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Biceps activity during windmill softball pitching: injury implications and comparison with overhand throwing
Idubijes L Rojas1, Matthew T Provencher, Sanjeev Bhatia
1Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL 60612, USA.
The American Journal of Sports Medicine
|January 29, 2009
Summary
Female windmill pitchers show greater biceps muscle activity compared to overhand throwing. This increased activity, particularly eccentric contractions during the 9-o'clock phase, may contribute to shoulder injuries in athletes.
Area of Science:
- Biomechanics of pitching
- Sports medicine
- Exercise physiology
Background:
- Windmill pitching involves high shoulder and elbow forces, increasing injury risk.
- The biceps labrum complex is susceptible to overuse injuries in windmill pitchers.
- Muscle firing patterns during windmill pitching are not well understood.
Purpose of the Study:
- To compare biceps muscle activity between windmill and overhand throwing in female athletes.
- To identify specific phases of the windmill pitch with maximal biceps activation.
Main Methods:
- Descriptive laboratory study involving seven female windmill pitchers.
- Simultaneous motion analysis and surface electromyography (sEMG) of biceps muscles.
- Comparison of sEMG data during windmill and overhand throws, analyzed by pitching phase.
Main Results:
- Biceps brachii peak activation was significantly higher during windmill pitching (38% MMT) versus overhand throwing (19% MMT).
- Highest biceps activity occurred during the 9-o'clock phase (eccentric contraction) in windmill pitching.
- Overhand throwing showed peak biceps activity during the arm cocking phase.
Conclusions:
- Biceps brachii activity is significantly greater in windmill pitchers than in overhand throwers.
- The 9-o'clock and follow-through phases exhibit the highest biceps activity in windmill pitching.
- Repetitive eccentric biceps contractions may explain anterior shoulder pain in elite windmill pitchers, suggesting targeted injury prevention strategies.
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