Injuries in baseball seem to be on the rise at every level of play and many of them are preventable.  This is a multifaceted concern with several possible culprits.  One potential issue is that athletes are designing their own strength and conditioning programs without the benefit of a scientific foundation or fundamental knowledge of exercise physiology and biomechanics. To say you don’t need a CSCS educated in baseball physiology and biomechanics would be like saying you don’t need a hitting or pitching coach.  Another common issue is that baseball players don’t train to improve stamina like they did in years past.  Ten years ago, the challenge was trying to convince players to lift weights whereas now the challenge is getting the guys out of the weight room and onto the running field. The key to preventing injury is conditioning, which involves tempo, fluidity, repeatability and helps improve recovery.  Over the past several years, we’ve found that our better conditioned pitchers performed significantly better than our poorly conditioned pitchers.  This doesn’t mean that if you run more you’ll automatically pitch better, as a better aerobic capacity will not directly improve your pitching velocity or give you the ability to throw more strikes.  Conditioning will, however, help you complete the tasks on the field, making them feel much easier.

It should be noted that the pathways we are taking toward maximizing power and athleticism do take on inherent risks.  To decrease that risk, a resistance training program for adolescents should fit the individual based on factors including, but not limited to, motor development, experience and aptitude.  By implementing a strategic program that blends both injury prevention and power producing techniques, you can help to minimize the high rate of preventable injuries.

Where it concerns resistance training injuries, the most likely cause is reported to be “inappropriate training techniques, excessive loading, poorly designed equipment, ready access to the equipment, or lack of qualified adult supervision,” according to Faigenbaum, et al., (2009) (S61).  Perhaps the biggest difference between adults and children lies in the exercises prescribed. One common mishap occurs when a youngster attempts exercises like a squat or bench press with improper technique and poor function and it goes unnoticed and/or uncorrected.  For example, due to the lack of core strength, an improperly functioning scapula can cause shoulder joint movement dysfunction, acting as the precursor to labrum and/or rotator cuff injuries later in the athlete’s career. Another potential result is knee valgus, which is common for young girls and often predisposes them to ACL tears.  A recent report, however, points out two things worth taking notice of for all of those who implement a youth resistance training program: first, prepubescent boys and girls are equally predisposed to knee valgus and second, there is no evidence of strength differences between preadolescent boys and girls (Barber-Westin, et al., 2005),  Faigenbaum, et al., (2009). Although acute injuries might not occur immediately, biomechanical predisposition and poor technique can lead to future problems for both genders.

In regards to duration, intensity and volume of training, many similarities seem to exist between both adult and prepubescent protocols.  Training volume for youths may be similar to suggestions given to adults but it is important to keep in mind that young athletes should not be treated as miniature adults.  When incorporating weight-lifting and plyometric exercises, a lower volume of training is preferred for young and/or inexperienced athletes.

When designing an effective program for a young person, it is important to learn what types of programs have shown to be effective in the past.  According to the National Strength and Conditioning Association (NSCA, nsca-lift.org) (by Faigenbaum, et al., 2009), the most common programs designed for young athletes take on an eight to twelve-week training cycle, and are performed two to three days per week on nonconsecutive days.  Every training session should begin with a five to ten-minute dynamic warm-up period.  To improve muscular endurance, 10-15 repetitions are used vs. using 6-10 repetitions when strength is the goal.  To improve power, the young athlete should perform one to three sets of three to six repetitions.  In all cases, one to three working sets seem to be sufficient after the appropriately prescribed warm up set(s).  We typically begin counting working sets when using over 65% of the individuals one-rep max.  To improve strength, a variety of multi-joint upper body and lower body exercises can be performed.  Routines should involve an overall effort on improving core strength, which will be explained in further detail later.  As strength improves, resistance should increase gradually (5-10%) and we do not progress by adding weight until two sets can be completed comfortably at the prescribed rep range.  Every session should end with a cool down incorporating less intense calisthenics and static stretching exercises.

Another important priority when implementing a program for young people is having the practitioner devise a list of exercise progressions and classify each exercise based on its difficulty level.  There are a wide range of exercises available that differ in intensity.  Eccentric contractions, as well as heavy load isometric contractions, are more likely to cause muscle damage (Elsayed & Reilly, 2010).  Examples of highly eccentric exercises include weight-lifting under extremely heavy loads as well as high impact plyometrics like depth jumps and downhill running.  The presence of higher eccentric contractions involved in these exercises might make them unsuitable for the prepubescent athlete, partly because the active stretch creates more strain on the muscle fibers.  While high load, highly eccentric contractions are an effective way for well-trained adults to gain strength, this mode of training (especially performed over many repetitions) might not be best for young athletes.

It is important to also consider that prepuberty children have a faster lactate clearance rate (Beneke, Hütler, Jung, & Leithäuser, 2005).  With a high aerobic capacity and a higher resistance to fatigue, training using higher repetitions (>10) might offer a proper stimulus to increase motor unit recruitment and muscle firing patterns.  Improvements in coordination made via neural adaptations are often made best over many repetitions.  Rest times can also mimic the sport that is being played.   In the case of a baseball player, average rest time in between pitches is 20 seconds (Szymanski, 2009).

