DXA, particularly the advanced iDXA technology, is considered to be precise enough for this kind o...
Article
Full-text available
Background Bulbine natalensis is a perennial herb indigenous to South Africa that is currently being marketed as a prosexual product for men. As the first step in a series of experiments designed to assess in the in vivo effects of Bulbine natalensis (ProLensis™) supplementation, we performed a placebo-controlled, double-blind clinical trial to ass...
Article
Full-text available
Position Statement: Admittedly, research to date examining the physiological effects of meal frequency in humans is somewhat limited. More specifically, data that has specifically examined the impact of meal frequency on body composition, training adaptations, and performance in physically active individuals and athletes is scant. Until more resear...
Article
ESTIMATION OF OPTIMAL PROTEIN AND/OR AMINO ACID INTAKE FOR PHYSICALLY ACTIVE INDIVIDUALS HAS BEEN HISTORICALLY PROBLEMATIC BECAUSE (A) SUBJECTS CONSUMING THE SAME ABSOLUTE AMOUNT OF PROTEIN COULD CONSUME DIFFERENT AMOUNTS AND TYPES OF AMINO ACIDS, (B) THE TIMING OF INGESTION (PRE VERSUS POST EXERCISE) ALTERS PROTEIN KINETICS (SYNTHESIS VERSUS BREAK...
Article
Full-text available
Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of th...
Article
Full-text available
Position Statement: The position of The Society regarding caffeine supplementation and sport performance is summarized by the following seven points: 1.) Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg/kg) and overall does not result in further enhancement in performance wh...
Article
To determine the effects of a dried aqueous extract of cinnamon on antioxidant status of people with impaired fasting glucose that are overweight or obese. Twenty-two subjects, with impaired fasting blood glucose with BMI ranging from 25 to 45, were enrolled in a double-blind placebo-controlled trial. Subjects were given capsules containing either...
Article
Full-text available
Position Statement: The position of the Society regarding nutrient timing and the intake of carbohydrates, proteins, and fats in reference to healthy, exercising individuals is summarized by the following eight points: 1.) Maximal endogenous glycogen stores are best promoted by following a high-glycemic, high-carbohydrate (CHO) diet (600 - 1000 gra...
Article
Full-text available
ABSTRACT: Correction After publication of this work, we noted that we inadvertently failed to include the complete list of all coauthors. The full list of authors has now been added and the Authors' contributions and Competing interests section modified accordingly. Competing Interests The authors declare they have no competing interests. Authors'...
Data
Table 2 – Summary table of studies involving protein metabolism and nutrient timing after exercise.
Data
Table 1 – Summary table of pre-exercise nutrition studies (Adapted from Hawley and Burke [22]).
Data
Table 3 – Summary table of studies involving post-exercise nutrition administration and resistance training.
Article
Full-text available
The purpose of this study was to compare changes in muscle insulin-like growth factor-I (IGF-I) content resulting from resistance-exercise training (RET) and creatine supplementation (CR). Male (n=24) and female (n=18) participants with minimal resistance-exercise-training experience (=1 year) who were participating in at least 30 min of structured...
Chapter
Full-text available
The ability to recover from intense exercise often separates good athletes from great ones. In the past, “recovery” often simply included rest, physical modalities (e.g., massage, hydration therapy) and meeting basic nutritional needs for fluid and energy intake. Today, athletes have a number of additional options to help them recover from high int...
Article
Although it has been fairly well established that most athletes ingest sufficient protein in their habitual diet, recent scientific evidence has shown that the type (animal versus vegetable) and timing of protein intake (pre-versus post-exercise) can affect protein kinetics and adaptations to training. This chapter reviews basic protein and amino a...
Article
Numerous hormones and hormone supplements are used by athletes in the hope of improving performance. Often, the marketing claims and gym lore regarding the utility of a given supplement do not agree with empirically obtained evidence. It is incumbent upon those who work with athletes to maintain a solid knowledge base regarding the science of hormo...
Article
Full-text available
Position Statement: The following nine points related to the use of creatine as a nutritional supplement constitute the Position Statement of the Society. They have been approved by the Research Committee of the Society .
Article
Full-text available
Position Statement The following seven points related to the intake of protein for healthy, exercising individuals constitute the position stand of the Society. They have been approved by the Research Committee of the Society. 1) Vast research supports the contention that individuals engaged in regular exercise training require more dietary protein...
Article
Full-text available
The purpose of this study was to determine the effects of supplementation with a water-soluble cinnamon extract (Cinnulin PF(R)) on body composition and features of the metabolic syndrome. Twenty-two subjects with prediabetes and the metabolic syndrome (mean +/- SD: age, BMI, systolic blood pressure [SBP], fasting blood glucose [FBG]: 46.0 +/- 9.7...
