0000000000038481

AUTHOR

Disa L. Hatfield

showing 11 related works from this author

Effects of Stretching on Upper-Body Muscular Performance

2008

The purpose of this investigation was to examine the influence of upper-body static stretching and dynamic stretching on upper-body muscular performance. Eleven healthy men, who were National Collegiate Athletic Association Division I track and field athletes (age, 19.6 +/- 1.7 years; body mass, 93.7 +/- 13.8 kg; height, 183.6 +/- 4.6 cm; bench press 1 repetition maximum [1RM], 106.2 +/- 23.0 kg), participated in this study. Over 4 sessions, subjects participated in 4 different stretching protocols (i.e., no stretching, static stretching, dynamic stretching, and combined static and dynamic stretching) in a balanced randomized order followed by 4 tests: 30% of 1 RM bench throw, isometric ben…

AdultMaleOrthodonticsAMAXUpper bodyRepetition maximumPhysical Therapy Sports Therapy and RehabilitationGeneral MedicineIsometric exerciseAthletic PerformanceBench pressDynamic stretchingUpper ExtremityStatic stretchingMuscle Stretching ExercisesExercise TestHumansOrthopedics and Sports MedicineMuscle SkeletalThrowingMathematicsJournal of Strength and Conditioning Research
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Factors Affecting Flutter Kicking Speed in Women Who Are Competitive and Recreational Swimmers

2009

The purpose of this study was to determine the relationships between possible predictive measures of a 50 m front crawl swimming and a 22.86 m flutter kicking speed. Ten women who were National Collegiate Athletic Association Division I collegiate swimmers and 10 women who were recreational swimmers (mean +/- SD = 20.6 +/- 1.6 years; 66.7 +/- 10.3 kg; 166.7 +/- 8.8 cm) volunteered for the study. Anthropometric measures were obtained including height, leg length, lower leg length, and foot length. Ankle flexibility was assessed by measuring ankle plantar flexion and ankle inversion. Lower body power was measured using a vertical jump. Swimming and kicking speed were measured as the time to c…

medicine.medical_specialtyFlexibility (anatomy)Ankle inversionPhysical Therapy Sports Therapy and RehabilitationAthletic PerformanceYoung AdultVertical jumpmental disordersmedicineHumansOrthopedics and Sports MedicineRange of Motion ArticularSwimmingAgedLegGeneral Medicinebody regionsmedicine.anatomical_structurePhysical therapyFlutterFemaleAnklePsychologyRange of motionhuman activitiesFront crawlAnkle JointLower Leg LengthJournal of Strength and Conditioning Research
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Influence of HMB Supplementation and Resistance Training on Cytokine Response to Resistance Exercise

2014

The purpose of this study was to determine the effects of a multinutritional supplement including amino acids, β-hydroxy-β-methylbutyrate (HMB), and carbohydrates on cytokine responses to resistance exercise and training.Seventeen healthy, college-aged men were randomly assigned to a Muscle Armor™ (MA; Abbott Nutrition, Columbus, OH) or placebo supplement group and 12 weeks of resistance training. An acute resistance exercise protocol was administered at 0, 6, and 12 weeks of training. Venous blood samples at pre-, immediately post-, and 30-minutes postexercise were analyzed via bead multiplex immunoassay for 17 cytokines.After 12 weeks of training, the MA group exhibited decreased interfer…

Malemedicine.medical_specialtyStrength trainingmedicine.medical_treatmentInterleukin-1betaMedicine (miscellaneous)Immune functionGranulocytePlaceboBody Mass IndexInterferon-gammaYoung AdultDouble-Blind MethodMuscle damageInternal medicineMyokineMyokinemedicineDietary CarbohydratesValeratesHumansMicronutrientsAmino Acidsta315Chemokine CCL4Immune function; Muscle damage; Myokine; Nutrition; Strength trainingChemokine CCL2NutritionNutrition and DieteticsInterleukin-13business.industryInterleukin-6MonocyteBody WeightInterleukin-8InterleukinResistance TrainingVenous bloodHealthy VolunteersInterleukin-10Cytokinemedicine.anatomical_structureEndocrinologyNutrition AssessmentImmunologyDietary SupplementsCytokinesStrength trainingbusiness
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Endocrine Response Patterns to Acute Unilateral and Bilateral Resistance Exercise in Men

2009

Rehabilitation programs and research experiments use single-arm protocols in which the contralateral arm is not functional or used as a control limb. This study was interested in determining the hormonal signal impacts of such one- versus two-arm exercise responses that might have an impact on adaptational changes with training. The purpose was to examine the acute hormonal responses to a unilateral and a bilateral upper-body resistance exercise (RE) protocol. A balanced randomized treatment intervention with series time frame for blood collections before and after exercise was used as the basic experimental design. Ten recreationally resistance trained men (18-25 years, 20.4 +/- 1.2 years,…

AdultMalemedicine.medical_specialtyAdolescentHydrocortisonemedicine.medical_treatmentPhysical ExertionPhysical Therapy Sports Therapy and RehabilitationHematocritlaw.inventionHemoglobinsYoung AdultRandomized controlled triallawInternal medicinemedicineHumansInsulinEndocrine systemTestosteroneOrthopedics and Sports MedicineYoung adultTestosteroneRehabilitationmedicine.diagnostic_testHuman Growth HormoneInsulinResistance TrainingGeneral MedicineEndocrinologyHematocritAnesthesiaArmLactatesPsychologyHormoneJournal of Strength and Conditioning Research
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Recovery from a national collegiate athletic association division I football game: muscle damage and hormonal status.

