scholarly journals Effect of dynamic and static strength training on hormonal activity in elite boxers

2020 ◽  
Vol 12 (3) ◽  
pp. 1-10
Author(s):  
ESER AĞGÖN ◽  
ÖZTURK AGIRBAŞ ◽  
HAMIT HAKAN ALP ◽  
IZZET UÇAN ◽  
RECEP GÜRSOY ◽  
...  

Background: The aim of this study was to determine hormonal responses to acute and chronic exposure to static and dynamic strength training programs using resistance bands in boxers. Material and methods: 19 male national boxers participated in the study. Boxers were instructed to perform strength exercises with resistance bands for 3 days a week for 8 weeks involving either dynamic (n=10) or static (n=9) resistance exercises. Blood samples were taken before exercise, immediately after the initial exercise session, and 8 weeks later following the last exercise session. Cortisol, growth hormone, adrenocorticotropic hormone adrenaline and noradrenaline levels were measured. Statistical analyses involved non-parametric analysis with an alpha level of .05. Results: Dynamic strength exercises were effective stimuli to growth hormone, adrenaline and noradrenaline, while static strength exercises provoked cortisol, growth hormone, adrenaline and noradrenaline responses both initially after exercise and after 8 weeks of chronic training. Neither dynamic nor static strength exercises were effective in prompting adrenocorticotropic changes after an exercise session or after 8 weeks of training. Conclusions: We showed that dynamic and static strength exercise protocols using resistance bands both could provoke acute and chronic hormonal responses in boxers similar to more traditional modes of such exercise. Abbreviations: ACTH ̶ Adrenocorticotropic Hormone, GH ̶ Growth Hormone, C ̶ Cortisol.

2019 ◽  
Vol 7 (3) ◽  
pp. 14
Author(s):  
Ozturk Agirbas

The aim of this study is to determine the effects of both static and dynamic strength trainings on oxidative stress and DNA damage in elite boxers. 19 elite male boxers participated in the study. Boxers were instructed to perform strength exercises 3 days a week for 8 weeks. Blood samples were taken before exercises (resting), after the first exercise (acute) and after 8 weeks following the last exercise (chronic). MDA, SOD, GPx and 8-OHdG levels of blood were examined. Statistical analyses were carried out using the SPSS 22 for Windows. The data were found to not be distributed normally. Thus, Friedman, Wilcoxon and Mann-Whitney U tests were used. The results were evaluated using an alpha level of .05. In the dynamic strength exercise group, there was no significance at GPx, however MDA, SOD and 8-OHdG levels decreased in 8 weeks. In static strength exercise group, although there was no significance at SOD, GPx and 8-OHdG, MDA levels decreased both after a single session and in 8 weeks. In addition, significant difference was found between dynamic and static exercise groups at SOD, GPx and 8-OHdG levels in pre-exercise and at 8-OHdG levels after 8 weeks.  Dynamic strength exercises with Thera-Band are effective on MDA, SOD and 8-OHdG chronically, static strength exercises are effective on MDA both acutely and chronically. Neither dynamic nor static strength exercises are not effective on GPx both acutely and chronically.


1986 ◽  
Vol 111 (4) ◽  
pp. 516-521
Author(s):  
Nina Clausen ◽  
Per-Eric Lins ◽  
Ulf Adamson ◽  
Bertil Hamberger ◽  
Suad Efendić

Abstract. Hypothyroidism has been alleged to modulate insulin action and influence the secretion of growth hormone and catecholamines. We recently investigated the influence of hypothyroidism on glucose counterregulatory capacity and the hormonal responses to insulin-induced hypoglycaemia in 6 patients with primary hypothyroidism (age 32–52 years, TSH-values 66–200 mU/l). Hypoglycaemia was induced in the hypothyroid state and again when the subjects were euthyroid. After an overnight fast a constant rate infusion of insulin (2.4 U/h) was given for 4 h. Glucose was measured every 15 min and insulin, C-peptide, glucagon, epinephrine, norepinephrine, growth hormone and cortisol every 30 min for 5 h. During insulin infusion somewhat higher concentrations of the hormone were obtained in the hypothyroid state and simultaneously glucose levels were 0.5 mmol/l lower. As expected, basal norepinephrine levels were higher in hypothyroidism. However, no increase in circulating norepinephrine during hypoglycaemia was registered in the two experiments. The responses of counterregulatory hormones showed an enhanced response of cortisol, similar responses of growth hormone and epinephrine while the glucagon response was paradoxically impaired. Our findings suggest that hypothyroidism alters insulin metabolism, and that the glucagon response to hypoglycaemia is impaired in this condition.


