El test de una repetición máxima incrementa los índices séricos referentes a daño y dolor muscular en varones entrenados y no entrenados

Introducción: El objetivo de este estudio fue examinar el efecto del test de una repetición máxima sobre el daño y el dolor muscular en hombres entrenados y no entrenados. Métodos: Participaron en el estudio 10 hombres entrenados (E) y 10 no entrenados (NE). Los sujetos realizaron un test de una repetición máxima (1RM) en el ejercicio de sentadilla, y se valoró la actividad de la creatincinasa (CK), la concentración de la proteína C reactiva (PCR) y el dolor muscular (cuádriceps e isquiotibiales) al inicio y a las 24, 48 y 72 horas posteriores al test 1RM. Resultados: Se observaron incrementos significativos de la actividad de la CK y el dolor muscular a las 24, 48 y 72 horas posteriores al test 1RM, así como diferencias significativas entre los sujetos entrenados y los no entrenados (p < 0,05). En las concentraciones de PCR, ambos grupos mostraron incrementos significativos en el descanso, a las 24, 48 y 72 horas posteriores al test 1RM, y a las 72 horas en comparación con las 24 horas (p < 0,05). No se detectaron diferencias significativas de la concentración de la PCR (p > 0,05) entre los dos grupos. Conclusión: En conclusión, el test 1RM en el ejercicio de sentadilla (alta intensidad y bajo volumen) incrementa la actividad de la CK, la concentración de la PCR en el plasma y el dolor muscular en sujetos entrenados y no entrenados. Puede observarse que el test 1RM puede inducir daño muscular, lo que significaría un factor negativo tanto para los deportistas como para el resto de individuos, puesto que el dolor muscular se asocia a una disminución del rendimiento. © 2012 Consell Català de l’Esport. Generalitat de Catalunya. Publicado por Elsevier España, S.L. Todos los derechos reservados

El test d’una repetició màxima incrementa els índexs sèrics

Introducció. L’objectiu d’aquest estudi fou examinar l’efecte del test d’una repetició màxima en el dany i el dolor muscular en homes entrenats i no entrenats. Mètodes: Participaren a l’estudi 10 homes entrenats (E) i 10 no entrenats (NE). Els subjectes realitzaren un test d’una repetició màxima (1RM) de l’exercici d’esquat, i s’avaluà l’activitat de la creatina cinasa (CK), la concentració de la proteïna C reactiva (PCR) i el dolor muscular (quàdriceps i isquiotibials), a l’inici i al cap de 24, 48 i 72 hores després del test 1RM. Resultats: S’observaren increments significatius de l’activitat de la CK i dolor muscular a les 24, 48 i 72 hores després del test 1RM, així com diferències significatives entre els subjectes entrenats i els no entrenats (p < 0,05). En les concentracions de PCR, ambdós grups mostraren increments significatius en el descans, a les 24, 48 i 72 hores posteriors al test 1RM, i a les 72 hores en comparació amb les 24 hores (p < 0,05). No es detectaren diferències significatives de la concentració de la PCR (p > 0,05) entre els dos grups. Conclusió: En conclusió, el test d’1RM en l’exercici d’esquat (intensitat alta i volum baix) incrementa l’activitat de la CK, la concentració de la PCR en el plasma i el dolor muscular en subjectes entrenats i no entrenats. Es pot observar que el test 1RM pot induir dany muscular, cosa que suposaria un factor negatiu tant per als esportistes com per a la resta d’individus, donat que el dolor muscular s’associa a una disminució del rendiment. © 2012 Consell Català de l’Esport. Generalitat de Catalunya. Publicat per Elsevier España, S.L. Tots els drets reservats

One repetition maximum test increases serum indices of muscle

Introduction: The purpose of this study was to examine the effect of one repetition maximum test on muscle damage and soreness in trained and untrained males. Methods: Ten trained (T) and 10 untrained (UT) males participated in this study. Subjects performed one repetition maximum (1RM) test for the back squat exercise and creatine kinase (CK) activity, C-reactive protein (CRP) concentration, and muscle soreness (quadriceps and hamstring) were assessed at pre, 24, 48 and 72 h post 1RM test. Results: Significant increases in CK activity and muscle soreness were observed at 24, 48 and 72 h post 1RM test, and there were also significant differences between T and UT (p < 0.05). In the CRP concentration, both groups indicated significant increases above resting at 24, 48 and 72 h post 1RM test and 72 h compared to 24 h (p < 0.05). There were no significant differences between T and UT in the CRP concentration (p > 0.05). Conclusion: In conclusion, the 1RM back squat test (high intensity and low volume) increases CK activity, CRP concentration in the plasma and muscle soreness in the T and UT. It can be observed that 1RM test can induce muscle damage, which would be a negative factor for athletes and individuals, since the muscle injury is associated with decreased performance. © 2012 Consell Català de l’Esport. Generalitat de Catalunya. Published by Elsevier España, S.L. All rights reserved

