European Journal of Applied Physiology

, Volume 117, Issue 11, pp 2335–2354 | Cite as

Cross-education of muscular strength following unilateral resistance training: a meta-analysis

  • A. Manca
  • D. Dragone
  • Z. Dvir
  • Franca DeriuEmail author
Original Article



Cross-education (CE) of strength is a well-known phenomenon whereby exercise of one limb can induce strength gains in the contralateral untrained limb. The only available meta-analyses on CE, which date back to a decade ago, estimated a modest 7.8% increase in contralateral strength following unilateral training. However, in recent years new evidences have outlined larger contralateral gains, which deserve to be systematically evaluated. Therefore, the aim of this meta-analysis was to appraise current data on CE and determine its overall magnitude of effect.


Five databases were searched from inception to December 2016. All randomized controlled trials focusing on unilateral resistance training were carefully checked by two reviewers who also assessed the eligibility of the identified trials and extracted data independently. The risk of bias was assessed using the Cochrane Risk-of-Bias tool.


Thirty-one studies entered the meta-analysis. Data from 785 subjects were pooled and subgroup analyses by body region (upper/lower limb) and type of training (isometric/concentric/eccentric/isotonic–dynamic) were performed. The pooled estimate of CE was a significant 11.9% contralateral increase (95% CI 9.1–14.8; p < 0.00001; upper limb: + 9.4%, p < 0.00001; lower limb: + 16.4%, p < 0.00001). Significant CE effects were induced by isometric (8.2%; p = 0.0003), concentric (11.3%; p < 0.00001), eccentric (17.7%; p = 0.003) and isotonic–dynamic training (15.9%; p < 0.00001), although a high risk of bias was detected across the studies.


Unilateral resistance training induces significant contraction type-dependent gains in the contralateral untrained limb. Methodological issues in the included studies are outlined to provide guidance for a reliable quantification of CE in future studies.


