Parent and Athlete Resource Center

The First Step in Prevention is Education

Why a Parent and Athlete Resource Center?

“A.C.L.: Accelerated Conditioning and Learning” is an educational resource for athletic trainers, physical therapists, coaches, personal trainers, athletes, and parents developed by Trent Nessler, sports physical therapist.  As a part of Accelerated Conditioning and Learning, we developed a resource center specifically for parents and athletes to provide sound education based on the most current research related to injury prevention and athletic performance.  Through our own research and clinical experience, we developed a research based exercise program developed to address lower limb (low back, hip, knee and ankle) and A.C.L. injuries that plague female athletes.  Currently, this will serve to educate athletes and parents about ACL injuries, factors leading to as well as how to prevent (along with a quick test to determine if you or your son/daughter are at risk).  Knowing the abundance of information available on the internet, we are also providing you with a link to download several short articles related to injury prevention and training that is based on the most current research available.  I will also provide you with links to the medical literature most commonly used in sports medicine.  This portion of our site will remain under constant construction with addition of new articles quarterly.  With new research comes new knowledge base and as such, we will be updating you with the most current articles related to athletic performance and injury prevention.

Athletic Injuries, Are Females More Prone To Injury?

In the following segments, we hope to educate you in the most current literature as it relates to lower limb injuries.  We will summarize some of the most current research related to why ACL injuries occur in female athletes and why, we hypothesize, so many low back and lower limb injuries occur as well.  Why are these injuries more frequent in female athletes?  We will answer the question, “When watching my daughter/athlete play, what factors should I be looking for”?  What does the literature tell us we should be doing with exercise from a preventative and performance perspective? 

In the sections below, we hope to answer these and many more questions.  More importantly, provide you with an avenue to access this evidence based program.

Why this, Why now?

The Accelerated Conditioning Learning Injury Prevention Program was originally developed to address one of the most devastating injuries to affect female athletes, rupture of the anterior cruciate ligament (ACL).  Suffering from this type of injury can result in months of rehabilitation, often resulting in loss of a season and sometimes even an athletic career.  As health care providers and coaches, we have seen this preventable injury affect the lives of too many of our female athletes when there are preventative measures that can be taken.  As such, we combined the expertise of an Orthopedic Surgeon, Physical Therapist, Speed and Agility Coaches as well as Basketball Coaches to develop “A.C.L.: Accelerated Conditioning and Learning”.  Overtime, what we have found is that this program not only improves some of the common movement patterns seen with ACL/ankle/hip/low back injuries but also results in a significant improvement in athletic performance. 

The intention of this program is to provide the female athlete, parent, coach and fitness professional with the most current research related to ACL injuries and the female athlete.  For, it is the understanding of this research, information and concepts that is imperative in order for the female athlete to make both the emotional and physical commitment to the training regime that is required to prepare the athlete for performance and prevent lower extremity injuries.  It is also imperative that both the parent and athlete understand how mastering these exercises and concepts in our program will lead to increased athletic performance and reduce the potential for lower extremity injuries (ankle sprains/strains, knee injuries, hip injuries, ACL and low back injuries).

What the research tells us about ACL injuries

Anterior cruciate ligament (ACL) tears and ruptures occur more frequently in female athletes when compared to male athletes.  Studies comparing injury rates between male and female athletes participating in the same sport have shown a 3-8 times greater incidence of ACL injuries in female athletes. 1,2 This problem is not restricted to just collegiate athletes.  Assessment of ACL injuries in 893 men’s and women’s NCAA soccer and basketball programs from 1989 to 1993 found the rate of ACL injury per exposure for female athletes to be as much as 3 times greater than that of their male counterparts.2  Recent figures reported by the National Collegiate Athletic Association have shown that over a period of 13 years (1990-2002) the rate of injuries in female athletes has remained virtually unchanged.1 This is unchanged despite the fact that female athletes are participating at a younger age and being involved in resistance strength training programs earlier in their athletic careers.

Of greatest concern related to the ACL injury is a non-contact ACL injury, one that occurs in the absence of contact with another player or object. This mechanism accounts for up to ~70% of ACL injuries3,16 and is commonly described as occurring during a forceful cutting maneuver or when landing from a jump (as in the picture above), and typically while the athlete is decelerating or changing direction. As the demands of basketball, soccer and volleyball require the athlete to perform these maneuvers repeatedly during practice and competition; female athletes participating in these sports are considered to be at greater risk for non-contact ACL injuries.

