Abstract Information 
Abstract ID
20260132
Category
Sports Medicine: Epidemiology and Injury Prevention
Preferable Presentation
Both
Title
INSUFFICIENT TAPERING AND WORKLOAD SPIKES AS PREDICTORS OF GRADE I HAMSTRING STRAIN INJURIES: A LONGITUDINAL LEAD-UP ANALYSIS IN ELITE ATHLETES
Author
  • Full Name: PUWAPONG NIMKINGRATANA
  • Affiliation/Institution: Department of Orthopedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
  • Country: Thailand
  • Full Name: NONTAPAT KHAMPIN
  • Affiliation/Institution: Medical Department, Lamphun Warrior Football Club, Lamphun, Thailand
  • Country: Thailand
  • Full Name: GAN GITILUE
  • Affiliation/Institution: Medical Department, Lamphun Warrior Football Club, Lamphun, Thailand
  • Country: Thailand
  • Full Name: WORRAWAT THANANCHAI
  • Affiliation/Institution: Medical Department, Lamphun Warrior Football Club, Lamphun, Thailand
  • Country: Thailand
  • Full Name: NUTTASIT CHAISANG
  • Affiliation/Institution: Medical Department, Lamphun Warrior Football Club, Lamphun, Thailand
  • Country: Thailand
  • Full Name: TANACHOTE CHUMCHUEN
  • Affiliation/Institution: Medical Department, Lamphun Warrior Football Club, Lamphun, Thailand
  • Country: Thailand
  • Full Name: NATTAPONG PONGNIKORN
  • Affiliation/Institution: Medical Department, Lamphun Warrior Football Club, Lamphun, Thailand
  • Country: Thailand
  • Full Name: THANAT KANTHAWANG
  • Affiliation/Institution: Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
  • Country: Thailand
  • Full Name: NUTTAYA PATTAMAPASPONG
  • Affiliation/Institution: Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
  • Country: Thailand
  • Full Name: PICHITCHAI ATTHAKOMOL
  • Affiliation/Institution: Department of Orthopedics, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
  • Country: Thailand
Presenter
NONTAPAT KHAMPIN
Abstract
Background: Hamstring strain injuries (HSIs) often occur during competition or high-intensity training sessions. While absolute workload is a known risk factor, the role of "taper failure"—the inability to sufficiently reduce intensity in the 24–48 hours preceding a match—remains a critical but under-researched area in elite sports medicine.
Objective: To analyze the 10-day longitudinal workload profile leading up to Grade I HSIs and determine if insufficient tapering and injury-day workload spikes predict the subsequent return-to-play (RTP) duration.

Study Design & Methods: A retrospective longitudinal study analyzed 28 professional athletes (Grade I: n=15; Grade II: n=13). GPS-derived High Metabolic Load (HML) distance and Acute: Chronic Workload Ratios (ACWR) were tracked for the 10 sessions preceding the injury (MD-9 to MD-0). Tapering efficiency was calculated as the ratio of MD-1 intensity to the preceding 3-day average. Pearson correlations were used to assess the relationship between injury-day spikes and RTP weeks.

Results: Athletes sustaining Grade I injuries exhibited a clear "Taper Failure" pattern, characterized by an average ACWR of 1.41±0.85on the day before injury (MD-1), significantly exceeding the recommended 1.3 risk threshold. In the three days preceding the injury, Grade I players were twice as likely to experience a workload spike compared to Grade II players (30.3% vs 14.3%). Furthermore, for Grade I injuries, the magnitude of the workload spike on the injury day (MD-0) was a statistically significant predictor of recovery duration (r = 0.64, p = 0.034).

Conclusions: Grade I hamstring injuries are primarily driven by relative loading errors and poor tapering strategies. The "rebound spike" in intensity on MD-1 suggests that these athletes enter competition in a state of relative overreach, increasing tissue vulnerability. Because the magnitude of the spike directly dictates the RTP timeline (p < 0.05), monitoring ACWR during the tapering window is essential for both injury prevention and accurate clinical prognosis.
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