Contralateral training Strength Resistance training Meta-analysis 





Confidence interval


Inconsistency statistic


Randomized controlled trial


Repetition maximum


Standard deviation


Standardized mean difference


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. Abazovíc E, Kovacevíc E, Kovac S, Bradíc J (2015) The effect of training of the non-dominant knee muscles on ipsi- and contralateral strength gains. Isokinet Exerc Sci 23:177–182CrossRefGoogle Scholar
  2. Beckerman H, Roebroeck ME, Lankhorst GJ, Becher JG, Bezemer PD, Verbeek AL (2001) Smallest real difference, a link between reproducibility and responsiveness. Qual Life Res 10:571–578CrossRefPubMedGoogle Scholar
  3. Beyer KS, Fukuda DH, Boone CH, Wells AJ, Townsend JR, Jajtner AR, Gonzalez AM, Fragala MS, Hoffman JR, Stout JR (2016) Short-term unilateral resistance training results in cross education of strength without changes in muscle size, activation, or endocrine response. J Strength Cond Res 30:1213–1223CrossRefPubMedGoogle Scholar
  4. Cannon RJ, Cafarelli E (1987) Neuromuscular adaptations to training. J Appl Physiol 63:2396–2402PubMedGoogle Scholar
  5. Carolan B, Cafarelli E (1992) Adaptations in coactivation after isometric resistance training. J Appl Physiol 73:911–917PubMedGoogle Scholar
  6. Carroll TJ, Herbert RD, Munn J, Lee M, Gandevia SC (2006) Contralateral effects of unilateral strength training: evidence and possible mechanisms. J Appl Physiol 101:1514–1522CrossRefPubMedGoogle Scholar
  7. Cohen J (1988) Statistical power analysis for the behavioral sciences, 2nd edn. Lawrence Earlbaum Associates, HillsdaleGoogle Scholar
  8. Coombs TA, Frazer AK, Horvath DM, Pearce AJ, Howatson G, Kidgell DJ (2016) Cross-education of wrist extensor strength is not influenced by non-dominant training in right-handers. Eur J Appl Physiol 116:1757–1769CrossRefPubMedGoogle Scholar
  9. Coratella G, Milanese C, Schena F (2015) Cross-education effect after unilateral eccentric-only isokinetic vs dynamic constant external resistance training. Sport Sci Health 11:329–335CrossRefGoogle Scholar
  10. Dragert K, Zehr EP (2013) High-intensity unilateral dorsiflexor resistance training results in bilateral neuromuscular plasticity after stroke. Exp Brain Res 225:93–104CrossRefPubMedGoogle Scholar
  11. Dvir Z (2004) Isokinetics: muscle testing, interpretation, and clinical applications. 2nd edn, Elsevier Health Sciences, AmsterdamGoogle Scholar
  12. Dvir Z (2015) Difference, significant difference and clinically meaningful difference: the meaning of change in rehabilitation. J Exerc Rehabil 11:67–73CrossRefPubMedPubMedCentralGoogle Scholar
  13. Ehrensberger M, Simpson D, Broderick P, Monaghan K (2016) Cross-education of strength has a positive impact on post-stroke rehabilitation: a systematic literature review. Top Stroke Rehabil 23:126–135CrossRefPubMedGoogle Scholar
  14. Evetovich TK, Housh TJ, Housh DJ, Johnson GO, Smith DB, Ebersole KT (2001) The effect of concentric isokinetic strength training of the quadriceps femoris on electromyography and muscle strength in the trained and untrained limb. J Strength Cond Res 15:439–445PubMedGoogle Scholar
  15. Farthing JP, Chilibeck PD (2003) The effect of eccentric training at different velocities on cross-education. Eur J Appl Physiol 89:570–577CrossRefPubMedGoogle Scholar
  16. Farthing JP, Zehr EP (2014) Restoring symmetry: clinical applications of cross-education. Exerc Sport Sci Rev 42:70–75CrossRefPubMedGoogle Scholar
  17. Farthing JP, Chilibeck PD, Binsted G (2005) Cross-education of arm muscular strength is unidirectional in right-handed individuals. Med Sci Sports Exerc 37:1594–1600CrossRefPubMedGoogle Scholar
  18. Farthing JP, Borowsky R, Chilibeck PD, Binsted G, Sarty GE (2007) Neuro-physiological adaptations associated with cross-education of strength. Brain Topogr 20:77–88CrossRefPubMedGoogle Scholar
