by Jason Boyer, M.D.
ACL injuries mostly occur as non-contact injuries in sports in which sudden stops, landing, and rotation maneuvers are repeatedly performed – as in soccer, basketball and many others. Female players suffer up to ten times more often from these injuries compared to males. By following a simple routine for prevention, you can considerably lower your risk of ACL injury.
The anterior cruciate ligament (ACL) is one of the major stabilizing ligaments in the knee joint. This ligament basically prevents excessive movements of the lower leg against the thigh. Unlike most ligaments in the body, the ACL ligament can be injured without an external force being active. In fact, 70 % of all ACL injuries are non-contact in nature, while the remaining 30% involve an outside force such as an opposing player, a goalpost, or another object on the field of play.
While contact injuries cannot be foreseen and therefore leave little room to avoid them, a good understanding of injury mechanisms in non-contact ACL injuries might help to prevent them. Typical mechanisms involve a one step-stop deceleration, cutting tasks, a sudden change of direction, landing from a jump with the knee and hip at or near full extension - or simply a lapse of concentration.
What are factors that increase or decrease rates of ACL injuries?
The effectiveness of functional knee braces in preventing non-contact ACL injuries is not proven and therefore braces are not encouraged.
Playing Surfaces and Shoes
Uneven playing surfaces may play a role such as landing or stepping on an uneven surface like a hole in the grass or the foot of another player, as may irrigation of the field.
Cold weather seems to be associated with the risk of lower knee and ankle injury in outdoor stadiums–both natural grass and turf.
Why do men and women have different rates of ACL injuries?
There are multiple differences in knee architecture between men and women and it was once assumed that they could explain the higher risk for female players. However, current evidence on the impact of these differences is inconclusive.
There seems to be no direct link of an increase in ACL injury to a predictable time within the menstrual cycle.
Strength and Balance
Muscular strength and balance are crucial to stabilize your knee, and this varies between men and women. Basically, the muscle that extends the knee, called quadriceps, works “against” the ACL while the ones that flex the knee, called hamstrings, work “with” the ACL. At the same time, these two muscle groups should countervail each other when stabilizing the knee. If the hamstrings are weak or contract not exactly attuned to the quadriceps, the ACL may be at an increased risk for injury. The same applies for landing from a jump with extended hip and knee.
How to protect your ACL
On average, you will miss approximately six to nine months of competitive play as a result of an ACL injury and undergoing reconstructive surgery and rehabilitation. In about two thirds of all complete ACL tears there is concomitant damage to the menisci and the cartilage of the knee joint. In addition, complete ACL tears can lead to long-term problems, including instability and an early onset of arthrosis of the knee. Arthrosis is normally found in elderly people as a consequence of ageing. Having your ACL reconstructed can significantly reduce your risk for later injuries and damage, but it cannot totally avert them. Therefore, you should aim to prevent ACL tears from occurring in the first place.
There are several programs focusing on the prevention of ACL tears and injuries. They have been shown to reduce severe ACL injuries by 60 to 89%, but it can take approximately six to eight weeks for such a program to show an effect. We present here the program developed by the Santa Monica Orthopaedic and Sports Medicine Research Foundation.
This prevention program consists of a warm-up, stretching, strengthening, plyometrics, and specific agilities to optimize the strength and coordination of the stabilizing muscles around your knee joint. It is important to use the proper technique during all of the exercises. Therefore, you need to pay full attention to correct posture, avoid excessive side-to-side movement when jumping and ensure soft landings.
This program should be completed 2 to 3 times a week at a minimum and should take approximately 15 minutes to complete. Alongside each exercise you will notice a box with the approximate amount of time that should be spent on each activity. This will serve as a guideline to you in order to conduct your warm-up in a time-efficient manner.
The field should be set up 10 minutes prior to the warm-up. This will allow for a smooth and quick transition between all of the activities.
Warming up and cooling down are a crucial part of a training program. The purpose of the warm-up section is to prepare your body for activity. By warming up your muscles first, you greatly reduce the risk of injury.
a. Jog Line to Line (cone to cone)
Elapsed Time: 0 - 30 seconds
Purpose: Ensure a good running technique. Keep your hip/knee/ankle in straight alignment without your knee caving in or your feet whipping out to the side.
