Resistance training where you use weights with which you can manage 10-14 reps and take rests of several minutes in between probably results in just as much muscle growth as training that involves weight with which you can only manage 2-4 reps and one-minute rest periods. Sports scientists at the University of Central Florida write about this in Physiological Reports.
Study
The researchers got ten well-trained men to train their legs on two different occasions by doing squats, leg presses, leg extensions, leg curs and calf raises.
On one occasion they did their weight sets at 70 percent of their maximal weight and rested for one minute between sets. [High Volume; HI] On the other occasion the men did their weight sets at 90 percent of their maximal weight and rested for three minutes between sets. [High Intensity; HI]
Results
The researchers attached electrodes to the subjects’ leg muscles, which enabled them to see that the muscles had to work a little harder during the high-intensity workout. The difference was not significant, however.
The concentration of LDH [shown above] and myoglobin in the blood increased by more after the high-intensity workout than after the workout using lighter weights. LDH and myoglobin are markers for muscle damage.
The two workouts had no appreciable effects on the men’s IGF-1 or testosterone levels. The concentration of growth hormone rose by more after the high-volume workout than after the workout with heavier weights. The concentration of cortisol also rose by more after the high-volume workout than after the high-intensity workout.
The researchers measured the activity of anabolic signal molecules such as mTOR and Akt in the men’s leg muscles just before the workouts started and 1 and 5 hours after they had ended. Both workouts resulted in approximately the same increase in activity.
Conclusion
Strength training with relatively heavy weights [90 percent of your maximal weight] and short rests has different physiological effects than strength training with relatively light weights [70 percent of your maximal weight] and slightly longer rest periods. But both types of training probably stimulate muscle growth equally.
Intramuscular anabolic signaling and endocrine response following high volume and high intensity resistance exercise protocols in trained men.
Abstract
Resistance exercise paradigms are often divided into high volume (HV) or high intensity (HI) protocols, however, it is unknown whether these protocols differentially stimulate mTORC1 signaling. The purpose of this study was to examine mTORC1 signaling in conjunction with circulating hormone concentrations following a typical HV and HI lower-body resistance exercise protocol. Ten resistance-trained men (24.7 ± 3.4 years; 90.1 ± 11.3 kg; 176.0 ± 4.9 cm) performed each resistance exercise protocol in a random, counterbalanced order. Blood samples were obtained at baseline (BL), immediately (IP), 30 min (30P), 1 h (1H), 2 h (2H), and 5 h (5H) postexercise. Fine needle muscle biopsies were completed at BL, 1H, and 5H. Electromyography of the vastus lateralis was also recorded during each protocol. HV and HI produced a similar magnitude of muscle activation across sets. Myoglobin and lactate dehydrogenase concentrations were significantly greater following HI compared to HV (P = 0.01-0.02), whereas the lactate response was significantly higher following HV compared to HI (P = 0.003). The growth hormone, cortisol, and insulin responses were significantly greater following HV compared to HI (P = 0.0001-0.04). No significant differences between protocols were observed for the IGF-1 or testosterone response. Intramuscular anabolic signaling analysis revealed a significantly greater (P = 0.03) phosphorylation of IGF-1 receptor at 1H following HV compared to HI. Phosphorylation status of all other signaling proteins including mTOR, p70S6k, and RPS6 were not significantly different between trials. Despite significant differences in markers of muscle damage and the endocrine response following HV and HI, both protocols appeared to elicit similar mTORC1 activation in resistance-trained men.
PMID: 26197935 [PubMed] PMCID: PMC4552541
Source: http://www.ncbi.nlm.nih.gov/pubmed/26197935