With the knowledge gained over the past 10 years with respect to possible risk factors for ACL injury, one would expect this trend to subside and for the incidence of female ACL injuries to mimic those of their male counterparts.  However, this continues to be a fairly common season ending and often career ending injury for many female athletes. At an average health care cost of $17,000 per episode and prolonged rehabilitation (ranging from 17 to 36 weeks) process, we know the devastating impact this can have on the psychological status of our collegiate/high school athletes and hence short and long term performance.  As athletes, parents, coaches, physicians and physical therapists, we know this is a trend that must not continue.   The best tool is taking a proactive approach with preventative measures.

Although the majority of this literature is focused on ACL injuries and prevention, it is imperative that the intention of our program not be misconstrued.  Our program is designed to improve athletic performance and prevent back and lower extremity injuries including ACL injuries.

What puts my daughter/athlete at risk?

In order to address this issue proactively, it is important to understand the factors contributing to these injuries.  There has been much speculation as to why the incidence of ACL injuries are so much higher in women than men, however many of the previous hypotheses remain anecdotal (not proven one way or the other in the research).  Because of the higher incidence of non-contact ACL injuries in female athletes, research attempting to identify risk factors for ACL injury has focused on the differences between males and females.  In general, gender related risk factors can be grouped into four categories: hormonal, structural, biomechanical, and neuromuscular.19 The following is a brief description of each of these factors and how they may relate to ACL injury.

Hormonal:
Effects of gender specific hormones (i.e. estrogen and progesterone) on joint laxity and ligament strength. As the type and amount of circulating hormones are gender specific, studies have focused on the effects of “female” hormones on joint and ligament integrity.  It is speculated that the release of these hormones affects the laxity of the joint and possibly the strength of the ACL. However, currently there is little consensus on the relationship between the female menstrual cycle and ACL injury.9

Structural:
Wider pelvis of female athletes adding to increased Q-angles at the knee.  We all know that the female pelvis is wider than the males therefore adding to increased ease with pregnancy and delivery.  This wider position of the pelvis adds to increased Q-angles at the knee where the tibia and femur articulate.  While it has long been speculated that these factors contribute to ACL loading by positioning the knee in valgus (knock knee) and placing stress on the ACL, it has not been supported by any experimental data.17

Decrease femoral notch.  The ACL is attached to the femur at its distal end in an area called the femoral notch. It is speculated that a decreased notch space can lead to increased stress on the ACL, most notably with twisting and cutting motions (where borders of the notch actually wear on the ACL).  It is thought that a decreased notch space coupled with excessive hip or knee rotation would result in excessive loading of the ligament.

Biomechanical:
Studies focusing on biomechanical risk factors have identified gender related differences in the position of the hip, knee and ankle during performance of landing and cutting tasks. It is thought that the patterns demonstrated by the female place them at greater risk for ACL injury due in part to their potential to load the ligament. In particular, internal rotation of the hip and knee valgus are thought to place increased stress on the ACL.  Studies have found that when compared with males, females demonstrate greater hip internal rotation 7,12and knee valgus7,8,14 when performing landing tasks (i.e. jump stop). In addition, females have been found to demonstrate greater valgus torques at the knee during cutting15,18 and landing tasks,5 further increasing the potential for excessive loading of the ligament.

Neuromuscular:
Decreased muscular strength in female athletes.  Women are thought to be participating in activities with strength and endurance demands that are higher than their current level of conditioning. In addition, it is thought that decreased attention to hip and trunk strength training has resulted in poor control of the lower extremities leading to the altered biomechanical patterns described above. In particular, weakness of the hip muscles have been found to be associated with ACL injury.11

Decreased kinesthetia/body awareness/proprioception.  Decreased sense of lower extremity positioning and body awareness is thought to be the result of decreased amount and type of athletic experience.  Decreased kinesthetia (body awareness) or proprioception (sense of joint position) has been indicated as a causative factor in non-contact ALC injuries, as it affects the athletes’ ability to adapt to unexpected obstacles and safely control sudden changes in movement.

It is likely that the problem of non-contact ACL injuries is multifactorial. However, while hormonal and structural factors are relatively fixed, biomechanical and neuromuscular factors are related to the performance of specific tasks and therefore may be amenable to intervention.  Support of this concept lies in the success of injury prevention training programs on reduction of ACL injury rates.

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How do I identify these abnormal movements in my daughter or athlete?  Do you pass the test?

Of the above contributing factors, the ones that are most easily influenced with training are abnormal biomechanics noted with landing and the neuromuscular aspects.   So, it is likely after reading the above information; you may be asking yourself, how do I identify this in my daughter or athlete?  You can determine if your daughter/athlete demonstrates some of these pre-disposing factors by going through the following tests.