  19. Farthing JP, Krentz JR, Magnus CR (2009) Strength training the free limb attenuates strength loss during unilateral immobilization. J Appl Physiol 106:830–836CrossRefPubMedGoogle Scholar
  20. Farthing JP, Krentz JR, Magnus CR, Barss TS, Lanovaz JL, Cummine J, Esopenko C, Sarty GE, Borowsky R (2011) Changes in functional magnetic resonance imaging cortical activation with cross education to an immobilized limb. Med Sci Sports Exerc 43:1394–1405CrossRefPubMedGoogle Scholar
  21. Fimland MS, Helgerud J, Solstad GM, Iversen VM, Leivseth G, Hoff J (2009) Neural adaptations underlying cross-education after unilateral strength training. Eur J Appl Physiol 107:723–730CrossRefPubMedGoogle Scholar
  22. Gandevia SC (2001) Spinal and supraspinal factors in human muscle fatigue. Physiol Rev 81:1725–1789PubMedGoogle Scholar
  23. Garfinkel S, Cafarelli E (1992) Relative changes in maximal force, EMG, and muscle cross-sectional area after isometric training. Med Sci Sports Exerc 24:1220–1227CrossRefPubMedGoogle Scholar
  24. Goodwill AM, Kidgell DJ (2012) The effects of whole-body vibration on the cross-transfer of strength. Sci World J 2012:504837. doi: 10.1100/2012/504837
  25. Goodwill AM, Pearce AJ, Kidgell DJ (2012) Corticomotor plasticity following unilateral strength training. Muscle Nerve 46:384–393CrossRefPubMedGoogle Scholar
  26. Hendy AM, Teo WP, Kidgell DJ (2015) Anodal transcranial direct current stimulation prolongs the cross-education of strength and corticomotor plasticity. Med Sci Sports Exerc 47:1788–1797CrossRefPubMedGoogle Scholar
  27. Higgins JP, Thompson SG, Deeks JJ, Altman DG (2003) Measuring inconsistency in meta-analyses. BMJ 327:557–560CrossRefPubMedPubMedCentralGoogle Scholar
  28. Hortobágyi T, Barrier J, Beard D, Braspennincx J, Koens P, Devita P, Dempsey L, Lambert J (1996) Greater initial adaptations to submaximal muscle lengthening than maximal shortening. J Appl Physiol 81:1677–1682PubMedGoogle Scholar
  29. Hortobágyi T, Lambert NJ, Hill JP (1997) Greater cross education following training with muscle lengthening than shortening. Med Sci Sports Exerc 29:107–112CrossRefPubMedGoogle Scholar
  30. Hortobágyi T, Scott K, Lambert J, Hamilton G, Tracy J (1999) Cross-education of muscle strength is greater with stimulated than voluntary contractions. Motor Control 3:205–219CrossRefPubMedGoogle Scholar
  31. Hortobágyi T, Richardson SP, Lomarev M, Shamim E, Meunier S, Russman H, Dang N, Hallett M (2011) Interhemispheric plasticity in humans. Med Sci Sports Exerc 43:1188–1199CrossRefPubMedPubMedCentralGoogle Scholar
  32. Housh TJ, Housh DJ, Weir JP, Weir LL (1996a) Effects of eccentric-only resistance training and detraining. Int J Sports Med 17:145–148CrossRefPubMedGoogle Scholar
  33. Housh TJ, Housh DJ, Weir JP, Weir LL (1996b) Effects of unilateral concentric-only dynamic constant external resistance training. Int J Sports Med 17:338–343CrossRefPubMedGoogle Scholar
  34. Kannus P, Alosa D, Cook L, Johnson RJ, Renström P, Pope M, Beynnon B, Yasuda K, Nichols C, Kaplan M (1992) 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. Eur J Appl Physiol Occup Physiol 64:117–126CrossRefPubMedGoogle Scholar
  35. Khouw W, Herbert R (1998) Optimisation of isometric strength training intensity. Aust J Physiother 44:43–46CrossRefPubMedGoogle Scholar
  36. Kidgell DJ, Stokes MA, Pearce AJ (2011) Strength training of one limb increases corticomotor excitability projecting to the contralateral homologous limb. Motor Control 15:247–266CrossRefPubMedGoogle Scholar
  37. Kidgell DJ, Frazer AK, Daly RM, Rantalainen T, Ruotsalainen I, Ahtiainen J, Avela J, Howatson G (2015) Increased cross-education of muscle strength and reduced corticospinal inhibition following eccentric strength training. Neuroscience 6:566–575CrossRefGoogle Scholar