Oxidative dna damage and lipid peroxidation to cluster vs. traditional sets resistance exercise in professional volleyball players

Cells continuously produce free radicals and reactive oxygen species (ROS) as part of metabolic processes. Exercise can induce an imbalance between ROS and antioxidants, which is referred to as oxidative stress. Acute bout of resistance exercise (RE) induces activation of several distinct systems of radicals generation, but the effects of different RE loading on oxidative stress response is not clear. Therefore, the purpose of this study was to examine the influence of cluster vs. traditional sets of RE on oxidative DNA damage, lipid peroxidation and uric acid response in athletes. To elicit blood oxidative stress, 12 professional young male volleyball players undertook two different RE loading patterns: 1) cluster loading pattern, 2) traditional loading pattern which was standardized for total volume and completed in a randomized crossover fashion with a four-day interval between trials. Blood samples were collected before and after RE for markers of oxidative stress and damage. In response to both the cluster and traditional sets, 8-hydroxy-2-deoxyguanosine (8-OHdG), 4-hydroxy-2-nonenal (4-HNE), and uric acid were significantly elevated post exercise (p<.05). Although no statistically significant differences between loading patterns were observed, the rate of elevations in 8-OHdG (effect size [ES]: 1.4 vs. 1.3) and 4-HNE (ES: 8.1 vs. 7.9) was greater for the traditional sets; likewise, the rate of uric acid excretion was greater for the cluster RE (ES: 1.6 vs. 1.4). These data suggests that RE induced DNA damage, and lipid peroxidation, but they were greater for the traditional RE. Therefore, strength and conditioning professionals in the field of volleyball must keep in their mind that RE induces oxidative stress and should use proper RE loading patterns in their training schedule

The effects of different doses of caffeine on performance, rating of perceived exertion and pain perception in teenagers female karate athletes

The present study set to examine the effects of different doses of caffeine on performance, rating of perceived exertion (RPE), and pain perception in female teenager athletes of karate. Ten female karate athletes (16.8±1.23 years; height 1.59±0.28 m; body-mass 57.73±8.33 kg; BMI 22.71±3.05 kg/m2) participated in the study. A double-blind, randomized, and crossover counterbalanced design was used. In three sessions (with an interval of seven days'), ten female karate athletes ingested low dose (2 mg/kg), moderate dose (5 mg/kg) caffeine, and placebo. Sixty minutes after consumption, they performed the tests as below: one repetition maximum and 60% of one repetition maximum in the leg press, explosive power test, and anaerobic RAST test. After the tests, the participants' RPE (6-20 scale) and pain perception (0-10 scale) were recorded using various categorical scales. The results showed that caffeine ingestion at moderate dose significantly reduced RPE and pain perception values compared with the placebo during muscular endurance test (P=0.0001 and P=0.039, respectively). The findings suggest that caffeine dose of 5 mg/kg body mass appears to improve RPE and pain perception in female teenager athletes of karate. The dose of 2 mg/kg body mass does not confer any additional improvement in performance

Crosstalk between tight junction genes and muscle strength: Applying supplement and resistance training to old male wistar rats

Aim of this study was to determine the relations among the tight junction (TJs) genes, muscle strength and cross-sectional area (CSA) influenced by resistance training with or without specific supplement (a combination of lactobacillus and bifidobacterium probiotics, leucine amino acid and Vitamin-D). For this purpose, 25 male wistar rats in two age groups (3 months in young control and 16-24 months in four other groups) randomly divided in 5 equal groups (old and young control, resistance training, supplement and resistance training plus supplement). After 8 weeks of resistance training trice a week and oral gavage of supplement 5 times per week there were no any relation between grip strength and muscle CSA with zonula occludens-1 (ZO-1) and occludin (Occ) genes. But result of one-way ANOVA revealed that there were significantly differences among study groups in TJs genes, muscle strength and CSA (P≤0.05). Our finding showed that resistance training along with supplement can increase the level of ZO-1 (P=0.011), and Occ genes (P=0.023) expression. Indeed, resistance training plus supplement had synergistic effect on muscle CSA and grip strength (P=0.001) that can be comparable with young group. In addition, supplement alone appears that doesn’t have beneficial impact on physical function but surprisingly our finding shows strong inverse correlation between Occ and grip strength (p=0.015, r= -1.0) in supplement group which implies that although supplement alone can’t improve physical function but can maintain intestinal barrier function

The relationship between second-to-fourth digit ratio (2D:4D), muscle strenght and body composition to bone mineral density in young women

