Behavior of cortisol, ck and lactate in a session of variable resistance
01 Aug 2018-Revista Brasileira De Medicina Do Esporte (Sociedade Brasileira de Medicina do Exercício e do Esporte)-Vol. 24, Iss: 4, pp 268-272
TL;DR: Variables for muscular injury showed no evidence of alterations 24 hours after the CT sessions, hence confirming that the workload did not generate significant post-stress muscular injury.
Abstract: Introduction: Complex Training (CT) has been used to achieve Post-activation Potentiation (PAP) of physical capabilities and, in doing so, improve the sports performance of athletes. However, few studies have considered alterations in serum Cortisol, Metabolic Creatine Kinase (MB-CK), Total Creatine Kinase (Total-CK), and Lactate concentrations ([La]) resulting from this training method. Objective: This study determined the behavior of the following blood serum substances in a CT session: Cortisol, MB-CK, Total CK and [La]. Method: Ten military athlete volunteers aged 28.5 ± 4.8 years; 66.2 ± 2.8 kg, 171.4 ± 3.7 cm, 22.6 ± 1.2 kg/m2; 11.3 ± 2.9% of fat tissue took part in the study. The study had a quasi-experimental, intrasubject design. The variable measurements were: Cortisol, MB-CK, Total-CK, and [La], measured before physical exercise and 24 hours post-stress. The CT session consisted of: four series of five repetitions at 30% of 1RM, plus four repetitions at 60% of 1RM, plus three throws of a 575 g projectile, 15 seconds apart. The statistical analysis was carried out through repeated measure ANOVA for Lactate and a Wilcoxon Matched Pairs t-Test for Cortisol, MB-CK and Total-CK. Results: There was no evidence of alterations in the indicators for fatigue ([La] p = 0.36), and muscular injury (Cortisol p = 0.16; MB-CK p = 0.23; Total-CK p = 0.64) after the training sessions. Conclusion: Variables for muscular injury showed no evidence of alterations 24 hours after the CT sessions, hence confirming that the workload did not generate significant post-stress muscular injury. Level of Evidence I; Therapeutic Study: Investigating Treatment Results.
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TL;DR: In this article, the authors present a systematic review of existing studies that have used indicators of muscle fatigue established in the search terms during and after strength training as measurement variables, including [La], HR and RPE, DOM, MR variation, and ammonium.
Abstract: Introduction: The development of strength has shown to be beneficial to sports performance and health. However, during strength training, they also produce alterations in muscle fatigue indicators, leading to a decrease in the ability to generate strength. Despite this, there is still not enough knowledge about the levels of muscle fatigue generated by different methods of strength training and how this information can be integrated into sports planning. Review and analyze the studies existing between January 2009 and January 2019 that have used indicators of muscle fatigue established in the search terms during and after strength training as measurement variables. Evidence acquisition: The study corresponds to a systematic review of previously published studies, following the PRISMA model. Articles published between 2009 and 2019 that measured muscle fatigue indicators during and after strength training were evaluated. The electronic search was conducted through Web of Science, Scopus, Sport Discus, PubMed, and Medline. We included all articles that used a strength protocol and also measured indicators of muscle fatigue and its possible effect on physical performance. Evidence synthesis: A total of 39 articles were found, which were stratified according to the protocol used: (i) plyometric training, (ii) Bodypump® training, (iii) occlusion training, (iv) variable resistance training, (v) conventional strength training, (vi) eccentric strength training, (vii) rest times in strength training and (viii) concurrent training. Conclusion: At the end of the systematic review, it was shown that the different training methodologies for strength development generate increases in muscle fatigue indicators, and the increase generated in the different muscle fatigue indicators depends both on the methodology used and on the type of population, sex, level of training and type of sport. The most-reported indicators are [La], HR and RPE, DOM, MR variation, and ammonium.
4 citations
TL;DR: All those sessions oriented to increasing strength levels with a pre-activation protocol through intra-set variable resistance must consider rests longer than 24 hours between sessions in order not to increase creatine kinase in female athletes significantly.
Abstract: [Purpose] The purpose of this study was to determine the behavior of creatine kinase before and after the execution of a pre-activation protocol with intra-set variable resistance in order to generate post-activation potentiation in female athletes. [Participants and Methods] Six sprint women were part of the study. The study had a quasi-experimental intra-participant design. The experimental condition included a pre-activation with intra-set variable resistance + 1 minute rest + 30-m sprint × 3. The variables were metabolic creatine kinase, total creatine kinase, and 30-m sprints. [Results] Both the experimental condition and the control condition showed an increase in creatine kinase and total creatine kinase 24 hours post-effort. Only the experimental condition showed improvement in 30-m sprints after the pre-activation with intra-set variable resistance. [Conclusion] All those sessions oriented to increasing strength levels with a pre-activation protocol through intra-set variable resistance must consider rests longer than 24 hours between sessions in order not to increase creatine kinase in female athletes significantly.