  38. Komi PV, Viitasalo JT, Rauramaa R, Vihko V (1978) Effect of isometric strength training of mechanical, electrical, and metabolic aspects of muscle function. Eur J Appl Physiol Occup Physiol 15:45–55CrossRefGoogle Scholar
  39. Kraemer WJ (1994) General adaptations to resistance and endurance training programs. In: Baechle T (ed) Essentials of strength training and conditioning. Human Kinetics, Champaign, pp 127–150Google Scholar
  40. Lagerquist O, Zehr EP, Docherty D (2006) Increased spinal reflex excitability is not associated with neural plasticity underlying the cross-education effect. J Appl Physiol 100:83–90CrossRefPubMedGoogle Scholar
  41. Latella C, Kidgell DJ, Pearce AJ (2012) Reduction in corticospinal inhibition in the trained and untrained limb following unilateral leg strength training. Eur J Appl Physiol 112:3097–3107CrossRefPubMedGoogle Scholar
  42. Lee M, Gandevia SC, Carroll TJ (2009a) Unilateral strength training increases voluntary activation of the opposite untrained limb. Clin Neurophysiol 120:802–808CrossRefPubMedGoogle Scholar
  43. Lee M, Gandevia SC, Carroll TJ (2009b) Short-term strength training does not change cortical voluntary activation. Med Sci Sports Exerc 41:1452–1460CrossRefPubMedGoogle Scholar
  44. Lepley LK, Palmieri-Smith RM (2014) Cross-education strength and activation after eccentric exercise. J Athl Train 49:582–589CrossRefPubMedPubMedCentralGoogle Scholar
  45. Leung M, Rantalainen T, Teo WP, Kidgell D (2015) Motor cortex excitability is not differentially modulated following skill and strength training. Neuroscience 1:99–108CrossRefGoogle Scholar
  46. Lexell JE, Downham DY (2005) How to assess the reliability of measurements in rehabilitation. Am J Phys Med Rehabil 84:719–723CrossRefPubMedGoogle Scholar
  47. Magnus CR, Barss TS, Lanovaz JL, Farthing JP (2010) Effects of cross-education on the muscle after a period of unilateral limb immobilization using a shoulder sling and swathe. J Appl Physiol 109:1887–1894CrossRefPubMedGoogle Scholar
  48. Magnus CR, Arnold CM, Johnston G, Dal-Bello Haas V, Basran J, Krentz JR, Farthing JP (2013) Cross-education for improving strength and mobility after distal radius fractures: a randomized controlled trial. Arch Phys Med Rehabil 94:1247–1255CrossRefPubMedGoogle Scholar
  49. Manca A, Pisanu F, Ortu E, De Natale ER, Ginatempo F, Dragone D, Tolu E, Deriu F (2015a) A comprehensive assessment of the cross-training effect in ankle dorsiflexors of healthy subjects: a randomized controlled study. Gait Posture 42:1–6CrossRefPubMedGoogle Scholar
  50. Manca A, Solinas G, Dragone D, Dvir Z, Deriu F (2015b) Characterization of ankle dorsiflexors performance in healthy subjects following maximal-intensity isokinetic resistance training. J Electromyogr Kinesiol 25:773–781CrossRefPubMedGoogle Scholar
  51. Manca A, Cabboi MP, Ortu E, Ginatempo F, Dragone D, Zarbo IR, de Natale ER, Mureddu G, Bua G, Deriu F (2016a). Effect of contralateral strength training on muscle weakness in people with multiple sclerosis: proof-of-concept case series. Phys Ther 96:828–838CrossRefPubMedGoogle Scholar
  52. Manca A, Ginatempo F, Cabboi MP, Mercante B, Ortu E, Dragone D, De Natale ER, Dvir Z, Rothwell JC, Deriu F (2016b) No evidence of neural adaptations following chronic unilateral isometric training of the intrinsic muscles of the hand: a randomized controlled study. Eur J Appl Physiol 116:1993–2005CrossRefPubMedGoogle Scholar
  53. Manca A, Cabboi MP, Dragone D, Ginatempo F, Ortu E, De Natale ER, Mercante B, Mureddu G, Bua G, Deriu F (2017) Resistance training for muscle weakness in multiple sclerosis: direct versus contralateral approach in individuals with ankle dorsiflexors’ disparity in strength. Arch Phys Med Rehabil. doi: 10.1016/j.apmr.2017.02.019 (Epub ahead of print) Google Scholar
