ACL Injuries and Yoga
By SUSANNA NICHOLSON, M.Phil.

Heyam duhkhamanagatam
(Future suffering should be avoided). Patanjali’s Sutra II.16

Each year, over 25,000 high school and middle-school female athletes and 13,000 female college athletes will suffer Anterior Cruciate Ligament (ACL) injuries. The ACL is the ligament in the middle of the knee, and it is the primary stabilizer of the knee and the tibia. It is a broad cord (narrower in females) that restricts the tibia from sliding forward and stops excessive rotation at the knee. ACL tears are likely to happen when the athlete tries to pivot, twist, cut, land a jump, or “stop-jump,” and creating too much shear force on the ACL and resulting in forward slippage of the tibia.

The injury can shock players with sudden pain, and it is often treated with surgery and a long rehabilitation period. Some athletes never fully recover post-ACL repair surgery and give up their sport. If they continue to play, about 6% are likely to suffer injury to the other knee. Women with ACL tear history are five times more likely to develop arthritis in the knees in their twenties, and they can have significant bone-mineral density loss in the tibia.

My interest in the “mini-epidemic” of ACL tears began when the mother of a new Yoga student called me. Her daughter had been sidelined from basketball for months with an ACL injury. The girl was both resigned and miserable. At a teen residential center where I taught, another female athlete had been sidelined by an ACL injury. In the wake of the injury, she lacked both the immediate support of family and of her team, and she reacted with frustration and anger. The same painful injury triggered suffering in both girls, and I offered an individualized Yoga therapy practice to suit each student.

However, mindful of the statistics about the high prevalence of this injury, I realized that a preventive, or rakshana, approach might help many more young women. Yoga therapy commonly takes a rehabilitation approach, but the inspiration for a practice that protects from future injury can be found in Pantanjali’s Sutra II.16, which states that Yoga prevents future suffering.

UNDERSTANDING THE CAUSE OF INJURY
My first step was to understand the causes of the injury. The current literature on ACL injuries indicates that women are anywhere from four to eight times more likely than men to develop the injury. The most frequently cited risk factors relate to gender, such as ligament laxity caused by female hormones (which reach especially high levels at the pre-ovulatory stage of the menstrual cycle). But the information about gender, although interesting to discover, was also quite negative and posed challenges from the teaching perspective.

Other risk factors are a more appropriate focus for a protective practice. In recent studies, poor attention, memory, and proprioception have been cited as important factors for ACL injury risk. Injury is strongly related to cognitive deficits (such as lack of concentration and impaired short term memory), neurological deficits (such as slow reaction time), and less strongly, to misalignment of the hips, knees, and feet. Asana sequences, if applied with appropriate breath and mental focus, can address these issues.

DESIGNING A PROTECTIVE PRACTICE FOR TEENS
For a typical class of teens not at risk for injury, a teacher might offer a series of sun salutation-type sequences linking together increasingly challenging traditional poses, which later lead to full mastery of the postures in longer holds. The students grow through learning the rules and discipline inherent in a challenging practice of sun salutations, extended sequences, and skillful action and alignment in the postures. Yet some young people need something other than this rigorous practice plan.

In designing practices for the young, it is a good idea to work with their motivation to acquire new skills. Furthermore, school-aged women live with a long list of “don’ts,” and more information about future harm may not be effective. For these reasons, I took an understated approach as far as warnings were concerned. Instead. I used a variety of tools to hold students’ interest over time and to extend their mastery. A protective practice can be challenging and fun enough to be taught in any class for young people.
           
The most important strategy to prevent ACL tears (and other mishaps) is to improve the quality of the student’s awareness, always within the context of a trusted relationship with a teacher. Below, I describe the more specific strategies and practices I used in working with teenage girls. The goals listed here should be applied with discretion.

