Thread: unilaterally training contralateral limb when injured?

Originally Posted by Yanick

I was doing triples on Monday and felt a twinge in my left shoulder. I thought nothing of it and kept on going. When it came time to do dips i couldn't even hit a BW dip (I was up to adding 45lbs for reps) so I stopped all pressing movements and just finished off with upper pulling stuff. Next day i couldn't even pick up my arm to take my shirt off. Its progressively getting better but I won't be pressing or doing anything with my arms overhead for a while.

Anyway, I'd like some opinions on unilaterally working the healthy arm with DB's. A while ago i remember reading some stuff that working the contralateral side will halt atrophy of the injured limb. This was a while ago and i don't remember if it was an article, study or what.

Opinions? Articles? Studies? Anything would be helpful.

I remember reading this, too; but, like you, I can't remember where I read it. I'll see if I can track it down.

You really should see a doctor about that shoulder. It could be any number of things, but you run the risk of making a small thing into something big.

I posted a study here awhile back from my exercise phys. text book about training the opposite arm and the body trying to maintain symetry by attempting to keep the strength in the non-working arm. Can't remeber the thread though. I can try and find the study in a few minutes.

I would go and see a doctor though.

found it:

Effect of one-legged exercise on the strength, power and endurance of the contralateral leg. A randomized, controlled study using isometric and concentric isokinetic training.

Kannus P, Alosa D, Cook L, Johnson RJ, Renstrom P, Pope M, Beynnon B, Yasuda K, Nichols C, Kaplan M.


European Journal of Applied Phyisology and Occupational Physiology
vol. 64, no. 2, pg. 117-26, 1992.


The purpose of this investigation was to study the effect of one-legged exercise on the strength, power and endurance of the contralateral leg. The performance of the knee extensor and flexor muscle of 20 healthy young adults (10 men and 10 women) was first tested by Cybex II+ and 340 dynamometers. Then 10 subjects were chosen at random to train using one leg three times a week for 7 weeks whilst the other 10 served as controls. During the 8th week, the tests were repeated. Both quadriceps and hamstring muscles of the trained subjects showed a cross-transfer effect from the trained limb to the untrained side. This concerned the strength and power, as well as endurance characteristics of these muscles. The average change in peak torque of the quadriceps muscle was +19% (P less than 0.001) in the trained limb, +11% (P less than 0.01) in the untrained limb and 0% in the control limbs. In hamstring muscles the changes were +14% (P less than 0.01), +5% and -1%, respectively. Concerning muscle endurance (work performed during the last 5 contractions in the 25-repetition test) the corresponding changes were +15% (P less than 0.01), +7% (P less than 0.01), and -1% in quadriceps muscle, and +17% (P less than 0.05), +7%, and -3% in hamstring muscles. The average strength benefit in the untrained limb was +36% (hamstring muscles) and +58% (quadriceps muscle) of that achieved in the trained limb. Untrained hamstring muscle showed better benefits in the endurance parameters than in strength or power parameters, while in the quadriceps muscle this effect was reversed. A positive relationship was observed between the changes (greater improvement in the trained limb resulted in greater improvement in the untrained limb) (hamstring muscles: r = 0.83, P less than 0.001, quadriceps muscle: r = 0.53, P less than 0.001). In endurance parameters, this relationship was almost linear while in the strength and power parameters the results were more in favour of a curvilinear relationship with limited benefit.

Sweet thanks for the abstract.

I found another on pubmed:

The effect of unilateral concentric weight training and detraining on joint angle specificity, cross-training, and the bilateral deficit.

• Weir JP,
• Housh DJ,
• Housh TJ,
• Weir LL.

Program in Physical Therapy, University of Osteopathic Medicine and Health Sciences, Des Moines, IA, USA.
Changes in strength following concentric-only weight training and detraining are poorly understood. The purpose of this investigation was to examine the effects of unilateral concentric leg extension weight training and detraining on joint angle specificity, cross-training, and the bilateral deficit (individual limb strength > bilateral strength/2). Sixteen males volunteered to be subjects for this investigation (concentric training group, N = 8; control group, N = 8). The training group performed 8 weeks of training with the nondominant limb three times per week (3-5 sets X six repetitions), followed by 8 weeks of detraining. These subjects were tested pretraining, posttraining, and following detraining for maximal isometric strength at three joint angles (15, 45, and 75 degrees) in both limbs as well as for the one repetition maximum (1-RM) concentric strength of the trained limb, untrained limb, and bilaterally. The results of this investigation indicated that the effects of the concentric weight training were not joint angle specific as the isometric strength increases occurred at all three joint angles. This effect was found in both limbs, indicating that cross-training occurred. The results of the 1-RM analyses showed that initially there was a bilateral deficit (untrained limb > bilateral, trained limb at pretraining). [b]While the concentric training resulted in increases in 1-RM strength in the trained limb, untrained limb, and bilaterally, differences between bilateral strength and the untrained limb were reversed posttraining and the trained limb values exceeded both the bilateral and untrained limb values. Finally, the effects of detraining were more pronounced for isometric strength vs. 1-RM strength as there was a significant decrease from posttraining in the isometric scores, but the detraining 1-RM values were not significantly decreased from posttraining for either limb or bilaterally.
PMID: 9083945 [PubMed - indexed for MEDLINE]

And another one, opposing it. I'm not sure but maybe the fact that they worked the muscles isometrically on a dyno had some effect on the results?

