Do hand exercises influence physiological hand tremor?

Purpose: Physiological hand tremor appears to be one of the most common types of tremors that occurs during lifespan. Activities most prominently affected by hand tremor are those involving the movement of small muscles, such as fine motor skills which in turn could be influenced from several factors, including lateral dominance. The difference in skills due to the lateral dominance is defined as interlimb imbalance or inter-limb asymmetry. When this asymmetry is attributed to the tremor and to the difference in tremor between the limbs, it could be defined as inter-limb asymmetry of tremor. This study aimed to evaluate the acute effects wobble board hand exercise training on inter-limb asymmetry of tremor. Methods: Thirty-two (18 male and 14 female) participants (age: 25.2 ± 2.6 years, weight: 63.9 ± 10.5 kg, height: 1.66 ± 0.8 m, BMI: 22.8 ± 2.3 kg/m2) were involved in the study. Before (PRE) and after (POST) the wobble board hand exercise, postural hand tremor was evaluated using a tri-axial accelerometer fixed under the palm. Recordings were taken for 15 s. One-way Analysis of Variance (ANOVA) was used to examine the effects of hand exercises on interlimb (dominant vs non- dominant) asymmetry of tremor in testing time (PRE vs POST) in relation to sex (male vs female). The statistical significance was set at p\0.05. Results: Significant differences were found in physiological hand tremor between limbs (dominant vs non-dominant) in PRE evaluation (p = 0.03) independently from sex while no differences were found in POST evaluation. A significant difference emerged in PRE evaluation for male (p = 0.04) and female (p = 0.03) in relationship with testing time and preferred hand. This difference was no longer present in POST evaluation. Conclusion: In conclusion, wobble board hand exercise could represent an effective strategy to reduce inter-limb asymmetry. These results emphasize the importance of task specific training to maximize the reduction of inter-limb asymmetry of tremor following wobble board hand exercise.