A recent articleMagic for Stroke Patients: The One-Sided Workout, by Christopher Wanjek, LiveScience Bad Medicine Columnist | LiveScience.com – Thu, Dec 20, 2012, discussed cross-education in strength training, with a focus on Stroke Victims.

Doctors have known for more than 100 years that short-term, high-intensity resistance training on one side of the body causes some degree of strength gain in the contralateral, untrained limb — for example, the left leg when only the right leg is exercised. The phenomenon is called cross-education, and the strength gain in the untrained limb is up to half of what it is in the trained limb.

No study has applied cross-education after stroke, said Zehr and his co-author, Katie Dragert, who recently completed her doctoral degree in Zehr’s lab. So they applied cross-education to 19 stroke sufferers who, on average, had experienced a debilitating stroke 80 months before the study.

The study focused on the legs and ankles with an eye toward walking recovery. The participants spent six weeks rigorously exercising their less-affected ankle dorsiflexors, the muscles that flex the foot and enable natural walking. The training was in 25-minute sessions three times weekly.

To their surprise, the scientists found equivalent strength gains in both legs, about 30 percent. Four participants who were barely able to flex their feet on their more-affected side before training could do so post-intervention.

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Zehr said the initial strength gains found in the four to six weeks after people start strength training are neurological adaptations, as the brain and nervous system create new connections to the muscles.

* * *

Zehr added that a group led by Jonathan Farthing at the University of Saskatchewan has performed complementary research in cross-education for limbs in casts, to prevent muscle atrophy in the immobilized limb.

So what is my take-a-way from this study?

  • The Therapists – in the very earliest of days – who said – “Do this motion with the unaffected side first – then the affected side” – had a good point but never carried it far enough.
  • The Therapists – in the later days – who said – “We’re going to work the hell out of the affected side.” Were missing the point.
  • My insistence on doing bilateral exercises was correct.
  • I’m going to push increasing the weights on my wife’s unaffected side.
  • I’ve learned some new exercises by searching on “ankle dorsiflexors” – my wife is not going to be happy – but hopefully her gait will improve.
  • The 6 month rule of thumb – often cited as the limit of recovery – is a stupid rule that undermines everyone’s – the patients,  the therapists and insurance companies’ willingness to work past that date.
  • Our bodies are strange and wonderful creations.
  • ETA:  We worked the ankle and wrist dorsiflexors this morning – need to make it more efficient and easier to use – but she can see the value.
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