Effects of unilateral isometric strength training on joint angle specificity and cross-training.

• Weir JP,
• Housh TJ,
• Weir LL,
• Johnson GO.

Department of Movement Sciences and Education, Teachers College, Columbia University, New York, NY 10027, USA.
The purpose of this study was to examine the effects of unilateral isometric leg extension strength training on the strength and integrated electromyogram (IEMG) of both the trained and untrained limbs at multiple joint angles. A training (TRN) group [nine women; mean (SD) age, 20(1) years] exercised for 6 weeks with isometric leg extensions at 80% of maximal isometric torque. A control (CTL) group [eight women; 21(1) years] did not exercise. The training was performed three times per week on a Cybex II isokinetic dynamometer at a joint angle where the lever arm was 0.79 rad below the horizontal plane. The subjects were tested pre- and posttraining for maximal unilateral isometric torque in both limbs at joint angles of zero, 0.26, 0.79, 1.31, and 1.57 rad below the horizontal plane. Bipolar surface electrodes were used to record the IEMG of the vastus lateralis (VL) and vastus medialis (VM) during the isometric tests. Three univariate (torque, IEMG-VL, and IEMG-VM) four-way (group x time x limb x angle) mixed factorial ANOVAs were used to analyze the data. The results indicated joint angle specificity for isometric torque in the TRN group only, with significant increases in torque at 0.79 (P = 0.0004) and 1.31 (P = 0.0039) rad. No significant increases in torque were found in the untrained limb of the TRN group or in either limb of the CTL group. Similarly, there were no significant changes in IEMG as a result of the training for the VL or VM.(ABSTRACT TRUNCATED AT 250 WORDS)
PMID: 7649145 [PubMed - indexed for MEDLINE]

Two more but i can't find anymore that evaluate cross training while working concentrically. The isometrically trained limbs don't seem to show a cross training effect.

Electromyographic evaluation of joint angle specificity and cross-training after isometric training.

• Weir JP,
• Housh TJ,
• Weir LL.

Center for Youth Fitness and Sports Research, University of Nebraska-Lincoln 68588-0229.
The purpose of this study was to examine the effects of unilateral strength training on the strength and integrated electromyogram (IEMG) of the trained and untrained limbs at several joint angles. A training group [TRN; 4 females and 3 males, age 22 +/- 4 yr (SD)] exercised for 6 wk with isometric leg extensions at 80% of maximal isometric torque. A control group (3 females and 3 males, age 24 +/- 4 yr) did not exercise. The training was performed three times per week at 0.79 rad below the horizontal plane. The subjects were tested at joint angles of 0.00, 0.26, 0.79, 1.31, and 1.57 rad. Bipolar surface electrodes were used to record the IEMG of the vastus lateralis. The results indicated a cross-training effect and joint angle specificity for isometric torque in TRN only, with significant (P < 0.0005) increases in torque (collapsed across limb) at 0.26 (23.3%) and 0.79 (22.3%) rad. There was a dissociation, however, between changes in torque and IEMG with an increase (P < 0.05) in IEMG (collapsed across limb and angle) for TRN. The dissociation between the IEMG and strength changes was possibly due to differential responses to training in the four muscles of the quadriceps femoris.
PMID: 7961233 [PubMed - indexed for MEDLINE]

Mechanomyographic and electromyographic responses to unilateral isometric training.

• Ebersole KT,
• Housh TJ,
• Johnson GO,
• Perry SR,
• Bull AJ,
• Cramer JT.

Center for Youth Fitness and Sports Research, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA. ebersole@uwm.edu
The purpose of this investigation was to examine the effects of unilateral, isometric training of the forearm flexors on strength and the mechanomyographic (MMG) and electromyographic (EMG) responses of the biceps brachii in the trained and untrained limb at three joint angles. Seventeen adult females (mean age +/- SD = 21 +/- 2 years) were randomly assigned to a control (CTL; N=7) or a training (TRN; N=10) group. The TRN group performed isometric training of the non-dominant forearm flexors on a Cybex II Dynamometer at a joint angle such that the Cybex lever arm was positioned 60 degrees above the horizontal plane. The training consisted of 3 to 5 sets of 8, 6-second repetitions at 80% of maximal voluntary contraction 3 times per week for 8 weeks. The results indicated a significant increase in flexed arm circumference as well as isometric strength in the trained limb at all three joint angles. There were, however, no changes in MMG or EMG amplitude in the trained or untrained limb and no cross-training effect for strength or flexed arm circumference. These findings suggested that the increased strength may have been due to factors associated with hypertrophy, independent of neural adaptations in the biceps brachii. Furthermore, hypertrophy may have had counteractive effects on the MMG signal that could be responsible for the lack of a training-induced change in the MMG amplitude.
PMID: 11991770 [PubMed - indexed for MEDLINE]

And Finally, this one is great Seems to be sealing the deal for me right here. And its from 2007

Cross education : possible mechanisms for the contralateral effects of unilateral resistance training.

