This week I wanted to go back a bit to an article that discusses range of motion and body composition. Friesen et al. (2021) studied 147 female softball pitchers ranging from youth to young adult ages to see whether body mass index (BMI) was related to hip and shoulder range of motion. Each athlete’s height and weight were measured to calculate BMI, and pitchers were placed into four groups: underweight, normal weight, overweight, and obese. Using a handheld inclinometer, the researchers measured passive internal rotation (IR) and external rotation (ER) of both hips and both shoulders. All measurements were taken in standardized positions by the same examiner to improve consistency. A multivariate analysis of variance (MANOVA) was used to compare range of motion across BMI groups and determine whether BMI category affected hip and shoulder mobility.
They found:
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BMI significantly affected overall hip and shoulder range of motion, although effect sizes were small
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Hip internal rotation (IR) showed the clearest differences between BMI groups
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Pitchers in the underweight group had significantly more hip IR than pitchers in the obese group:
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Throwing-side hip IR: ~12° greater
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Glove-side hip IR: ~12° greater
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No statistically significant differences were found in shoulder range of motion after correcting for multiple comparisons
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Obese pitchers showed lower hip IR values overall, suggesting reduced lower-body mobility
Implications: The authors concluded that higher BMI is associated with reduced hip internal rotation in softball pitchers, which may negatively affect pitching mechanics. Because the hips play a major role in transferring energy through the body during the windmill pitch, limited hip motion could force pitchers to compensate with increased trunk rotation or upper-body effort. This may increase stress on the shoulder and arm over time. While shoulder range of motion did not differ significantly between BMI groups, the authors note that the hips are weight-bearing joints and may be more affected by excess body mass. The study suggests that body composition should be considered when evaluating movement quality and injury risk in pitchers. Coaches and medical staff may benefit from emphasizing conditioning, mobility, and healthy body composition to help maintain proper mechanics and reduce injury risk. The authors also note that BMI has limitations as a measure and recommend future studies using body-fat percentage and direct pitching biomechanics.
Also…
I had a conversation a few weeks ago with a HS softball coach that was transitioning from one strength coach to a new, less receptive strength coach. Last year I presented basic softball strength and conditioning at a coach’s clinic and at some point, I am planning on creating a master class to help HS coaches with these issues. I know there are time constraints, communication issues and maybe a lack of confidence to have these conversations with strength coaches that are likely specialists in a totally different sport. The answer is education. Here is a good post about what HS strength by Jake Lewis. Check it out. And, let me know if a class like that could be beneficial.
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