scholarly journals Decreased exercise capacity in young athletes using self-adapted mouthguards

Author(s):  
Johannes Lässing ◽  
Roberto Falz ◽  
Antina Schulze ◽  
Christoph Pökel ◽  
Maximilian Vondran ◽  
...  

Abstract Purpose There is evidence of both the preventive effects and poor acceptance of mouthguards. There are various effects on performance depending on the type of mouthguard model. Hemodynamic responses to wearing a mouthguard have not been described. The aim of this study was to investigate the effects of self-adapted mouthguards with breathing channels (SAMGvent). Methods In this randomized crossover study, 17 healthy, active subjects (age 25.12 ± 2.19 years) underwent body plethysmography and performed two incremental exertion tests wearing a (SAMGvent) and not wearing (CON) a mouthguard. Blood lactate, spirometrics, and thoracic impedance were measured during these maximum exercise tests. Results The mean values using a SAMGvent revealed significantly greater airway resistance compared to CON (0.53 ± 0.16 kPa·L−1 vs. 0.35 ± 0.10 kPa·L−1, respectively; p = < 0.01). At maximum load, ventilation with SAMGvent was less than CON (118.4 ± 28.17 L min−1 vs. 128.2 ± 32.16 L min−1, respectively; p = < 0.01). At submaximal loads, blood lactate responses with SAMGvent were higher than CON (8.68 ± 2.20 mmol·L−1 vs. 7.89 ± 1.65 mmol·L−1, respectively; p < 0.01). Maximum performance with a SAMGvent was 265.9 ± 59.9 W, and without a mouthguard was 272.9 ± 60.8 W (p < 0.01). Maximum stroke volume was higher using a SAMGvent than without using a mouthguard (138.4 ± 29.9 mL vs. 130.2 ± 21.2 mL, respectively; p < 0.01). Conclusion Use of a self-adapted mouthguard led to increased metabolic effort and a significant reduction in ventilation parameters. Unchanged oxygen uptake may be the result of cardiopulmonary compensation and increased breathing efforts, which slightly affects performance. These results and the obvious preventive effects of mouthguards support their use in sports.

Retos ◽  
2021 ◽  
Vol 44 ◽  
pp. 357-363
Author(s):  
Arkaitz Castañeda-Babarro ◽  
Borja Gutiérrez Santamaría ◽  
Aitor Coca ◽  
Julio Calleja-González ◽  
Ruth Cayero

