studi

[relim7.]

vorrei fare un post con un po di studi interessanti e relativi commenti.

aspetto commenti soprattutto di chi conosce l'inglese meglio di me :

Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.

Acute and long-term effects of resistance-training regimens with varied combinations of high- and low-intensity exercises were studied. Acute changes in the serum growth hormone (GH) concentration were initially measured after 3 types of regimens for knee extension exercise: a medium intensity (approximately 10 repetition maximum [RM]) short interset rest period (30 s) with progressively decreasing load ("hypertrophy type"); 5 sets of a high-intensity (90% of 1RM) and low-repetition exercise ("strength type"); and a single set of low-intensity and high-repetition exercise added immediately after the strength-type regimen ("combi-type"). Postexercise increases in serum GH concentration showed a significant regimen dependence: hypertrophy-type > combi-type > strength-type (p < 0.05, n = 8). Next, the long-term effects of periodized training protocols with the above regimens on muscular function were investigated. Male subjects (n = 16) were assigned to either hypertrophy/combi (HC) or hypertrophy/ strength (HS) groups and performed leg press and extension exercises twice a week for 10 weeks. During the first 6 weeks, both groups used the hypertrophy-type regimen to gain muscular size. During the subsequent 4 weeks, HC and HS groups performed combi-type and strength-type regimens, respectively. Muscular strength, endurance, and cross sectional area (CSA) were examined after 2, 6, and 10 weeks. After the initial 6 weeks, no significant difference was seen in the percentage changes of all variables between the groups. After the subsequent 4 weeks, however, 1RM of leg press, maximal isokinetic strength, and muscular endurance of leg extension showed significantly (p < 0.05) larger increases in the HC group than in the HS group. In addition, increases in CSA after this period also tended to be larger in the HC group than in the HS group (p = 0.08). The results suggest that a combination of high- and low-intensity regimens is effective for optimizing the strength adaptation of muscle in a periodized training program.

[relim7.]

Department of Physical Education & Sport Science, Democritus University of Thrace, Komotini, Greece.

PURPOSE: This study examined the effects of the number of sets on testosterone, cortisol, and growth hormone (hGH) responses after maximum strength (MS), muscular hypertrophy (MH), and strength endurance (SE) protocols. METHODS: Eleven young men performed multi-joint dynamic exercises using MS (5 reps at 88% of one-repetition maximum (1-RM), 3-min rest) and MH (10 reps at 75% of 1-RM, 2-min rest) protocols with 2, 4, and 6 sets at each exercise; and an SE (15 reps at 60% of 1-RM, 1-min rest) with 2 and 4 sets. Hormonal concentrations were measured before exercise, immediately after, and at 15 and 30 min of recovery. RESULTS: The number of sets did not affect the hormonal responses after the MS protocol. Cortisol and hGH were higher (P < 0.05) after the four-set compared with the two-set sessions in the MH and SE protocols. No differences were observed between the six-set and the four-set sessions in the MH protocol. Cortisol and hGH were higher (P < 0.05) than the MS after the SE and MH protocols, and only when four and six sets were performed in the latter. hGH was higher than the MH after the SE protocol, whether two or four sets were executed, whereas cortisol (P < 0.05) was higher after the SE protocol only when two sets were performed. Testosterone did not change with any workout. CONCLUSION: The number of sets functions up to a point as a stimulus for increased hormonal concentrations in order to optimize adaptations with MH and SE protocols, and has no effect on a MS protocol. Furthermore, the number of sets may differentiate long-term adaptations with MS, MH, and SE protocols causing distinct hormonal responses.

Publication Types:

• Clinical Trial

[relim7.]

Department of Physical Education and Sports Science, Aristotelio University of Thessaloniki, Greece.

This study examined the acute effects of maximum strength (MS), muscular hypertrophy (MH), and strength endurance (SE) resistance exercise protocols on serum leptin. Ten young lean men (age = 23 +/- 4 yr; body weight = 79.6 +/- 5.2 kg; body fat = 10.2 +/- 3.9%) participated in MS [4 sets x 5 repetitions (reps) at 88% of 1 repetition maximum (1 RM) with 3 min of rest between sets], MH (4 sets x 10 reps at 75% of 1 RM with 2 min of rest between sets), SE (4 sets x 15 reps at 60% of 1 RM with 1 min of rest between sets), and control (C) sessions. Blood samples were collected before and immediately after exercise and after 30 min of recovery. Serum leptin at 30 min of recovery exhibited similar reductions from baseline after the MS (-20 +/- 5%), MH (-20 +/- 4%), and SE (-15 +/- 6%) protocols that were comparable to fasting-induced reduction in the C session (-12 +/- 3%) (P < 0.05). Furthermore, no differences were found in serum leptin among the MS, MH, SE, and C sessions immediately after exercise and at 30 min of recovery (P > 0.05). Cortisol was higher (P < 0.05) after the MH and SE protocols than after the MS and C sessions. Glucose and growth hormone were higher (P < 0.05) after exercise in the MS, MH, and SE protocols than after the C session. In conclusion, typical resistance exercise protocols designed for development of MS, MH, and SE did not result in serum leptin changes when sampled immediately or 30 min postexercise.

