Fear of pain influences outcomes after exercise-induced delayed onset muscle soreness at the shoulder.

OBJECTIVES: This study investigated whether anxiety, fear of pain, or pain catastrophizing were predictive of pain-related outcomes after induced delayed onset muscle soreness (DOMS) at the shoulder.
METHODS: Healthy participants (19 males and 23 females) were eligible for participation if they had (a) no history of neck or shoulder pain, (b) no sensory or motor impairments of the upper-extremity, (c) not regularly participating in upper-extremity weight training, (d) not currently or regularly taking pain medication, and (e) no history of upper-extremity surgery. Participants completed self-report measures for fear of pain, pain catastrophizing, and anxiety. Then, participants underwent a standard fatigue protocol to induce DOMS in the shoulder external rotator muscles. Participants were reassessed 24 hours after DOMS induction on clinical and evoked pressure pain reports, muscle force production, self-report of upper-extremity disability, and kinesiophobia. Stepwise regression models considered sex, anxiety, pain intensity, fear of pain, and pain catastrophizing as outcome predictors.
RESULTS: Fear of pain alone explained 16% (P=0.008) of the variance in clinical pain and 10% (P=0.047) evoked pressure pain intensity. Clinical pain intensity alone explained 11% (P<0.031) of the variance in muscle force production. Clinical pain intensity and fear of pain explained 50% (P<0.001) of the variance in upper-extremity disability, whereas fear of pain and sex accounted for 26% (P=0.005) of the variance in kinesiophobia.
CONCLUSIONS: With the exception of muscle force production, fear of pain had a consistent influence on shoulder DOMS outcomes, even after controlling for pain intensity. This study suggests fear of pain may be a relevant psychologic factor to consider in clinical studies investigating the development and treatment of chronic shoulder pain.