Voor de mensen die geinteresseerd zijn in wat wetenschap achter de sport.

[Worf]

Niet drinken tijdens (kracht)training heeft negatieve invloed op hormonen
Effect of hydration state on resistance exercise-induced endocrine markers of anabolism, catabolism, and metabolism.
Judelson DA (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Judelson%20DA%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Maresh CM (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Maresh%20CM%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Yamamoto LM (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Yamamoto%20LM%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Farrell MJ (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Farrell%20MJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Armstrong LE (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Armstrong%20LE%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Kraemer (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Kraemer%20WJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus)

Hypohydration (decreased total body water) exacerbates the catabolic hormonal response to endurance exercise with unclear effects on anabolic hormones. Limited research exists that evaluates the effect of hypohydration on endocrine responses to resistance exercise; this work merits attention as the acute postexercise hormonal environment potently modulates resistance training adaptations. The purpose of this study was to examine the effect of hydration state on the endocrine and metabolic responses to resistance exercise. Seven healthy resistance-trained men (age = 23 +/- 4 yr, body mass = 87.8 +/- 6.8 kg, body fat = 11.5 +/- 5.2%) completed three identical resistance exercise bouts in different hydration states: euhydrated (EU), hypohydrated by approximately 2.5% body mass (HY25), and hypohydrated by approximately 5.0% body mass (HY50). Investigators manipulated hydration status via controlled water deprivation and exercise-heat stress. Cortisol, epinephrine, norepinephrine, testosterone, growth hormone, insulin-like growth factor-I, insulin, glucose, lactate, glycerol, and free fatty acids were measured during euhydrated rest, immediately preceding resistance exercise, immediately postexercise, and during 60 min of recovery. Body mass decreased 0.2 +/- 0.4, 2.4 +/- 0.4, and 4.8 +/- 0.4% during EU, HY25, and HY50, respectively, supported by humoral and urinary changes that clearly indicated subjects achieved three distinct hydration states. Hypohydration significantly 1) increased circulating concentrations of cortisol and norepinephrine, 2) attenuated the testosterone response to exercise, and 3) altered carbohydrate and lipid metabolism. These results suggest that hypohydration can modify the hormonal and metabolic response to resistance exercise, influencing the postexercise circulatory milieu.


Meer geforceerde herhalingen zorgen niet voor meer krachttoename
Increased number of forced repetitions does not enhance strength development with resistance training.
Drinkwater EJ (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Drinkwater%20EJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Lawton TW (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Lawton%20TW%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), McKenna MJ (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22McKenna%20MJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Lindsell RP (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Lindsell%20RP%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Hunt PH (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Hunt%20PH%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Pyne DB (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Pyne%20DB%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus).
School of Human Movement Studies, Charles Sturt University, Bathurst, NSW, Australia. [email protected] ([email protected])

Some research suggests that strength improvements are greater when resistance training continues to the point at which the individual cannot perform additional repetitions (i.e., repetition failure). Performing additional forced repetitions after the point of repetition failure and thus further increasing the set volume is a common resistance training practice. However, whether short-term use of this practice increases the magnitude of strength development with resistance training is unknown and was investigated here. Twelve basketball and 10 volleyball players trained 3 sessions per week for 6 weeks, completing either 4 x 6, 8 x 3, or 12 x 3 (sets x repetitions) of bench press per training session. Compared with the 8 x 3 group, the 4 x 6 protocol involved a longer work interval and the 12 x 3 protocol involved higher training volume, so each group was purposefully designed to elicit a different number of forced repetitions per training session. Subjects were tested on 3- and 6-repetition maximum (RM) bench press (81.5 +/- 9.8 and 75.9 +/- 9.0 kg, respectively, mean +/- SD), and 40-kg Smith Machine bench press throw power (589 +/- 100 W). The 4 x 6 and 12 x 3 groups had more forced repetitions per session (p < 0.01) than did the 8 x 3 group (4.1 +/- 2.6, 3.1 +/- 3.5, and 1.2 +/- 1.8 repetitions, respectively), whereas the 12 x 3 group performed approximately 40% greater work and had 30% greater concentric time. As expected, all groups improved 3RM (4.5 kg, 95% confidence limits, 3.1- 6.0), 6RM (4.7 kg, 3.1-6.3), bench press throw peak power (57 W, 22-92), and mean power (23 W, 4-42) (all p < or = 0.02). There were no significant differences in strength or power gains between groups. In conclusion, when repetition failure was reached, neither additional forced repetitions nor additional set volume further improved the magnitude of strength gains. This finding questions the efficacy of adding additional volume by use of forced repetitions in young athletes with moderate strength training experience.