Tug of war (TOW) involves 2 teams of eight people, pulling against each other on a rope. The main goal of TOW is to pull the opposing team towards a centre line over a distance of 4 m. The measurement of physiological parameters is key to understanding the demands of an activity and to identifying its limiting performance factors. The main aim of this study was to evaluate the intensity and effort demands of TOW pullers during competition, as follows: Data were collected from 7 male pullers (Height: 175.14±4.85; Body Mass: 77.39±3.92; Age: 39.86±11.68; %Fat: 17.56±5.21; VO2max: 44.24±8.38) in the 560 kg category. The blood lactate concentrations (LAC) were assessed before and at the end of each pull, and the global rating of perceived exertion (RPE) at the end of the pulls. The following week, pullers performed a graded exercise test (GXT). Heart rate, LAC and RPE were assessed before, during and at the end of the GXT to calculate the individual anaerobic threshold. The mean blood lactate concentrations recorded at the end of the pulls (6±1.9 mmol/l) were 32% higher than the mean values recorded for the individual anaerobic threshold intensity (4.1±0.5 mmol/l). For their part, the mean RPE values of athletes after the pulls (6±1.5 mmol/l) were 21% lower than those obtained for intensity of the individual anaerobic threshold (7.6±0.8 mmol/l). The intensity and effort response are greater and kept above the anaerobic threshold during the competition in TOW pullers. Resumen. Tug of war (TOW) involucra a 2 equipos de ocho personas, tirando una contra la otra con una cuerda. El objetivo principal es llevar al equipo contrario hacia una línea central a una distancia de 4 m. La medición de parámetros fisiológicos es clave para comprender las demandas de una actividad y para identificar sus factores limitantes de rendimiento. El objetivo principal de este estudio fue evaluar la intensidad y las demandas de esfuerzo de los tiradores de TOW durante la competición. 7 tiradores masculinos (altura: 175,14 ± 4,85; masa corporal: 77,39 ± 3,92; edad: 39,86 ± 11,68; % de grasa: 17,56 ± 5,21; VO2max: 44,24 ± 8,38) en la categoría de 560 kg. Se evaluaron concentraciones de lactato (LAC) antes y después de cada tirada, y el esfuerzo percibido (RPE) al final. La siguiente semana, los tiradores realizaron una prueba de esfuerzo (GXT). La FC, LAC y RPE se evaluaron antes, durante y después del GXT para calcular el umbral anaeróbico individual. Las concentraciones de LAC registradas medios registrados para la intensidad del umbral anaeróbico individual (VT2) (4,1 ± 0,5 mmol/l). Los valores medios de RPE de los deportistas en competición (6 ± 1,5 mmol/l) fueron un 21% inferiores a los obtenidos para la intensidad del VT2 (7,6 ± 0,8 mmol/l). La intensidad y la respuesta al esfuerzo son mayores y se mantienen por encima del VT2 durante la competición en tiradores TOW al final de los tirones (6 ± 1,9 mmol/l) fueron un 32% más altas que los valores.


2018 ◽  
Vol 91 (1) ◽  
pp. 48-52
Author(s):  
Cristian Tudor Buescu ◽  
Cristian Mircea Dudescu ◽  
Sergiu Caterev ◽  
Dan Gheorghe Osvald Lucaciu

Background and aims. Using free quadriceps tendon graft for anterior cruciate ligament (ACL) reconstruction has become more popular in the last years due to the low morbidity at the harvest site and biomechanical and structural properties similar to other types of graft (hamstring and patellar tendons). As long as the tibial tunnel fixation with interference screws is considered the standard fixation, femoral fixation is still an open subject. Even though the most common type of femoral tunnel fixation are the cortical suspension devices, the type of suture used for tying the graft to the loop is still evaluated and discussed. We aimed to evaluate the resistance and elongation of a double whip stitch used for tying a tendon to the loop of a cortical suspension device.Method. We used 10 porcine flexor digitorum profundus as free graft for a graft-suture-cortical suspension device construct using the double whip stitch. The total length of the construct and tendon length were recorded before and after the test was performed. Tensioning curves, total construct elongation and maximum tension at breaking point were electronically recorded on the testing device's software. The mean values and coefficient of variance were assessed.Results. We noted the breaking of the suture wire where the wires passed through the loop of the cortical suspension device as final point for all tests. The mean of maximum load was 505.68N (Max=639.38 N; min=358.93 N; SD=82.88078 N) and the mean of total construct elongation was 39.54784mm (Max= 48.60466 mm; min=31.74853 mm; SD=4.85371 mm).Conclusion. With some minor improvement in technique and graft preconditioning and pretensioning, the double whip stitch can be used in connecting a free tendon to a cortical suspension device.


1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.


1986 ◽  
Vol 55 (01) ◽  
pp. 108-111 ◽  
Author(s):  
M Köhler ◽  
P Hellstern ◽  
C Miyashita ◽  
G von Blohn ◽  
E Wenzel

