The acronym RICE—more often now with an added “P” to spell PRICE—has for decades represented the broadly defined guidelines for effective rehab from sports injury. The key components of this traditional recovery protocol are protection (such as casting the injury if necessary), rest (from the activity), ice, compression (such as wrapping the injury in an elastic bandage) and elevation (of the injured body part). Yet as clinical recommendations evolve and new technologies develop, it’s wise to update injury management from time to time, and it could be time right now for a (P)RICE overhaul.
In an editorial published two years ago in the British Journal of Sports Medicine, a strong case is made for a new roadmap to runners’ rehab called POLICE. What’s new here is that rest has been replaced with the more nuanced concept of optimal loading, represented by the “OL” in POLICE. And the increasingly popular new mechanism by which this type of treatment is delivered is the weightless treadmill.
Companies like AlterG, Inc. are developing very promising treatment protocols using these “anti-gravity” machines that support your weight at adjustable percentages while you run or walk. Reduced bodyweight running can be effective in reducing lower extremity pain induced by full weight-bearing exercise. What is gained by optimal loading instead of rest is the benefit from metabolic load, while over time slowly building up structures for a faster healing process than rest until full load bearing is tolerated can provide.
Short periods of unloading immediately following soft tissue injury are usually required for the healing process to begin, but we are outgrowing the idea that protection and rest should be prolonged. Before anti-gravity treadmills, load tended to be all or nothing; now there are ways to fine-tune what a patient bears for the best possible scenario of rest and active recovery. As the editorial notes, “Longer periods of unloading are harmful and produce adverse changes to tissue biomechanics and morphology. Progressive mechanical loading is more likely to restore the strength and morphological characteristics of collagenous tissue.” This gradual load increase over time is sometimes termed “functional rehabilitation” to distinguish it from more traditional all-out rest.
Functional rehabilitation invokes principles of “mechanotherapy,” during which loading prompts cellular responses that promote favorable tissue structural change. With ankle sprain, for example, early weight bearing usually with an external support is now widely seen as better than cast immobilization of the ankle. The difficult clinical challenge lies in finding the balance between loading and unloading—the optimal part of POLICE.
The editorial notes that, “If tissues are stressed too aggressively after injury, the mechanical insult may cause re-bleeding or further damage. But too much emphasis [on rest] creates a default mindset that loading has no place in acute management. Rest may be harmful and inhibit recovery.”
Research on weightless treadmilling reveals that jogging at 4.5 mph with 50% bodyweight support
provides the same vertical knee joint reaction force as walking with full bodyweight. The promising reality here is that for any given amount of weight support, metabolic demand can be increased by increasing walking or running speed. The treadmill has applications beyond acute injury recovery as well.
In one study, 25 obese adults with moderate knee osteoarthritis pain participated in a 12-week weightless treadmill exercise program, twice a week for 25 minutes each session. Reducing bodyweight loading by 18% (about 35 lbs) was effective in reducing knee joint pain during initial walking. Strength levels for the quadriceps and hamstring muscle groups increased significantly following the program.
Another small study found improvements in balance, mobility and lower extremity strength in eldery women who participated in an eight-week program. In general, exercise routines aimed at improving cardiorespiratory fitness can be effective in reducing the risk of early mortality in sedentary adults. Therefore, partial bodyweight support has indirect effects on weight reduction by enabling exercise in people otherwise unable to do so. If POLICE refines a more traditional healing paradigm for better results for injured athletes, new technologies like the weightless treadmill help deploy the new strategies with greater precision for promising use in both sports rehab and general wellness interventions.