Posts tagged baseball
Imaging's Role in Youth Baseball

In our previous blog posts we have written on the limitations of MRI for many injuries and conditions.  In general, these expensive tests have high rates of false positives where patients without pain often have positive results including ligament/labrum tears or tendon changes.  The incidence of false of positives increases in athletes with the majority of major league baseball players, regardless of symptoms, demonstrating rotator cuff tears or labrum injury.   It appears these changes are no different in our little leaguers.  

An article in the Journal of Bone and Joint Surgery examined 10-13 year old little league baseball players.  Each player underwent an MRI on both elbows at the start of the season.   The authors found many of the players with or without pain had imaging findings in their elbow.  Adding to our existing data that many athletes have positive MRI findings without pain or injury.  Two factors were associated with a positive MRI and elbow pain including year round baseball play and working with a private pitching coach.  

Athletes are encouraged to work with a local Physical Therapist to treat their elbow pain and reduce their risk of throwing injuries. 

Biomechanics and Stresses of Baseball Pitches

As we move through the Spring and into Summer many of our Boulder youth athletes are into their competitive baseball seasons.  With increased games come increased pitch counts, arm fatigue, and over use injuries.  From the literature we know there are some specific risk factors for future arm injury including pitching with a fatigued arm, pitching more than 80 pitches in a game, and pitching more than 8 months a year.  Thankfully many of these risk factors are manageable with proper education of athletes, coaches, and parents.  One of the debatable risk factors for injury involves utilization of different pitch types and their impact on future arm injury.  

Previous authors have studied the biomechanics of different pitches including fastballs, change ups, and curve balls (Fleisig et al.).  The authors have not shown increased arm stress during a curveball compared to other pitches.  A recent study confirms these findings.  Fleisig and colleagues studies 111 healthy pitchers across all levels of baseball from youth to the Minor and Major Leagues.  The authors were studied in an indoor biomechanics lab as they threw these 3 different pitch types.  The authors concluded a lack of support for the theory that curveballs are more stressful for young pitchers.

It is important to note the analysis involved healthy, non fatigued baseball pitchers with relatively low pitch counts.  It is possible the healthy pitchers have modified and corrected known risk factors and/or demonstrate adequate strength and mechanics to avoid injury.  Baseball pitchers are encouraged to work with a local PT to address risk factors, pitching mechanics, and muscle imbalances to ensure a successful and healthy end to their baseball season. 

Sports Specialization in Kids

In our Physical Therapy practice, we continue to see early sports specialization in our youth athletes (pre pubescent).  These athletes focus on playing one sport >8 months out of the year instead of changing sports more frequently or incorporating longer periods of rest.  Despite scientific evidence showing a lack of performance benefit and a higher injury risk among these "specialized" athletes this trend continues to rise across our country.  

Recently the American Orthopedic Society for Sports Medicine provided a consensus statement in the Orthopedic Journal of Sports Medicine (LaPrade et al. 2016) regarding youth athletes and early sports specialization.  Experts in the field stated there was "no evidence that young children will benefit from early specialization in the majority of sports".  The authors went on to note the available evidence indicates athletes who specialize early are at risk for overuse injury and burnout.  Importantly, they noted multi sport athletes are not at risk of reduced performance in their future careers.  

Coaches and parents are encouraged to allow extended rest periods and/or multi sport participation among their youth athletes.

The Impact of Core and Leg Muscle Fatigue on Baseball Throwing Mechanics

As we move into Spring we begin to see our youth athletes return to the baseball diamond often with a sudden increase in practice volume.  The sudden increase in throwing volume, either in the field or on the mound, places the athlete's shoulder and elbow at greater risk of baseball injuries. The greatest risk factors for injury include throwing more than 80 pitches/game, playing baseball greater than 8 months/year, and pitching with arm fatigue. As discussed in our prior posts, an athlete's throwing velocity is driven by their legs strength and power. Athletes with leg weakness are more likely to suffer from progressive changes in performance and increased injury risks.