Publication Types:

• Clinical Trial

[relim7.]

Timing of postexercise protein intake is important for muscle hypertrophy with resistance training in elderly humans.

Esmarck B, Andersen JL, Olsen S, Richter EA, Mizuno M, Kjaer M.

Sports Medicine Research Unit, Bispebjerg Hospital, Denmark. bep01@bbh.hosp.dk

1. Age-associated loss of skeletal muscle mass and strength can partly be counteracted by resistance training, causing a net synthesis of muscular proteins. Protein synthesis is influenced synergistically by postexercise amino acid supplementation, but the importance of the timing of protein intake remains unresolved. 2. The study investigated the importance of immediate (P0) or delayed (P2) intake of an oral protein supplement upon muscle hypertrophy and strength over a period of resistance training in elderly males. 3. Thirteen men (age, 74 +/- 1 years; body mass index (BMI), 25 +/- 1 kg m(-2) (means +/- S.E.M.)) completed a 12 week resistance training programme (3 times per week) receiving oral protein in liquid form (10 g protein, 7 g carbohydrate, 3 g fat) immediately after (P0) or 2 h after (P2) each training session. Muscle hypertrophy was evaluated by magnetic resonance imaging (MRI) and from muscle biopsies and muscle strength was determined using dynamic and isokinetic strength measurements. Body composition was determined from dual-energy X-ray absorptiometry (DEXA) and food records were obtained over 4 days. The plasma insulin response to protein supplementation was also determined. 4. In response to training, the cross-sectional area of m. quadriceps femoris (54.6 +/- 0.5 to 58.3 +/- 0.5 cm(2)) and mean fibre area (4047 +/- 320 to 5019 +/- 615 microm(2)) increased in the P0 group, whereas no significant increase was observed in P2. For P0 both dynamic and isokinetic strength increased, by 46 and 15 %, respectively (P < 0.05), whereas P2 only improved in dynamic strength, by 36 % (P < 0.05). No differences in glucose or insulin response were observed between protein intake at 0 and 2 h postexercise. 5. We conclude that early intake of an oral protein supplement after resistance training is important for the development of hypertrophy in skeletal muscle of elderly men in response to resistance training.

PMID: 11507179

[David70]

?

[Sancez]

MI riassumi in italiano il tutto!!

[relim7.]

Strength training. Single versus multiple sets.

Carpinelli RN, Otto RM.

Human Performance Laboratory, Adelphi University, Garden City, New York, USA.

Perhaps the most controversial element of any strength training programme is the number of sets required to increase muscular strength and hypertrophy. There is a prevalent belief that at least 3 sets of each exercise are required to elicit optimal increases in strength and hypertrophy. However, most of the studies that reported the results of training with single versus multiple sets do not substantiate this tenet. In fact, the preponderance of evidence suggests that for training durations of 4 to 25 weeks there is no significant difference in the increase in strength or hypertrophy as a result of training with single versus multiple sets. Because of the design limitations of these studies, conclusions concerning the efficacy of multiple sets should be tentative. However, there is little scientific evidence, and no theoretical physiological basis, to suggest that a greater volume of exercise elicits greater increases in strength or hypertrophy. This information may represent an important practical application of time-efficient, low-volume exercise.

Publication Types:

• Review
• Review, Tutorial

[relim7.]

Muscular adaptation to concentric and eccentric exercise at equal power levels.

Mayhew TP, Rothstein JM, Finucane SD, Lamb RL.

Department of Physical Therapy, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0224, USA.

