Arterial Compliance is Positively associated with Shoulder Muscle Strength in Tai Chi Qigong-Trained Survivors of Nasopharyngeal Cancer: a Pilot Study

Objective: The aim of this pilot study was to explore the association between arterial compliance and shoulder rotator muscle strength in Tai Chi (TC) Qigong-trained survivors of Nasopharyngeal Cancer (NPC). Methods: Thirteen survivors of NPC (mean age ±SD=55.3±6.8years; five males and eight females) who had more than 1 month of TC Qigong experience participated in the study. The maximum isometric muscle strength of the internal and external rotators in the shoulder of the dominant arm was measured using the Lafayette Manual Muscle Test System with standardized measurement procedures and dynamometer placements. Arterial compliance, represented by large and small artery elasticity indices, was measured using an HDI Pulse Wave CR-2000 Research Cardiovascular Profiling System. Pearson's r was used to determine the degree of association between the artery elasticity indices and the outcomes of the shoulder muscle strength measurements. Results: In TC Qigong-trained survivors of NPC, a large artery elasticity index was highly and positively associated with muscle strength in the internal rotator (r=0.580, p=0.038) and external rotator (r=0.758, p=0.003) of the shoulder. A small artery elasticity index was also highly and positively associated with muscle strength in the external rotator of the shoulder (r=0.814, p=0.001) but not the internal rotator (r=0.388, p=0.190). Conclusion: Arterial compliance was positively associated with shoulder muscle strength in TC Qigong-trained survivors of NPC. Our results suggest that arterial compliance might not be jeopardized by increased muscular strength due to practicing TC Qigong.