Knee injuries: the major problem of female athletes and how to prevent them.

Female athletes who compete in ground-based sports have been suffering a plague of non-contact knee injuries, specifically to the anterior cruciate ligament (ACL). It is estimated that one out of every 100 high school girls and one out of every 10 college women will tear her ACL (Adams).

What can you the strength coach, do about it? You may be interested in the general strategies and specific plans we use at Michigan State for the reduction of non-contact ACL injuries.

Our first strategy is to prescribe a full-body strengthening program, paying special attention to the gluteals, quadriceps, abductors (lateral thigh), adductors (medical thigh), hamstrings, and calves. The maximal strengthening of these muscles will counter deceleration forces, decrease the forward movement of the shin bone, assist in keeping the knee in a stable position, help influence safe postures in sport movements.

The weight-room exercises we most often prescribe are the squat, forward and lateral lunge, forward and lateral step-up, and a weighted pulley or band circuit (movements include the lateral shuffle, carioca, and forward and backward march).

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Researchers suggest that many females are significantly weaker in their hamstrings than in their quadriceps (Hewett). It is because of this that we pay special attention to the hamstrings. We will often perform 2-3 high effort hamstring exercises per workout. The leg curl, bent-knee bridge, glute/ham/gastroc raise, and straight-leg deadlifts are some of our favorites exercises. For the calves, we prescribe both straight leg and bent knee toe raises.

All athletes are inspired to systematically work their muscles harder over time and, more specifically, they are instructed to increase their weight load as much as possible every time they accomplish the assigned repetition target for a set or exercise.

If the repetition target isn't achieved, they will be asked to progressively accomplish more repetitions until the target is attained. To ensure purposeful training, the athletes chart their progress on workout cards every time they lift.

STAY BALANCED:

Some research suggests that general balancing movements may lower the risk of ACL injury (Caraffa). The specific mechanism of the lower ACL injury risk from balance exercises is not fully understood.

We perform a variety of single-leg balancing drills, lasting 15 and 60 seconds per exercise. Difficulty is progressively increased by changing the surface, adding work time, closing one or both eyes, turning the head to the right or left, and moving the free leg to various positions (front, side or hip open like a swinging gate).

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STRENGTHEN ON THE FIELD OR COURT:

After reviewing a number of ACL injury-prevention programs from around the world, we combined the best aspects of each and came up with our own. We try to perform this program an average of two nonconsecutive days per week.

The Spartan program combines strengthening, balance, and dynamic sport-performance movements. It serves as a great adjunct to our weight-room prescription and sometimes replaces the weight-room workout during the busy in-season.

Athletes start by performing the following dynamic warm-up movements over a 40-yard distance: shuffle with 180-degree turns, high knee skipping, 360 degree turns while jogging/running, forward hopping on one leg to the right and left for 20-yards, and diagonal stepping (bounding). We also perform lateral cone jumps (1x9 each direction) and scissor jumps (1x10 each leg).

The coaching focus for the dynamic movements is on teaching athletes to demonstrate control and body awareness during acceleration and deceleration while moving in a variety of directions.

The strengthening portion of the program comes next, beginning with lower-body lunge matrix. The matrix consists of six rotations of lunges performed in three planes (directions)--sagittal (forward), frontal (lateral), and transverse (plant foot remains stationary while turning/opening the hip like a gate swinging open).

A total of 18 lunges are performed with each leg. Two more rotations of the lower body matrix are then performed with the arms raised above the head. This adaptation provides a slight increase in difficulty and a great stretch of the abdominals.

We end our lower-body matrix training with one rotation of matrix hops. The movements in this last rotation are not actually lunges--they are hops in each of the previously mentioned directions. Once the athletes become skilled at sticking the landings without losing their balance, we make the exercise more challenging by having the athletes close one or both eyes and turn their head to the right or left.

We next move on to one set of 10 repetitions of manual resistance leg curls and body-weight glute/ham negatives. These negatives are performed with a partner anchoring the ankles while the lifter is on her knees lowering her body as slowly as possible to the ground.

We end the strengthening portion of the program by performing a static bridge with alternating hip flexions. The athlete lies on the ground or floor and balances on her shoulders and toes while alternately lifting each knee towards the head 20 times.

The last part of the workout consists of a single-leg balance drill. The weighted leg is stationary and slightly bent while the other leg is elevated for 15 seconds in front of the body, 15 seconds lifted laterally, and 15 more seconds with the hip rotated or open to the side.

EDUCATE, EDUCATE, EDUCATE:

The coaching staff uses every chance it can get to instruct athletes to keep their knees between their first and second toes when bending during weight training, jumping, decelerating, and cutting. The athletes are also instructed to land softly from jumps with toe-to-heel "rocker" landings, use several small steps when decelerating from sprinting, and initiate movement from the gluteals and hamstrings. These are the ways to decrease landing forces through the knees.

We also warn against high-risk sport-specific positions, postures, and movements and suggest safe reactionary counter measures. Some of these high-risk positions include playing with straight legs and twisting the body with the knee aligned inside the big toe.

CONDITION SPORT-SPECIFICALLY:

Our coaches condition in a sport-specific manner, meaning we use identical sport movement in the conditioning process. This kind of conditioning appears to teach the athletes to stabilize the knee more quickly by activating the hamstring and calf during the performance of the sport (Wojtys, Huston and Bastian).

FINAL REP:

The large number of ACL injuries in female athletics is a significant problem across the nation. At Michigan State, we have researched, planned, and implemented a comprehensive injury prevention program.

The underpinnings of our program include intense full-body multi-directional strengthening using both single and multi-joint exercises, with an emphasis on all the lower body muscular compartments, balance, sport-specific conditioning, and constant stress on high risk positions, avoidance techniques, and recovery strategies. Your commitments to these underpinnings will give you and your female warriors the best chance to stay healthy during their "battles".

REFERENCES

* Adams, E: "An increased risk of ACL rupture in female athletes," Institute of Sports Medicine, 2002.

* Hewett, T. E., Stroupe, A. L., Nance, T. A., and Noyes, F. R.: "Plyometric training in female athletes, Decreased impact forces and increased hamstring torques." American Journal of Sports Medicine, 1996.

* Caraffa, A., Cerulli, G., Projetti, M., Aisa, G., Rizzo, A.: "Prevention of anterior cruciate ligament injuries in soccer: A prospective controlled study of proprioceptive training, knee surgery," Sports Traumatology, 1996.

* Wojtys, E. M., Huston, L. J., and Bastian, S. D.: "Neuromuscular adaptations in isokinetic, isotonic and agility training programs," American Journal of Sports Medicine, 1996.

BY TIM WAKEHAM (MS, CSCC)

Assistant Strength & Conditioning Coach

Michigan State University