SummaryThis study was performed to evaluate the influence of different routes of administration on the efficacy of DDAVP treatment. Ten healthy volunteers received DDAVP intranasally (i.n.), subcutaneously (s.c.) and intravenously (i.v.) in a randomized cross-over trial. Factor XII and high molecular weight (HMW)-kininogen levels increased only slightly after DDAVP administration. The mean increase of factor VIII: C was 3.1 (i. v.), 2.3 (s. c.), and 1.3 (i.n.) - fold over baseline. Ristocetin cofactor (von Willebrand factor antigen) increased 3.1 (2.5), 2.0 (2.3) and 1.2 (1.2) - fold over baseline mean values after i.v., s.c. and i.n. DDAVP, respectively. The half-disappearance time of factor VIII and von Willebrand factor (vWF) after DDAVP ranged from five (factor VIII: C) to eight hours (vWF). The mean increase of fibrinolytic activity was more pronounced after i.v. DDAVP. The antidiuretic effect was moderate with no apparent differences between the routes of application. This study provides further evidence that both i.v. and s.c. DDAVP administration result in an appropriate and reliable stimulation of haemostasis. An additional advantage of s. c. administration is its suitability for home treatment.


2018 ◽  
Vol 4 (4) ◽  
pp. 519-522
Author(s):  
Jeyakumar S ◽  
Jagatheesan Alagesan ◽  
T.S. Muthukumar

Background: Frozen shoulder is disorder of the connective tissue that limits the normal Range of motion of the shoulder in diabetes, frozen shoulder is thought to be caused by changes to the collagen in the shoulder joint as a result of long term Hypoglycemia. Mobilization is a therapeutic movement of the joint. The goal is to restore normal joint motion and rhythm. The use of mobilization with movement for peripheral joints was developed by mulligan. This technique combines a sustained application of manual technique “gliding” force to the joint with concurrent physiologic motion of joint, either actively or passively. This study aims to find out the effects of mobilization with movement and end range mobilization in frozen shoulder in Type I diabetics. Materials and Methods: 30 subjects both male and female, suffering with shoulder pain and clinically diagnosed with frozen shoulder was recruited for the study and divided into two groups with 15 patients each based on convenient sampling method. Group A patients received mobilization with movement and Group B patients received end range mobilization for three weeks. The outcome measurements were SPADI, Functional hand to back scale, abduction range of motion using goniometer and VAS. Results: The mean values of all parameters showed significant differences in group A as compared to group B in terms of decreased pain, increased abduction range and other outcome measures. Conclusion: Based on the results it has been concluded that treating the type 1 diabetic patient with frozen shoulder, mobilization with movement exercise shows better results than end range mobilization in reducing pain and increase functional activities and mobility in frozen shoulder.


1966 ◽  
Vol 53 (2) ◽  
pp. 177-188 ◽  
Author(s):  
P. Lund-Johansen ◽  
T. Thorsen ◽  
K. F. Støa

ABSTRACT A comparison has been made between (A), a relatively simple method for the measurement of aldosterone secretion rate, based on paper chromatography and direct densitometry of the aldosterone spot and (B) a more elaborate isotope derivative method. The mean secretion rate in 9 normal subjects was 112 ± 26 μg per 24 hours (method A) and 135 ± 35 μg per 24 hours (method B). The »secretion rate« in one adrenalectomized subject after the intravenous injection of 250 μg of aldosterone was 230 μg per 24 hours (method A) and 294 μg per 24 hours (method B). There was no significant difference in the mean values, and correlation between the two methods was good (r = 0.80). It is concluded that the densitometric method is suitable for clinical purposes as well as research, being more rapid and less expensive than the isotope derivative method. Method A also measures the urinary excretion of the aldosterone 3-oxo-conjugate, which is of interest in many pathological conditions. The densitometric method is obviously the less sensitive and a prerequisite for its use is an aldosterone secretion of 20—30 μg per 24 hours. Lower values are, however, rare in adults.