Instruction: Complete a slow jog from near to far sideline.
b. Shuttle Run (side to side)
Elapsed Time: 30 - 60 seconds
Purpose: Engage your hip muscles at the inner and outer thigh. This exercise will promote increased speed. Carefully avoid inward caving of the knee joint.
Instruction: Start in an athletic stance with a slight bend at the knee. Leading with the right foot, sidestep pushing off with the left foot (back leg). When you drive off with the back leg, be sure your hip/knee/ankle are in a straight line. Switch sides at half field.
c. Backward Running
Elapsed Time: 1 - 1.5 minutes
Purpose: Continue your warm-up, engage your hip extensors/hamstrings. Make sure you land on your toes. Watch for locking of your knee joint. As you bring your foot back, make sure you maintain a slight bend to your knee.
Instruction: Run backwards from sideline to sideline. Land on your toes without snapping the knee back. Stay on your toes and keep the knees slightly bent at all times.
It is important to warm-up prior to stretching: Never stretch a "cold muscle". By doing the exercises outlined here, you can improve and maintain your range of motion, reduce stiffness in your joints, reduce post-exercise soreness, reduce the risk of injury and improve your overall mobility and performance.
a. Calf Stretch (30 seconds x 2 repetitions)
Elapsed Time: 1.5 - 2.5 minutes
Purpose: Stretch the calf muscle of you lower leg.
Instruction: Stand leading with your right leg. Bend forward at the waist and place your hands on the ground (V formation). Keep your right knee slightly bent and your left leg straight. Make sure your left foot is flat on the ground. Do not bounce during the stretch. Hold for 30 seconds. Switch sides and repeat.
b. Quadriceps Stretch (30 seconds x 2 repetitions)
Elapsed Time: 2.5 - 3.5 minutes
Purpose: Stretch the quadriceps muscle of the front of your thigh.
Instruction: Place your left hand on your partner’s left shoulder. Reach back with your right hand and grab the front of your right ankle. Bring your heel to buttock. Make sure your knee is pointed down toward the ground. Keep your right leg close to your left. Do not allow your knee to wing out to the side and do not bend at the waist. Hold for 30 seconds and switch sides.
c. Figure Four Hamstring Stretch (30 sec x 2 repetitions)
Elapsed Time: 3.5 - 4.5 minutes
Purpose: To stretch the hamstring muscles of the back of your thigh.
Instruction: Sit on the ground with your right leg extended out in front of you. Bend your left knee and rest the bottom of your foot on your right inner thigh. With a straight back, try to bring your chest toward your knee. Do not round your back. If you can, reach down toward your toes and pull them up toward your head. Do not bounce. Hold for 30 seconds and repeat with the other leg.
d. Inner Thigh Stretch (20 sec x 3 repetitions)
Elapsed Time: 4.5 - 5.5 minutes
Purpose: Elongate the muscles of your inner thigh (adductors)
Instruction: Remain seated on the ground. Spread you legs evenly apart. Slowly lower yourself to the center with a straight back. You want to feel a stretch in the inner thigh. Now reach toward the right with the right arm. Bring your left arm overhead the stretch over to the right. Hold the stretch and repeat on the opposite side.
e. Hip Flexor Stretch (30 sec x 2 repetitions)
Elapsed Time: 5.5 - 6.5 minutes
Purpose: Elongate the hip flexors of the front of your thigh.
Instruction: Lunge forward leading with your right leg. Drop your left knee down to the ground. Placing your hands on top of your right thigh, lean forward with your hips. The hips should be square with your shoulders. If possible, maintain your balance and lift back for the left ankle and pull your heel to your buttocks. Hold for 30 seconds and repeat on the other side.
This portion of the program focuses on increasing leg strength. This will lead to increased leg strength and a more stable knee joint. Please note that here, technique is everything! Pay close attention to exactly perform the exercises in order to avoid injury.
a. Walking Lunges (3 sets x 10 repetitions)
Elapsed Time: 6.5 - 7.5 minutes
Purpose: Strengthen the thigh (quadriceps) muscle.
