single vs. multi-joint resistance exercises: effects on muscle strength and hypertrophy

Background: some authors suggest that single joint (sj) exercises promote greater muscle hypertrophy because they are easier to be learned and therefore have less reliance on neural factors. on the other hand, some authors recommend an emphasis on multi-joint (mj) exercises for maximizing muscle strength, assuming that mj exercises are more effective than sj exercises because they enable a greater magnitude of weight to be lifted. objectives: the present study aimed to compare the effects of mj vs. sj exercises on muscle size and strength gains in untrained young men. patients and methods: twenty-nine young men, without prior resistance training experience, were randomly divided into two groups. one group performed (n = 14) only mj exercises involving the elbow flexors (lat. pull downs), while the other (n = 15) trained the elbow flexors muscles using only sj exercises (biceps curls). both groups trained twice a week for a period of ten weeks. the volunteers were evaluated for peak torque of elbow flexors (pt) in an isokinetic dynamometer and for muscle thickness (mt) by ultrasonography. results: there were significant increases in mt of 6.10% and 5.83% for mj and sj, respectively; and there were also significant increases in pt for mj (10.40%) and sj (11.87%). however, the results showed no difference between groups pre or post training for mt or pt. conclusions: in conclusion, the results of the present study suggest that mj and sj exercises are equally effective for promoting increases in upper body muscle strength and size in untrained men. therefore, the selection between sj and mj exercises should be based on individual and practical aspects, such as, equipment availability, movement specificity, individual preferences and time commitment.