A recent study from the Santa Cecilia University and other universities in Brazil tried to answer this and related questions in a group of trained subjects: Their study evaluated the differential effects on alterations in upper body muscle strength and size of resistance training protocols involving only multi-joint (MG) or both multi-joint (MJ) and single-joined (SJ) exercises in a single workout session in trained men (França. 2015).
The participants were randomly assigned to one out of two groups: A combination group with both multi- and single joint exercise MJ+SJ (n = 10, 27.7 + 6.6 year) and a multi-joint only group MJ (n = 10, 29.4 + 4.6 years). To be included in the study, participants had to be currently practicing RT and have been continuously training for at least two years previous to the beginning of the study. Their programs had to involve both MJ and SJ exercises and had to be geared towards muscle hypertrophy. People with a history of anabolic steroid use were not accepted. Furthermore, all participants were instructed not change their nutritional habits or ingest ergogenic aids during the study. Minimum training attendance was set at 85% (all 20 volunteers complied).
"In order to increase ecological validity, RT [resistance training] program design and exercise choice were based on the common practices used in gyms and fitness centers by experienced trainees who desire to increase muscle strength and size. RT followed a linear periodization model with sequences of ordinary (two), shock (one) and restorative (one) microcyles as shown in Table 1" (de França. 2015).During the ordinary microcycle, sets were performed to concentric failure - with one minute rest interval between sets. During the shock microcycle, each exercise was performed with the same load of the ordinary week, however, after failure, external assistance was given during the concentric phase to allow the performance of 2-5 additional repetitions, a method that's usually called forced repetitions (Ahtiainen. 2003).
|Table 1: Periodization scheme used in the study (explanation follows | de França. 2015)|
"Participants were instructed to take one second to perform the concentric and two seconds to perform the eccentric phase, whenever possible. Rest intervals were set at one minute between sets and two minutes between exercises" (de França. 2015).Each session lasted approximately 35 and 50 minutes for MJ and MJ+SJ, respectively, and the subjects trained according to an A-B regimen that was performed twice a week for a total of four training days per week. In that, the lower limbs, low back and abdominal muscles were trained on Wednesdays and Saturdays through the same complementary training program for both groups.
|Table 2: Overview of the RT programs | * denotes exercises done only in the MJ+SJ group (de França. 2015).|
Why is it important that the scientists measured the size gains 5-7 days after the last workout? As a SuppVersity reader you should know that the exercise induced cell-swelling will mess with the results for at least 52h. If you don't remember that, read up on it in my previous article Cell Swelling Keeps Muscles "Pumped" For More Than 52h. Size Increases of Up to 16% After a Single Leg Workout!" (read it!)To assess the results of the program, the researchers did 1-RM tests (for strength) and measured the flexed arm circumference (FAC) and arm muscle circumference (AMC) before the training program and 5-7 days after the last training session (see red box to learn why this is important).
|Figure 1: Pre-/post-changes in arm circumference and biceps + triceps strength (de Franca. 2015).|
- Ahtiainen, Juha P., et al. "Acute hormonal and neuromuscular responses and recovery to forced vs maximum repetitions multiple resistance exercises." International journal of sports medicine 24.6 (2003): 410-418.
- de França, Henrique Silvestre, et al. "The Effects Of Adding Single-Joint Exercises To A Multi-Joint Exercise Resistance Training Program On Upper Body Muscle Strength And Size In Trained Men." Applied Physiology, Nutrition, and Metabolism (2015): Ahead of print.
- Willardson, Jeffrey M., Roberto Simão, and Fabio E. Fontana. "The effect of load reductions on repetition performance for commonly performed multijoint resistance exercises." The Journal of Strength & Conditioning Research 26.11 (2012): 2939-2945.