(486) Changes in physical activity and its association with pain-related negative affect and pain sensitivity before and after exercise-induced low back pain

Abstract

This study examined changes in physical activity (PA) after exercise-induced delayed muscle soreness (DOMS) in healthy subjects. Additionally, we investigated the extent to which pain-related negative affect is associated with objective measures of PA, and the relationship between PA and measures of pain sensitivity. Thirty-seven pain-free volunteers (Females=22, age=24.6±5 y/o) participated. Subjects wore an activity monitor 12 hours/day for 10 days. PA variables used for analysis were total activity, mean activity counts per minute, and peak activity count. Subjects completed the fear of pain questionnaire and the pain catastrophizing scale. Pain sensitivity was measured using pressure pain threshold (PPT) and heat pain threshold and tolerance. DOMS was induced 5 days after baseline testing. Subjects were tested again 48 hours later and were asked to rate their worst pain experienced within the last 48 hours using the numeric rating scale (NRS). Pearson’s correlation moments were used to examine the association among variables of interest. Paired sample t-test compared levels of PA pre- and post-DOMS. Before DOMS total PA was associated only with fear (r=-0.389; p=0.017). Positive associations between total PA and PPT (r=0.527; p=0.001), heat pain threshold (r=0.452; p=0.005), and heat pain tolerance (r=0.319; p=0.054) were observed. After DOMS subjects reported pain of 24.1±21.7 on the NRS. Peak activity count decreased after DOMS from 9641±5229 to 7859±4571 (p=0.001) and mean activity counts decreased from 470.3±205.9 to 408.2±165.5 (p=0.003). Results from this study suggest that fear of pain but not catastrophizing is an important psychological factor that influences PA in healthy subjects. Additionally, higher levels of PA activity may enhance descending pain modulatory systems that could protect against pain conditions. Finally, PA intensity after DOMS was reduced as shown by a decrease in mean activity counts per minute and peak PA. This study examined changes in physical activity (PA) after exercise-induced delayed muscle soreness (DOMS) in healthy subjects. Additionally, we investigated the extent to which pain-related negative affect is associated with objective measures of PA, and the relationship between PA and measures of pain sensitivity. Thirty-seven pain-free volunteers (Females=22, age=24.6±5 y/o) participated. Subjects wore an activity monitor 12 hours/day for 10 days. PA variables used for analysis were total activity, mean activity counts per minute, and peak activity count. Subjects completed the fear of pain questionnaire and the pain catastrophizing scale. Pain sensitivity was measured using pressure pain threshold (PPT) and heat pain threshold and tolerance. DOMS was induced 5 days after baseline testing. Subjects were tested again 48 hours later and were asked to rate their worst pain experienced within the last 48 hours using the numeric rating scale (NRS). Pearson’s correlation moments were used to examine the association among variables of interest. Paired sample t-test compared levels of PA pre- and post-DOMS. Before DOMS total PA was associated only with fear (r=-0.389; p=0.017). Positive associations between total PA and PPT (r=0.527; p=0.001), heat pain threshold (r=0.452; p=0.005), and heat pain tolerance (r=0.319; p=0.054) were observed. After DOMS subjects reported pain of 24.1±21.7 on the NRS. Peak activity count decreased after DOMS from 9641±5229 to 7859±4571 (p=0.001) and mean activity counts decreased from 470.3±205.9 to 408.2±165.5 (p=0.003). Results from this study suggest that fear of pain but not catastrophizing is an important psychological factor that influences PA in healthy subjects. Additionally, higher levels of PA activity may enhance descending pain modulatory systems that could protect against pain conditions. Finally, PA intensity after DOMS was reduced as shown by a decrease in mean activity counts per minute and peak PA.