Krachttraining combineren met condiietraining heeft geen nadelig effect op krachtgains
Volgens dit onderzoek uit Dec. 2004 doet wat duurtraining in combinatie met krachtsport niks nadeligs met je krachtgains.
Glowacki SP (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Glowacki%20SP%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Martin SE (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Martin%20SE%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Maurer A (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Maurer%20A%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Baek W (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Baek%20W%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Green JS (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Green%20JS%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Crouse SF (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Crouse%20SF%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus).
Texas A&M University, College Station, TX 77843-4243, USA. [email protected]
The specificity of training principle predicts that combining resistance and endurance training (concurrent training) could interfere with the maximum development of strength and endurance capacity that results from either type of training alone. PURPOSE: To determine whether endurance and resistance training performed concurrently produces different performance and physiologic responses compared with each type of training alone. METHODS: Untrained male volunteers were randomly assigned to one of three groups: endurance training (ET, N = 12); resistance training (RT, N = 13); and concurrent training (CT, N = 16). The following measurements were made on all subjects before and after 12 wk of training: weight, percent body fat, peak oxygen consumption (VO(2peak)), isokinetic peak torque and average power produced during single-leg flexion and extension at 60 and 180 degrees.s, one-repetition maximum (1RM) leg press, 1RM bench press, vertical jump height, and calculated jump power. RESULTS: Weight and lean body mass (LBM) increased significantly in the RT and CT groups (P < 0.05). Percent body fat was significantly decreased in the ET and CT groups. VO(2peak) was significantly improved only in the ET group. Peak torque during flexion and extension at 180 degrees.s(-1) increased in the RT group. Improvements in 1RM leg press and bench press were significant in all groups, but were significantly greater in the RT and CT compared to the ET group. Jump power improved significantly only in the RT group, and no group showed a significant change in vertical jump height. CONCLUSIONS: Concurrent training performed by young, healthy men does not interfere with strength development, but may hinder development of maximal aerobic capacity.

[Worf]

Paste niet allemaal in 1 topic:


Essentiele aminozuren gecomineerd met koolhydraten na de (kracht) training geven een beter spieropbouwend en herstellend resultaat dan beide apart
Independent and combined effects of liquid carbohydrate/essential amino acid ingestion on hormonal and muscular adaptations following resistance training in untrained men.

Bird SP, Tarpenning KM, Marino FE. Februari 2006

School of Human Movement Studies, Charles Sturt University, Allen House 2.13, Bathurst, NSW, Australia, [email protected].

This investigation examined chronic alteration of the acute hormonal response associated with liquid carbohydrate (CHO) and/or essential amino acid (EAA) ingestion on hormonal and muscular adaptations following resistance training. Thirty-two untrained young men performed 12 weeks of resistance training twice a week, consuming ~675 ml of either, a 6% CHO solution, 6 g EAA mixture, combined CHO + EAA supplement or placebo (PLA). Blood samples were obtained pre- and post-exercise (week 0, 4, 8, and 12), for determination of glucose, insulin, and cortisol. 3-Methylhistidine excretion and muscle fibre cross-sectional area (fCSA) were determined pre- and post-training. Post-exercise cortisol increased (P<0.05) during each training phase for PLA. No change was displayed by EAA; CHO and CHO + EAA demonstrated post-exercise decreases (P<0.05). All groups displayed reduced pre-exercise cortisol at week 12 compared to week 0 (P<0.05). Post-exercise insulin concentrations showed no change for PLA; increases were observed for the treatment groups (P<0.05), which remained greater for CHO and CHO + EAA (P<0.001) than PLA. EAA and CHO ingestion attenuated 3-methylhistidine excretion 48 h following the exercise bout. CHO + EAA resulted in a 26% decrease (P<0.01), while PLA displayed a 52% increase (P<0.01). fCSA increased across groups for type I, IIa, and IIb fibres (P<0.05), with CHO + EAA displaying the greatest gains in fCSA relative to PLA (P<0.05). These data indicate that CHO + EAA ingestion enhances muscle anabolism following resistance training to a greater extent than either CHO or EAA consumed independently. The synergistic effect of CHO + EAA ingestion maximises the anabolic response presumably by attenuating the post-exercise rise in protein degradation.


Lengte van de training heeft invloed op het spierafbrekend hormoon cortisol
Influence of exercise duration on post-exercise steroid hormone responses in trained males.
Tremblay MS, Copeland JL, Van Helder W.

Statistics Canada Tunney's Pasture, Main Building Room 2200, Section S, Ottawa, ON, K1A0T6, Canada. [email protected]

The purpose of this study was to systematically evaluate the effect of endurance exercise duration on hormone concentrations in male subjects while controlling for exercise intensity and training status. Eight endurance-trained males (19-49 years) completed a resting control session and three treadmill runs of 40, 80, and 120 min at 55% of VO2max . Blood samples were drawn before the session and then 1, 2, 3 and 4 h after the start of the run. Plasma was analyzed for luteinizing hormone (LH), dehydroepiandrosterone sulfate (DHEAS), cortisol, and free and total testosterone. LH was significantly greater at rest compared to the running sessions. Both free and total testosterone generally increased in the first hour of the 80 and 120 min runs and then showed a trend for a steady decline for the next 3 h of recovery. Dehydroepiandrosterone sulfate increased in a dose-response manner with the greatest increases observed during the 120-min run, followed by the 80-min run. Cortisol only increased in response to the 120-min run and showed a decline across time in all other sessions. The ratios of anabolic hormones (testosterone and DHEAS) to cortisol were greater during the resting session and the 40-min run compared to the longer runs. The results indicate that exercise duration has independent effects on the hormonal response to endurance exercise. At a low intensity, longer duration runs are necessary to stimulate increased levels of testosterone, DHEAS and cortisol and beyond 80 min of running there is a shift to a more catabolic hormonal environment.