2008

The purpose of this study was to examine markers of skeletal muscle tissue damage and circulating anabolic and catabolic hormones to gain insight into the recovery process from Friday until Monday, when a new practice week begins. Twenty-eight National Collegiate Athletic Association Division I football players gave consent to participate in the investigation in the ninth game of the season. Sixteen players started the game and played the entire game (PL), and 12 others did not play and were on the bench during the game (DNP). Each player had fasted blood samples obtained at the same time of day between 1000 and 1200 hours the day before the game (Friday; T1), 18-20 hours after the game (Su…

Malemedicine.medical_specialtyTime FactorsAnabolismHydrocortisoneUniversitiesFootballAmerican footballPhysiologyPhysical Therapy Sports Therapy and RehabilitationEndocrine SystemFootballAthletic PerformanceRisk AssessmentCohort StudiesYoung AdultmedicineHumansOrthopedics and Sports MedicineTestosteroneMuscle SkeletalCreatine KinaseTestosteronebiologyL-Lactate DehydrogenaseCatabolismbusiness.industryMyoglobinGeneral MedicineRecovery of Functionmedicine.diseaseSoft tissue injuryMuscle FatiguePhysical therapybiology.proteinCreatine kinasebusinesshuman activitiesBlood Chemical AnalysisHormoneJournal of strength and conditioning research
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On “The Basics of Training for Muscle Size and Strength”

2020

medicine.medical_specialtyText miningMuscle sizePhysical medicine and rehabilitationbusiness.industrySports scienceMEDLINEmedicineTraining (meteorology)Physical Therapy Sports Therapy and RehabilitationOrthopedics and Sports MedicinebusinessPsychologyMedicine & Science in Sports & Exercise
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Effects of L-Carnitine L-Tartrate Supplementation on Muscle Oxygenation Responses to Resistance Exercise

2008

Previous research has shown that L-carnitine L-tartrate (LCLT) supplementation beneficially affects markers of hypoxic stress following resistance exercise. However, the mechanism of this response is unclear. Therefore, the primary purpose of this study was to determine the effects of LCLT supplementation on muscle tissue oxygenation during and after multiple sets of squat exercise. Nine healthy, previously resistance-trained men (25.2 +/- 6.years, 91.2 +/- 10.2 kg, 180.2 +/- 6.3 cm) ingested 2 g.d of LCLT or an identical placebo for 23 days in a randomized, balanced, crossover, double-blind, placebo-controlled, repeated-measures study design. On day 21, forearm muscle oxygenation was measu…

AdultMaleMuscle tissuemedicine.medical_specialtyPhysical Therapy Sports Therapy and RehabilitationProstacyclinPlaceboOxygen ConsumptionDouble-Blind MethodForearmCarnitineMalondialdehydeInternal medicinemedicineHumansOrthopedics and Sports MedicineMuscle SkeletalExerciseTartratesL-Carnitine L-TartrateCross-Over StudiesSpectroscopy Near-Infraredbusiness.industryGeneral MedicineOxygenationCrossover studySurgeryOxygenmedicine.anatomical_structureDietary SupplementsVitamin B ComplexCardiologybusinessmedicine.drugBlood drawingJournal of Strength and Conditioning Research
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Effects of amino acids supplement on physiological adaptations to resistance training.

2009

KRAEMER, W. J., D. L. HATFIELD, J. S. VOLEK, M. S. FRAGALA, J. L. VINGREN, J. M. ANDERSON, B. A. SPIERING, G. A. THOMAS, J. Y. HO, E. E. QUANN, M. IZQUIERDO, K. HAKKINEN, and C. M. MARESH. Effects of Amino Acids Supplement on Physiological Adaptations to Resistance Training. Med. Sci. Sports Exerc., Vol. 41, No. 5, pp. 1111-1121, 2009. Introduction: Previous research has demonstrated that ingestion of essential amino acids and their metabolites induce anabolic effects with the potential to augment gains in lean body mass and strength after resistance exercise training. Purpose: The purpose of the present study was to examine the effects of an essential amino acid-based formula (Muscle Armor…