• Lee M,
• Carroll TJ.

School of Medical Sciences, Health and Exercise Science, University of New South Wales, Sydney, New South Wales, Australia.
Resistance training can be defined as the act of repeated voluntary muscle contractions against a resistance greater than those normally encountered in activities of daily living. Training of this kind is known to increase strength via adaptations in both the muscular and nervous systems. While the physiology of muscular adaptations following resistance training is well understood, the nature of neural adaptations is less clear. One piece of indirect evidence to indicate that neural adaptations accompany resistance training comes from the phenomenon of 'cross education', which describes the strength gain in the opposite, untrained limb following unilateral resistance training. Since its discovery in 1894, subsequent studies have confirmed the existence of cross education in contexts involving voluntary, imagined and electrically stimulated contractions. The cross-education effect is specific to the contralateral homologous muscle but not restricted to particular muscle groups, ages or genders. A recent meta-analysis determined that the magnitude of cross education is approximate, equals7.8% of the initial strength of the untrained limb. While many features of cross education have been established, the underlying mechanisms are unknown.This article provides an overview of cross education and presents plausible hypotheses for its mechanisms. Two hypotheses are outlined that represent the most viable explanations for cross education. These hypotheses are distinct but not necessarily mutually exclusive. They are derived from evidence that high-force, unilateral, voluntary contractions can have an acute and potent effect on the efficacy of neural elements controlling the opposite limb. It is possible that with training, long-lasting adaptations may be induced in neural circuits mediating these crossed effects. The first hypothesis suggests that unilateral resistance training may activate neural circuits that chronically modify the efficacy of motor pathways that project to the opposite untrained limb. This may subsequently lead to an increased capacity to drive the untrained muscles and thus result in increased strength. A number of spinal and cortical circuits that exhibit the potential for this type of adaptation are considered. The second hypothesis suggests that unilateral resistance training induces adaptations in motor areas that are primarily involved in the control of movements of the trained limb. The opposite untrained limb may access these modified neural circuits during maximal voluntary contractions in ways that are analogous to motor learning. A better understanding of the mechanisms underlying cross education may potentially contribute to more effective use of resistance training protocols that exploit these cross-limb effects to improve the recovery of patients with movement disorders that predominantly affect one side of the body.
PMID: 17190532 [PubMed - in process]

Okay now i'm happy. This is enough for me, even if its a little bit i'm still happy that i have a reason to do some more work in the gym.

Contralateral effects of unilateral strength training: evidence and possible mechanisms.

• Carroll TJ,
• Herbert RD,
• Munn J,
• Lee M,
• Gandevia SC.

Health and Exercise Science, School of Medical Sciences, University of New South Wales, Sydney, Australia.
If exercises are performed to increase muscle strength on one side of the body, voluntary strength can increase on the contralateral side. This effect, termed the contralateral strength training effect, is usually measured in homologous muscles. Although known for over a century, most studies have not been designed well enough to show a definitive transfer of strength that could not be explained by factors such as familiarity with the testing. However, an updated meta-analysis of 16 properly controlled studies (range 15-48 training sessions) shows that the size of the contralateral strength training effect is approximately 8% of initial strength or about half the increase in strength of the trained side. This estimate is similar to results of a large, randomized controlled study of training for the elbow flexors (contralateral effect of 7% initial strength or one-quarter of the effect on the trained side). This is likely to reflect increased motoneuron output rather than muscular adaptations, although most methods are insufficiently sensitive to detect small muscle contributions. Two classes of central mechanism are identified. One involves a "spillover" to the control system for the contralateral limb, and the other involves adaptations in the control system for the trained limb that can be accessed by the untrained limb. Cortical, subcortical and spinal levels are all likely to be involved in the "transfer," and none can be excluded with current data. Although the size of the effect is small and may not be clinically significant, study of the phenomenon provides insight into neural mechanisms associated with exercise and training.
PMID: 17043329 [PubMed - indexed for MEDLINE]

Oh yeah as far as the injury, I doubt its anything serious. Feels like i pulled a tendon/muscle at the top of the distal clavicle (where the delt would attach). Its getting better everyday, i hope its good enough for some light pressing next monday.

pubmed's "find all releatd topics" function is a real gem.

What'll they think of next

Pretty friggin amazing that the body would do that.