Does the MLB's collision at home plate rule change prevent concussion injuries in catchers?

Background: In 2013, appropriate conduct of both the catcher and baserunner at the home plate was outlined with the addition of rule 7.13. This new rule was mandated in order to protect athletes from 'egregious' collisions at the home plate. The aims of this study were to quantify the impact of the Collision at Home Plate rule on concussion rates among MLB catchers, and time spent on the DL with concussion symptoms, before and after rule 7.13 was officially enacted (2012-2013, 2015-2016). Hypothesis: We hypothesized that the rate of concussions suffered by MLB catchers would be significantly lower after the enactment of rule 7.13 and that there would be no significant difference in time spent on the DL between the two cohorts. Study design: Retrospective Cohort Level of evidence: Level 3 Methods: The data was compiled using publicly available information extracted from MLB transactions. All MLB catchers placed on the DL for a concussion injury from 2012 to 2013 and 2015 to 2016 were included in this study. Relative risk (with 95% CI) was calculated by using the number of injuries per 1,0000 athletic exposures for the 2 seasons under the rule change (2015-2016) versus the previous 2 seasons (2012-2013). Results: Among catchers the relative risk of concussion per 1000 athletic exposures was 0.31 (95% CI, 0.11-0.85) when comparing the 2 seasons after the introduction of rule 7.13 (2015, 2016) versus the 2 seasons before (2012, 2013). There was no significant statistical difference in average time catchers spent on the DL for concussion injuries when comparing the 2012 and 2013 seasons versus 2015 and 2016. Conclusions: The MLB's rule limiting home plate collisions significantly reduced the number of concussions suffered by MLB catchers. Clinical relevance: This study provides important insight regarding patterns and injury rates in professional baseball catchers and can serve as a benchmark for discussion about injury prevention in players of this position. To our knowledge, no other study has focused on rule 7.13 and its effect on concussion rates in MLB catchers.

Major League Baseball pace-of-play rules and their influence on predicted muscle fatigue during simulated baseball games.

Major League Baseball (MLB) has proposed rule changes to speed up baseball games. Reducing the time between pitches may impair recovery from fatigue. Fatigue is a known precursor to injury and may jeopardise joint stability. This study examined how fatigue accumulated during baseball games and how different pace of play initiatives may influence fatigue. Pitcher data were retrieved from a public database. A predictive model of muscle fatigue estimated muscle fatigue in 8 arm muscles. A self-selected pace (22.7 s), 12 s pace (Rule 8.04 from the MLB) and a 20 s rest (a pitch clock examined in the 2014 Arizona Fall League (AFL)) were examined. Significantly more muscle fatigue existed in both the AFL and Rule 8.04 conditions, when compared to the self-selected pace condition (5.01 ± 1.73%, 3.95 ± 1.20% and 3.70 ± 1.10% MVC force lost, respectively). Elevated levels of muscle fatigue are predicted in the flexor-pronator mass, which is responsible for providing elbow stability. Reduced effectiveness of the flexor-pronator mass may reduce the active contributions to joint rotational stiffness, increasing strain on the ulnar collateral ligament (UCL) and possibly increasing injury risk.

The later evolution of modern sport in Latin America: the North American influence.

American impact on modern sports in Latin America overlaps geographically and chronologically with the European, especially British, impact. Principally baseball in the Caribbean basin, more recently basketball and volleyball across the hemisphere and occasionally American football in more limited areas illustrate a north-to-south movement executed by businessmen, educators, missionaries, military personnel, returning travelers (often students), sports entrepreneurs and television. Often initially supported by promoters of development within Latin America, this transfer has altered local recreational patterns and attracted Latin athletes to pursue careers in North America, provoking accusations of cultural imperialism and exploitation.