PRACTICE GOALS AND TEACHING STRATEGIES
1) Improving attention, focus, and memory is the first-line strategy when teaching teens potentially at risk of injury.  Alignment awareness as a practice goal is not sufficient alone, given the recent reports on lack of attention, concentration, memory, and spatial awareness in those young athletes most at risk for this injury. Asana sequences, in which movement is supported by and coordinated with breath, should address these skills, increasing in length, difficulty, detail, and complexity, as students develop more steadiness and skill. Students will develop concentration and focus through instruction on the quality and consistency of breathing, perhaps using breath ratios or mantra to focus attention throughout the practice. In individual or very small group work, the attention to breath can go further. If the older teen or the college athlete lets me know that they are  interested, I’ll work gradually (over a period of weeks) toward a pranayama such as 1-1-1-1. Traditional meditation may be beneficial for adults, but the practice is not suitable for young people who for the most part need to stay active. There are other tools for attention, memory, and focus such as chanting, visualization, or mantra, that can be used within or between posture sequences.

2) Improve proprioception, the athlete’s sensory awareness of her body’s position, movements, and relationship to space and gravity. ACL tears have been linked to slow reaction time and neuromuscular deficits, which may be improved through increased proprioception, which supports the ability to coordinate muscular action to prevent falls and injury. All alignment instructions for yoga postures can promote proprioception, but. balancing postures in particular are helpful. Including postures that require balancing on the toes and balls of the feet can help athletes develop the ability to land from a jump on the front of foot.

3) Help student adapt to developmental changes that create lateral stress on the knees.  “Knock-knees” (also described as knee abduction or valgus alignment), caused by an external rotation of the tibia, is a risk factor for ACL tears. Another risk factor is the typical young woman’s wider hip-to-knee alignment.  Train students in better hip and knee alignment by strengthening muscles of one side in motion; for example, moving in coordination with the breath from Virabhadrasana to a one-legged balancing Virabhadrasana variation.

4) Increase hamstring strength relative to quadriceps strength, which is important for athletes’ ability to safely land from jumps. Females have a lower ratio of hamstring to quad strength, and this is another hypothesized cause of ACL tears. Some sports clinics report that if they can coach girls to use hamstrings properly, the injury rate plummets. Yoga programs for active younger women can address the muscle imbalance, by focusing on poses that strengthen hamstrings, with some modest gains in quadriceps strength when needed. For stabilizing and strengthening joints, longer stays would be an important goal over time.

5) Counter the tendency to hyperextend the knees when standing. Landing a jump on hyperextended knees is a common cause of ongoing knee stress among girls in basketball, and it is a known factor in ACL tears. Part of this habitual hyperextension comes from weak quadriceps, but part of it is the typically greater joint laxity of girls than boys, probably due to hormonal differences. Yoga practice for this group, unlike most Yoga group classes, will focus on asking girls to create a soft rather than a hard stretch in the back of extended knees, and to work on creating stability around the knee joint when standing. Through appropriate Yoga instruction, players gradually learn to engage hamstrings and quads for knee stability instead of landing on hyperextended knee joints.

6) Use postures that will improve the skill and safety of common athletic movements, such as the crouch position that supports lateral reaching for a ball. Finding the right balance between stretching and strengthening is critical. For example, a long-term goal may be to improve strength and stability in a wide-angled leg-crouch position that requires hip rotation. Build the elements of such a position in appropriate order; if the athletes’s hip extensors and flexors are not first properly stretched and strengthened, a strong hip rotation can stress the knee ligaments. 

7) Increase core stability through back and abdominal strength, while also improving spinal flexibility in a variety of directions. Lack of core flexibility or strength can lead an athlete to pivot on the knee joint to reach for a ball or to block another player. It’s safer and more effective to use the stronger structures of the core rather than the knees, to reach and twist. In Yoga practice, core stability is created not simply through moves such as abdominal flexion, but also through breath control during flexion, abdominal release, back strengthening in backbends, and axial extension. One sign of success is when the students have developed the “subtle, long” breathing (specified in the sutras) throughout their posture practice.

SUSANNA NICHOLSON M.Phil. teaches yoga at a studio in Martha Jefferson Hospital,  Charlottesville, Virginia (for a bibliography of studies cited here contact: reply@unionyogaloft.com). She has been certified as a Yoga teacher by the Krishnamacharya Healing & Yoga Foundation and Yoga Alliance (500 hrs.). She thanks her teacher Sonia Nelson, founder of the Vedic Chant Center, Santa Fe, and also Sara Avant Stover RYT, Fran Ubertini RYT, and Catherine Haney, PT for their insights on this subject.