Sport-specific endurance, strength, power, and neuromuscular patterning have their places in the grand scheme of things athletic. However, we can also look at the rehabilitation and postrehabilitation of a joint in the same fashion. Joint stability, range of motion (ROM), and strength (relative, absolute, and functional) are essential elements to ensure a positive outcome for patient and practitioner alike.
While rotary, or single-joint, movements have their valid place in the realms of stability and ROM in the therapeutic environment, compound-or multijoint-movements produce the best and safest functional strength gains. So what is functional strength? Let's look at the three general types of strength comparatively.
Absolute strength is the greatest amount of resistance you can overcome no matter what your size. Relative strength is the amount of resistance you can overcome relative to your size, and it is typically expressed as a factor or a power to weight ratio. And functional strength is, as it sounds, the application of strength to overcome your individual, real-world resistances (activities of daily living, or ADL).
Functional strength is crutial when working with an over-50 population where sarcopenia, osteoarthritis, and obesity conspire to rob patients of their independence. For example, a 65-year-old with a total knee replacement (TKR) can leg press 350 pounds. This is his absolute strength. Without knowing anything else, we would be inclined to think this patient is pretty strong. When we come to find out that our 65-year-old weighs 360 pounds, a fact that probably played a role in his need for a new knee, we see that his relative strength is average. Now we observe that our 360-pound TKR patient who can leg press 350 pounds can't get out of a chair under his own power. His functional strength is poor.
There are many options for working on functional strength with patients, and each one has its unique benefit. Here we will look at some of the options and which patients can benefit from each.
AEROBIC EQUIPMENT
Strength endurance is an essential component of functional strength. The stronger, trained muscle, with its greater surface area and mitochondrial density, takes up oxygen more efficiently. This lessens the load on the cardiopulmonary system. For example, you have COPD and need to carry a basket of laundry up a flight of stairs; it is a great example of functional strength.
Recumbent bikes, recumbent steppers, and recumbent ellipticals are necessary in a therapy environment. Let's take a look at what is available today.
The new T5XR recumbent cross trainer from NuStep Inc, Ann Arbor, Mich, has many improvements over the company's T4.
"The seat now swivels 360 degrees, and step-through height has been reduced from 18 to 4 inches," explains NuStep representative Richard Newton. "Also, the articulating foot bed has
Scifit, Tulsa, Okla, is also offering a recumbent stepper as well as its REX recumbent elliptical exerciser. The REX offers bidirectional resistance as well as isokinetic capability. In isokinetic mode, the PT can set the RPM ceiling. Once the user bumps into that ceiling, an electromagnetic brake maintains it. The harder the user pushes against the ceiling RPM, the harder the brake clamps down to maintain the RPM. The user's power is measured in watts. With this system, isokinetic resistance can never overpower the user but can only match their output.
Biodex Medical Systems, Shirley, NY, offers the Biostep semirecumbent elliptical. While the Biodex unit also offers isokinetic capability, it only goes as low as 50 RPM. Many users, specifically those who are extremely deconditioned or who have neuromuscular impairment, might not achieve that speed under their own power even with zero resistance.
RELATIVE STRENGTH TRAINING
Relative strength training for the lower extremity is a cost-effective and dynamic way to perform closed-chain compound movements. The ability to carry your own body weight through a ROM such as getting in and out of a car, climbing stairs, and getting off the toilet seat unassisted will gauge your functional strength. Even world-class athletes like those on the US Rowing Team measure strength relative to each athlete's body weight.
A hack squat, for example, is basically a squat performed on a padded board on an angled track. The back lies flat against the padded board; the steeper the angle of the track, the greater the percentage of body weight will be pushed. There are numerous hack squat devices on the market that allow the user to perform a squat movement pushing against all or portions of
Shuttle Systems from Contemporary Design Company, Glacier, Wash, have geriatric, therapeutic, and athletic applications. Shuttles operate as a sled in the horizontal plane utilizing Elasticord resistance. Some units have the versatile ability to lock out and serve as a solid, confidence-inspiring treatment table. The Shuttle Mini Press is a portable leg press about the size of a piece of carry-on luggage that also utilizes Elasticord resistance. The footplate adjusts from horizontal to 75, so it can be used supine or seated.
