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In Street Clothes

Covering sports injuries from the perspective of a certified athletic trainer and backed by analytics.

Bryce Harper and the Sliding Debate

For the second straight season Washington National outfielder Bryce Harper heads to the disabled list due to an injury attributed to his aggressive style of play. Last year he missed 31 games following a collision with an outfield wall in Dodgers Stadium. The impact resulted in a severe case of knee bursitis that ultimately required offseason surgery to fix. Now, less than a year later, Harper has gone back under the knife to repair a thumb injury suffered while sliding headfirst into third base.

The debate over the headfirst slide and the feet first slide is one of the oldest in baseball. Made famous by Pete Rose and Rickey Henderson, the general belief is that sliding headfirst is faster. However the scientific community has been unable to reach a definitive answer to this question despite multiple attempts. A study performed in 2002 found no significant difference between the feet-first and headfirst methods. The study was backed up less than a year later with a study focusing primarily on collegiate baseball players. Still others use physics to argue their point, suggesting the headfirst slide is actually faster.

While the advantages of each method remain debated, the inherent risks with each approach are better understood. Bleacher Report’s Will Carroll cites a 2000 study that illustrated the feet first slide leads to nearly twice as many injuries as the headfirst slide. The feet first slide gives the player more control and allows them to avoid contact with the base and any opposing players. This method is not without its risk as the player often creates a rigid, closed chain with each of their lower extremities. Doing so leaves the player vulnerable to ankle, knee, and hip injuries as the get caught on the ground or jammed into the base.

In a headfirst slide, the player loses control and make themselves susceptible to head or neck injuries. Additionally the player’s fingers and hands are more likely to be injured from being stepped on or hung up on the base. Several players, including Los Angeles Angels outfielder Josh Hamilton and Los Angeles Dodgers outfielder Yasiel Puig have already missed time this year after jamming their thumbs on a base. Cincinnati Reds outfielder Billy Hamilton also suffered a finger injury following a head first slide. Harper now joins the list suffering a complete tear of the ulnar collateral ligament (UCL) in his left thumb.

ulnar_collateral_ruptureAt the base of the thumb is the metacarpophalangeal (MCP) joint. The MCP joint is stabilized by the UCL at the bottom of the proximal phalanx.  The UCL of the thumb should not be confused with the elbow ligament that bares the same name and requires the infamous Tommy John surgery. When torn the UCL is repaired surgically and the affected individual spends the next six-to-eight weeks rehabbing the area. Therapy focuses on range of motion to start before progressing to grip strength. As a result the player is unable to pick up a bat for an extended period of time, though conditioning can be maintained. Upon return, it is common for MLB players to experiences a dip in power as they adjust to gripping and swinging a bat fluidly.

Harper is hoping to be back in July but until then he will continue to field questions about his style of play. His aggressiveness is part of what makes Harper so exciting and such a promising player. However given the risk associated with the headfirst slide, perhaps he can be convinced to reconsider his sliding method.