August 2016

Striking out hamstring strain: Protocol helps protect baseball players

In the moment: Sports medicine

8ITMsports-shutterstock_101267896-copyBy Katie Bell

A hamstring injury intervention program is effective for reducing the rate of hamstring injuries and reinjuries in professional baseball players, according to ongoing research from the University of Delaware presented in July at the annual meeting of the American Ortho­paedic Society for Sports Medicine.

Although more general injury prevention programs have been associated with reduced rates of hamstring injury, the authors thought a more baseball-specific protocol would have additional benefits.

“We attempted to make the dynamic movement patterns relevant to the sport of baseball to enhance player adoption and compliance,” said lead author Holly Silvers-Granelli, MPT, a PhD candidate in the Department of Biomechanics and Movement Science at the University of Delaware in Newark. “We designed a neuromuscular program that had an emphasis on eccentric hamstring strengthening and a posterior chain musculature, in addition to lateral hip strengthening. We also included movements to encourage dynamic stability with respect to the lumbar spine and pelvis during dynamic hip flexion and extension.”

In the prospective study, 213 major and minor league baseball players completed a questionnaire detailing their hamstring injury history. One major and minor league organization served as the intervention cohort, with 40 players and 173 players, respectively. The hamstring injury prevention program was distributed and explained to the team physician, athletic trainer, and strength and conditioning coach. Individual program compliance, injury incidence, and time lost due to injury, both acute and recurrent, were collected on a weekly basis for one season.

At the end of the season, results were compared with control data in Major League Baseball’s HITS (Health and Injury Tracking System) database, with 1160 players and 5685 players in the major and minor league control groups, respectively.

At the major league level, there were two hamstring injuries in the intervention group and 79 in the control group, representing a 25% lower rate of injury associated with the prevention protocol. At the minor league level, there were seven hamstring injuries in the intervention group versus 297 in the control group, resulting in a 40% lower rate of injury.

Average time lost due to injury for the major league players was 65.3% lower for the intervention group (nine days) than the control group (25.9 days). For the minor league players, average time lost due to injury in the intervention and control groups were 11.63 days versus 21.3 days, respectively, resulting in a 45.3% lower time lost rate associated with the intervention.

Timothy Tyler, MS, PT, ATC, research consultant at the Nicholas Institute of Sport Medicine and Athletic Trauma in New York City, noted the study findings are consistent with those of preventive eccentric exercise programs done in other sports (see “An eccentric approach to hamstring training,” February 2015, page 31).

“Nordic hamstring eccentric exercise have been shown to be excellent in preventing first-time hamstring strains in soccer players,” Tyler said. “The current study showed the same in major and minor league baseball.”

In the baseball study, as expected, participants’ compliance with the prevention program was much higher in those who did not suffer a hamstring injury (an average of 25.3 uses) than in those who did (13.53 uses).

“The notion of program adoption and compliance continues to be a challenge to injury reduction and prevention researchers globally,” Silvers-Granelli said. “We continue to investigate how compliance can be improved, and how program adoption may positively impact overall player and team performance.”

In a previous study, published in 2015 by the Amer­ican Journal of Sports Medicine,
Silvers-Granelli and colleagues found a 46.1% lower rate of hamstring injuries in male soccer players assigned to participate in the FIFA 11+ warmup program than in players who didn’t.

“We designed the FIFA 11+ to be a soccer-specific intervention that addressed all trunk and lower extremity injuries in youth and collegiate soccer players,” Silvers-Granelli said. “This program would not be completely relevant to baseball players, particularly at the professional level.”


Silvers H, Zachazewski J, Li B, et al. Hamstring injuries in major and minor league baseball: are they preventable? Presented at the 2016 American Orthopaedic Society for Sports Medicine annual meeting, Denver, CO, July 2016.

Silvers-Granelli H, Mandelbaum B, Adeniji O, et al. The efficacy of the FIFA 11+ program in the collegiate male soccer player (USA). Am J Sports Med 2015;43(11):2628-2637.

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