A description is given of the experimental technique devised to apply the method outlined theoretically in part I to the measurement of the dynamic compressive yield strength of various steels, duralumin, copper, lead, iron and silver. A polished piece of armour steel was employed as a target, and cylindrical specimens were fired at it at various measured velocities from Service weapons. The distance between the weapon and target was made short to ensure normal impact, and apparatus was devised for the precise measurement of striking velocity over this short range. The dynamic compressive yield strength was computed from the density of the specimen, the striking velocity, and from measurements of the dimensions of the test piece before and after test. Details are given of the accuracy of the various measurements, and of their effect on the values of yield strength. The method was found to be inaccurate at low and high velocities. For instance, with mild steel, satisfactory results were only obtainable within the range 400 to 2500 ft. /sec. The range of velocities within which satisfactory results could be obtained varied with the quality of the material tested, soft metals giving results within a much lower range than that necessary for harder materials. Because of its failure at low velocities, the method could not be employed to bridge the gap between static and dynamic tests. The rate of strain employed in the dynamic tests could not be measured, but was estimated to be of the order of 10,000 in. /in. /sec. With the materials tested little change of dynamic strength occurred within the range of striking velocities employed, probably because the rate of strain did not vary to any great extent with the striking velocity. Within the range of weapons available, that is, from a 0·303 in. rifle up to a 13 pdr. gun (calibre 3·12 in.), little change of dynamic strength occurred with alteration of the initial dimensions of the specimens, probably because the corresponding change of rate of strain was not large. In general, the dynamic compressive yield strength S was greater than the static strength Y represented by the compressive stress giving 0·2% permanent strain. For steels of various types, regardless of chemical composition and heat treatment, there was a relation between S / Y and the static strength Y , the ratio decreasing from approximately 3 when Y was 20 tons/sq. in. to 1 when Y was 120 tons/sq. in. A similar relation occurred with duralumin, S / Y varying from 2·5 at Y = 8 tons/sq. in. to 1·4 at Y = 25 tons/sq. in. Dynamic compressive yield values were obtained for soft materials such as pure lead, copper and Armco iron, which, under static conditions, gave no definite yield values. A plot of the unstrained length of the specimen X , expressed as X / L (where L = initial overall length), versus the final overall length L 1 , expressed as L 1 / L , was made for the various materials. Any specified value of X / L was associated with greater values of L 1 / L for the more ductile materials, such as copper and lead, than for the brittle materials, such as armour plate and duralumin.


2021 ◽  
Vol 20 (1) ◽  
pp. 106-118
Author(s):  
Thorben Menrad ◽  
Jürgen Edelmann-Nusser

Abstract To control and monitor strength training with a barbell various systems are on the consumer market. They provide the user with information regarding velocity, acceleration and trajectory of the barbell. Some systems additionally calculate the 1-repetition-maximum (1RM) of exercises and use it to suggest individual intensities for future training. Three systems were tested: GymAware, PUSH Band 2.0 and Vmaxpro. The GymAware system bases on linear position transducers, PUSH Band 2.0 and Vmaxpro base on inertial measurement units. The aim of this paper was to determine the accuracy of the three systems with regard to the determination of the average velocity of each repetition of three barbell strength exercises (squat, barbell rowing, deadlift). The velocity data of the three systems were compared to a Vicon system using linear regression analyses and Bland-Altman-diagrams. In the linear regression analyses the smallest coefficient of determination (R2.) in each exercise can be observed for PUSH Band 2.0. In the Bland-Altman diagrams the mean value of the differences in the average velocities is near zero for all systems and all exercises. PUSH Band 2.0 has the largest differences between the Limits of Agreement. For GymAware and Vmaxpro these differences are comparable.


2000 ◽  
Vol 14 (4) ◽  
pp. 399-404
Author(s):  
CHARILAOS TSOLAKIS ◽  
DIMOSTHENIS MESSINIS ◽  
APOSTOLOS STERGIOULAS ◽  
ATHANASIOS DESSYPRIS

2018 ◽  
Vol 36 (28) ◽  
pp. 2854-2862 ◽  
Author(s):  
Ralph E. Vatner ◽  
Andrzej Niemierko ◽  
Madhusmita Misra ◽  
Elizabeth A. Weyman ◽  
Claire P. Goebel ◽  
...  

