Address work fatigue for patients who are on their feet all day with orthotic support

In a study about the effects of orthotics during the workday, police officers turned out to be excellent test subjects.¹ Insoles made with elastomeric polymers were found to significantly decrease both fatigue and foot symptoms in this study. Most of the officers wore stiff-soled work boots, and reported that the shock-absorbing insoles were comfortable and helped decrease their foot fatigue and symptoms at work, as well as afterward.

The Police Study
Semicustom, flexible insoles were worn by 122 New York City Police Department officers for 5 weeks, for an average of 7 hours per day. The researchers were interested in studying people who spent considerable portions of the workday on their feet. They found that police officers made the ideal subjects for such an investigation, since they spent the majority of their workdays standing or walking on hard surfaces.

Responses to questionnaires collected before and after the 5-week study were used to quantify their foot problems and symptoms, and their satisfaction levels to measure the effects of the supportive insoles. The orthotics used in this investigation were semicustom, in that they were designed for low-, normal-, and high-arched feet. The officers were all in good health, and any who were currently receiving treatment for back, leg, or foot problems were excluded from the study.

Results. The officers walked an average of 3 miles per day during the 5-week study. Before the study began, one fifth of the police officers reported that they regularly experienced foot pain or discomfort at the end of their workday; 15% had calluses, corns, or athlete’s foot; 18% had sought treatment for a foot problem in the past; and 20% had worn foot orthotics at some point previously. After 5 weeks of wearing the semicustom insoles, there was a significant reduction in tiredness in the feet at the end of the day, with 68% reporting less foot discomfort. At the end of the study, 70% of the officers said they planned to continue wearing the insoles.

A similar study demonstrated lower oxygen consumption and improved energy levels in healthy women who were fitted with flexible orthotics and tested on a treadmill.² During walking, their heart rates and blood pressures were consistently lower than the control group, which did not receive shoe inserts. In this study, the orthotics were built based on a “weight-bearing, functional position”² image of the foot, and included support for the medial longitudinal arch.

Shock Absorption
Standing and walking on concrete and other types of rigid flooring during working hours is a significant source of both foot discomfort and spinal complaints. The best materials for work orthotics are the viscoelastic polymers, a group of man-made materials specifically created to improve the body’s ability to dissipate shock to sensitive and easily damaged tissues.

G. R. Johnson, a mechanical engineer, tested four different types of shoes and nine insoles of various materials for magnitude of shock absorption. He reported that “statistically significant reductions of shock factor were noted in 58% of cases; the largest improvement (30% reduction in shock factor) was achieved by lightweight Sorbothane.”³ Since his research, a number of newer biomaterials have been developed that have even better viscoelastic properties.

A study of Voloshin and Wosk is of special interest to doctors of chiropractic.⁴ They found that viscoelastic shoe inserts significantly reduced the reported pain levels in patients with low back pain. Another relevant report comes from Denmark, where a controlled study on soccer referees participating in a 5-day tournament found “the incidence of soreness in Achilles tendons, calves, and backs were significantly reduced by the use of shock-absorbing heel inserts.”⁵ However, it has recently been noted that placing shock absorption under the heel increases the mechanical loads in the anterior part of the foot during walking.⁶ This means that the best orthotics are the newer, full-length insoles made from viscoelastic materials that extend shock absorption to the forefoot.

Work fatigue and musculoskeletal symptoms can be significantly decreased with the use of flexible, shock-absorbing orthotics. Even in patients with no need for specific foot or back treatments, supportive insoles can improve energy levels at work and help reduce subjective reports of tiredness. Whether this is considered a workplace improvement, a wellness initiative, injury prevention, or simply providing needed support for the weight-bearing musculoskeletal system, orthotics should be considered for everyone who spends part of their day standing and walking on concrete, asphalt, or rigid flooring.

The studies referred to in this article spurred me to discuss with my staff our patients who are exposed to extended periods of standing during their normal working hours, such as restaurant staff, factory workers, department store clerks, etc. We all take more of an interest now in our patients’ occupations; and when we note a patient who spends an excessive amount of time on her feet, I often bring up the police study as I perform my regular pedal examinations (checking for collapsed arches, foot flare during gait, and bowed Achilles tendon). Most patients are eager to learn more about anything which may help their tired, aching joints feel better.

Timothy J. Maggs, DC, specializes in sports and industrial medicine and is a graduate of the National College of Chiropractic. He writes and produces a talk radio show on sports medicine and speaks at numerous engagements. Maggs can be reached via email: run ningdr@aol.com.

References
1. Sobel E, Levitz SJ, Caselli MA. The effect of customized insoles on the reduction of postwork discomfort. J Am Podiatr Med Assoc. 2001; 91:515–520.
2. Otman S, Basgoze O, Gokce-Kutsal Y. Energy cost of walking with flat feet. Prosthet Orthot Int. 1988; 12(2):73–76.
3. Johnson GR. The effectiveness of shock-absorbing insoles during walking. Prosthet Orthot Int. 1988; 12(2):91–95.
4. Voloshin A, Wosk J. An in vivo study of low back pain and shock absorption in the human locomotor system. J Biomech. 1982; 15(1):21–27.
5. Fauno P, Kalund S, Andreasen I. Soreness in lower extremities and back is reduced by use of shock absorbing heel inserts. Int J Sports Med. 1993; 14(5):288–290.
6. Hsi WL, Lai JS, Yang PY. In-shoe pressure measurements with a viscoelastic heel orthosis. Arch Phys Med Rehabil. 1999; 80(7):805–810.