When the goal is improving strength in young athletes, it’s easy to assume that kids just need to get outside to play more and participate in team sports, but practitioners cannot solely rely on anaerobic conditioning drills.  Basketball is an effective means to improve maximal aerobic capacity and reduce body fat; however, this form of exercise will not significantly improve strength or joint mobility (Vamvakoudis, et al., 2007).  Basketball is a fun conditioning option that can co-exist with a strength building routine in an effort to improve overall fitness and prevent injuries.  Since strength is relative to mass, it is likely that strength gains achieved during pre-pubertal years will lead to an earlier development of additional lean muscle mass after puberty, if training continues.

When building strength in young people (or beginners of any age), their regime should focus on improving core stability, coordination, movement technique and reactive skills.  To that end, upper body exercises selected for youth need to focus on “core” musculature that ultimately alleviates stress on less stable joints.  Core exercises should strengthen the musculature supporting three important structures of the body: the scapulae, the spine and the pelvic girdle.   One example is a Push-Up Plank Hold (see figure 1), an upper-body exercise that focuses on core stability. For an athlete that lacks the core strength and the stamina to hold this position accurately, stress is added to the shoulder joint and increases the likelihood of injury when that athlete moves on to a more advanced exercise, like a traditional push-up.

Appropriate resistance training exercises for youth will lead to neuromuscular adaptations, resulting in increased strength.  Unilateral body weight squats are a challenging exercise that can be incorporated into youth resistance training routines in an effort to improve balance, coordination and lower limb strength.  Conversely, bilateral squats might be a safer alternative when the goal is to achieve maximum strength and power using higher external loads.  One study (McCurdy, et al., 2005) concluded that unilateral and bilateral lower body resistance training were both equally effective in improving strength during the early phases of training in untrained adults.  A typical two to three-day resistance training program for youth should strategically incorporate both unilateral and bilateral exercises.  It is anticipated that youth can experience similar neuromuscular adaptations to adults in the first 10 weeks of training.

A positive, injury-free experience is easily attained with proper exercise progressions, optimal technical performance and a strategic program formulation.  For anyone concerned about the increased likelihood of injury resulting from resistance training, it is good to know that the risk is no greater than participating in sport-related activities (Faigenbaum, et al., 2009).  New updates in research and growing support among adults continue to drive the development of youth exercise programs and fitness initiatives. In fact, physical education curricula now commonly include activities to improve muscular strength and endurance (Faigenbaum & Myer, 2010).  The growing number of youths participating in these types of activities is a positive change but it is also the probable cause for the rise in reported injuries attributed to resistance training. Creating proper exercise progressions—as well as establishing the appropriate intensity, volume and frequency of fitness regimens—remains an integral component of safe youth and adolescent resistance training programs.

References

Barber-Westin, S., Galloway, M., Noyes, F., Corbett, G., & Walsh, C., (2005, December).  Assessment of lower limb neuromuscular control in prepubescent athletes.  American Journal of Sports Medicine, 33(12), 1853-1860.

Beneke, R., Hütler, M., Jung, M., & Leithäuser, R., (2005 August).  Modeling the blood lactate kinetics at maximal short-term exercise conditions in children, adolescents, and adults.  Journal of Applied Physiology, 99(2):499-504.

Clarkson P., (2006, February).  Case report of exertional rhabdomyolysis in a 12-year-old boy.  Medicine and Science in Sports and Exercise, 38(2), 197-200.

Elsayed, E.F., & Reilly, R., (2010, January).  Rhabdomyolysis: a review, with emphasis on the pediatric population. Pediatric Nephrology, 25(1), 7-18.

Faigenbaum, A., Kraemer, W., Blimkie, C., Jeffreys, I., Micheli, L., Nitka, M., & Rowland, T., (2009, August).  Youth resistance training: Updated position statement paper from the national strength and conditioning association.  Journal of Strength and Conditioning Research. 23(5). August 2009.

Faigenbaum, A., & Myer G., (2010, May-June).  Pediatric resistance training: benefits, concerns, and program design considerations.  Current Sports Medicine Reports, 9(3), 161-8.

Malina, R., (2006).  Weight training in youth: growth, maturation, and safety: an evidence based review.  Clinical Journal of Sport Medicine, 16, 478–487.

McCurdy, K., Langford, G., Doscher, M., Wiley, L., & Mallard, K.,  (2005, February).  The effects of short-term unilateral and bilateral lower-body resistance training on measures of strength and power.  Journal of Strength and Conditioning Research, 19(1), 9-15.

Ozmun, J.C., Mikesky, A., & Surburg, P., (1994, April).  Neuromuscular adaptations following prepubescent strength training.  Medicine and Science in Sports and Exercise, 26(4), 510-514.

Ramsay, J., Blimkie, C., Smith, K., Garner, S., MacDougall, J., & Sale, D., (1990, October).  Strength training effects in prepubescent boys.  Medicine and Science in Sports and Exercise, 22(5), 605-614.

Vamvakoudis, E., Vrabas, I., Galazoulas, C., Stefanidis, P., Metaxas, T., & Mandroukas, K., (2007, August).  Effects of basketball training on maximal oxygen uptake, muscle strength, and joint mobility in young basketball players.  Journal of Strength and Conditioning Research, 21(3), 930-936.