Publications by Type: Journal Article

Background: While higher ground reaction forces (GRF) have been a suspected cause of plantar fasciitis (PF), its relationship is still unclear. Muscle fatigue is known to cause higher GRFs, but no known studies have examined the relationship between pretibial strength and PF. Purpose: The purpose of this study is to compare pretibial strength and specific gait characteristics in those with unilateral PF with gender-matched healthy participants. Study Design: Case-control study. Methods: Twenty participants with unilateral PF (mean age 47 years, 13 females) were compared between involved and uninvolved feet as well as with twenty gender-matched healthy controls (mean age 43 years, 13 females). A handheld dynamometer was used to measure the strength of tibialis anterior (TA) and extensor hallucis longus (EHL). A pressure treadmill was utilized to quantify gait parameters such as initial toe contact and max GRF. Results: Some evidence demonstrated EHL strength to be weakened in involved feet of the PF group when compared to healthy controls (0.07 kg (0.02) vs 0.08 kg (0.03), P=0.11, η2=0.4). As well, the involved side of the PF group exhibited some evidence of early toe initial contact versus healthy controls (34.6% gait cycle (10.6) vs 38.8% gait cycle (13.3), P=0.14, η2=0.4). Mean max GRF was also found to be significantly higher in the PF group versus healthy controls (involved versus controls, 780.4 N (98.6) vs 700.2 N (126.9) P=0.02, η2=0.7; uninvolved vs controls, 789.8 N (100.0) vs 692.7 N (126.0) P=0.01, η2=0.9). Discussion/Conclusion: While no significant differences were noted with TA strength between groups, some evidence for a weak EHL coinciding with early initial toe contact during gait may exist in those with PF. This study is relevant as it possibly identifies a muscle group needing to be strengthened when treating PF.

BACKGROUND: Ultrasound is a widely used diagnostic tool for patients with plantar fasciitis. However, the lack of standardization during the measurement for plantar fascia thickness has made it challenging to understand the etiology of plantar fasciitis, as well as identify risk factors, such as gender. The purpose of this study was to investigate gender differences regarding plantar fascia thickness while controlling for metatarsophalangeal (MTP) joint position in the healthy and those with unilateral plantar fasciitis. METHODS: Forty participants (20 with unilateral plantar fasciitis and 20 controls) with plantar fascia thickness (mean age, 44.8 ± 12.2 years) participated in this study. The majority were females (n = 26, 65%). Plantar fascia thickness was measured via ultrasound 3 times at 3 different MTP joint positions: (1) at rest, (2) at 30 degrees of extension, and (3) at maximal extension. RESULTS: When comparing gender differences, the males in the plantar fasciitis group had a significantly thicker plantar fascia than the females ( P = .048, η2 = 2.35). However, no significant differences were observed between healthy males and females. The males with unilateral plantar fasciitis also had significantly thicker asymptomatic plantar fasciae collectively compared with controls ( P \textless .05), whereas females with unilateral plantar fasciitis had a similar but not significant change. CONCLUSION: It appears that healthy males and females have similar plantar fascia thickness. However, as plantar fasciitis develops, males tend to develop thicker plantar fasciae than their female counterparts, which could have future treatment implications. LEVEL OF EVIDENCE: Level III, case-control comparative study.

Ultrasound is an inexpensive method for quantifying plantar fascia thickness, especially in those with plantar fasciitis. Ultrasound has also been used to assess the effectiveness of various treatments for plantar fasciitis by comparing plantar fascia thickness before and after an intervention period. While a plantar fascia thickness over 4 mm via ultrasound has been proposed to be consistent with plantar fasciitis, some researchers believe the 4 mm plantar fascia thickness level to be a dubious guideline for diagnosing plantar fasciitis due to the lack of standardization of the measurement process for plantar fascia thickness. In particular, no universal guidelines exist on the positioning of the metatarsophalangeal (MTP) joints during the procedure and the literature also has inconsistent protocols. The purpose of this study is to investigate and compare the influence of MTP joint extension on plantar fascia thickness in healthy participants and those with unilateral plantar fasciitis. The plantar fascia thickness of forty participants (20 with unilateral plantar fasciitis and 20 control) was measured via ultrasound three times at three different MTP joint positions: 1) at rest, 2) 30° of extension from the plantar surface, and 3) maximal extension possible. The plantar fascia became significantly thinner as MTP joint extension increased in both the plantar fasciitis group (p \textless 0.001) and the control group (p \textless 0.001). In the plantar fasciitis group, the involved plantar fascia was 1.2 to 1.3 mm thicker (p \textless 0.001) than the uninvolved side depending on the MTP joint position. In the control group, the difference in plantar fascia thickness between the two sides was less than 0.1 mm (p \textless 0.92) at any MTP joint position. MTP joint position can influence the ultrasound measurement of plantar fascia thickness. It is recommended that plantar fascia thickness measurements be performed with the toes at rest. If MTP joints must be extended, then the toes should be extended maximally and then noted to ensure subsequent ultrasound procedures are repeated. Standardizing the position of the MTP joints is not only important for attaining the most accurate thickness measurement of the plantar fascia, but is also important to researchers who use plantar fascia thickness to determine the effectiveness of various plantar fasciitis interventions.