IPSILATERAL TRANSFER OF MOTOR SKILL FROM LOWER TO UPPER LIMB IN HEALTHY ADULTS: A RANDOMIZED CONTROLLED TRIAL

S. Frenkel-Toledo^1,2, N. Sherman¹, Z. Kozol¹, O. Elion¹

¹Ariel Univserity, Physiotherapy, Ariel, Israel, ²Loewenstein Rehabilitation Medical Center, Physiotherapy, Raanana, Israel

Background: Implementation of motor learning principles is essential for improving motor skill in healthy and people with neurological and orthopedic conditions. Training of upper limb (UL) can improve strength and motor skill of the contralateral untrained UL, which is termed contralateral transfer. While contralateral transfer has been extensively studied, very few studies have investigated ipsilateral transfer. Specifically, it is not known whether UL motor skill can be improved following the practice of that skill with the lower limb (LL).

Purpose: To investigate whether motor skill of the LL can be ipsilaterally transferred to the UL in healthy adults.

Methods: In a single-blind randomized controlled study, 45 healthy subjects randomly participated in one of three single session interventions: (1) Practicing reaching movement (RM) sequences (300 movements) with the non-dominant left LL towards illuminating switches (LL group); (2) Observing the same sequences of the illuminating switches (Switches Observation (SO) group); and (3) Observing nature movies (Nature Observation (NO) group). Each intervention lasted 10 minutes. Subjects’ ability to perform the RM sequences (60 movements) with the left UL as fast and accurate as possible towards the illuminating switches was tested before and immediately after the single session intervention, and retested after 24 h. All groups were instructed prior to the tests that the switches will light up in a fixed sequence. Response time of the RM sequences was measured.

Results: Response time of RM sequences with the left UL did not differ between groups in pretest; however, in the posttest it was shorter (improved) in the LL group compared to the SO and NO groups. In the retention test, response time was shorter only in the LL group compared to the NO group.

Conclusions: An ipsilateral transfer of RM sequences from the LL to the UL was found immediately following LL practice. It seems that the cognitive element embedded in the observation of the RM sequences improves UL performance of RM sequences as well; however, it is not as effective as the LL practice.

Implications: Ipsilateral transfer may serve as a novel strategy aimed to improve the functional outcome of an affected UL. It is particularly important in the case of UL movement since modalities for rehabilitation of the neurologically affected UL, such as following stroke, are generally of limited benefit.

Funding acknowledgements: This work was supported by a research award from Ariel University to author N.S.

Keywords:
Ipsilateral transfer
Upper limb
Motor learning

Topics:
Research methodology, knowledge translation & implementation science
Professional practice: other
Musculoskeletal: upper limb

Did this work require ethics approval? Yes

Institution: Ariel University

Committee: Ariel University Institutional Ethical Board

Ethics number: AU-HEA-OE-20210610