Vitamine C nuttig voor sporters?
Effect of vitamin C supplementation on lipid peroxidation, muscle damage and inflammation after 30-min exercise at 75% v.o(2max).
Nakhostin-Roohi B (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Nakhostin-Roohi%20B%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Babaei P (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Babaei%20P%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Rahmani-Nia F (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Rahmani-Nia%20F%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus), Bohlooli S (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=Search&Term=%22Bohlooli%20S%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus).
Department of Exercise Physiology, Guilan University, Rasht, Iran

AIM: Hypothetically, supplementation with the antioxidant vitamins C could alleviate exercise-induced lipid peroxidation. The purpose of this study was to evaluate the effect of vitamin C supplementation on exercise-induced lipid peroxidation, muscle damage and inflammation. METHODS: Sixteen healthy untrained male volunteers participated in a 30-min exercise at 75% Vo2max. Subjects were randomly assigned to one of two groups: 1) placebo and 2) vitamin C (VC: 1 000 mg vitamin C). Blood samples were obtained prior to supplementation (baseline), 2 h after supplementation (immediately pre-exercise), post-exercise, 2 and 24 h after exercise. Plasma levels of VC, total antioxidant capacity (TAC), creatine kinase (CK), malondealdehyde (MDA), total leukocytes, neutrophils, lymphocytes, interleukin-6 (IL-6) and cortisol were measured. RESULTS: Plasma vitamin C concentrations increased significantly in the VC in response to supplementation and exercise (P<0.05). TAC decreased significantly in Placebo group 24 h after exercise compared to pre-exercise (P<0.05). Although MDA levels were similar between groups at baseline, it increased significantly 2 h after exercise only in the Placebo group (P<0.05). CK increased immediately and 2 h after exercise in both groups and 24 h after exercise only in placebo group compared to pre-exercise (P<0.05). Markers of inflammation (total leukocyte counts, neutrophil counts and IL-6) were increased significantly in response to the exercise (P<0.05). In VC group, there was significant increase in lymphocyte counts immediately after exercise compared with pre-exercise (P<0.05). Serum cortisol concentrations significantly declined after supplementation compared with baseline (P<0.05) as well as declined 2 and 24 h after exercise compared with immediately after exercise in VC group (P<0.05). CONCLUSION: VC supplementation prevented endurance exercise-induced lipid peroxidation and muscle damage but had no effect on inflammatory markers. In een notedop: Het komt erop neer dat in dit onderzoek vitamine C schade veroorzaakt door vrije radicalen aan de spieren voorkomt.

[SamE]

Goede info maar al wel bekend :) Jouw conclusie bij de vitamine C studie klopt alleen niet helemaal

[SamE]

Hakinen heeft naar mijn mening duidelijk aangetoond dat duurtrainingen wel degelijk een nadelig effect kunnen hebben op kracht/power afhankelijk van de duur en de frequentie.

[chief108]

en hopla alles in 1 thread... :p

[Igorvdw]

Krachttraining combineren met condiietraining heeft geen nadelig effect op krachtgains
Volgens dit onderzoek uit Dec. 2004 doet wat duurtraining in combinatie met krachtsport niks nadeligs met je krachtgains.


Klopt niet.. Blijkt uit zowel eigen ervaring, als in andere wetenschappelijke onderzoeken..

Anderzijds:
Wel goede info, toch maar dingen meegepikt!! Thnx

[FOCUS]

top Worf, dit soort shit mag vaker gepost worden
@Same, I agree, maar die aanname mag dus zo lijkt het wel wat genuanceerd worden.

[Worf]

Goede info maar al wel bekend :) Jouw conclusie bij de vitamine C studie klopt alleen niet helemaal

CONCLUSION: VC supplementation prevented endurance exercise-induced lipid peroxidation and muscle damage but had no effect on inflammatory markers


Lipid peroxidation refers to the oxidative (http://en.wikipedia.org/wiki/Redox) degradation of lipids (http://en.wikipedia.org/wiki/Lipid). It is the process whereby free radicals (http://en.wikipedia.org/wiki/Radical_%28chemistry%29) "steal" electrons from the lipids in cell membranes (http://en.wikipedia.org/wiki/Cell_membranes), resulting in cell damage.



Inflammation is the body's response to injury or infection and may be acute or chronic.

Hoezo klopt mijn conclusie dan niet? Hou wel van wat discussie op dit gebied :)

[kristel]

Voor iedereen die geïnteresseerd is in artikelen: pubmed.com
Door verschillende termen te gebruiken kun je gerichter zoeken. Gebruik dan AND en/of OR (hoofdletters) en nog een paar kleine tips…blijf een beetje kritisch (geloof niet alles wat gepubliceerd wordt) en lees niet alleen het abstract.

groetjes Kristel