1970 ◽  
Vol 64 (2) ◽  
pp. 265-272 ◽  
Author(s):  
A. A. van der Gugten ◽  
M. Sala ◽  
H. G. Kwa

ABSTRACT Eight female and eight male rats were castrated at the age of 8 to 10 weeks. Four spayed and four orchidectomized rats received one oestrone/cholesterol pellet (200 μg oestrone) on the day of operation (day 0), a second pellet on day 11 and a third on day 23. The remaining animals received four oestrone/cholesterol pellets at these times. The fluctuations in the prolactin levels in the circulation induced by the oestrogen challenges in these animals were followed during 31 days by radioimmunoassays performed on days 3, 7, 9, 14, 15, 17, 23, 24, 25, 28 and 31. The results suggested that the homoeostatic mechanism regulating plasma levels of prolactin was capable of withstanding the three time-spaced oestrogen challenges only in the spayed animals receiving the lower doses of oestrogen, since it allowed the mean values of the prolactin levels to remain fairly constant during the first 4 weeks. The levels in this group rose to much higher levels only on day 31. The higher doses of oestrone in the spayed rats and both dose levels of oestrone in the orchidectomized animals apparently resulted in a primary break-down of the homoeostatic mechanism, since the prolactin levels in the animals of these groups rose to much higher levels either on day 7 or on day 9. This was followed by a period during which the prolactin levels appeared to be more or less under control, until a second and probably definitive failure of the homoeostatic mechanism allowed the mean levels to rise sharply again.


2017 ◽  
Vol 13 (1) ◽  
Author(s):  
Izabel Aparecida Soares ◽  
Mauro Sérgio Téo ◽  
Carlise DEBASTIANI ◽  
Suzymeire BARONI ◽  
Vanessa Silva RETUCI

O trabalho teve por objetivo verificar diferenças entre rendimento do concentrado proteico e proteína bruta da folha da mandioca (Manihot esculenta Crantz), obtidos a partir de três variedades comerciais: branca, cascuda e vermelha. As manivas foram plantadas seguindo o delineamento experimental inteiramente casualizado com três repetições. Nas comparações entre as variedades, considerou coletas escalonadas pós-plantio, realizadas aos 12, 14 e 16 meses. O concentrado proteico foi obtido a partir da farinha das folhas inteiras e submetido ao método de termo - coagulação ácido e a proteína bruta pelo método padrão AOAC. Os dados foram submetidos a análise de variância e comparados pelo teste de Tukey - 5% de probabilidade. Os resultados não indicaram diferença significativa entre as médias obtidas para rendimento de concentrado proteico. Para a variável porcentagem de proteína bruta a variedade Branca foi a que apresentou maior valor, com média de 46,25%, seguida pela Cascuda e Vermelha, 44,52% e 37,30%, sucessivamente. Conclui-se que outros estudos devem avaliar condições que possam influenciar no teor de proteína foliar, como clima e solo, e, avaliar os níveis de ácido cianídrico de cada variedade, indicando qual das três é a melhor para a extração do concentrado proteico das folhas. Palavras chaves: Manihot esculenta Crantz, variedades comerciais, concentrado proteico, proteína bruta. ABSTRACT: The study aimed to assess the differences between income protein concentrate, crude protein of cassava leaf (Manihot esculenta Crantz), obtained from three commercial varieties: white, red and cascuda. The cuttings were planted following the completely randomized design with three replications. Comparisons between the varieties considered after planting staggered collections, held on 12, 14 and 16 months. The protein concentrate was obtained from flour of whole sheets and subjected to the term method - acid coagulation and crude protein by AOAC standard method. The data were submitted to ANOVA and Tukey test - 5% probability. The results indicated no significant difference between the mean values obtained for protein concentrate income. For the variable percentage of crude protein White variety showed the highest, with an average of 46.25%, followed by cascuda and Red, 44.52% and 37.30%, successively. We conclude that further studies should evaluate conditions that may affect the leaf protein content, such as climate and soil, and evaluate the hydrocyanic acid levels of each variety, indicating which of the three is the best for the extraction of protein concentrate from leaves Key words: Manihot esculenta Crantz, commercial varieties, protein concentrate, crude protein.


