Athletic Medicine and Rehabilitation

October 2003
From the Editor Mike Braid, M.S. E. D. , A.T., C.


As the summer winds down, the fall sports season approaches, school is beginning, and we once again return with another addition of the Hackley Athletic Medicine Advisor.

In this issue we discuss the topic of Anterior Cruciate Ligament injuries. ACL injuries have always been very common in sports, and lately have become a very hot topic among female athletes. Athletic trainers and physicians have a very important role in properly recognizing and managing these significant knee injuries.

If you have any questions or comments, please feel free to contact us at (231) 728-4820. Read on and Enjoy!

Female ACL Injuries
Michelle Zahrt, A.T.,C., C.S.C.S.


The term "ACL" has become more prevalent in recent years, especially in regards to female athletes. Most of us who are involved in sports in some way can mention at least one female athlete that we know of who has suffered from an ACL injury. What is the ACL? Are female athletes more susceptible to these injuries? Can these devastating injuries be prevented? The following article will help to answer these questions.

What is the ACL?
The ACL (Anterior Cruciate Ligament) is the main stabilizing ligament of the knee. It is responsible for limiting anterior translation of the tibia on the femur. ACL deficiency often causes symptoms of instability including "giving way" or "buckling" of the knee and athletes risk meniscus (cartilage) tears when this occurs. When left untreated, ACL deficiency can lead to early osteoarthritis and chronic pain of the knee.

Why are female athletes more susceptible to ACL injuries?
Recent studies indicate that females are more likely to tear their ACL's than their male counterparts. This increase is due to many possible factors, including but not limited to:
1. Increased width of the female pelvis which increases the angle at the knee (Q-Angle)
2. Less quadriceps muscle tone and strength in female athletes compared to males
3. Hormone level fluctuations throughout menstrual cycle which may increase ligament laxity
4. Decreased recruitment of the hamstring muscles in stabilizing the knee
5. Decreased core stability in females (trunk, abdominals, gluts, hip)
6. Poor biomechanics and/or exercise techniques, especially with jumping/landing exercises/sports.

How can these injuries be prevented?
Until recently, prevention of ACL injuries in female athletes has concentrated mainly on strengthening of the quadriceps and hamstring muscles. However, more recent studies have shown more emphasis on exercise technique and body mechanics in preventing these injuries.

Due to the increased Q-Angle of the knee in female athletes, combined with decreased hip and quad strength and stabilization, it is important to teach female athletes (especially YOUNG female athletes) to keep their knees in line with their toes during squatting and jumping exercises (DON'T LET KNEES COME IN TOWARD EACH OTHER). It is also important to teach these athletes to concentrate on keeping their core stabilized during these exercises to prevent their pelvis from dropping (STAND TALL, SHOULDERS BACK, STOMACH TIGHT, WEIGHT ON BALLS OF FEET). This good technique will increase recruitment of both the quads and the hamstrings in squatting/jumping exercises.

Combined with a good strengthening program, these exercise techniques may help to prevent female athlete ACL injuries, especially when taught to them at a young age. Many clinicians believe that teaching proper biomechanics, especially with jumping and landing exercises, is crucial in optimizing ACL prevention strategies.

Knee Injury Prevention
Ted Quick A.T.,C., C.S.C.S.


An increasing number of athletes seem to be sustaining knee injuries. Various studies have reported that female knee injuries occur at a rate five times more often than they occur in males, and that female athletes injure their ACL's 7-8 times more frequently than male athletes. The female high school athlete appears to have a 1:100 chance of sustaining an ACL injury, whereas the male high school athlete appears to have a 1:500 chance. It is also estimated that there will be over 30,000 collegiate and high school female athletes that sustain knee injuries each year. The majority of these injuries are non-contact injuries. In fact, they often occur from landing from a jump or pivoting when running. The best way to address this issue is from a preventative approach. While all knee injuries cannot be avoided, there are programs being utilized that decrease the harmful forces at the knee. Most of these programs address four main areas: flexibility, lower extremity strength, plyometrics, and core strength.

The purpose of a flexibility program is to achieve maximum muscle length in order to balance muscle strength and flexibility. General recommendations include correct techniques of static stretching (3-5 reps, hold 10-30 seconds), perform the stretches in a pain free range of motion, and stretching all major muscle groups. In addition, a dynamic, sport-specific warm up may be beneficial.