David Beaudoin of Jackson County Physical Therapy, Ashland, Ore, utilizes different squats, lunges, smith machine activities, and leg presses. Beaudoin introduces half round foam rollers and BOSU balls to squat and lunge work for stability training.
"The simpler the program, the greater the compliance," Beaudoin says.
From the spartan and effective pulley systems from Rehab Pro, Phoenix, to the elaborate, electronically adjusted Power Tower from EFI Sports Medicine, San Diego, these units offer an attractive price point and relative ease of use. Lower-extremity exercises such as squats, split squats, and jump squats-both single- and double-legged-work well on these units.
AIR FOR RESISTANCE
In addition to body weight resistance and band resistance, there is compressed air resistance. Functionally, you are only as strong as the weakest point in a given ROM. Whereas acceleration has the potential to allow a person to mask, or cheat, a lack of muscular strength when using free weight, pneumatic resistance does not.
Keiser, Fresno, Calif, and HUR USA Inc, Northbrook, Ill, both offer pneumatic leg presses that are able to adjust the weight in 1-pound increments. The leg presses record information via Keiser's E-chip and HUR's Smart Card technology.
Both band and pneumatic strength movements offer ROM that is progressive; as the user's mechanical strength increases, so too does the resistance. Put another way, the resistance remains constant relative to the mechanical advantage of the user. This is not only physiologically superior to a free weight stack, it is safer as well. It is virtually impossible to out-accelerate the resistance, so the user cannot "throw" the weight, which could eventually injure the joint and connective tissues or transferring the load away from the muscle.
FREE WEIGHTS
Of course,plate-loaded machines and free weights have their place in functional strength training.
Dana Bacon, PT, at AGMC Sports and Physical Therapy in Akron, Ohio, utilizes two plate-loaded leg presses from Cybex, Medway, Mass. One is seated and one is supine. With her stroke and Parkinson's patients she also gets functional strength gains through step-ups.
"We use the step-ups to focus on weight transfer from side to side, foot to foot, and for quad/glute recruitment. The other really nice thing about the step-up is that the patient can practice aft/fore weight transfer as they shift their body weight forward onto the foot that is stepping up."
Cindy Powell, PT, at Kleiman & Stamper in Ashland, Ore, uses a plate-loaded leg press by Precor, Woodinville, Wash, for postoperative knee patients, patients who cannot load their spine, and anyone who is not yet weight-bearing.
"In our decision-making process we said, 'What would be the one piece of equipment that captures the widest audience?' and our answer was the leg press," Powell says. "Once the patient is fully load-bearing we progress to standing partial squats, forward and side lunges, and then on to the Smith machine."
ERGOMETERS
Rowing ergometers, such as the one from Concept2, Morrisville, Vt, offer as complex a movement as can be found, involving flexion and extension of the ankles, knees, and hips in a dynamic, nonconcussive environment.
When coached sufficiently, the user will also recruit postural musculature for more efficient functional power and proprioception. Similar to Keiser, the ergometer uses air resistance, but rather than using an air compressor, the user generates his own wind resistance by spinning a bladed flywheel. The faster the flywheel spins, the greater the resistance. Like the Scifit isokinetic phase,the user's effort will determine the ergometer's resistance.
COMPOUND BIOMECHANICAL FORCE/LOAD DYNAMICS
Scifit's new Function Line is made up of four pieces of equipment (terminal trunk extension, terminal knee extension, compound hamstring curl, and core flexion) integrating the Humac 360 visual feedback and balance testing technology from CSMi Solutions, Stoughton, Mass. With the Function Line, multiplane resistance reinforces the brain's dominant neuromuscular pattern of a given movement by introducing a separate plane resistance, recruiting supplemental muscle groups and an additional neuromuscular pattern. This reduces shear and axial load on the joint structure being worked. Less shear and load preserves the integrity of the joint structure which, with sufficient muscular support, preserves function.
TIMING IS EVERYTHING
Understanding osteokinematics, the gross movements of the joints and bones, is not enough to fully understand the joint structure. Arthrokinematics-the smaller movements of roll, glide, and spin in the bone ends of the joint-also need to be accounted for.
Michael Jones, PhD, PT, president of the American Academy of Health, Fitness, and Rehabilitation Professionals, reminds us that the primary engagement is of the therapist working manually with the patient.