The effect of training with concentric and eccentric contractions on fiber hypertrophy and isometric torque production was investigated in 20 healthy subjects. One group (eight female and two male subjects) performed concentric contractions of their quadriceps femoris muscles at an intensity of 90% of their maximal concentric power. The other group (six female and four male subjects) performed eccentric contractions at the same relative power level. Both groups exercised three times per week for 4 wk at a constant speed of 60 degrees.s-1 on a Kin-Com dynamometer. Needle biopsies were obtained from the vastus lateralis before and after the exercise program. Fiber-type differentiation was performed using a myosin ATPase stain at a preincubation of 10.5. Maximal isometric knee extension torque was also measured before and after the exercise program. An analysis of covariance was used to determine whether there were significant differences between the exercise groups in: 1) the post-exercise fiber areas and 2) maximal isometric torque (MIso), while controlling for initial differences. Results showed a significant difference between the Type II fiber areas (P < 0.01) and the MIso (P = 0.01). These data indicate that, when exercising at the same relative power level, a subject performing concentric contractions will show greater muscle hypertrophy and improve in MIso production more than a subject training with eccentric contractions.

[Drugo84]

xchè invece di postarne 3 al giorno nn en psoti 1 ogni 2 giorni ma lo traduci?

[relim7.]

Protein nutrition for the athlete.

Dohm GL.

Endurance exercise results in a protein catabolic state characterized by decreased protein synthesis, increased amino acid oxidation, and increased conversion of amino acids to glucose. The adaptive response to performance of strength exercise, on the other hand, results in an anabolic state in hypertrophying muscles, and the accretion of protein is the result of increased protein synthesis. Because of changes in protein metabolism there is an increased dietary requirement for protein in both endurance and strength exercise. However, the normal dietary intake of protein is adequate for athletes as long as the energy intake is sufficient to maintain body weight. There is little scientific evidence that consumption of large protein supplements will have any beneficial effect on muscle hypertrophy, muscular strength, or physical performance.

PMID: 6571233 [PubMed - indexed for MEDLINE]

[Luna Caprese]

tutte putt...te : ogni 3 mesi escono studi che dicono il contrario di ciò che veniva detto 3 mesi prima ; tra 20 anni ci diranno perchè Sandow aveva ragione cent' anni fa

[relim7.]

xchè invece di postarne 3 al giorno nn en psoti 1 ogni 2 giorni ma lo traduci?

[relim7.]

tutte putt...te : ogni 3 mesi escono studi che dicono il contrario di ciò che veniva detto 3 mesi prima ; tra 20 anni ci diranno perchè Sandow aveva ragione cent' anni fa

è un casino luna .... non c'è una strada chiara da seguire, è vero gli studi spesso vengono contraddetti e sulle riviste e libri un giorno si dice una cosa poi un'altra.... il tutto basandosi appunto sugli studi... ma almeno se te li guardi ti fai un'idea di come alcuni di questi vengano usati strumentalmente per convalidare una tendenza piuttosto che un'altra...

tu hai molta esperienza e l'idea di ravvicinare gli all per uno stesso gruppo mi trova daccordo ma le tue schede mi sembrano ancora un pelo troppo lunghe e stressanti, il recupero per i natural non è sempre veloce anzi...
puoi dare un'occhiata al mio 3d sul sistema nervoso ?
grazie

[Eagle]

No, non sono tutte cazzate, sono solo situazioni particolari.
Gli studi possono e devono essere presi solo e soltanto per qello che sono, senza strane estrapolazioni ...

Ci possono aiutare a tracciare delle linee guida, a formulare delle ipotesi, ma e' poco sensato (e stupido oserei dire) costruirci delle teorie come se fossero delle verita' (come fanno tutti i "guru" ... qualche studio sui maialini, su qualche donna anziana ... e la teoria e' fatta ... ).

Comunque studi interessanti ce ne sono, ce ne sono eccome ... bisogna pero' saperli "leggere" ... negli anziani e nelle donne, ad esempio, le cose stanno diversamente che nei giovani maschi ... e spesso, gli stessi studi, hanno visto risultati opposti in queste categorie ...

Eagle

[relim7.]

No, non sono tutte cazzate, sono solo situazioni particolari.
Gli studi possono e devono essere presi solo e soltanto per qello che sono, senza strane estrapolazioni ...

Ci possono aiutare a tracciare delle linee guida, a formulare delle ipotesi, ma e' poco sensato (e stupido oserei dire) costruirci delle teorie come se fossero delle verita' (come fanno tutti i "guru" ... qualche studio sui maialini, su qualche donna anziana ... e la teoria e' fatta ... ).

Comunque studi interessanti ce ne sono, ce ne sono eccome ... bisogna pero' saperli "leggere" ... negli anziani e nelle donne, ad esempio, le cose stanno diversamente che nei giovani maschi ... e spesso, gli stessi studi, hanno visto risultati opposti in queste categorie ...

Eagle