Article
Full-text available
For more than 50 years, the Food and Nutrition Board of the National Academy of Sciences has been reviewing nutrition research and defining nutrient requirements for healthy people, referred to as the Recommended Dietary Allowances (RDA). As new nutrition research is published, the importance of vitamins as vital nutrients is underscored, and new p...
Article
Full-text available
The effects of supplemental dietary creatine and a botanical extract consisting of ginseng and astragalus were evaluated in 44 adults aged 55-84 years participating in a 12-week strength-training program. Participants consumed creatine only (Cr), creatine plus botanical extract (CrBE), or placebo (PL), and performed bench press, lat pull down, bice...
Article
Full-text available
For more than 50 years, the Food and Nutrition Board of the National Academy of Sciences has been reviewing nutrition research and defining nutrient requirements for healthy people, referred to as the recommended dietary allowances (RDA). As new nutrition research is published, the importance of vitamins as vital nutrients is underscored, and new p...
Article
For more than 50 years, the Food and Nutrition Board of the National Academy of Sciences has been reviewing nutrition research and defining nutrient requirements for healthy people, referred to as the recommended dietary allowances (RDA). As new nutrition research is published, the importance of vitamins as vital nutrients is underscored, and new p...
Article
We hypothesized that creatine supplementation would interfere with normal body fluid shifts that occur during exercise in a hot environment due to its osmotic effect intracellularly. This study examined the effects of acute creatine loading (20 g/d for 5 d) on the thermoregulatory response of the body during a bout of exercise at 39 degrees C. Subj...
Article
The effects of extracts of Rhodiola rosea radix on blood levels of inflammatory C-reactive protein and creatinine kinase were studied in healthy untrained volunteers before and after exhausting exercise. Rhodiola rosea extract exhibited an antiinflammatory effect and protected muscle tissue during exercise.
Article
The effects of extracts ofRhodiola rosea radix on blood levels of inflammatory C-reactive protein and creatinine kinase were studied in healthy untrained volunteers before and after exhausting exercise.Rhodiola rosea extract exhibited an antiinflammatory effect and protected muscle tissue during exercise.
Article
summary: New research has shown that consuming carbohydrate and protein after exercise speeds the recovery process and optimizes the adaptive response.
Article
Full-text available
Abstract Sport nutrition is a constantly evolving field with literally thousands of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper presents a well-referenced overview of the current state of the science related to how to optimize training through nutrition. More specificall...
Article
We studied the effects of oral treatment with extracts from Rhodiola rosea (50 mg/kg) and Rhodiola crenulata (50 mg/kg) roots on the duration of exhaustive swimming and ATP content in mitochondria of skeletal muscles in rats. Treatment with R. rosea extract significantly (by 24.6%) prolonged the duration of exhaustive swimming in comparison with co...
Article
This study used a randomized, placebo-controlled, crossover design to evaluate the effects of oral ribose supplementation on short-term anaerobic performance. After familiarization, subjects performed 2 bouts of repeated cycle sprint exercise (six 10-second sprints with 60-second rest periods between sprints) in a single day. After the second exerc...
Article
Natural sulfated polysaccharides (SPs) derived from brown seaweed comprise a complex group of macromolecules with a wide range of important physiological properties. SPs have been shown to bind and directly regulate the bioactivity of growth factors and cytokines such as basic fibroblast growth factor, interferon, various enzymes and transforming g...
Article
Despite a relative dearth of information on their effects, supplementation with prohormones has become a popular practice. Unlike synthetic anabolic-androgenic steroids, many of these over-the-counter androgens are produced endogenously by adrenal, gonadal and peripheral steroidogenic pathways as part of the normal sexual and reproductive hormonal...
Article
Despite a relative dearth of information on their effects, supplementation with prohormones has become a popular practice. Unlike synthetic anabolic-androgenic steroids, many of these over-the-counter androgens are produced endogenously by adrenal, gonadal and peripheral steroidogenic pathways as part of the normal sexual and reproductive hormonal...
Article
Full-text available
We measured the effect of 3 d of creatine (Cr) supplementation on repeated sprint performance and thigh muscle volume in elite power athletes. Ten male (mean +/- standard deviation of body mass and percentage of fat (81.1 +/- 10.5 kg and 9.8 +/- 3.5) and ten female (58.4 +/- 5.3 kg and 15.0 +/- 3.4) athletes were matched for sex and 10-s cycle spri...