"Remember that the machines are nothing more than tools," he says. "The therapist needs to fully understand the clinical anatomy and pathology first. Work with the joint, then the muscle, and then the neurology in that order. The machines come in the later stages of treatment."
While rotary, or single-joint, movements have their valid place in the realms of stability and ROM in the therapeutic environment, compound-or multijoint-movements produce the best and safest functional strength gains. So what is functional strength? Let's look at the three general types of strength comparatively.
Absolute strength is the greatest amount of resistance you can overcome no matter what your size. Relative strength is the amount of resistance you can overcome relative to your size, and it is typically expressed as a factor or a power to weight ratio. And functional strength is, as it sounds, the application of strength to overcome your individual, real-world resistances (activities of daily living, or ADL).
Functional strength is crutial when working with an over-50 population where sarcopenia, osteoarthritis, and obesity conspire to rob patients of their independence. For example, a 65-year-old with a total knee replacement (TKR) can leg press 350 pounds. This is his absolute strength. Without knowing anything else, we would be inclined to think this patient is pretty strong. When we come to find out that our 65-year-old weighs 360 pounds, a fact that probably played a role in his need for a new knee, we see that his relative strength is average. Now we observe that our 360-pound TKR patient who can leg press 350 pounds can't get out of a chair under his own power. His functional strength is poor.
There are many options for working on functional strength with patients, and each one has its unique benefit. Here we will look at some of the options and which patients can benefit from each.
AEROBIC EQUIPMENT
Strength endurance is an essential component of functional strength. The stronger, trained muscle, with its greater surface area and mitochondrial density, takes up oxygen more efficiently. This lessens the load on the cardiopulmonary system. For example, you have COPD and need to carry a basket of laundry up a flight of stairs; it is a great example of functional strength.
Recumbent bikes, recumbent steppers, and recumbent ellipticals are necessary in a therapy environment. Let's take a look at what is available today.
The new T5XR recumbent cross trainer from NuStep Inc, Ann Arbor, Mich, has many improvements over the company's T4.
"The seat now swivels 360 degrees, and step-through height has been reduced from 18 to 4 inches," explains NuStep representative Richard Newton. "Also, the articulating foot bed has
Scifit, Tulsa, Okla, is also offering a recumbent stepper as well as its REX recumbent elliptical exerciser. The REX offers bidirectional resistance as well as isokinetic capability. In isokinetic mode, the PT can set the RPM ceiling. Once the user bumps into that ceiling, an electromagnetic brake maintains it. The harder the user pushes against the ceiling RPM, the harder the brake clamps down to maintain the RPM. The user's power is measured in watts. With this system, isokinetic resistance can never overpower the user but can only match their output.
Biodex Medical Systems, Shirley, NY, offers the Biostep semirecumbent elliptical. While the Biodex unit also offers isokinetic capability, it only goes as low as 50 RPM. Many users, specifically those who are extremely deconditioned or who have neuromuscular impairment, might not achieve that speed under their own power even with zero resistance.
RELATIVE STRENGTH TRAINING
Relative strength training for the lower extremity is a cost-effective and dynamic way to perform closed-chain compound movements. The ability to carry your own body weight through a ROM such as getting in and out of a car, climbing stairs, and getting off the toilet seat unassisted will gauge your functional strength. Even world-class athletes like those on the US Rowing Team measure strength relative to each athlete's body weight.
A hack squat, for example, is basically a squat performed on a padded board on an angled track. The back lies flat against the padded board; the steeper the angle of the track, the greater the percentage of body weight will be pushed. There are numerous hack squat devices on the market that allow the user to perform a squat movement pushing against all or portions of
Shuttle Systems from Contemporary Design Company, Glacier, Wash, have geriatric, therapeutic, and athletic applications. Shuttles operate as a sled in the horizontal plane utilizing Elasticord resistance. Some units have the versatile ability to lock out and serve as a solid, confidence-inspiring treatment table. The Shuttle Mini Press is a portable leg press about the size of a piece of carry-on luggage that also utilizes Elasticord resistance. The footplate adjusts from horizontal to 75, so it can be used supine or seated.
David Beaudoin of Jackson County Physical Therapy, Ashland, Ore, utilizes different squats, lunges, smith machine activities, and leg presses. Beaudoin introduces half round foam rollers and BOSU balls to squat and lunge work for stability training.
