Resistance exercise load does not determine training-mediated hypertrophic gains in young men.
Eighteen men (21±1 yr, 22.6±2.1 kg∙m-2 means±SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity (% of maximal strength [1RM]) or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1 and, 80%-3. Subjects trained each leg with their assigned regime for a period of 10wk, 3 times/wk. We made pre- and post-training measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and post-training biopsies of the vastus lateralis, and a single post-exercise (1h) biopsy following the first bout of exercise, to measure signalling proteins. Training-induced increases in MR-measured muscle volume were significant (P<0.01), with no difference between groups: 30%-3 = 6.8±1.8%, 80%-1 = 3.2±0.8%, and 80%-3= 7.2±1.9%, P=0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30% -3 (P=0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P =0.92). Biopsies taken 1h following the initial resistance exercise bout showed increased phosphorylation (P<0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signalling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.
Ovennævnte studie (2012) er interessant, da det stiller spørgsmålstegn til den ellers almene opfattelse, at moderat-høj intensitets styrketræning er nødvendigt for muskelvækst. Studiet tyder på at hvis målet alligevel “kun” er at blive stor (og du er utrænet), er det ligegyldigt om du træner med 30 eller 80% 1RM.
Hvis man derimod har skjulte lyster om ligeledes at blive stærk (og ikke nødvendigvis stor som et hus), er det fordelagtigt engang imellem at løfte tungt for ligeledes at høste de neurale adaptationer der er kendetegnet ved højintenst-styrketræning, – og efterfølgende øget styrke.