1 citations
TL;DR: In this article , a systematic review and meta-analysis of studies published between 2012 and 2022 that used variable resistance (VR) to generate post-activation performance enhancement (PAPE) in muscle power-dominant sports was conducted.
Abstract: Variable resistance (VR) is a methodology that has shown good results in developing muscular strength and power. However, no updated information relates to the use of VR as an activation to trigger post-activation performance enhancement (PAPE). The primary objective of this systematic review and meta-analysis was to review and qualitatively describe studies published between 2012 and 2022 that used VR to generate PAPE in muscle power-dominant sports. The secondary objective was to calculate the effect size of the different power outcomes reported in the selected studies. The search was designed following the PRISMA® guidelines for systematic reviews and meta-analyses and performed in the Web of Science (WOS), Scopus, SPORTDiscus, PubMed, and MEDLINE between 2012 and 2022. The methodological quality and risk of bias were evaluated with the Cochrane Collaboration tool. The main variables were the throwing speed, time in sprint tests, and jump height. The analysis was conducted with a pooled standardized mean difference (SMD) through a Hedges’ g test (95% CI). Twenty-two studies were included in the systematic review and ten in the meta-analysis, revealing a trivial effect for throwing speed (SMD = 0.06; CI = 95%: −0.23–0.35; p = 0.69), a small effect for the time in sprint tests (SMD = −0.37; CI = 95%: −0.72–−0.02; p = 0.04), and a moderate effect for jump height (SMD = 0.55; CI = 95%: 0.29–0.81; p ˂ 0.0001). All forms of VR used for neuromuscular activation effectively triggered PAPE. Specifically, the results showed that activation with VR generates performance increases in time, in sprint tests and jump height, and a trivial effect in throwing tests (speed and distance).
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TL;DR: Skinfold thicknesses at four sites – biceps, triceps, subscapular and supra-iliac – and total body density were measured on 209 males and 272 females aged from 16 to 72 years, finding it necessary to use the logarithm of skinfold measurements in order to achieve a linear relationship with body density.
Abstract: The fat content of the human body has physiological and medical importance. It may influence morbidity and mortality, it may aIter the effectiveness of drugs and anaesthetics, and it may affect the ability to withstand exposure to cold and starvation. Thus the measurement of the total body fat provides useful information. In many people, but by no means everyone, a moderately satisfactory estimate of the body fat content can be obtained from the height and weight. However, for more precise evaluation several methods are available which give a reasonably accurate measure of body fat both in normal subjects and in individuals with unusual body builds. Most of these methods are based on the assumption that the body can be considered to consist of two compartments of relatively constant composition but which are distinctly different; these compartments are: (I) the body fat, which includes the entire content of chemical fat or lipids in the body, and (2) the fat-free mass (FFM), which includes all the rest of the body apart from fat. The body fat compartment is anhydrous, contains no potassium and has a fairly constant density of about 0.90 x 103 kg/m3. The fat-free compartment on the other hand probably has a fairly constant density of about 1.10 x 103 kg/m3, a potassium content of about 68 mequiv./kg in males (about 10% less in females) and a water content of about 720 g/kg. Thus measurement of body density or of total body K or of total body water allows a calculation of the relative proportion of these two compartments in the body and therefore also of the total fat content. The accuracy of these measures, however, is limited by the variability of the composition and density of the fat-free compartment in different individuals. In particular, individuals with a relatively high or
6,287 citations
TL;DR: This study analyzed the contribution of the propulsive and braking phases among different percentages of the one-repetition maximum (1RM) in the concentric bench press exercise and determined the relative load that maximized the mechanical power output (P(max).
Abstract: & This study analyzed the contribution of the pro-pulsive and braking phases among diff erent per-centages of the one-repetition maximum (1RM) in the concentric bench press exercise. One hun-dred strength-trained men performed a test with increasing loads up to the 1RM for the individual determination of the load-power relationship. The relative load that maximized the mechanical power output (P max ) was determined using three diff erent parameters: mean concentric power (MP), mean power of the propulsive phase (MPP) and peak power (PP). The load at which the brak-ing phase no longer existed was 76.1 ± 7.4 % 1RM. P max was dependent on the parameter used: MP (54.2 % ), MPP (36.5 % ) or PP (37.4 % ). No signi fi -cant diff erences were found for loads between 40 – 65 % 1RM (MP) or 20 – 55 % 1RM (MPP and PP), nor between P max % 1RM) ( when using MPP or PP. P max was independent of relative strength, although certain tendency towards slightly lower loads was detected for the strongest subjects. These results highlight the importance of con-sidering the contribution of the propulsive and braking phases in isoinertial strength and power assessments. Referring the mean mechanical val-ues to the propulsive phase avoids underestimat-ing an individual ’ s true neuromuscular potential when lifting light and medium loads.