After performing the above tests, your answer should be clear.  If unsure, you can always see a sports medicine trained orthopedist or physical therapist for further testing.

Current Prevention Programs

Intervention programs that have been successful in reducing incidence of ACL injuries have incorporated various strategies and types of training. For example, a recent study showed that following the implementation of a jump training program, the incidence of knee injuries in trained female athletes was 3.6 times lower than the un-trained athletes.10In a study incorporating solely proprioceptive training there was a reduced incidence of ACL injury 7 times lower in trained male soccer players vs untrained.4 Furthermore, the incidence of ACL tears in female soccer players who participated in a “sport specific training” program was 88% less than females who did not participate in the program.13 While these results are a promising indicator that training can improve biomechanical and neuromuscular aspects of performance, the question still remains: What will help my daughter or athletes prevent lower extremity and specifically ACL injuries while improving athletic performance?

This is the question that has been asked over and over again. With increased exposure and awareness to the problem of ACL injuries, physicians, researchers, clinicians, athletic trainers, strength and conditioning trainers, coaches and parents have begun the search for “the solution”. The information gained from observation and research has narrowed the focus to several key variables and most successful injury prevention programs have incorporated these variables at some level.

These variables include:
Strength and endurance training– Muscular strength and endurance are crucial for skillful performance as well as injury prevention. Traditional strength training for the female athlete incorporates traditional weightlifting along with powerlifting techniques.  These provide exceptional results in both strength and power (force/time), which have been shown to provide increased athletic performance specifically in the 40-yard dash and vertical jump.  However, one major limitation is most traditional programs do not address the weaknesses of the pelvic girdle most commonly seen in the female athletes (gluteus medius, hip internal/external rotators).  Thus, the potential for the internal rotation and valgus stresses at the knee may not be reduced. This needs to be a focus due to the fact that fatigued athletes have been found to demonstrate a breakdown in lower extremity mechanics, thus making them more susceptible to lower extremity injury.

What does all that mean to me?

There are factors that place females at more risk for lower limb and ACL injuries than their male counterparts.  In order to assess whether or not your daughter or athlete presents with the “predictable” risk factors, we have put some simple tests in here.  These tests simply assess for the factors that can be influenced with training.  If you have positive findings on these tests, it would be advantageous (both in order to prevent injury as well as improve performance) to take a proactive role in seeking some type of prevention/performance enhancement program (like that offered with Accelerated Conditioning and Learning).  However, keep in mind, a prevention program does not equal performance training and vice versa.  A well rounded program should address all factors as indicated above as well as applying the research and science to strength training. 

Special thanks:

I would like to thank Dr. Damon Petty, sports certified orthopedic surgeon with Petty Orthopedics and Sports Medicine, for his willingness to assist with this project.  It is through numerous interactions with him and his patients that has kept us focused on bringing this program into reality.  Thank you Dr. Petty for assisting in making this program a reality and for the impact you have had and will continue to have on athletes around the country.

Links:

Below are links to the most current research related to the sports performance, injury prevention, training and diagnostic techniques.  These would include The American Journal of Sports Medicine, the Journal of Shoulder and Elbow Surgery, Journal of Arthroscopic Surgery, Journal of Sports Physical Therapy, Journal of Athletic Training, The National Strength and Conditioning Association Journal and Journal of the American Academy of Orthopedic Surgeons.

Articles:

We would like to offer you free articles related to athletic performance, injury prevention and training based on the most current research available. Below are pdf format of articles related to athletic performance, injury prevention and training.  These have all been written by Trent Nessler, PT and are provided here as a free educational resource to parents and athletes.  Enjoy and please let us know if you have any questions. For a copy of this quarter's articles, please email us at: info@aclprogram.com.

References:

