Physiologic and Psychological Measurements of Performance Stress and Onset of Injuries in Professional Ballet Dancers

M. Liederbach, M.S., A.T.C., G.W. Gleim, Ph.D., J.A. Nicholas, M.D.

From the Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, New York

Urinary excretion of free norepinephrine (NE) and epinephrine (E) was measured and mood states and onset of injury were assessed over 5 weeks of an intensive ballet season. First morning voids were collected at the start of the season and after the only off-day of each week, with final collection on the last day of the season. Profile of Mood States (POMS) questionnaires were completed by each dancer at the same time that the morning urine samples were taken. Injury records were kept by the company's certified athletic trainer throughout the season. NE and E excretions (ng/mg creatinine) increased significantly with time from beginning to end of the season (r = 0.91, p <0.02, and r = 0.94, p <0.01, respectively). From week 1 to week 4 POMS ratings of fatigue/inertia increased from 8.2 +/- 1.4 to 16.1 +/- 1.9 (p = 0.009), whereas ratings of vigor/activity decreased from 17.1 +/- 1.7 to 13.2 +/- 1.2 (p = 0.02). Injury rate, as calculated by Kaplan-Meier time-injury analysis, was 66% by week 4. Adaptations to psychological and physiologic stress, as measured by urinary catecholamines and POMS, occurred in the studied population over the course of a performance season and coincided with time of onset of injury.

Med Probl Perform Art 9:1-14, 1994.