Injury Breakdown: Exercises in Futility – Part 3
By Abby Sims
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Parts three and four of the “Exercises in Futility” series will continue to address lower body exercises more likely to result in injury than benefit. Safe alternatives utilizing better and less stressful mechanics are offered in order to reduce the potential for injury. Dead lifts (#1) were reviewed in the prior post. Some of the other prime offenders targeting the lower body are:
2. Full Arc Leg Extensions
3. Deep Squats
4. Full Arc Back Extensions
5. Hurdlers Stretches
6. Hamstring Stretches with the Leg Propped Up too High
2. Full Arc Leg Extensions
The Leg Extension Machine targets the quadriceps muscle group (in the front of the thigh) and, though it may be a favorite of trainers in the gym, this exercise has many detractors in the sports medicine community. The primary role of the quads is to extend (straighten) the knee, though one of the four muscles in the group also crosses the hip and acts to flex the hip (drawing the knee toward the chest).
By straightening the knee through a long arc of motion, particularly against resistance, excessive shearing and compressive forces are placed on the patellofemoral joint*. These stresses can predispose to a wearing down of the smooth and glassy cartilaginous surface that lines each of the bones. Conditions such as patellofemoral syndrome, patellofemoral joint degeneration or chondromalacia (literally meaning a softening of the cartilage) may be unfortunate and painful outcomes.
In life (unlike this exercise), your knee is rarely required to bend and straighten against resistance while the foot moves freely. Even when kicking a soccer ball with correct form the knee is essentially straight. Generally, when you bend or straighten your knee against resistance, your foot is planted on the floor (as when climbing stairs, lowering yourself to sit down or when rising from a chair). In these cases, the resistance is that of gravity plus your body weight. These functional motions, with the foot firmly planted, are known as closed chain activities. The foot being fixed closes the chain.
*The patella (kneecap) and the femur (thigh bone) below don’t actually form a true joint, because the patella must be mobile and ride up and down in the groove at the base of the femur in order to allow the knee to work as a hinge. Feel your kneecap ride upward as you straighten (extend) your knee and downward as you bend (flex). The more flexed the knee as it is loaded, the greater the compressive forces. The end result is often wear and tear of the smooth surfaces of the patella and the groove in the femur where it glides. Normally these surfaces resemble the glassy ice at the skating rink after the Zamboni does its thing. With Chondromalacia, for example, the degenerative changes cause the boney surfaces to look more like crabmeat. At their worst, the surfaces are so worn that they are described as being “bone on bone”. The end result is pain with bending and straightening the knee, particularly as it is loaded. Symptoms are generally most evident when going up or down stairs, with running, with sitting in one place for an extended period or, paradoxically, with some exercises that strengthen the quadriceps.
Well, that said, here is the dilemma – the best thing to do for arthritic changes or pain under the kneecap (or anywhere at the knee for that matter) is to strengthen the weak muscles and stretch any tight muscles of the lower body to create symmetry (right/left), normal strength, endurance and flexibility. The quadriceps muscles are of paramount importance, and weakness, poor endurance or tightness of the quads often ties directly into kneecap pain. However, as always, all exercises should be pain-free and should not reproduce symptoms, even mildly.
Alternatives to the Leg Extension Machine:
The simplest way to begin strengthening the quads is to do Straight Leg Raises. Those executed while lying on your back are for the quads and they can be progressed to higher levels by doing them in more upright positions – such as sitting with your leg extended and resting on your (bent) elbows, resting on outstretched arms (extended elbows) or at their most difficult, sitting upright against the wall. All these straight leg raises should be performed slowly, with the opposite knee bent and with tight abdominals to take the stress off your back. They can be progressed further by adding cuff weights to your ankles.
Another alternative involves straightening the knee just as with the leg extension but only through a modified/small arc of motion. This exercise is called Terminal Knee Extension because it involves working through the end range of motion. Rest the knee on a foam roll or pillow so that it is slightly bent (no more than 30 degrees) and proceed to straighten it through that short range. Just as with straight leg raises, resistance can be progressed with ankle cuff weights. The forces at the kneecap in this terminal range are focused more at the bottom of the patella and are not as dangerous as those when the knee is flexed more completely.
Other alternatives to the leg extension machine involve a series of progressively more difficult “closed kinetic chain” exercises for the lower body. Closed chain exercises are the focus of any solid rehab and strengthening program. Remember, in closed chain exercises for the lower body the foot is fixed (planted) and weight bearing (as for function). These exercises are great preparation for ski season, and, from basic to more advanced they include:
a. Terminal Knee Extension: Just as with the “open chain” (foot in motion)
version described above, this closed chain alternative focuses on the final 30 degrees of motion when straightening your knee.
Secure a resistive band to a stationary object and stand inside the circle formed by the band, wrapping it just above the crease in the back of your knee. Stand in a staggered stance (like you are going to do a small lunge), and control your knee as you allow it to bend slowly. Then straighten your knee against the resistance of the band. Keep your knee behind the plane of your toes at all times.
b. Bridges: Lie with knees bent and feet flat & in contact with the exercise mat. Tighten abdominals to perform a pelvic tilt (this rotates the pelvis to flatten your back) and press through the front of your feet while raising your buttocks off the mat. Keep your heels in contact with the mat at all times and avoid raising the butt so high that it causes your back to arch.
