Site-Specific Tissue Property Differences Between Plantar Fasciopathy and Healthy Groups After One Instrument-Assisted Soft Tissue Mobilization

Plantar fascia tissue is heterogeneous and reacts to external load differently across its length. This characteristic reveals the need to examine tissue mechanical properties from different tissue sites. Ultrasound B-mode and elastography measurements of the plantar fascia origin show it is thicker and less stiff in those with symptomatic plantar fasciopathy, but diagnostic accuracy outcomes are inconsistent. Instrument-Assisted Soft Tissue Mobilization (IASTM) is one clinical treatment choice for treating plantar fasciopathy. Preliminary studies show IASTM improves plantar fasciopathy symptoms, but the mechanism is unclear.This dissertation consists of two studies. The first study's purposes were to examine tissue property differences at origin and navicular sites in pathological and healthy control (PF and CON) groups and to explore the diagnostic accuracy of site-specific tissue property measurements. The purposes of the second study were to compare the short-term effects of IASTM on tissue properties, and ankle and first metatarsal phalangeal joint (MTPJ) weight-bearing range of motion (ROM) in PF and CON groups and to identify PF group symptom changes after an IASTM intervention. Fifty subjects (7 males and 18 females per group) matched on age ±5 years (43.02 ± 10.38), BMI ± 3 kg/m2 (26.46 ± 3.84), and physical activity level were recruited. Symptomatic PF subjects were experienced:1) plantar heel pain for more than three months, 2) discomfort during heel palpation, and 3) pain during the first-morning step. The intervention for the second study included a 5-minute biking warm-up and a 10-minute IASTM intervention. Tissue stiffness, as shear wave velocity (SWV in m/s), and tissue thickness (mm) were measured before and after IASTM intervention. In the first study, two-way mixed ANOVAs were used to analyze group and site effects on SWV and, Mann-Whitney U tests were used to determine group effect on origin thickness. Receiver operating characteristic curves were used to perform diagnostic accuracy analyses. In the second study, two-way mixed ANOVAs were used to confirm group or intervention effects on tissue properties and weight-bearing ROM, and a Wilcoxon Signed-Rank test was used to examine the pre-post intervention effect on symptoms. For the first study, site (p<.001; navicular > origin sites) and group (p=.005; CON > PF group) main effects were found. Significantly greater origin site thickness (p<0.001) and lower first MTPJ ROM (p=0.003) were identified in the PF group. A thickness cutoff score of 3.52 mm presented the best diagnostic accuracy. For the second study, subjects exhibited a group main effect for origin site stiffness (p=.014; ηp2=.12; CON> PF) and navicular site stiffness (p=.036; ηp2=.088; CON> PF). A statistically significant interaction was found in origin thickness (p=.001; ηp2=.203). A greater group difference was found before the IASTM intervention than after. An intervention main effect was found in ankle ROM (p<0.001; ηp2=.413; Post >Pre). Group (p=0.014; ηp2=.119; CON>PF) and intervention (p=0.039; ηp2=.086; Post > Pre) main effects were identified in first MTPJ ROM. Lastly, VAS pain was significantly decreased after IASTM (p<0.001; ηp2=.633). In conclusion, the navicular and origin site stiffness decreased in PF group. Origin site thickness can serve as a single diagnostic criterion to determine chronic plantar fasciopathy. Clinicians should address toe ROM in plantar fasciopathy treatments. A single bout of IASTM leads to immediate increases in weight-bearing first MTPJ and ankle ROM and significantly decreases pain in people with plantar fasciopathy.