Research Update: Using lighter weights and higher reps was shown to be better than heavier weights and lower reps

[Lindsay]

Research Update: Using lighter weights and higher reps was shown to be better than heavier weights and lower reps at increasing muscle protein synthesis at 4 and 24 hours post exercise. This is despite an equal amount of work done..

Essentially what this study is saying is that the old notion that lighter weights and higher rep protocols are NOT good for increasing muscle size should be reconsidered. The traditional lower reps using higher weight did create a better acute response in muscle building (4hours), but the lighter weight taken to failure was significantly better at 24 hours.

Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0012033

Abstract Top

Background

We aimed to determine the effect of resistance exercise intensity (% 1 repetition maximum—1RM) and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression.

Methodology/Principal Findings

Fifteen men (21±1 years; BMI = 24.1±0.8 kg/m2) performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM) until volitional failure (90FAIL), 30% 1RM work-matched to 90%FAIL (30WM), or 30% 1RM performed until volitional failure (30FAIL). Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX), myofibrillar (MYO), and sarcoplasmic (SARC) protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121%) and MYO (87%) protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199%) above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P = 0.023) and mTORSer2448 phosphorylation at 4 h post-exercise (P = 0.025). Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05) only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237%) and 30FAIL (312%) conditions. Pax7 mRNA expression increased at 24 h post-exercise (P = 0.02) regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition.

Conclusions/Significance

These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes.

....the higher volume/or greater amount of work done by the lighter weight group made the difference. You have to make sure in these studies the work completed is equal when comparing two different protocol otherwise there is not a fair comparison.

The participants did 4 sets to failure of leg extension with 3 minutes rest between. The weights and reps used in the group using light weights and going to failure was 30% of the maximum the person could lift on the exercise (30% of a 1RM).. (roughly 28 kilo or 61lbs on average) compared to t he group going heavier who used a 90% of maximum load (90% 1RM) ( 82kilo or 180lbs).

RM stands for rep max. 1RM means a weight that can be lifted one time but not 2.