AdultMalemedicine.medical_specialtyAnabolismPhysical Therapy Sports Therapy and RehabilitationYoung AdultDouble-Blind MethodInternal medicinemedicineIngestionHumansOrthopedics and Sports MedicineMuscle StrengthAmino AcidsTestosteroneHydrocortisonebiologybusiness.industrySkeletal muscleResistance TrainingAdaptation PhysiologicalEndocrinologymedicine.anatomical_structureDietary SupplementsLean body massbiology.proteinCreatine kinasebusinessmedicine.drugBlood drawingMedicine and science in sports and exercise
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Hormonal stress responses of growth hormone and insulin-like growth factor-I in highly resistance trained women and men

2021

Abstract The purpose of this study was to examine the responses of growth hormone (GH) and insulin-like growth factor-I (IGF I) to intense heavy resistance exercise in highly trained men and women to determine what sex-dependent responses may exist. Subjects were highly resistance trained men (N = 8, Mean ± SD; age, yrs., 21 ± 1, height, cm, 175.3 ± 6.7, body mass, kg, 87.0 ± 18.5, % body fat, 15.2 ± 5.4, squat X body mass, 2.1 ± 0.4; and women (N = 7; Mean ± SD, age, yrs. 24 ± 5, height, cm 164.6 ± 6.7, body mass, kg 76.4 ± 8.8, % body fat, 26.9 ± 5.3, squat X body mass, 1.7 ± 0.6). An acute resistance exercise test protocol (ARET) consisted of 6 sets of 10 repetitions at 80% of the 1 RM w…

AdultMale0301 basic medicinemedicine.medical_specialtyAnabolismEndocrinology Diabetes and Metabolismmedicine.medical_treatment030209 endocrinology & metabolismSquatGrowth hormone03 medical and health sciencesInsulin-like growth factorSex Factors0302 clinical medicineEndocrinologyStress PhysiologicalInternal medicineHumansMedicineInsulin-Like Growth Factor IHuman Growth Hormonebusiness.industryInsulinGrowth factorResistance TrainingPrognosisSexual dimorphism030104 developmental biologyEndocrinologyFemalebusinessBiomarkersFollow-Up StudiesHormoneGrowth Hormone & IGF Research
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Effect of resistance exercise on muscle steroid receptor protein content in strength-trained men and women

2009

The purpose of this study was to examine the acute effect of resistance exercise (RE) on muscle androgen receptor (AR) and glucocorticoid receptor (GR) protein content. Fifteen resistance-trained men (n=8; 21+/-1 years, 175.3+/-6.7 cm, 90.8+/-11.6 kg) and women (n=7; 24+/-5 years, 164.6+/-6.7 cm, 76.4+/-15.6 kg) completed 6 sets of 10 repetitions of heavy squats. Blood samples were obtained before RE, after 3 and 6 sets of squats, and 5, 15, 30 and 70 min after RE. Muscle biopsies from the vastus lateralis were obtained before RE, and 10 min and 70 min after RE. Blood samples were analyzed for total and free testosterone concentrations and muscle samples were analyzed for AR and GR protein …

AdultMalemedicine.medical_specialtymedicine.drug_classmedicine.medical_treatmentClinical BiochemistryPhysical exerciseBiologyBiochemistrySteroidYoung AdultReceptors GlucocorticoidSex FactorsEndocrinologyGlucocorticoid receptorInternal medicinemedicineHumansTestosteroneMuscle SkeletalReceptorExerciseMolecular BiologyTestosteronePharmacologyOrganic ChemistryResistance trainingResistance TrainingAndrogenAndrogen receptorEndocrinologyReceptors AndrogenFemaleSteroids
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Epinephrine Preworkout Elevation May Offset Early Morning Melatonin Concentrations to Maintain Maximal Muscular Force and Power in Track Athletes

2014

The optimal time of day for training has become an important question for many strength and conditioning specialists, and this study was designed to add some insights into this complex question. The primary purpose of this investigation was to examine physical performance within the temporal context of the relationship between physical performance, epinephrine, and melatonin concentrations in the early morning (0530 hours) and late (1500 hours) afternoon in elite collegiate male track and field athletes (jumpers and sprinters). Subjects had a mean (±SD) age, height, and body mass of 20.4 (±1.6) years, 185.8 (±9.4) cm, and 77.9 (±8.5) kg, respectively. Blood was obtained before each AM and P…

Malemedicine.medical_specialtyTime FactorsAdolescentEpinephrineAdrenergicPhysical Therapy Sports Therapy and RehabilitationAthletic PerformanceRunningArousalMelatoninYoung AdultVertical jumpPineal glandInternal medicinemedicineHumansOrthopedics and Sports MedicineMuscle Strengthta315Muscle SkeletalExerciseMelatoninMorningCross-Over StudiesbiologyAthletesTrack and FieldGeneral Medicinebiology.organism_classificationEndocrinologymedicine.anatomical_structureEpinephrineCardiologyPsychologyPhysical Conditioning Humanmedicine.drugJournal of Strength and Conditioning Research
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