A recent study in the Orthopedic Journal of Sports Medicine authors analyzed the impact of fatigue on throwing velocity, accuracy, and throwing mechanics (Chalmers et al. 2016). Authors studied 28 elite adolescent (13-16 year old) pitchers as they pitched a simulated game (90 pitches). Each pitch was analyzed for velocity and accuracy while every 15th pitch was analyzed for pitching mechanics. As expected the velocity, accuracy, and mechanics suffered with increased pitch counts. Importantly, the authors showed the loss of velocity, accuracy, and biomechanics were preceded first by core and leg muscle fatigue.

This study adds to the importance of controlling pitch counts and treating the lower extremities in order to improve throwing performance and reduce injury risk.  

Improving Throwing Velocity

A common question we receive from young throwers and their parents is how to improve throwing velocity safely without undue stress on their arms.  Our prior posts on throwing have focused on reducing arm stress through injury prevention and lower quarter strengthening.  This post will focus on the research surrounding exercise programs designed to improve a thrower's velocity of their pitches.  Ellenbecker et al. previously reported the lower body contributes 50% towards hand forces, while the shoulder only contributes 15%  (JOSPT, 2007).  As we would expect whole body, multimodal training aimed at the entire body improves throwing velocity both in short and long term training programs.

A recent analysis of the available evidence in the Journal of Strength and Conditioning Research examined the training programs shown to have the greatest impact on ball velocity in baseball, softball, or tennis (Myers, N. 2015).  13 articles were included in the final analysis and included interventions from plyometric training, medicine ball throws, and traditional upper and lower body resistance training.  These articles were scored as moderate to high quality based on a methodological analysis.  The training programs included were as short as 6 weeks or up to 9 months in length in a periodization format.  

The authors noted improvements in ball velocity across sports if the athletes were given whole body exercises focused on the connection between the legs and arm.   Longer term programs were most often used but short term programs, 6 weeks, also reported improvements in velocity.  Specifically, in tennis a 17 and 20 mph serve speed increase was noted with a 4 and 9 month resistance training program.  Athletes should speak with a Physical Therapist to determine how to structure their resistance training, plyometrics, and medicine ball throws in order to have an optimal impact on their ball velocity.  

Improving Throwing Velocity Through Leg Strengthening
leg-strengthening-baseball-arm-injury

In our practice, we commonly see adolescent baseball athletes suffering from shoulder and elbow injuries.  On average 1 in 2 youth throwers will develop arm injuries and on average major league throwers lose 22 days per season due to arm injury (Conte et al. 2001).  These injuries are mainly overuse in nature secondary to muscle imbalances, skeletal immaturity in youth, and poor pitching mechanics.  In particular, the majority of these athletes are throwing primarily with their arms and not taking advantage of the power generated by the lower body during the pitching sequence.  Injured throwers may also present with lower extremity weaknesses leading to increased arm stresses during pitching.

Baseball pitching is a whole body movement pattern requiring coordinated movement and strength from multiple joint regions in legs and arm described as the kinetic chain.  In pitching, the kinetic chain allows the transfer of power through a series of body regions from the feet through the throwing hand (Pappas, 1995).   Kibler et al. stated proximal stability (foundation) allows for effective distal mobility and acceleration of the arm (2006).  Effective utilization of the kinetic chain is responsible for fastballs exceeding 100 mph.  Major league throwers with the highest velocity, accuracy, stamina, often have the greater leg strength and power compared with lessor pitchers. 

boulder physical therapy, leg strength and pitching

Prior research has demonstrated up to 50% of a thrower’s velocity is produced by the lower body (Calbrese et al. 2013).  We also know the utilization of this strength in a pitching movement, either a lateral or forward hop, is directly related to pitching velocity (Lehman et al. 2013, Nakata et al. 2013).  Clearly the strength and movement produced by the legs improves the ability of the arm to produce forces and movements needed in baseball.

A recent article in the Journal of Strength and Conditioning Research examined if stride forces between the foot and the ground could predict pitching velocity  (McNally et al. 2015).  The authors found contact forces during the cocking and acceleration phase of the throw was associated with increased ball velocity by the pitchers.  The throwers with the highest ground reaction forces were able to produce the fastest throws. 

boulder physical therapy, baseball injury

In short, a thrower with inadequate leg strength and mechanics is at higher risk for arm injury and limited effectiveness on the mound.