Author(s): WILCZYNSKI, B., MACHALEWSKI, D., ZORENA, K., Institution: MEDICAL UNIVERSITY OF GDAŃSK, Country: POLAND, Abstract-ID: 681

INTRODUCTION:
Time-under-tension provocation tests can reproduce symptoms and track change in adolescent knee pain, but the feasibility and symptom provocation profile of static versus dynamic tasks in Osgood-Schlatter disease (OSD) remains unclear. We evaluated pain responses and task tolerability during a standardized functional battery performed in a real-world club settings.
METHODS:
The dataset comprised 231 trials; 196 were completed (84.8%). Overall, 35 trials (15.2%) were interrupted (22 due to pain, 13 due to technical difficulties). Baseline KOOS-Child scores were generally high, but lower for Sport/Rec (76.8 +/- 15.4) and knee-related QoL (62.8 +/- 19.0); mean EQ VAS was 80.1 +/- 13.0. Dynamic tasks (132 trials) showed low pain and very low interruption: median NRS 0.0 (IQR 0.0-3.0), pain interruptions 2/132 (1.5%), technical interruptions 0/132 (0%). Isometric tasks (99 trials) showed higher pain and higher interruption: median NRS 1.0 (IQR 0.0-5.75), pain interruptions 20/99 (20.2%), technical interruptions 13/99 (13.1%). Isometric tasks were associated with higher NRS than dynamic tasks (beta = 0.993, 95% CI 0.137 to 1.850). The odds of pain interruption were higher for isometric versus dynamic tasks (OR = 19.70, 95% CI 2.50 to 155.03); absolute risk difference 21.7 percentage points (cluster bootstrap 95% CI 7.2 to 38.2). Task-specific summaries indicated single-leg wall-sit as the main driver of interruptions (pain interruptions 34.0%; technical interruptions 27.1%), while CMJ and hop had 0% interruptions.
RESULTS:
The dataset comprised 231 trials; 196 were completed (84.8%). Overall, 35 trials (15.2%) were interrupted (22 due to pain, 13 due to technical difficulties). Dynamic tasks (132 trials) showed low pain and very low interruption: median NRS 0.0 (IQR 0.0-3.0), pain interruptions 2/132 (1.5%), technical interruptions 0/132 (0%). Isometric tasks (99 trials) showed higher pain and higher interruption: median NRS 1.0 (IQR 0.0-5.75), pain interruptions 20/99 (20.2%), technical interruptions 13/99 (13.1%). Isometric tasks were associated with higher NRS than dynamic tasks (beta = 0.993, 95% CI 0.137 to 1.850). The odds of pain interruption were higher for isometric versus dynamic tasks (OR = 19.70, 95% CI 2.50 to 155.03); absolute risk difference 21.7 percentage points (cluster bootstrap 95% CI 7.2 to 38.2). Task-specific summaries indicated single-leg wall-sit as the main driver of interruptions (pain interruptions 34.0%; technical interruptions 27.1%), while CMJ and hop had 0% interruptions.
CONCLUSION:
Isometric wall-sit type tasks were less tolerable and more likely to be interrupted due to pain than dynamic tasks, whereas CMJ and hop were consistently completed without interruption. These preliminary findings suggest sustained static holds may be poorly tolerated in earlier-stage OSD and should be used cautiously as provocation or early rehabilitation tasks, pending confirmation in larger controlled studies.