Friday, November 25, 2016

Do You Need Single Joint Exercises for Strength or Hypertrophy Training?

Weighted dips for pectorals, shoulders and triceps.  © Don Matesz 2016

Do you need single-joint exercises (such as barbell curls, tricep extensions, leg curls, and leg extensions) in a strength training program, or can you get the same results using only multi-joint exercises (such as squats, chin ups, dips, rowing and overhead press)?

Gentil et al. assigned untrained males to train the elbow flexors (biceps, brachialis) with either shoulder-width supinated grip barbell curls (a single-joint exercise, SJ group, n=15) or pronated wide grip lat. pull downs (a multi-joint exercise, MJ group, n=14).  Both groups also performed leg press, leg flexion, trained twice weekly for 10 weeks, using 3 sets of 8-12 repetitions with maximum effort (i.e. to failure).  They were supervised and instructed to perform the lifting and lowering phases of each repetition in 2 seconds each phase, with no pause between repetitions.  They rested 1.5-2.5 minutes between sets.  If necessary, weights were adjusted for each set in order to keep repetitions in the 8-12 range.  Before and after the 10 weeks, they tested the subjects elbow flexors for peak torque (PT) and muscle thickness (MT).

At the end of the 10 weeks, the MJ and SJ groups had increased elbow flexor MT by 6.1% and 5.38% respectively, and PT by 10.4% and 11.87%, respectively.  These differences were statistically non-significant.

L-sit pull-ups with a supinated grip. © Don Matesz 2016
I find it this study particularly interesting because the MJ group used pronated grip pulldowns, and the pronated grip places the biceps in a mechanically disadvantaged position.  The biceps are the largest of the elbow flexors and they can exert more force when the wrist is supinated, so that people can handle more resistance in a supinated barbell curl, pull-up or pull-down than in pronated grip versions of these exercises.  This study suggests that the biceps are loaded just as effectively by pronated pull-ups as by supinated barbell curls.  In fact the subjects who did only pronated pull-ups had slightly greater bicep hypertrophy than the subjects who did only supinated-grip barbell curls.  The take home message is that it probably does not matter whether you use a supinated or a pronated grip for pull-ups.

de France et al. found that adding SJ movements to a resistance training routine composed of MJ movements for 8 weeks did not improve results in individuals who had a minimum of 2 years training experience.  This study involved training upper body pushing movements (chest, shoulders, triceps)on Mondays and Thursdays, upper body pulling movements (back and biceps) on Tuesdays and Fridays, and lower limbs, low back, and abdomen on Wednesdays and Saturdays.  Here's the selection of movements used for the upper body training:

 All exercises were performed for 3 sets of 10 repetitions except during the "shock" weeks which involved 3 sets of 12-15 repetitions including assisted post-fatigue repetitions.  The MJ only routine took only 35 minutes to complete, the MJ+SJ routine took 50 minutes to complete.  The training program was periodized as shown in Table 1.

Table 3 displays the results:

There was no significant difference in results between the group that used SJ movements and the group that did not.  Once again, the addition of single joint movements did not provide any additional benefit.  Over the course of 8 weeks, the MJ+SJ group spent 8 hours more time training (an extra 15 minutes per session, 4 times weekly, for 8 weeks), without any additional compensation.

Twisting back extension.  © Don Matesz 2016

These are just 2 examples of studies of this topic.  Gentil et al. conducted a review of 23 studies of the acute effects and long-term adaptations of SJ and MJ exercises in resistance training.  They found:

1. "For the upper and lower limbs, analysis of surface electromyographic (sEMG) activation suggests that there are no differences between SJ and MJ exercises when comparing the prime movers."
2.  For the lumbar extensors, the evidence supports including a SJ exercise (i.e. back extensions vs. deadlifts).
3.   "Long-term studies comparing increases in muscle size and strength in the upper limbs reported no difference between SJ and MJ exercises and no additional effects when SJ exercises were included in an MJ exercise program."
4.  Only one study directly compared the effects of MJ and SJ on recovery and its results suggest that SJ exercises produce increased muscle fatigue and soreness.

In short, the evidence to date indicates that, unless you just have time to burn and like working more hours for no additional compensation, you should build your routine of basic multi-joint exercises like squats, pull-ups, dips, rows, overhead presses, and limit your inclusion of SJ exercises in your strength training routine to those that address the lower back (back extensions), and possibly the neck, calves, and forearms, except in cases where an SJ exercise may be needed for rehabilitation. 

Weighted Cossack squats train hip and thigh strength and flexibility.  © Don Matesz 2016

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