The Effects of Rehabilitation and Minimalist Shoes on Pain, Strength, and Function in Adults With Plantar Fasciopathy

Individuals with plantar fasciopathy (PF) can struggle with even the most simple of daily tasks due to their foot pain, leading to reduced physical activity, recurrent episodes, and an overall decline in quality of life. There are a host of deficits in physical function that can both cause and be a result of pain, including reduced intrinsic foot muscle (IFM) strength and size, poorer postural control, and compensations in gait mechanics, such as reduced impact forces on the painful limb. Combined with the increased levels of kinesiophobia and fear-avoidance that also often occur, individuals with PF can experience a cycle of reduced activity, poorer physical function, and increased fear of movement that hinders their recovery. The problem is that most individuals are recommended and pursue more passive interventions of rest, ice, orthoses, stiffer shoes, or more invasive corticosteroid injections. There are much fewer recommendations of implementing active, movement-based interventions in order to improve physical function, as a treatment for this disorder. Previous research has indicated that strengthening the IFM via exercises or through wearing minimalist shoes are an effective treatment to reduce pain and improve function. However, these studies have not observed other functional measures or psychological outcomes after these interventions.
The purpose of all 3 manuscripts was to assess the effects of implementing an 8-week routine of daily strengthening exercises and wearing minimalist shoes (FRAMES group), compared to only exercises (control), on the recovery of individuals with PF regarding pain, function, physical attributes and psychological measures.

The purpose of Manuscript 1 was to specifically asses the effects of this program on self-reported measures of pain, perception of recovery, and function at baseline, 4-weeks, and 8-weeks, assessed with patient reported outcomes. We found that individuals with PF who performed strengthening exercises for 8 weeks, with or without the addition of minimalist shoes, were able to significantly decrease their pain and increase their function. A greater percentage of individuals in the FRAMES group were also able to achieve a minimally clinically important difference in self-perceived function. However, the most important aspect of these findings is that strengthening exercises are effective in this population, and the addition of minimalist shoes did not take away from their ability to recover.

The purpose of Manuscript 2 was to assess the effects of this intervention on objective functional measures of foot morphology, IFM strength assessed via dynamometers, IFM size via diagnostic ultrasound, single-leg balance with a force plate, and gait kinetics using pressure-sensing insoles. We found that all individuals in the study were able to achieve significant increases in IFM strength, and that several IFM muscles achieved significant increases in only the FRAMES group, which were the flexor hallucis brevis and quadratus plantae. However, there were no significant changes in single-limb balance in either group or any changes in impact forces during walking gait.

The purpose of Manuscript 3 was to determine what baseline factors of self-reported pain, function, psychological beliefs, and physical attributes are the most important in achieving the best improvements in pain and function after undergoing the intervention. The secondary purpose was to determine the effect of the interventions on psychological variables of kinesiophobia, fear-avoidance belief, and pain self-efficacy. We found that individuals with poorer baseline self-reported outcomes of lower function, higher pain, and higher kinesiophobia were associated with greater recoveries in pain and function, likely because of a larger margin for improvement. We also found that physical traits of stronger and larger IFM at baseline were associated with greater reductions in pain. However, first peak impact force during treadmill walking gait and center-of-pressure path length during single-limb balance were not associated with recovery of pain or function. It was also found that the total cohort was able to decrease their kinesiophobia and increase their self-efficacy after the intervention, although there were no changes in fear-avoidance belief and no differences between the groups.

These results show that implementing a short but daily strengthening intervention, with or without the use of minimalist shoes, can improve self-reported outcome measures of pain, function, and psychological beliefs, for individuals with PF. They are also able to significantly alter their physical function. Minimalist shoes can assist in improving IFM size over 8 weeks, however, and can increase self-reported function to a greater degree than the control group. This study is the first of its kind to assess physical function and psychological variables in individuals with PF after a movement-based intervention. These findings show that improving foot and total body function for this clinical population can be an effective treatment, and that minimalist shoes can potentially serve as an adjunct treatment.