This study compares the addition instrument-assisted soft tissue mobilization (IASTM) to a program of home strengthening and stretching exercises to see whether adding weekly IASTM treatments improves plantar fasciopathy pain and plantar fascia stiffness.

Plantar fasciopathy (PF) is the most common cause of inferior heel pain, and approximately 40% of patients report symptoms two years following initial diagnosis. Exercise therapy, including gastrocnemius and plantar fascia stretching, and high-load strengthening have been shown to improve plantar fascia pain and function; however, not everyone improves with these interventions, and they require several weeks or months to be effective. The addition of instrument-assisted soft tissue mobilization (IASTM) techniques may improve these outcomes. Moreover, shear wave elastography (SWE) is an imaging technology that may provide helpful information regarding PF diagnosis and prognosis. Therefore, research is required to investigate changes in plantar fascia stiffness following exercise and IASTM interventions.

This study is divided into two Parts. Part I is a parallel-group, pre-test post-test randomized controlled superiority trial comparing the long-term effects of stretching and strengthening exercises (SS) (Group 1, n=35) versus SS plus IASTM (SS+IASTM, Group 2, n=35) in subjects with PF. The study is approved by the local Intuitional Review Board. The Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidelines for reporting of randomized interventional trials will be followed. Exercise interventions will be reported according to the Consensus on Exercise Reporting Template (CERT) guideline. Part II is a pre-test, post-test comparison of the short-term effects of IASTM on PF. Subjects from Group 2 of Part I (n=35) and a age and sex-matched healthy comparison group (Group 3, n=35) will participate in Part II.

Random group allocation into SS and SS+IASTM Groups will be performed by an independent statistician using the R Statistics package using a 1:1 allocation ratio with permuted block sizes of 2 to 6. Although it is not possible to blind study participants, the investigators performing the weekly interventions and measurements will be blinded to the subjects' group allocation.

After randomization subjects will receive a booklet that describes their condition and contains exercise instructions and an exercise training and medication usage diary. Group 1 will receive a sheet listing evidence for the beneficial effects of stretching and high-load strengthening. Group 2 will additionally receive information regarding the hypothesized benefits of IASTM. After group allocation and reading the appropriate booklet, subjects will complete the Credibility/Expectancy Questionnaire (CEQ), which contains six items requiring subjects to rate the credibility of the intervention and their expectations.

Both groups will perform an identical exercise program but will additionally receive once weekly IASTM treatments over an 8-week period. The weekly and total treatment time in Groups 1 and 2 will be the same, 15 minutes/week for 8 weeks. Group 3 (Comparison Group) will be recruited in clusters of five after every 5 subjects are recruited into Group 2 (SS+IASTM) and will be matched to that group's age and BMI.

Overall, subjects in Groups 1 and 2 will visit the lab 10 times. First, they will attend eight weekly sessions, which will include initial screening tests and exercise education on visit 1, treatments according to group allocation on visits 1-8, and follow-up testing on visits 5, 9, and 10. Both groups will additionally perform daily stretching and strengthening exercises at home. Between sessions 9 and 10 (i.e., weeks 9-11), these subjects will be contacted via telephone for follow-up testing and encourage continued home exercise program compliance. Group 3 will attend one session. This session will include screening tests before and after one IASTM treatment.

Data will be summarized in descriptive statistics such as mean (standard deviation), median (interquartile range), and frequencies (percentage) as appropriate depending on the variable levels of measurement. Associations among categorical variables will be assessed using Chi-square or Fisher's exact test. Associations among continuous or ordinal level variables will be assessed using appropriate parametric or non-parametric correlation tests. Differences among demographic groups on continuous baseline variables will be assessed using t-test and ANOVA or their non-parametric alternatives (Mann-Whitney or Kruskal Wallis tests) where appropriate.

The examined data in this study are clustered (nested) in nature. For example, the Foot Health Status, a dependent variable which is measured for both groups (the SS and SS + IASTM) through different subscales including pain subscale, function subscale, footwear subscale, and general foot health subscale (level 1), at different time points (level 2), within each individual participant (level 3). Therefore, linear mixed modeling is a suitable analytical technique to handle the data and answer research questions.

Since the levels of the examined factors in the study constitute all the levels of interest for statistical inference, a covariance pattern fixed effects model that accounts for the covariance and correlational patterns among repeated measures could be the most suitable for this study to be utilized (among other different Mixed Model approaches that would be tested and implemented).

Inclusion Criteria for Plantar Fasciopathy Groups

• age 18-60 years
• self-reported history of plantar heel pain for a minimum of 2 months prior to enrollment
• pain on palpation of the medial calcaneal tubercle or the proximal plantar fascia
• pain is worst when first standing or walking after rest
• willing to attempt not to use additional treatments (e.g., shoe modifications, foot orthoses/braces, injections, or surgery) during the trial period (12 weeks)
• willing to attempt to discontinue taking all pain-relieving medications except Tylenol or ibuprofen for plantar heel pain during the trial period (12 weeks).

Inclusion Criteria for Healthy Comparison Group:

• age and BMI matched with Group 2 subjects
• no history or symptoms of plantar heel pain in the past 12 months

Exclusion Criteria for all three groups:

• history of direct trauma to the foot with plantar fasciopathy
• inflammatory arthritis in the feet/ankle (e.g., ankylosing spondylitis or rheumatoid arthritis)
• metabolic or endocrine disorders (e.g., Type I or II diabetes)
• neurological disorders (e.g., Charcot-Marie-Tooth disease)
• prior foot surgery on the foot with plantar fasciopathy
• pregnancy (by self-report)
• corticosteroid injection to treat plantar fasciopathy in the past 12 weeks
• body mass index > 35 kg/m2
• receiving or applied for worker compensation benefits
• no physical activity above 5 (moderate activity) on a 10-point Rating of Perceived Exertion scale in the past 24 hours prior to the initial screening visit.

Random group allocation into Groups 1 and 2 will be performed using a 1:1 allocation ratio with permuted block sizes of 2 to 6. The investigators responsible for the weekly progression of the stretching and strengthening exercise protocol and the outcome assessor will be masked to the participants' assigned groups. The investigators providing instrument-assisted soft tissue mobilization will not be blinded to group assignment.