Purpose There are sparse data defining the dose response of radiation therapy (RT) to the hypothalamus and pituitary in pediatric and young adult patients with brain tumors. We examined the correlation between RT dose to these structures and development of endocrine dysfunction in this population. Materials and Methods Dosimetric and clinical data were collected from children and young adults (< 26 years of age) with brain tumors treated with proton RT on three prospective studies (2003 to 2016). Deficiencies of growth hormone (GH), thyroid hormone, adrenocorticotropic hormone, and gonadotropins were determined clinically and serologically. Incidence of deficiency was estimated using the Kaplan-Meier method. Multivariate models were constructed accounting for radiation dose and age. Results Of 222 patients in the study, 189 were evaluable by actuarial analysis, with a median follow-up of 4.4 years (range, 0.1 to 13.3 years), with 31 patients (14%) excluded from actuarial analysis for having baseline hormone deficiency and two patients (0.9%) because of lack of follow-up. One hundred thirty patients (68.8%) with medulloblastoma were treated with craniospinal irradiation (CSI) and boost; most of the remaining patients (n = 56) received involved field RT, most commonly for ependymoma (13.8%; n = 26) and low-grade glioma (7.4%; n = 14). The 4-year actuarial rate of any hormone deficiency, growth hormone, thyroid hormone, adrenocorticotropic hormone, and gonadotropin deficiencies were 48.8%, 37.4%, 20.5%, 6.9%, and 4.1%, respectively. Age at start of RT, time interval since treatment, and median dose to the combined hypothalamus and pituitary were correlated with increased incidence of deficiency. Conclusion Median hypothalamic and pituitary radiation dose, younger age, and longer follow-up time were associated with increased rates of endocrinopathy in children and young adults treated with radiotherapy for brain tumors.


1998 ◽  
Vol 7 (3) ◽  
pp. 101-106
Author(s):  
Lee N. Burkett ◽  
Wayne T. Phillips ◽  
Brent Alvar ◽  
Lyle Bartelt ◽  
William Stone

2009 ◽  
Vol 64 (suppl_1) ◽  
pp. ONS62-ONS70 ◽  
Author(s):  
Eun Jig Lee ◽  
Jung Yong Ahn ◽  
Taewoong Noh ◽  
Se Hun Kim ◽  
Tai Seung Kim ◽  
...  

Abstract Objective: The microsurgical pseudocapsule can be found in the transition zone between an adenoma and the surrounding normal pituitary tissue. We investigated the precise histology of the pseudocapsule. Furthermore, we evaluated the remission rate, the changes in pituitary function, and the recurrence rate after intensive resection of the pseudocapsule. Methods: In 616 patients with pituitary adenomas (Hardy Types I–III) over a period of 14 years, we introduced intensive resection of the microsurgical pseudocapsule to achieve complete tumor removal. A combined pituitary function test and radiological study were performed on the patients before surgery, 1 year after surgery, and at subsequent 1.5-year intervals 2 to 13 years postoperatively. Results: Microsurgical pseudocapsules were identified in 343 (55.7%) of 616 patients, and the distinct microsurgical pseudocapsules were observed in 180 (52.5%) of these patients. In the remaining 163 patients, the microsurgical pseudocapsules were incompletely developed. Tumor cluster infiltration was present in the pseudocapsule in 71 (43.6%) of these patients. Aggressive resection of the microsurgical pseudocapsule was more often required in larger tumors than in smaller ones. The presence of a pseudocapsule was slightly more frequent in prolactin-secreting tumors (70.9%) than in growth hormone-secreting (55.0%) and adrenocorticotropic hormone-secreting (40.0%) tumors. In the 243 patients of the total resection group who underwent combined pituitary function tests more than 2 times after surgery, the surgical remission rate was 99.1 % in clinically nonfunctional tumors, 88% in growth hormone-secreting, 70.6% in prolactin-secreting, and 100% in adrenocorticotropic hormone-secreting tumors. The surgical remission rate was 86.2% in the presence of a pseudocapsule and 94.3% in the absence of a pseudocapsule. Preoperative hypopituitarism improved in 140 patients (57.6%), persisted in 47 patients (19.3%), and was aggravated in 33 patients (13.6%). There was no statistical difference in improvement or deterioration of pituitary function according to the existence or absence of the pseudocapsule. The tumor recurrence rate was 0.8% in the total resection group and was 42.1 % in the subtotal resection group. Conclusion: We have shown that tumor tissue is frequently present within the pseudocapsule, suggesting that any tumor remnant in the pseudocapsule could be a source of recurrence and an obstacle to achieving complete remission. These results indicate that intensive resection of the pseudocapsule could result in a higher remission rate without deteriorating pituitary function.


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