  54. Meyers CR (1967) Effects of two isometric routines on strength, size, and endurance in exercised and nonexercised arms. Res Q 38:430–440PubMedGoogle Scholar
  55. Munn J, Herbert RD, Gandevia SC (2004) Contralateral effects of unilateral resistance training: a meta-analysis. J Appl Physiol 96:1861–1866CrossRefPubMedGoogle Scholar
  56. Munn J, Herbert RD, Hancock MJ, Gandevia SC (2005) Training with unilateral resistance exercise increases contralateral strength. J Appl Physiol 99:1880–1884CrossRefPubMedGoogle Scholar
  57. Palmer HS, Håberg AK, Fimland MS, Solstad GM, Moe Iversen V, Hoff J, Helgerud J, Eikenes L (2013) Structural brain changes after 4 wk of unilateral strength training of the lower limb. J Appl Physiol 15:167–175CrossRefGoogle Scholar
  58. Papandreou M, Billis E, Papathanasiou G, Spyropoulos P, Papaioannou N (2013) Cross-exercise on quadriceps deficit after ACL reconstruction. J Knee Surg 26:51–58PubMedGoogle Scholar
  59. Pearce AJ, Hendy A, Bowen WA, Kidgell DJ (2013) Corticospinal adaptations and strength maintenance in the immobilized arm following 3 weeks unilateral strength training. Scand J Med Sci Sports 23:740–748CrossRefPubMedGoogle Scholar
  60. Sariyildiz M, Karacan I, Rezvani A, Ergin O, Cidem M (2011) Cross-education of muscle strength: cross-training effects are not confined to untrained contralateral homologous muscle. Scand J Med Sci Sports 21:359–364CrossRefGoogle Scholar
  61. Scripture EW, Smith TL, Brown EM (1894) On the education of muscular control and power. Stud Yale Psycol Lab 2:114–119Google Scholar
  62. Shaver LG (1970) Effects of training on relative muscular endurance in ipsilateral and contralateral arms. Med Sci Sports 2:165–171PubMedGoogle Scholar
  63. Shaver LG (1975) Cross transfer effects of conditioning and deconditioning on muscular strength. Ergonomics 18:9–16CrossRefPubMedGoogle Scholar
  64. Shima N, Ishida K, Katayama K, Morotome Y, Sato Y, Miyamura M (2002) Cross education of muscular strength during unilateral resistance training and detraining. Eur J Appl Physiol 86:287–294CrossRefPubMedGoogle Scholar
  65. Uh B, Beynnon BD, Helie BV, Alosa DM, Renstrom PA (2000) The benefit of a single-leg strength training program for the muscles around the untrained ankle: a prospective, randomized, controlled study. Am J Sports Med 28:568–573CrossRefPubMedGoogle Scholar
  66. van Middelkoop M, Rubinstein SM, Kuijpers T, Verhagen AP, Ostelo R, Koes BW, van Tulder MW (2011) A systematic review on the effectiveness of physical and rehabilitation interventions for chronic non-specific low back pain. Eur Spine J 20:19–39CrossRefPubMedGoogle Scholar
  67. Weir JP, Housh DJ, Housh TJ, Weir LL (1995) The effect of unilateral eccentric weight training and detraining on joint angle specificity, cross-training, and the bilateral deficit. J Orthop Sports Phys Ther 22:207–215CrossRefPubMedGoogle Scholar
  68. Weir JP, Housh DJ, Housh TJ, Weir LL (1997) The effect of unilateral concentric weight training and detraining on joint angle specificity, cross-training, and the bilateral deficit. J Orthop Sports Phys Ther 25:264–270CrossRefPubMedGoogle Scholar
  69. Yue G, Cole KJ (1992) Strength increases from the motor program: comparison of training with maximal voluntary and imagined muscle contractions. J Neurophysiol 67:1114–1123PubMedGoogle Scholar
  70. Zhou S (2000) Chronic neural adaptations to unilateral exercise: mechanisms of cross education. Exerc Sport Sci Rev 28:177–184PubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Department of Biomedical SciencesUniversity of SassariSassariItaly
  2. 2.Department of Physical Therapy, Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael

Personalised recommendations