Decrease in pressure pain thresholds of latent myofascial trigger points in the middle finger extensors immediately after continuous piano practice

Objectives: This study is designed to investigate the change of the pressure pain threshold [PPT] of latent myofascial trigger points [MTrPs], immediately after rapid repetitive contraction of the involved muscle. Methods: Forty 8-19 year-old students who had taken piano lessons for longer than one year. Three consecutive measurements of PPT were obtained on the latent MTrPs of bilateral extensor digitorium communis muscles 20 minutes before, immediately before, immediately after, and 20 minutes after continuous piano practice of fast music pieces for 20 minutes. Results: Mean pain threshold was significantly [P < 0.01] reduced immediately after piano practice, and returned to original value 20 minutes after practice. There was no statistically significant difference between the mean value of 20 minutes before practice and immediately before practice [control values]. There was no significant difference between the right and the left hands. Age and experience were not significantly correlated with the changes of pain threshold. Conclusion: A latent MTrP in a muscle may increase the irritability after rapid repetitive use [over loading of that muscle]. Usually, this change is a temporary phenomenon after an adequate rest period. Therefore, adequate rest may be important to reduce the probability in the development of an active MTrP.