Instruction: Lunge forward leading with your right leg. Push off with your right leg and lunge forward with your left leg. Drop the back knee straight down. Make sure that your keep your front knee over your ankle. Control the motion and try to avoid your front knee from caving inward. If you cannot see your toes on your leading leg, you are doing the exercise incorrectly.
b. Russian Hamstring (3 sets x 10 repetitions)
Elapsed Time: 7.5 - 8.5 min
Purpose: Strengthen your hamstrings.
Instruction: Kneel on the ground with hands at your side. Have a partner hold firmly at your ankles. With a straight back, lean forward leading with your hips. Your knee, hip and shoulder should be in a straight line as you lean toward the ground. Do not bend at the waist. You should feel the hamstrings in the back of your thigh working. Repeat the exercise for 3 sets of 10, or a total of 30 repetitions.
c. Single Toe Raises (30 reps x 2 repetitions)
Elapsed Time: 8.5 - 9.5 minutes
Purpose: This exercise strengthens your calf muscle and increases balance.
Instruction: Stand up with your arms at your side. Bend the left knee up and maintain your balance. Slowly rise up on your right toes with good balance. You may hold your arms out ahead of you in order to help. Slowly repeat 30 times and switch to the other side. As you get stronger, you may need to add additional repetitions to this exercise to continue the strengthening effect of the exercise.
These exercises are explosive and help to build, power, strength and speed. The most important element when considering performance technique is the landing. It must be soft! When you land from a jump, you want to softly accept your weight on the balls of your feet slowly rolling back to the heel with a bent knee and a straight hip. These exercises are basic, however, it is critical to perform them correctly. Please take the time to ensure safe and correct completion of these exercises.
a. Lateral Hops over Cone (20 repetitions)
Elapsed Time: 9.5 - 10 minutes
Purpose: Increase power/strength emphasizing neuromuscular control
Instruction: Stand with a 6" cone to your left. Hop to the left over the cone softly landing on the balls of your feet land bending at the knee. Repeat this exercise hopping to the right.
b. Forward/Backward Hops over Cone (20 repetitions)
Elapsed Time: 10 - 10.5 minutes
Purpose: Increase power/strength emphasizing neuromuscular control.
Instruction: Hop over the cone/ball softly landing on the balls of your feet and bending at the knee. Now, hop backwards over the ball using the same landing technique. Be careful not to snap your knee back to straighten it. You want to maintain a slight bend to the knee. Repeat for 20 repetitions.
c. Single Leg Hops over Cone (20 repetitions)
Elapsed Time: 10.5 - 11 minutes
Purpose: Increase power/strength emphasizing neuromuscular control.
Instruction: Hop over the cone/ball landing on the ball of your foot bending at the knee. Now, hop backwards over the ball using the same landing technique. Be careful not to snap your knee back to straighten it. You want to maintain a slight bend to the knee. Repeat for 20 reps. Now, stand on the left leg and repeat the exercise. Increase the number of repetitions as needed.
d. Vertical Jumps with Headers (20 repetitions)
Elapsed Time: 11 - 11.5 min
Purpose: Increase height of vertical jump.
Instruction: Stand forward with hands at your side. Slightly bend the knees and push off jumping straight up. Remember the proper landing technique; accept the weight on the ball of your foot with a slight bend to the knee. Repeat 20 times and switch sides.
e. Scissors Jump (20 repetitions)
Elapsed Time: 11.5 - 12 minutes
Purpose: Increase power and strength of vertical jump.
Instruction: Lunge forward leading with your right leg. Keep your knee over your ankle. Now, push off with your right foot and propel your left leg forward into a lunge position. Be sure your knee does not cave in or out. It should be stable and directly over the ankle. Remember the proper landing technique; accept the weight on the ball of your foot with a slight bend to the knee. Repeat 20 times.
a. Shuttle Run with Forward/Backward Running
Elapsed Time: 12 - 13 minutes
Purpose: Increase dynamic stability of the ankle/knee/hip complex.
