New study indicating that adding isolation exercises provides no benefit over just using multi-joint lifts for hypertrophy and strength purposes in trained lifters.
The aim of this study was compare changes in upper body muscle strength and size in trained men performing resistance training (RT) programs involving multi-joint plus single-joint (MJ+SJ) or only multi-joint (MJ) exercises. Twenty young men with at least two years of experience in RT were randomized in two groups: MJ+SJ (n = 10, 27.7 + 6.6 years) and MJ (n = 10, 29.4 + 4.6 years). Both groups trained for 8 weeks following a linear periodization model. Measures of elbow flexors and extensors 1RM, flexed arm circumference (FAC) and arm muscle circumference (AMC) were taken pre and post training period. Both groups significantly increased 1RM for elbow flexion (4.99 and 6.42% for MJ and MJ+SJ, respectively), extension (10.60 vs 9.79%, for MJ and MJ+SJ, respectively), FAC (1.72 vs 1.45%, for MJ and MJ+SJ, respectively) and AMC (1.33 vs 3.17% for MJ and MJ+SJ, respectively). Comparison between groups revealed no significant difference in any variable. In conclusion, eight weeks of RT involving MJ or MJ+SJ resulted in similar alterations in muscle strength and size in trained participants. Therefore, the addition of SJ exercises to a RT program involving MJ exercises does not seem to promote additional benefits to trained men suggesting MJ only RT to be a time efficient approach.
Applied Physiology, Nutrition, and Metabolism. 9 April 2015.