"The simpler the program, the greater the compliance," Beaudoin says.
From the spartan and effective pulley systems from Rehab Pro, Phoenix, to the elaborate, electronically adjusted Power Tower from EFI Sports Medicine, San Diego, these units offer an attractive price point and relative ease of use. Lower-extremity exercises such as squats, split squats, and jump squats-both single- and double-legged-work well on these units.
AIR FOR RESISTANCE
In addition to body weight resistance and band resistance, there is compressed air resistance. Functionally, you are only as strong as the weakest point in a given ROM. Whereas acceleration has the potential to allow a person to mask, or cheat, a lack of muscular strength when using free weight, pneumatic resistance does not.
Keiser, Fresno, Calif, and HUR USA Inc, Northbrook, Ill, both offer pneumatic leg presses that are able to adjust the weight in 1-pound increments. The leg presses record information via Keiser's E-chip and HUR's Smart Card technology.
Both band and pneumatic strength movements offer ROM that is progressive; as the user's mechanical strength increases, so too does the resistance. Put another way, the resistance remains constant relative to the mechanical advantage of the user. This is not only physiologically superior to a free weight stack, it is safer as well. It is virtually impossible to out-accelerate the resistance, so the user cannot "throw" the weight, which could eventually injure the joint and connective tissues or transferring the load away from the muscle.
FREE WEIGHTS
Of course,plate-loaded machines and free weights have their place in functional strength training.
Dana Bacon, PT, at AGMC Sports and Physical Therapy in Akron, Ohio, utilizes two plate-loaded leg presses from Cybex, Medway, Mass. One is seated and one is supine. With her stroke and Parkinson's patients she also gets functional strength gains through step-ups.
"We use the step-ups to focus on weight transfer from side to side, foot to foot, and for quad/glute recruitment. The other really nice thing about the step-up is that the patient can practice aft/fore weight transfer as they shift their body weight forward onto the foot that is stepping up."
Cindy Powell, PT, at Kleiman & Stamper in Ashland, Ore, uses a plate-loaded leg press by Precor, Woodinville, Wash, for postoperative knee patients, patients who cannot load their spine, and anyone who is not yet weight-bearing.
"In our decision-making process we said, 'What would be the one piece of equipment that captures the widest audience?' and our answer was the leg press," Powell says. "Once the patient is fully load-bearing we progress to standing partial squats, forward and side lunges, and then on to the Smith machine."
ERGOMETERS
Rowing ergometers, such as the one from Concept2, Morrisville, Vt, offer as complex a movement as can be found, involving flexion and extension of the ankles, knees, and hips in a dynamic, nonconcussive environment.
When coached sufficiently, the user will also recruit postural musculature for more efficient functional power and proprioception. Similar to Keiser, the ergometer uses air resistance, but rather than using an air compressor, the user generates his own wind resistance by spinning a bladed flywheel. The faster the flywheel spins, the greater the resistance. Like the Scifit isokinetic phase,the user's effort will determine the ergometer's resistance.
COMPOUND BIOMECHANICAL FORCE/LOAD DYNAMICS
Scifit's new Function Line is made up of four pieces of equipment (terminal trunk extension, terminal knee extension, compound hamstring curl, and core flexion) integrating the Humac 360 visual feedback and balance testing technology from CSMi Solutions, Stoughton, Mass. With the Function Line, multiplane resistance reinforces the brain's dominant neuromuscular pattern of a given movement by introducing a separate plane resistance, recruiting supplemental muscle groups and an additional neuromuscular pattern. This reduces shear and axial load on the joint structure being worked. Less shear and load preserves the integrity of the joint structure which, with sufficient muscular support, preserves function.
TIMING IS EVERYTHING
Understanding osteokinematics, the gross movements of the joints and bones, is not enough to fully understand the joint structure. Arthrokinematics-the smaller movements of roll, glide, and spin in the bone ends of the joint-also need to be accounted for.
Michael Jones, PhD, PT, president of the American Academy of Health, Fitness, and Rehabilitation Professionals, reminds us that the primary engagement is of the therapist working manually with the patient.
"Remember that the machines are nothing more than tools," he says. "The therapist needs to fully understand the clinical anatomy and pathology first. Work with the joint, then the muscle, and then the neurology in that order. The machines come in the later stages of treatment."
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