Instruction: Starting at the first cone, sprint forward to the second cone, run backward to the third cone, sprint forward to the fourth cone (etc.).
b. Diagonal Runs (3 passes)
Elapsed Time: 13 - 14 minutes
Purpose: To encourage proper technique/stabilization of the outside planted foot to deter the position from occurring.
Instruction: Face forward and run to the first cone on the left. Pivot off the left foot and run to the second cone. Now pivot off the right leg and continue onto the third cone. Make sure that the outside leg does not cave in. Keep a slight bend to the knee and make sure the knee stays over the ankle joint.
c. Bounding Run (44 yards)
Elapsed Time 14 - 15 minutes
Purpose: To increase hip flexion strength/increase power/speed.
Instruction: Starting on the near sideline, run to the far side with knees up toward chest. Bring your knees up high. Land on the ball of your foot with a slight bend at the knee and a straight hip. Increase the distance as this exercise gets easier.
6. ALTERNATIVE EXERCISES – Warm Down and Cool Down.
Cooling down your body is imperative. Please do not skip it! It allows your muscles that have been working hard throughout the training session to elongate and deters the onset of muscle soreness. The cool down should take approximately 10 minutes. It should begin with a slow jog to allow your heart rate to come down before stretching and be followed by some light strength training exercises. We are recommending two strengthening exercises (a and b). Finally, stretch your hamstrings, calves, inner thigh, quadriceps, and low back as described above. In addition to those basic stretches, try the additional stretches to target three muscle groups that are often forgotten as described under c, d and e. Make sure you have a water bottle by your side during the cool down and take in enough fluid.
a. Bridging with Alternating Hip Flexion (30 repetitions)
Purpose: Strengthen outer hip muscles (Hip abductors, flexors) and buttocks
Instruction: Lie on the ground with your knees bent with feet on the ground. Raise your buttocks up off the ground and squeeze. Now, lift your right foot off the ground and make sure that your right hip does not dip down. Lower your right foot and now lift your left foot making sure your left hip does not dip down. Repeat 30 times on each side. As you get stronger, you will place your feet on top of a ball and repeat the exercise.
b. Abdominal Crunches (30 repetitions x 2)
Purpose: Strengthen your abdominals.
Instruction: Lie on the ground with your knees bent. Place your hands behind your head with your elbows out wide. Support your neck lightly with your fingers. Take a deep breath in and slowly contract your abdominal muscles as you exhale. Repeat 30 times. Drop your legs off to the right side. Slowly crunch up with your elbows out wide. You should feel your oblique muscles working on the side of your waist. Repeat 30 times and switch to the other side.
c. Single and Double Knee to Chest (30 seconds x 2 repetitions)
Purpose: Elongate your low back muscles.
Instruction: Lie on your back. Bring your right knee toward your chest and hug firmly. Keep your left leg out straight in front of you. You should feel a stretch along your low back and into your buttocks. Hold the stretch for 30 seconds and switch sides. Now bring both knees to chest. If you feel any pain in the low back, discontinue the stretch and inform your coach/trainer.
d. Figure Four Piriformis Stretch - Supine (30 seconds x 2 repetitions)
Purpose: Elongate the rotators of the hip.
Instruction: Lie on your back and bend both of your knees. Fold your left ankle over your right knee. Place your hands behind your right thigh and pull your right knee to chest. You should feel a good stretch in the left buttock and the side of the thigh. Hold for 30 seconds and repeat on the other side. If you experience low back pain with this stretch, slowly lower your legs down and let your coach/trainer know.
e. Seated Butterfly Stretch – Seated (30 seconds x 2 repetitions)
Purpose: Elongate your inner thigh muscles (adductors).
Instruction: Sit up bringing your feet in so that the soles of your feet are touching. Gently place your elbows on your knees and slowly push down. You should feel a good stretch of the inner thigh. Hold this for 30 seconds and repeat 2 to 3 times.
sources include: http://la84.org
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Disclaimer: The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this website.
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