      1.   Agel, J., Arendt, E. A., and Bershadsky, B.: Anterior Cruciate Ligament Injury in National Collegiate Athletic Association Basketball and Soccer: A 13-Year Review. Am J Sports Med. 33:524-531, 2005.
      2.   Arendt, E. and Dick, R.: Knee injury patterns among men and women in collegiate basketball and soccer. NCAA data and review of literature. Am J Sports Med. 23:694-701, 1995.
      3.   Boden, B. P., Dean, G. S., Feagin, J. A., and Garrett, W. E.: Mechanisms of anterior cruciate ligament injury. Orthopedics. 23:573-578, 2000.
      4.   Caraffa, A., Cerulli, G., Projetti, M., Aisa, G., and Rizzo, A.: Prevention of anterior cruciate ligament injuries in soccer. A prospective controlled study of proprioceptive training. Knee Surg Sports Traumatol Arthrosc. 4:19-21, 1996.
      5.   Chappell, J. D., Yu, B., Kirkendall, D. T., and Garrett, W. E.: A comparison of knee kinetics between male and female recreational athletes in stop-jump tasks. Am. J. Sports Med. 30:261-267, 2002.
      6.   Chappell, J. D., Herman, D. C., Knight, B. S., Kirkendall, D. T., Garrett, W. E., and Yu, B.: Effect of Fatigue on Knee Kinetics and Kinematics in Stop-Jump Tasks. American Journal of Sports Medicine. 33:1022-1029, 2005.
      7.   Chaudhari, A. M., Hearn, B. K., and Andriacchi, T. P.: Sport-Dependent Variations in Arm Position During Single-Limb Landing Influence Knee Loading: Implications for Anterior Cruciate Ligament Injury. American Journal of Sports Medicine. 33:824-830, 2005.
      8.   DeRosa, C; Porterfield, J.  Mechanical Low Back Pain: Perspectives in Functional Anatomy.  Saunders, 1995.
            Ford, K. R., Myer, G. D., and Hewett, T. E.: Valgus knee motion during landing in high school female and male basketball players. Med. Sci. Sports Exerc. 35:1745-1750, 2003.
      9.   Griffin, L. Y., Agel, J., Albohm, M. J., Arendt, E. A., Dick, R. W., Garrett, W. E., Garrick, J. G., Hewett, T. E., Huston, L., Ireland, M. L., Johnson, R. J., Kibler, W. B., Lephart, S., Lewis, J. L., Lindenfeld, T. N., Mandelbaum, B. R., Marchak, P., Teitz, C. C., and Wojtys, E. M.: Noncontact anterior cruciate ligament injuries: risk factors and prevention strategies. J. Am. Acad. Orthop. Surg. 8:141-150, 2000.
    10.   Hewett, T. E., Lindenfeld, T. N., Riccobene, J. V., and Noyes, F. R.: The effect of neuromuscular training on the incidence of knee injury in female athletes. A prospective study. Am. J. Sports Med. 27:699-706, 1999.
    11.   Leetun, D. T., Ireland, M. L., Willson, J. D., Ballantyne, B. T., and Davis, I. M.: Core stability measures as risk factors for lower extremity injury in athletes. Med. Sci. Sports Exerc. 36:926-934, 2004.
    12.   Lephart, S. M., Ferris, C. M., Riemann, B. L., Myers, J. B., and Fu, F. H.: Gender differences in strength and lower extremity kinematics during landing. Clin. Sports Med.162-169, 2002.
    13.   Mandelbaum, B. R., Silvers, H. J., Watanabe, D. S., Knarr, J. F., Thomas, S. D., Griffin, L. Y., Kirkendall, D. T., and Garrett, W., Jr.: Effectiveness of a Neuromuscular and Proprioceptive Training Program in Preventing Anterior Cruciate Ligament Injuries in Female Athletes: 2-Year Follow-up. Am J Sports Med. 33:1003-1010, 2005.
    14.   McLean, S. G., Lipfert, S. W., and van den Bogert, A. J.: Effect of gender and defensive opponent on the biomechanics of sidestep cutting. Med. Sci. Sports Exerc. 36:1008-1016, 2004.
    15.   McLean, SG., Huang, X., and van den Bogert, A. J.: Association between lower extremity posture at contact and peak knee valgus moment during sidestepping: Implications for ACL injury. Clinical Biomechanics. 20:863-870, 2005.
    16.   McNair, P. J., Marshall, R. N., and Matheson, J. A.: Important features associated with acute anterior cruciate ligament injury. N Z Med J. 103:537-539, 1990.
    17.   Pantano, K. J., White, S. C., Gilchrist, L. A., and Leddy, J.: Differences in peak knee valgus angles between individuals with high and low Q-angles during a single limb squat. Clinical Biomechanics. In Press, Corrected Proof.
    18.   Sigward SM and Powers CM: The Influence of gender on knee kinematics, kinetics, and muscle activation patterns during side-step cutting. Clin Biomech. 2005. In press.
    19.   Traina, S. M. and Bromberg, D. F.: ACL injury patterns in women. Orthopedics. 20:545-549, 1997

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For questions, comments or a copy of Dr. Trent Nessler's CV, please email us at: info@aclprogram.com