Effect of long-toss throwing on elbow injuries in high school baseball pitchers

Long-toss throwing is a common practice in baseball for arm strengthening, arm recovery, and as part of an interval throwing program after elbow surgery. However, the effect of long-toss throwing on the throwing elbow remains controversial, with limited studies. Different long-toss techniques, such as using a crow-hop and varying the throw trajectory, may influence elbow stress and injury risk. This study investigated the association between long-toss distance, technique, and subjective elbow symptoms and clinical findings among high school baseball pitchers.

The objective of this study was to determine whether subjective elbow symptoms and clinical findings were associated with long-toss throwing techniques in high school baseball pitchers. We hypothesized that longer distances and specific techniques correlate with a higher incidence of elbow symptoms and clinical findings on physical examination and ultrasound.

One hundred eighty-two high school baseball pitchers from 49 schools participated in the study. After excluding two players who did not routinely use long-toss, 180 pitchers (mean age 16.2 ± 0.6 years, mean baseball experience 8.1 ± 1.8 years) completed a thorough history, physical examination, and elbow ultrasound examination. The history collected demographical data, elbow pain within the past year, and long-toss techniques (distance, use of crow-hop, and throw trajectory). Physical examination assessed medial, lateral, and posterior-sided elbow tenderness, moving valgus stress test, and extension stress tests. Ultrasound examination evaluated for abnormalities of the medial epicondyle, ulnar collateral ligament (UCL), and coronoid. Statistical analyses assessed the relationship between long-toss, positive clinical findings, and subjective elbow symptoms.

The mean long-toss distance was 67.0 m, with 75 m being the most common distance. Among the pitchers, 75 % used a crow-hop, and 58 % used a "not on a line" trajectory. Sixty-six pitchers (37 %) reported elbow pain within the past year. The mean long-toss distance was significantly longer for pitchers using a crow-hop, 68.8 m and a "not on a line" trajectory, 72.8 m compared to those not using these techniques, 61.8 m (p = 0.006) and 59.1 m (p < 0.001). Longer distances were associated with positive moving valgus stress tests (p = 0.041, cut-off = 82.8 m, Odds ratio (OR) = 3.4) and UCL abnormalities on ultrasound (p = 0.019, cut-off = 65.0 m, OR = 4.6). The use of a crow-hop was significantly associated with elbow pain within the past year (42 % vs. 20 %, adjusted p = 0.018, adjusted OR = 2.8), and a "not on a line" trajectory was linked to higher UCL abnormalities (14 % vs. 1 %, adjusted p = 0.039, adjusted OR = 10.7).

This study demonstrates a significant association between long-toss throwing practices, elbow symptoms, and clinical findings in high school baseball pitchers. Greater long-toss distances, the use of a crow-hop, and a "not on a line" trajectory appear associated with greater elbow stress and a higher prevalence of UCL abnormalities. These findings underscore the need for training programs that consider the mechanical loads placed on the elbow during long-toss throwing with particular techniques.

Descriptive epidemiology study.