This exercise can be advanced to an intermediate level by crossing one leg over the other and performing on one leg. An advanced version, also using only one side, requires that one knee is extended (straight) and that it remain parallel to the thigh of the working side throughout the exercise. It is important to use your abdominals throughout the exercise to maintain a level pelvis.
c. Wall Slides or Wall Squats: This exercise is a great one to help you progress to the free- standing squat. By leaning on the wall you are bearing some of your weight through your back and limiting the weight borne by your lower body. The wall squat can be performed against a glossy surface (such as a mirror), or using a ball placed at the low back to cut down on the friction as the exerciser slides on a wall.
Starting Position: Stand with your back and head against the mirror, feet/hips shoulder width apart and abdominals tight. Toes should be pointed forward and the knees should line up with the middle of your feet (the second toe). Walk your feet far enough away from the mirror, so that at the lowest point in the exercise (when your knees are bent to 90 degrees), your knees will be directly over your ankles.
The Exercise: Slide your trunk down the mirror by bending your knees until they are at a right angle. If your feet are too close to the wall, your knees will extend past the plane of your toes. If your feet are too far away, your knees will not even reach your ankles. Be sure to keep your weight on your heels and push through the heels to rise back up. Perform the exercise slowly and complete 2-3 sets of 10-15 reps.
If doing the exercise on a wall, using a ball at the low back, your back should remain parallel to the wall at all times (vertical) and your knees should not extend beyond your ankles at the low point of the range of motion.
You may have to work your way up to doing the full arc (90 degree) wall slide by beginning with a shorter arc and progressing from there.
d. Wall Sits: This exercise focuses on quadriceps endurance and is performed at the end-range position of the wall squat. Stand against the wall, as described above, with the hips and knees at right (90 degree) angles, abdominals tight, feet pointed forward and hip width apart. Maintain this position (with the knees directly over the ankles) for a selected period of time. Consider beginning with 20 seconds and gradually progressing to a minute or more. Repeat for several (3-5) repetitions.
e. Free Standing Squats: This exercise is simply a more advanced version of the wall squat. Now that the wall is out of the picture, 100% of your weight bearing is through your lower body. When performed symmetrically, as desired, that means 50% of your weight is on each leg. The free squat will also recruit your inner thigh muscles (adductors) and buttocks (gluts) more than the wall version. Avoid spreading your feet too far apart as it will de-emphasize your quads and result in your hamstrings helping out more.
To maintain your balance with the free squat, it is necessary to allow your knees to move past the plane of your ankles as you bend them. However, you should avoid allowing the knees to move beyond the plane of the toes. Bend forward (from your hips) as you bend your knees as if lowering yourself to a chair. This will help you control your center of gravity and correctly position your knees with respect to your toes. As with the wall squat, push through your heels as you slowly straighten your knees to rise up.
f. Step-Ups and Step-Downs: A step or platform can be used to work the lower body through controlled ranges of knee motion. The higher the step, the more quad strength and control required, because the working knee must bend and straighten through a larger range of motion. Step work challenges balance as well as strength and requires more strength than squats because the exercise demands that 100% of body weight is borne on one leg.
In all step exercises (except the most advanced forward step-downs), your knees should remain behind the plane of your toes to avoid excessive shearing forces at the patellofemoral joint. At the most basic level, the exercise is concentric only (a shortening contraction of the quads). This involves stepping up with one foot followed by the other and then stepping back to the floor in the same sequence.
An intermediate version entails stepping up with one foot and maintaining that foot on the step throughout the exercise as you slowly reach back to lower and raise the opposite foot, each time gently transferring the weight to the back foot as it touches down to the floor.
The most advanced version is similar. Keep one foot up on the step throughout the exercise, with the lowered foot touching down without bearing any weight at all. Slowly rise back up, maintaining your weight entirely on the foot that is on the step.
In all step exercises it is crucial to use a step that is low to start out (about 4 inches) and allow the step height to control the range of bending required of the knee. The foot that is lowered to the floor should be flexed at the ankle so that the heel touches down at the same time as the forefoot. Avoid reaching back too far with the foot as it is lowered. When the exercise is too easy, simply advance it by adding risers to the platform.
g. Lunges: Whether performed statically, or dynamically, lunges are great exercises for those who have developed a readiness for doing them. As with all exercises, they are only good for you if they are pain-free.
Assume a staggered stance with a reasonable but not excessive stride length. Bend the front knee toward a right angle while touching the back knee toward the floor. The keys to performing lunges correctly are:
Not to allow the front knee to reach forward of the ankle
To maintain your body weight on your front heel/foot
To avoid pushing off the rear foot as you rise back up
To control the speed of the exercise
As for squats, partial arc lunges may be helpful in progressing toward working through the full 90 degrees.
3. Deep Squats
Though the deep squat is a closed chain exercise, it is a dangerous one for all the reasons outlined in the description of why the correctly performed Free-Standing Squat is a better alternative. With the deep squat, the end-range of knee flexion (bending) becomes the focus. It is a range in which the forces placed on the knee are magnified and with resistance (body weight, gravity and any added weights) they are exaggerated further. The exercise makes it virtually impossible to keep the knee behind the plane of the toes, thereby increasing the compressive and shearing forces on the joint. Structures such as the meniscus (fibrocartilage) are also vulnerable in this position. Alternatives are all the exercises previously described.
Part 4 of this series on Exercises in Futility will cover the remaining lower body exercises.
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- Injury Breakdown: Exercises in Futility – Lower Body (newyork.cbslocal.com)