Cross Education Training (CET)
What is cross education training (CET)?
Cross education training (CET) is unilateral strength training completed with the intention of increasing or maintain strength in the untrained contralateral limb. An example of this would be in lower limb rehab where the injured leg is immobilised. The concept was first reported in 1858 but has become a more common practice within exercised based rehab in the last two decades. The exact mechanisms that underpin CET are unclear, but it is believed that there is a neural component.
What populations can benefit from CET?
Research has demonstrated CE can assist in preserving, promoting and/or restoring strength and motor function in several populations including:
Unilateral limb fractures
Post-surgical musculoligamentous injury rehabilitation
Post Arthroplasty
Hemiplegic stroke survivors
Below elbow amputees with prosthesis
Muscle weakness in MS and OA
Potential benefits of CET supported by research
Up to a 50% increase in the strength of the untrained limb.
Improvement in fine and gross motor skills.
Attenuation of post injury decline in strength.
ACL specific literature reports halving the decline in affect limb strength over a 10-week period (30% vs 16%)
Key points to consider
Cross transfer does not work for muscular endurance or hypertrophy training protocols.
Strength training protocols are the preferred training method (high load, low reps).
Clear link between CET and recruitment of fast twitch muscle fibres.
As close to maximal contraction as possible produces better results.
Dynamic movements are preferred but eccentric and isometric contractions have also been shown to be effective.
Transfer effect occurs in contralateral limbs (e.g. leg-leg not arm-leg).
Optimal dose for CET
Dynamic movements preferred.
Minimum 300-400 reps over a training block (approx. 8 weeks or 50 reps per week).
High load, low reps (3-5 sets, 3-5 reps, 5RM Intensity).
Allow adequate rest between sets (1.5mins)
Exercises that isolate muscle groups (e.g. knee extension) are preferred over compound movements (e.g. leg press).
Long muscle lengths are preferred for isometric exercises.
Bonus content: How do we conduct a 5RM test to set the correct intensity for CET?
Start at estimate 50% 5RM. Consider that people often underestimate their 5RM, especially if they have limited training experience.
Perform a couple a warm-up sets with small increments for each warm-up set.
Allow a 2-3min rest before commencing working sets.
Increase weight to desired starting weight (close to estimated 5RM) and commence working sets, aim to achieve 5RM in 3-4 working sets
Allow minimum 1.5mins between working sets
Max weight achieve for a full set of 5 reps in the clients 5RM