Resistance training to improve lower extremity strength is the basis of any conditioning program. Research has noted the increased risk of ligamentous injury in athletes that demonstrate quadriceps to hamstring strength imbalances and reduced hamstring to quadriceps muscle contraction patterns. A hamstring to quadriceps ratio of 80% is generally acceptable. Performing isotonic exercises in the weight room is a great way to establish "general" strength and power, utilizing equipment such as the leg press, hamstring curl machine, and squat racks. Functional techniques aid in establishing muscle contraction patterns and dynamic control. Examples include tri-planar lunges, vertical squats with stabilization, and balance drills. Dynamic exercises, those exercises performed at high speed, help train the muscles to withstand the demands of the sport as well as improve reaction times. The need for these exercises is especially important for the stabilizing muscles of the knee joint, the hamstrings and the gastrocnemius. Examples include high-speed isokinetics, backwards running, high speed knee flexion with resistance cords, high speed lateral jumping lunges, and use of agility ladders.

An excellent form of exercise to include is jump training, or plyometrics. Plyometrics develop muscle control and strength critical for reducing the risk of knee injury. The basic technique stressed with plyometric training are correct posture and body alignment, dynamic control of the valgus moment (knee valgus with femoral external rotation), and proper landing form (knees slightly flexed). The position of stability for the knee joint is knee flexion between 25-30 degrees which coactivates the quadriceps, hamstrings, and gastrocnemius muscles; plyometric exercises assist in training the athlete to land from jumping in this position, enhancing knee stability.

An area often overlooked in many conditioning programs is the hip/trunk. Hip and trunk stabilization is also critical, especially when landing from a jump. A frequently seen mechanism in ACL injuries involves hip adduction with internal rotation and knee valgus, with the body falling laterally over the lower extremity. This is often referred to as "the point of no return." By controlling the core of the body (hip/trunk), the athlete may be able to reduce adduction and abduction of the knee joint. The use of balance tools and exercises, plyometric drills, as well as exercises on a stability ball, are great ways to train for "core stabilization."

This is a very short overview of a very complex issue. If you have any questions or you are interested in additional information, please contact one of our Certified Athletic Trainers (A.T., C.) at 231.728.4820.

Commonly Used Knee Terms


- A.C.L: Anterior Cruciate Ligament. The main stabilizing ligament of the knee.
- Anterior Translation: Forward glide of the Tibia.
- Core Strength: Strength in the back, stomach, and hip muscles. This helps to maintain good posture and prevent back and shoulder pain.
- Femur: Large bone in upper leg/thigh.
- Isokinetic Exercise: Resistance is given at a fixed velocity of movement with accommodating resistance. This uses a computerized device such as the Biodex, and Kin-Com.
- Isotonic Exercise: Shortens and lengthens the muscle through a complete range of motion.
- Plyometric Exercise: Exercises that enable a muscle to reach maximum strength in a short amount of time. These exercises usually involve some form of jumping, but not always.
- Q-angle: A line is drawn from the middle of the knee to the edge of the hip and the middle of the tibia. An angle >20° is excessive and could result in injury to the knee.
- Tibia: Main weight bearing bone in lower leg.
- Valgus Movement: Knee moves into an inward position.

Athletic Injury Evaluations


Hackley Athletic Medicine will provide injury evaluations by an orthopedic physician and certified athletic trainer on Saturday mornings during the 2003 football season (September 6-October 24).

WHO: All Area Athletes
WHERE: Hackley Athletic Medicine Center
Hackley Professional Center
1675 Leahy St. Suite 200
Muskegon, MI 49443
WHEN: Saturday mornings, 8:00 a.m. (SHARP!)
COST: Free consultation; charges apply to diagnostic studies (x-ray, MRI, etc.)

For more information, please feel free to contact us at (231) 728-4820.

Athletic Medicine Training Services
Hackley Hospital Athletic Medicine provides athletic training services to 9 area high schools and Muskegon Community College. These schools are: Fruitport, Montague, Muskegon, Muskegon Heights, North Muskegon, Oakridge, Reeths-Puffer, Western Michigan Christian, and Whitehall.

Hackley Hospital has had an ongoing community outreach sports medicine program for close to 20 years. Besides providing coverage at the local schools, the athletic medicine staff at Hackley is actively involved in many other community events. Hackley Hospital is also the official medical provider for the Muskegon Fury.

Staff Profile
Aaron Ziemba, ATC


Aaron joined the Hackley Sports Medicine and Rehabilitation staff this summer. He is a native of Muskegon and graduated from Fruitport High School. Aaron was a three-sport athlete at Fruitport, participating in football, basketball, and baseball.

Aaron earned his Bachelor of Science degree from Western Michigan University in Exercise Science in 2000. He did his athletic training internship at Hackley in the fall of 1999, during which he was assigned to Muskegon High School, where he served as the Big Red's athletic trainer. His duties now include providing athletic training services to Reeths-Puffer High School, assisting with community outreach programs, and working with patients in the Hackley Sports Medicine Center.

Aaron lives in Muskegon and his hobbies include all sports, playing softball, and playing in a rock band.