Announcement

Collapse
No announcement yet.

Don't ignore eccentric phase b/c . . .

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Don't ignore eccentric phase b/c . . .

    J Appl Physiol. 2007 Feb;102(2):573-81. Epub 2006 Oct 12.
    Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types.
    Heinemeier KM, Olesen JL, Schjerling P, Haddad F, Langberg H, Baldwin KM, Kjaer M.

    In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) (P < 0.05), but the effect of eccentric training was greater than concentric and isometric training (P < 0.05). In tendon, myostatin mRNA was detected, but no changes were seen after exercise. IGF-IEa and MGF increased in muscle (up to 15-fold) and tendon (up to 4-fold) in response to training (P < 0.01). In tendon no difference was seen between training types, but in muscle the effect of eccentric training was greater than concentric training for both IGF-IEa and MGF (P < 0.05), and for IGF-IEa isometric training had greater effect than concentric (P < 0.05). The results indicate a possible role for IGF-IEa and MGF in adaptation of tendon to training, and the combined changes in myostatin and IGF-IEa/MGF expression could explain the important effect of eccentric actions for muscle hypertrophy.

    PMID: 17038487 [PubMed - in process]
    As a background myostatin negatively regulates muscle growth . . . see following for more info http://forum.bodybuilding.com/showthread.php?t=720382
    . . . and IGF1 anf MGF positively regulate muscle growth

    Anyway according to these results the eccentric phase is the most effective portion to promote gene expression in favor of muscle hypertrophy. So don't skimp on the eccentric phase (negatives)
    Disclaimer: While I have an M.D. the views I express are not to be taken as medical advice under any circumstances. Please check with your own doctor if you want medical advice as he/she has access to your info and can provide the most accurate advice.


    www.pubmed.gov . . . gotta love it

  • #2
    good info, thanks!

    Blessed be the Lord my strength, which teacheth my hands to war, and my fingers to fight. - Psalm 144:1

    As iron sharpens iron, so one man sharpens another - Proverbs 27:17


    Current Supps:
    Purple Wraath
    Green Magnitude
    Orange Triad
    White Flood
    Blue Up
    100% ON Classic Whey


    Ninety percent of everything is crap.

    Theodore Sturgeon
    US science fiction author (1918 - 1985)

    Comment


    • #3
      Nice !

      Comment


      • #4
        so then if its possible that you can do all negatives in training to promote muscle growth? Or/are you just saying negative is more important than positives for growth that is.

        Comment


        • #5
          I remember reading about a study done in Europe in the 70's that ONLY negative training was done, and the subjects built as much muscle as those doing both positives and negatives. While I beleive there is a balance in everything, the negative plays just as an important role as the positive.

          Comment


          • #6
            Originally posted by RenegadeRows
            While I beleive there is a balance in everything, the negative plays just as an important role as the positive.

            Comment


            • #7
              negatives rock ... during my lifts I power up the weight and then slowly control the eccentric part ... burn baby, burn!!!
              jdouchebag for president

              Comment


              • #8
                Originally posted by strester
                negatives rock ... during my lifts I power up the weight and then slowly control the eccentric part ... burn baby, burn!!!
                I just get someone I KNOW is able to get the weight off my chest if need be, and then go as heavy as I can and still control the weight. Last neg I did was 315 for 4. Not shabby considering my bench is sitting at 245x6 alone. Damn was it sore the next day though. Was about 4-5 sec to get down to my chest. LOVED IT.

                Blessed be the Lord my strength, which teacheth my hands to war, and my fingers to fight. - Psalm 144:1

                As iron sharpens iron, so one man sharpens another - Proverbs 27:17


                Current Supps:
                Purple Wraath
                Green Magnitude
                Orange Triad
                White Flood
                Blue Up
                100% ON Classic Whey


                Ninety percent of everything is crap.

                Theodore Sturgeon
                US science fiction author (1918 - 1985)

                Comment

                Working...
                X