Investigation of the affecting factors of hand grip strength-related upper extremity functionality after breast cancer surgery

This study was planned to investigate the effects of age, fatigue, subjective reported upper extremity function and physical inactivity parameters on hand grip strength related upper extremity function (HGSRUEf) in individuals who underwent breast cancer surgery. Investigating the mediator effects of sitting time,fatigue, and perceived barrier level towards exercise on HGSRUEf was planned as secondary purpose. 111 individuals were included in this study. Hand grip strength was evaluated with dynamometer, pain threshold and tolerance with algometer, shoulder muscle strength with digital dynamometer, fatigue with Fatigue Severity Scale, sitting time with International Physical Activity Questionnaire Short Form's 7th question, exercise beliefs/barriers with Exercise Benefits/Barriers Scale, subjective reported upper extremity function with Disabilities of Arm, Shoulder and Hand (DASH) questionnaire were evaluated. Significant predictive effects of age, sitting time and DASH on HGSRUEf (F(1,107)=12.057, R2=0.28, p<0.001) were found. No significant difference was found between right and left sides' shoulder muscle strengths in dominant side surgery (p>0.05) compared to those non-dominant side surgery while significant difference was found who had surgery in their non-dominant side in favor of their non-surgical side (p<0.001). Fatigue and function (r=0.475, p<0.001), age and sitting time (r=0.223, p=0.014) were found correlated. Significant mediating effect of sitting time on the effect of age on HGSRUEf (p=0.028), indirect effect of fatigue on HGSRUEf via the mediation effect of DASH were found significant (p=0.002). Pain tolerance were significantly lower on upper trapezius muscle proximal (p<0.001) and midline (p=0.021) points in surgical side compared to unaffected side. This study showed that the evaluation of hand grip strength for determining direct and indirect effects of upper extremity functionality after breast cancer surgery, and the structural equation model that examines these effects is compatible with the clinic. We offer to investigate the long-term consequences of the effect of physical inactivity on hand grip strength-related function.