Som jeg var inne på i del 2 av artikkelen om Spisekick på diett, og som sagt en del ganger her - jeg foretrekker å separere stimulansen fra styrketrening fra stimulansen fra kardio/utholdenhetstrening mest mulig, da det er motstridende signaler som kan kansellere hverandre ut. Spesielt gjelder dette AMPK, energisensorsignalet som øker etter utholdenhetstrening og som direkte reduserer proteinsyntesen (muskeloppbygging og restitusjon). AMPK er også noe vi forsøker å redusere ved å bruke Myo-reps når vi trener styrke, som er enda en god grunn til å ikke trene for høy mengde når man vil bli sterkere og bygge muskelmasse, og for å sørge for at man gjenoppfyller glykogenlagrene etter trening med karbohydrater.
Anbefalingen er derfor å trene kardio og styrketrening separert med minst 4 timer, for eksempel morgen + ettermiddag eller kveld, eller på separate dager. Vil man fokusere på utholdenhetstrening bør styrketrening kuttes ned til noe sånt som to ganger i uka, vil man fokusere på styrketrening og muskeloppbygging bør kardio begrenses til noe sånt som 20-30 minutter 3-4 ganger i uka. Vil man trene begge deler lilke mye må man også akseptere at det sannsynligvis vil gi dårligere resultater totalt sett. Jack of all trades, Master of none.
Utdrag fra en artikkel jeg har basert dette på, og som David Höök poengterte i en diskusjon om Geriljakardio på Iform:
Concurrent Strength and Endurance Training: From Molecules to Man. Medicine & Science in Sports & Exercise. 38(11):1965-1970, November 2006
"Strength and endurance training produce widely diversified adaptations, with little overlap between them. Strength training typically results in increases in muscle mass and muscle strength. In contrast, endurance training induces increases in maximal oxygen uptake and metabolic adaptations that lead to an increased exercise capacity. In many sports, a combination of strength and endurance training is required to improve performance, but in some situations when strength and endurance training are performed simultaneously, a potential interference in strength development takes place, making such a combination seemingly incompatible. The phenomenon of concurrent training, or simultaneously training for strength and endurance, was first described in the scientific literature in 1980 by Robert C. Hickson, and although work that followed provided evidence for and against it, the interference effect seems to hold true in specific situations. At the molecular level, there seems to be an explanation for the interference of strength development during concurrent training; it is now clear that different forms of exercise induce antagonistic intracellular signaling mechanisms that, in turn, could have a negative impact on the muscle's adaptive response to this particular form of training. That is, activation of AMPK by endurance exercise may inhibit signaling to the protein-synthesis machinery by inhibiting the activity of mTOR and its downstream targets. The purpose of this review is to briefly describe the problem of concurrent strength and endurance training and to examine new data highlighting potential molecular mechanisms that may help explain the inhibition of strength development when strength and endurance training are performed simultaneously."
"Acute endurance exercise bouts have generally been found to reduce total protein-synthesis rates of mixed skeletal muscles during the exercise. This depression is transient and can lead to a temporary decrease in protein synthesis within several hours after exercise (5,12,29). Overlapping endurance exercise bouts with resistance exercise may result in impaired adaptive responses in protein synthesis and, therefore, a decrease in strength-related performance, in part, due to the suboptimal or lack of increase in muscle-fiber cross-sectional areas (22). When performed several times a week, such combination training may be sufficient to disrupt the protein-synthesis mechanisms involved with the normal adaptation to the individual bouts of strength exercise, thus altering the long-term adaptations to training and resulting in impaired muscle-dependent strength gains. Another possibility, although hypothetical, is that the adaptive protein synthesis resulting from either form of exercise may create some sort of cellular incompatibility in which the muscle cell needs to decide whether to grow or manage the synthesis of its metabolic machinery."