Author(s):  
Ashraf Albrakati

Tramadol, a broadly in recent years, is an effective analgesic agent for the treatment of moderate to acute pain. Its metabolites are excreted by the kidney which may cause nephrotoxicity. Moringa oleifera leaves are commonly used to provide herbal and plant-derived medicinal products especially in developing nations. The present study was carried out to determine the biochemical and histopathological changes in the kidney of tramadol-treated albino mice and to evaluate the possible protective role of Moringa oleifera leaves against tramadol-induced nephrotoxicity. Twenty adult albino mice were divided into four groups. Control group (group i) received daily intraperitoneal injection of normal saline only, group ii received oral dose of Moringa oleifera leaves extract (20 mg/kg/bw) for three weeks, group iii received daily intraperitoneal dose of tramadol (0.3 mg/kg/bw) for the same period, group iv, received daily oral dose of Moringa oleifera leaves extract, (20 mg/kg/bw) three hours before injecting intraperitoneal dose of tramadol (0.3 mg/kg/bw), for the same period. Blood samples were withdrawn at the end of the experiment for kidney function tests and specimens from the kidney were processed for histological study. No significant differences in the mean values of the kidney function tests were noticed between Moringa oleifera group and control group. However, there was highly significant increase in the mean values of serum, urea and creatinine in tramadol-treated group as compared to the control group. Although tramadol + Moringa oleifera group revealed significant difference in the mean values of urea and creatinine when compared with tramadol-treated group. So, Moringa oleifera leaves extract have been shown to attenuate the renal dysfunction, improve the renal architecture, with nearly normalization of serum urea and creatinine levels which indicate improvement of renal function. In conclusion, in the light of biochemical results and histological findings, co-administration of Moringa oleifera leaves lessened the negative effects of tramadol-induced nephrotoxicity; possibly by its antioxidant action. Further investigation of these promising protective effects of Moringa oleifera leaves against tramadol-induced renal injury may have considerable impact on developing an adjunct therapy aiming to improve the therapeutic index of some nephrotoxic drugs.


Author(s):  
Rofail Rakhmanov ◽  
Elena Bogomolova ◽  
Mariya Shaposhnikova ◽  
Mariya Sapozhnikova

The biochemical blood parameters characterizing the students ’nutritional status were evaluated: protein, lipid, carbohydrate metabolism, a number of minerals. The mean values, errors of the mean, median (Me), boundary (Q) and the range of 25–75 percentiles were determined. In 9.1 % of students and 28.6 % of students, the total protein was increased. Creatinine in men was in the upper normal range, in women — at the upper limit of normal, of which 46.2 % was higher than normal. The interval Q25–75 of uric acid in students is determined in the lower normal zone. In 40.0 % of men, decreased high-density lipoprotein cholesterol (Q25–75 corresponded to 1.15–1.79), in women — below normal, Q25–75 5 was 1.3–1.5, decreased in 73.3 %. Me and Q25–75 iron were in the lower normal range; 14.1 % of men and 13.2 % of women are below normal. Me sodium and potassium at the level of the lower boundary of the norm, Q25–75 in the lower zone of the norm: in 16.0 % and 15.4 % of students the levels are reduced. Calcium is slightly above the lower limit of the norm, Q25–75–2.1–2.24, indicating an insufficient intake in the whole group; 25.0 % are below normal. The border of the 25th percentile of magnesium is at the level of the lower border of the norm, in 19.2 % it is reduced. 7.2 % lack of chlorine. Phosphorus is normal, but Q25–75 is in the upper zone; 17.9 % increased. Biochemical markers can identify individuals with metabolic disorders of nutrients. Statistical indicators — the median, the boundaries of 25–75 quartiles and their scope characterize the metabolism of macronutrients and minerals in the group and subgroups of students. Laboratory and mathematical methods can provide a basis for identifying the specific causes of these changes. For this, you can use the questionnaire method of studying the nutrition of students, possibly using the developed questionnaires for a specific situation.


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