Background: Windmill pitching produces high forces and torques at the shoulder and elbow, making the biceps labrum complex susceptible to overuse injury. Little is known about the muscle firing patterns during a windmill pitch. Hypothesis: Biceps muscle activity is greater during a windmill pitch than during an overhand throw. Study Design: Descriptive laboratory study. Methods: Seven female windmill pitchers underwent motion analysis and surface electromyography evaluation of their biceps muscles during windmill and overhand throwing. Marker motion analysis, muscle activity, and ball release were captured simultaneously. Surface electromyography trials were collected and related to the athletes’ phases of pitching and throwing, identified based on predefined softball and baseball pitching mechanics. Results: Throws were of similar velocity (24 m/s, 53 mph, P =. 71), but peak biceps brachii muscle activation during the windmill pitch was significantly greater than during the overhand throw when normalized (38% vs 19% manual muscle test, P =. 02). The highest muscle activity occurred at the 9-o'clock phase of the windmill pitch, during which the biceps brachii undergoes eccentric contraction. In the overhand throw, the highest level of biceps activity occurred during arm cocking. Conclusion: In female athletes, biceps brachii activity during the windmill pitch is higher than during an overhand throw and is most active during the 9-o'clock and follow-through phases of the pitch. Clinical Relevance: Repetitive eccentric biceps contractions may help explain the high incidence of anterior shoulder pain clinically observed in elite windmill pitchers. Injury prevention and treatment mechanisms should focus on the phases with the highest muscle activity.

Objective: Elevated joint loads during walking have been associated with the severity and progression of osteoarthritis (OA) of the knee. Footwear may have the potential to alter these loads. This study compares the effects of several common shoe types on knee loading in subjects with OA of the knee.Methods: Thirty‐one subjects (10 men, 21 women) with radiographic and symptomatic knee OA underwent gait analyses using an optoelectronic camera system and multicomponent force plate. In each case, gait was evaluated during barefoot walking and while wearing 4 different shoe types: 1) clogs, 2) stability shoes, 3) flat walking shoes, and 4) flip‐flops. Peak knee loads were compared between the different footwear conditions.Results: Overall, the clogs and stability shoes resulted in a significantly higher (∼15% higher) peak knee adduction moment (mean ± SD 3.1 ± 0.7 and 3.0 ± 0.7 divided by body weight [BW] × height [H] multiplied by 100, respectively; P < 0.05) compared with that of flat walking shoes (mean ± SD 2.8 ± 0.7 %BW × H), flip‐flops (mean ± SD 2.7 ± 0.8 %BW × H), and barefoot walking (mean ± SD 2.7 ± 0.7 %BW × H). There were no statistically significant differences in knee loads with the flat walking shoes and flip‐flops compared with barefoot walking.Conclusion: These data confirm that footwear may have significant effects on knee loads during walking in subjects with OA of the knee. Flexibility and heel height may be important differentiating characteristics of shoes that affect knee loads. In light of the strong relationship between knee loading and OA, the design and biomechanical effects of modern footwear should be more closely evaluated in terms of their effects on the disease.