Trained participants experience maximal strength gains training each muscle group 2 days per week with an average training intensity of 80% of their 1 RM, or approximately 8 RM. Four sets performed per muscle group elicited the most gains in both trained and untrained. Interestingly, only marginal benefits where observed between 2 and 4 sets per muscle group in trained individuals.
Rhea warns their dose-response curves represent mean training levels and should not be construed as supporting training at a particular volume or intensity on a constant basis. Instead, effective programs should incorporate varied training doses (volume, frequency, and/or intensity) [particularly for trained individuals].
Untrained participants (less than 1 year of consistent training) experience maximal strength gains with an average training intensity of 60% of their 1 RM or approximately a 12 RM, training each muscle group 3 days per week. Novices weight training 2 times per week may make approximately 80% of the strength gains as compared to training 3 times per week.
Rhea et al (2003) suggested caution when prescribing multiple-set programs to those who have not been training consistently for at least 1 year. Adequate time is required to become accustomed to the stress of resistance exercise and avoid over-stress injuries in the early phases of training. Novice trainees may also lack the desire to commit to a training program requiring the additional time needed to perform multiple sets and thus reduce adherence to the exercise regimen.
Braith RW, Graves JE, Pollock ML, Leggett SL, Carpenter DM, Colvin AB (1989). Comparison of 2 vs 3 days/week of variable resistance training during 10- and 18-week programs. Int J Sports Med. 10(6):450-4.
Rhea MR, Alvar BA, Burkett LN, Ball SD (2003). A meta-analysis to determine the dose response for strength development. Med Sci Sports Exerc. 35(3):456-64.
Hass et. al. compared one and three sets in long-term recreational weightlifters and found no significant difference in strength and muscular development.
Hass CJ, Garzarella L, de Hoyos D, Pollock ML (2000). Single versus multiple sets in long-term recreational weightlifters. Med Sci Sports Exerc. 32(1):235-42.
Rhea et. al. also compared one and three sets in recreationally trained individuals for the Bench Press and Leg Press. A statistically significant difference in strength gains was found favoring 3 sets in the leg press (p < 0.05, effect size [ES] = 6.5). However, only a small but statistically insignificant difference in strength gain was found for the bench press (p = 0.07, ES = 2.3).
Rhea MR, Alvar BA, Ball SD, Burkett LN (2002). 16(4):525-9. Three sets of weight training superior to 1 set with equal intensity for eliciting strength. J Strength Cond Res.
Schlumberger found greater strength gains in women performing 3 sets versus a single set. Both training groups made significant strength improvements in leg extension (multiple-set group, 15%; single-set group, 6%; p 0.05). However, in the seated bench press only the 3-set group showed a significant increase in maximal strength (10%).
Schlumberger A, Stec J, Schmidtbleicher D (2001). Single- vs. multiple-set strength training in women. J Strength Cond Res.15(3):284-9.
Single-set programs for an initial short training period in untrained individuals result in similar strength gains as multiple-set programs. As progression occurs multiple-set programs were more effective.
Wolfe BL, LeMura LM, Cole PJ (2004). Quantitative analysis of single- vs. multiple-set programs in resistance training. J Strength Cond Res.18(1):35-47.