2D:4D ratio is determined by balance between androgens and estrogens. Low level estrogen reduces bone mineral density (BMD) and incurs negative changes to bone microarchitecture, increasing the risk of osteoporosis and, as a consequence, fracture risk in women. The purpose of this study was to investigate the relationship between 2D:4D, muscle strength and body composition to BMD in young women. One hundred twenty-seven young women (age range 24-36 years) voluntarily participated in this study. Lengths of the second (index) and fourth (ring) fingers, upper and lower body strength and body composition (body mass index, BMI; waist to hip ratio, WHR) and body fat percentage were estimated. Also, blood levels of calcium and 25-hydroxyvitamin D (25OHD) were evaluated and dual-energy X-ray absorptiometry device was used to measure BMD in the lumbar spine (LS) and femoral neck (FN). The results showed that digit ratios, upper body and lower body muscle strength, BMI and fat percentage had a positive relationship with LS and FN BMD (LS BMD: r=.47, r=.56, r=.46, r=.34, r=.28, p≤.001, respectively; FN BMD: r=.34, r=.49, r=.51, r=.45, r=.27, p≤.001, respectively). In addition, there was no significant relationship between WHR and BMD of LS and FN (p˃.05). Multiple linear regression analysis showed the upper body strength was a stronger determinant of LS BMD and the lower body strength was a stronger determinant of FN BMD. Based on the results, the researchers concluded that upper and lower body strength, 2D:4D ratios and BMI were important determinants of young women’s BMD. Also, it seemed that some of these factors may be able to help predicting the osteoporosis potential in young women

Učinci konkurentnih trenažnih protokola na snagu, aerobni kapacitet, fleksibilnost i sastav tijela

In this study we evaluated the effect of concurrent resistance and endurance training on body composition, aerobic power and muscular endurance in college students and compared the two concurrent exercise protocols. Forty-two male students (22.02±1.91 years of age) were divided into three groups: Concurrent Distinct Endurance-Resistance (CDER), Concurrent Parallel Endurance-Resistance (CPER) and No Training controls (C). The subjects performed two training protocols per week for 12 weeks. In CDER group, resistance training and endurance training were performed on different days each week (two and two days per week). CPER group performed endurance and resistance training on the same days each week (two days per week). After a 12-week training period, fat-free mass, muscular strength [weight lifted in squat and bench press (kg)], muscular endurance [pull-ups and sit-ups (numbers)], aerobic power, flexibility and Sargent jump height increased similarly in both experimental groups (CDER and CPER). Also, decreases in body fat percentage, mean time in 60 m running and agility occurred in CDER and CPER. A significant difference in body fat percentage was seen in CPER when compared to CDER and C. Body mass increased significantly in CPER when compared to CDER and C. Although body mass increased only after the CPER protocol application, it can be concluded that both CDER and CPER protocols were similarly effective in positive transformation of body composition, aerobic power and muscular endurance.U ovom su istraživanju vrednovani učinci konkurentnoga treninga s opterećenjem i treninga izdržljivosti na sastav tijela, aerobnu izdržljivost i mišićnu izdržljivost studenata i ta su dva konkurentna protokola vježbanja uspoređena. Uzorak ispitanika činila su 42 studenta (22,02±1,91 godina) koji su podijeljeni u tri grupe: CDER – konkurentni programi su se primjenjivali odvojeno, CPER – konkurentni program su se primjenjivali usporedo i kontrolna grupa (C). Eksperimentalni programi vježbanja su se provodili tijekom 12 tjedana. U CDER grupi je trening izdržljivosti i trening s opterećenjem organiziran u različitim danima u tjednu (4 dana u tjednu). CPER grupa je provodila trening izdržljivosti i trening s opterećenjem istoga dana u tjednu (2x tjedno). Nakon 12 tjedana treninga u obje eksperimentalne grupe (CDER i CPER) zabilježeno je jednako povećanje u bezmasnoj masi tijela, u maksimalnoj snazi (mjereno čučnjem i potiskom s ravne klupe), repetitivnoj snazi (mjereno zgibovima i pretklonima trupa iz ležanja), aerobnom kapacitetu, fleksibilnosti i visini skoka u Sargentovom testu. Također, u obje eksperimentalne grupe zabilježeno je i smanjenje postotka tjelesne masti, te poboljšanje rezultata u sprintu na 60 metara te u testu agilnosti. Značajna razlika u postotku tjelesne masti zabilježena je između CPER grupe te CDER i C grupe. Značajno povećanje mase tijela zabilježeno je u CPER grupi u odnosu na grupe CDER i C. Iako je zabilježeno povećanje tjelesne mase samo nakon primjene CPER protokola, može se zaključiti kako su oba protokola primjene konkurentnoga treninga podjednako učinkovita u smislu pozitivne transformacije sastava tijela, aerobnoga kapaciteta i mišićne izdržljivosti