Intermanual Transfer Effects on Performance Gain Following Dominant Hand Training in Community-Dwelling Healthy Adults: A Preliminary Study

Twelve Weeks of Web-Based Low to Moderate Physical Activity Breaks with Coordinative Exercises at the Workplace Increase Motor Skills but Not Motor Abilities in Office Workers-A Randomised Controlled Pilot Study

Integrating physical activity interventions at the workplace can have positive effects on the employees' health. This study aimed to evaluate a physical activity break with coordinative exercises (PAB) including juggling and balance tasks and to assess its effects on motor abilities. Thirty-two university employees were randomly allocated to an intervention (IG:20) or a control (CG:12) group. The IG participated two times per week for 12 weeks in a PAB with a duration of 15 to 20 min. We measured the unimanual, bimanual finger, and hand dexterity with the Purdue Pegboard Test, the reaction time with the Fall Stick Test, and the dynamic balance with the Y Balance Test. Juggling performance was assessed by measuring the time(s) of performing a three-ball-cascade. Furthermore, an evaluation of the PAB was executed. Participants in the IG improved their juggling performance after six and twelve weeks. These increases were significantly different compared to the CG. However, no other parameters changed significantly. The evaluation showed that the PAB was enjoyable and led to subjective improvements in the participants health and working routine. To conclude, PAB can lead to improvements in juggling performance, subjective health, and the working routine.

tDCS over the primary motor cortex contralateral to the trained hand enhances cross-limb transfer in older adults

Transferring a unimanual motor skill to the untrained hand, a phenomenon known as cross-limb transfer, was shown to deteriorate as a function of age. While transcranial direct current stimulation (tDCS) ipsilateral to the trained hand facilitated cross-limb transfer in older adults, little is known about the contribution of the contralateral hemisphere to cross-limb transfer. In the present study, we investigated whether tDCS facilitates cross-limb transfer in older adults when applied over the motor cortex (M1) contralateral to the trained hand. Furthermore, the study aimed at investigating short-term recovery of tDCS-associated cross-limb transfer. In a randomized, double-blinded, sham-controlled setting, 30 older adults (67.0 ± 4.6 years, 15 female) performed a short grooved-pegboard training using their left hand, while anodal (a-tDCS) or sham-tDCS (s-tDCS) was applied over right M1 for 20 min. Left (LH_trained) - and right-hand (RH_untrained) performance was tested before and after training and in three recovery measures 15, 30 and 45 min after training. LH_trained performance improved during both a-tDCS and s-tDCS and improvements persisted during recovery measures for at least 45 min. RH_untrained performance improved only following a-tDCS but not after s-tDCS and outlasted the stimulation period for at least 45 min. Together, these data indicate that tDCS over the M1 contralateral to the trained limb is capable of enhancing cross-limb transfer in older adults, thus showing that cross-limb transfer is mediated not only by increased bi-hemispheric activation.

Impact of handedness on interlimb transfer depending on the task complexity combined with motor and cognitive skills

PURPOSE

Task complexity could affect acquisition efficiency of motor skills and interlimb transfer; however, how task complexity affects interlimb transfer remains unclear. We hypothesized that left- and right-handed participants may have different interlimb transfer efficiency depending on the task complexity.

METHODS

Left-hand (n = 28) and right-hand (n = 28) dominant participants (age = 24.70 ± 4.02 years, male:female = 28:28) performed a finger sequence test with two levels of complexity (simple: one-digit with four fingers vs. complex: two-digit with five fingers) before and after ten trials of 2-min practice each on the same apparatus. The speed and task errors were measured and analyzed.

RESULTS

Right-handed participants failed to improve performance on their right hand (non-trained hand) after contralateral left-hand practice in the simple finger sequence task. In contrast, the left-handed participants improved performance on non-trained hands both right and left after contralateral practices. In the complex task, however, both the left- and right-handed participants improved performance on non-trained hands by contralateral practices.

CONCLUSION

Our results showed that task complexity of skilled practice gave different effects on interlimb transfer between right- and left-handed subjects. It appears that a certain level of appropriate complexity is necessary to detect inter-limb transfers in motor learning in right-handed subjects.