Forget those 1-minute rest intervals in the muscle magazines. Your performance from set to set will decline quickly. Short rest intervals and training to failure repeatedly will increase human growth hormone levels, but I have not found any studies that correlate it with long-term increases in muscle mass. I have found studies that have concluded just the opposite. [i] [ii]Countless studies have demonstrated that progressive overload is the key to muscle and strength gains.
If you want to build strength and muscle, it is best done naturally by resting 3 to 5 minutes between working sets. The only time I recommend one-minute rest intervals are between low-intensity warm-up sets. A study conducted by the Kennesaw State University found that subjects that rested 2.5 minutes between sets made substantially greater gains in muscle mass than the subject that only rested 1-minute between sets.[iii]
Eastern Illinois University conducted a study that concluded, “When the training goal is maximal strength development, 3 minutes of rest should be taken between sets to avoid significant declines in repetitions. The ability to sustain repetitions while keeping the intensity constant may result in a higher training volume and consequently greater gains in muscular strength.”[iv] Another study by the State University of Rio de Janeiro found that resting longer, 3 to 5 minutes between sets led to more repetitions being performed over multiple sets and higher rates of muscular power.[v] These two factors would result in greater overload being applied to the muscle. Progressive overload is required to produce increases in muscular size and strength.
I could site more studies, but I think is clear that resting a minimum of three minutes between sets is best for producing strength and muscle gains. If you are like me, you don’t want to sit and wait for 3-minutes before performing your next set. I recommend you structure your workouts so that you superset opposing muscle groups, or you include sets for unrelated muscle groups during your rest interval so you can perform more work in less time while still allowing yourself 3-minutes or more between working sets.
[i] Cameron J Mitchell, Tyler A Churchward-Venne, Leeann Bellamy, Gianni Parise, Steven K Baker, and Stuart M Phillips, “Muscular and Systemic Correlates of Resistance Training-Induced Muscle Hypertrophy,” PLoS One. October 9, 2013 https://doi.org/10.1371/journal.pone.0078636.
[ii] Mitchell CJ, Churchward-Venne TA, Bellamy L, Parise G, Baker SK, Phillips SM., “Muscular and systemic correlates of resistance training-induced muscle hypertrophy,” PLoS One. 2013 Oct 9; 8(10):e78636. doi: 10.1371/journal.pone.0078636. eCollection 2013.
[iii] Buresh R, and Berg K, French J, “The effect of resistive exercise rest interval on hormonal response, strength, and hypertrophy with training,” Strength Cond Res. 2009 Jan; 23(1):62-71. doi: 10.1519/JSC.0b013e318185f14a.
[iv] Willardson JM, and Burkett LN, “The effect of rest interval length on bench press performance with heavy vs. light loads,” J Strength Cond Res. 2006 May; 20(2):396-9.
[v] Salles BF, Simão R, Miranda F, Novaes Jda S, Lemos A, and Willardson JM, “Rest interval between sets in strength training,” Sports Med. 2009;39(9):765-77. doi: 10.2165/11315230-000000000-00000.