343 citations
TL;DR: It seems likely that BCAA provided greater bioavailablity of substrate to improve protein synthesis and thereby the extent of secondary muscle damage associated with strenuous resistance exercise is increased.
Abstract: It is well documented that exercise-induced muscle damage (EIMD) decreases muscle function and causes soreness and discomfort. Branched-chain amino acid (BCAA) supplementation has been shown to increase protein synthesis and decrease muscle protein breakdown, however, the effects of BCAAs on recovery from damaging resistance training are unclear. Therefore, the aim of this study was to examine the effects of a BCAA supplementation on markers of muscle damage elicited via a sport specific bout of damaging exercise in trained volunteers. Twelve males (mean ± SD age, 23 ± 2 y; stature, 178.3 ± 3.6 cm and body mass, 79.6 ± 8.4 kg) were randomly assigned to a supplement (n = 6) or placebo (n = 6) group. The damaging exercise consisted of 100 consecutive drop-jumps. Creatine kinase (CK), maximal voluntary contraction (MVC), muscle soreness (DOMS), vertical jump (VJ), thigh circumference (TC) and calf circumference (CC) were measured as markers of muscle damage. All variables were measured immediately before the damaging exercise and at 24, 48, 72 and 96 h post-exercise. A significant time effect was seen for all variables. There were significant group effects showing a reduction in CK efflux and muscle soreness in the BCAA group compared to the placebo (P<0.05). Furthermore, the recovery of MVC was greater in the BCAA group (P<0.05). The VJ, TC and CC were not different between groups. The present study has shown that BCAA administered before and following damaging resistance exercise reduces indices of muscle damage and accelerates recovery in resistance-trained males. It seems likely that BCAA provided greater bioavailablity of substrate to improve protein synthesis and thereby the extent of secondary muscle damage associated with strenuous resistance exercise. Clinical Trial Registration Number: NCT01529281.
175 citations
TL;DR: Postactivation potentiation is an increase in muscle isometric twitch and low frequency tetanic force following a “conditioning” activity and increases the force of shortening contractions.
Abstract: The role of postactivation potentiation in enhancement of strength and speed performance requires further research
Postactivation potentiation (PAP), also known as activity-dependent potentiation, is an increase in muscle isometric twitch and low frequency tetanic force following a “conditioning” activity.1,2 Examples of conditioning activity are a series of evoked isometric twitches (staircase or treppe), an evoked isometric tetanic contraction (post-tetanic potentiation), a sustained isometric maximal voluntary contraction (MVC), and a series of dynamic contractions. In fact, any type of contractile activity is likely to activate the mechanism of PAP—that is, phosphorylation of myosin regulatory light chains, which increases Ca2+ sensitivity of the myofilaments.2 The result is an amplified level of myosin cross bridge activity in response to submaximal concentrations of myoplasmic Ca2+. A notable feature of PAP is that it has no effect on the force of high frequency tetanic isometric contractions, because in such contractions a “saturating” concentration of Ca2+ is attained, making any increase in Ca2+ sensitivity inconsequential. Although less studied, PAP also increases the force of shortening (concentric) contractions,3 and the highest frequency at which PAP is effective is greater for rapid shortening (concentric) contractions than for isometric contractions.4
On the basis of the foregoing, it would appear that PAP …
174 citations
TL;DR: From a practical standpoint, strength and conditioning coaches should consider the athletes' strength levels when constructing postactivation complexes (CA + performance activity) as strength will dictate the time frame required between the conditioning and the performance activity.
Abstract: The purpose of this investigation was to determine whether stronger individuals are able to express postactivation potentiation (PAP) earlier than weaker individuals during a vertical squat jump test. Eighteen junior elite rugby league players were divided into strong (relative 1 repetition maximum [1RM] back squat ≥ 2 × body mass) and weak (relative 1RM back squat <2.0 × body mass) groups. Each subject performed squat jumps before, 15 seconds, 3, 6, 9, and 12 minutes after a conditioning activity (CA) that contained 1 set of 3 back squats performed at 90% of 1RM. A force plate, which sampled at 1000 Hz, was used to determine the power output and height for each squat jump. Stronger individuals expressed PAP between 3 and 12 minutes post-CA, whereas their weaker counterparts displayed potentiation between 6 and 12 minutes post-CA. Moreover, the stronger group exhibited a significantly (p ≤ 0.05) higher PAP response than the weaker group at all post-CA squat jump tests. The stronger group displayed the greatest potentiation at 6 minutes post-CA, whereas the weaker group displayed the greatest potentiation response at 9 minutes following the CA. Based on these results, stronger individuals appear to be able to express PAP earlier after a CA than weaker individuals. Additionally, stronger individuals express significantly greater postactivation responses than weaker individuals. From a practical standpoint, strength and conditioning coaches should consider the athletes' strength levels when constructing postactivation complexes (CA + performance activity) as strength will dictate the time frame required between the conditioning and the performance activity.
154 citations