Plantar Heel Pain: Multisegment Foot Motion and Muscle Function, FFI Translation, and Evaluation of Treatments

Plantar Heel Pain: Multisegmental Foot Motion and Muscle Function, FFI Translation, and Evaluation of Physical Therapy Treatments

Plantar fasciitis (PF) is a prevalent musculoskeletal condition of plantar heel pain (PHP) that leads to pain, functional limitations, and reduced quality of life, especially among active adults aged 25 to 65. Understanding the biomechanical alterations in foot motion among individuals with PF is essential to inform targeted treatment strategies and prevent symptom chronicity. However, research exploring detailed multi-segment foot motion changes in this population remains limited.

Assessing foot function is a key component in understanding symptom development and treatment outcomes. The Foot Function Index (FFI) is an internationally recognized, reliable, and valid questionnaire used to measure foot pain and disability. To facilitate its use in Thai populations and enable cross-cultural comparisons, it is crucial to translate and validate the FFI into Thai.

Although exercise interventions such as strengthening and stretching are widely used to manage PHP, evidence regarding their relative effectiveness on pain reduction and gait improvement is inconclusive. Rigorous evaluation of these programs is needed to establish evidence-based guidelines for physical therapy in this population.

Study 1: Comparative Study of Gait and Foot Segment Motion Between Individuals with Plantar Fasciitis and Healthy Controls This study aimed to compare multi-segment foot motion during walking between individuals with plantar fasciitis (PF) and healthy controls. A matched case-control design was used, with gait data collected via a 3D motion capture system and analyzed using the Oxford Foot Model.

Study 2: Translation and Validation of the Thai Version of the Foot Function Index (FFI-Th) This study aimed to translate the Foot Function Index (FFI) into Thai (FFI-Th) and evaluate its psychometric properties individuals with plantar foot complaints.

Study 3: Effects of Strengthening and Stretching Exercise Programs on Pain and Gait in Patients with Plantar Fasciitis: A Randomized Controlled Trial This study aimed to investigate the effects of physical therapy interventions-specifically strengthening versus stretching exercise programs-on pain and temporospatial gait parameters in patients with PF.

Study Overview

• Status: Completed
• Conditions: Plantar Fasciitis
• Intervention / Treatment: Procedure: Strengthening exercises; Procedure: Stretching exercises

Detailed Description

Procedure

Study 1: Comparative Study of Gait and Foot Segment Motion Between Individuals with Plantar Fasciitis and Healthy Controls

A matched case-control study recruited individuals with PF and matched healthy controls by age, gender, weight, and height. After informed consent, anthropometric data were collected, and participants wore tight clothing to allow accurate marker placement. Forty-two reflective markers were attached to define foot and lower limb segments following the Oxford Foot Model and Plug-In-Gait protocols. A static calibration trial was recorded, after which some markers were removed. Then, participants performed walking trials along an 8-meter walkway while motion capture cameras and force plates recorded kinematic and kinetic data simultaneously. Each participant completed 3-5 gait trials at a self-selected comfortable speed, with two trials matching the control group's gait speed and cadence selected for analysis. Data were filtered and normalized over the gait cycle for further assessment. Outcome measures included ground reaction forces (GRFs) during braking and propulsion phases and peak multi-segment foot joint angles in three planes.

Study 2: Translation and Validation of the Thai Version of the Foot Function Index (FFI-Th)

This study used a cross-sectional design to translate and validate the Foot Function Index (FFI) into Thai (FFI-Th) following a standardized cross-cultural adaptation process. The steps included independent forward translation by two bilingual translators, synthesis by an expert committee, backward translation by two native English speakers, harmonization through consensus meetings, cognitive interviews with 20 individuals to ensure clarity, and final proofreading by a linguist. To assess criterion validity, participants also completed the EuroQol five-dimensional questionnaire (EQ-5D-5L) for health-related quality of life and a pain visual analogue scale (pain-VAS). These instruments provided comparative data for evaluating the FFI-Th's validity.

Study 3; Effects of Strengthening and Stretching Exercise Programs on Pain and Gait in individuals with Plantar Fasciitis: A Randomized Controlled Trial

This double-blind, randomized controlled trial was used. Individuals with PF were screened and recruited based on specific inclusion and exclusion criteria. After obtaining informed consent, participants were randomly assigned into two groups: strengthening exercises or stretching exercises. All participants received a standardized physical therapy treatment including therapeutic ultrasound and manual therapy, followed by their assigned exercise programs instructed by blinded physical therapists. Participants performed home-based exercises three times daily for 4 weeks, then continued at home for 2 months with exercise logs to monitor compliance. Outcome assessments were conducted five times: baseline, mid-intervention, post-intervention, and at 1- and 2-month follow-ups. Data collected included demographics, pain intensity via visual analogue scale (VAS), and temporospatial gait parameters measured by a force distribution platform and synchronized video system.

• Study Type: Interventional
• Enrollment (Actual): 84
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Thailand
  • Bangkok, Thailand, 10700
    • Physical therapy center, Physical therapy faculty, Mahidol University
  • Nakhonpathom
    • Salaya, Nakhonpathom, Thailand
      • Motion analysis laboratory

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 76 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Study 1: Comparative Study of Gait and Foot Segment Motion Between Individuals with Plantar Fasciitis and Healthy Controls

Inclusion Criteria (PF Group):

• Aged 20-80 years
• Plantar fasciitis (PF) symptoms for at least one month
• Pain or tenderness at the medial calcaneal tubercle or proximal plantar fascia

• At least one of the following symptoms:

  • Morning pain (first steps in the morning)
  • Pain after prolonged sitting
  • Pain during weight-bearing activities

Exclusion Criteria (PF Group):

• Other painful conditions in the lower extremity or back
• History of rheumatoid arthritis
• Neurological or vascular diseases
• Leg length discrepancy >1 cm
• Severe pain preventing walking

Inclusion Criteria (Healthy Controls):

• No current or previous history of PF symptoms
• No foot pain

Exclusion Criteria (Healthy Controls):

• Same as those listed for the PF group

Study 2: Translation and Validation of the Thai Version of the Foot Function Index (FFI-Th) Inclusion Criteria (Individuals with plantar problems)

• Aged 20-80 years
• Experienced plantar foot pain or tenderness for at least one month (at rest or during weight-bearing activities)
• Able to read and communicate in Thai
• No uncorrected visual impairments Exclusion Criteria (Individuals with plantar problems)
• Pain in other areas of the lower extremities
• History of systemic inflammatory diseases
• History of neurological diseases
• Received any treatment during the study period

Study 3: Effects of Strengthening and Stretching Exercise Programs on Pain and Gait in Patients with Plantar Fasciitis: A Randomized Controlled Trial Inclusion Criteria:

• Aged 20-80 years
• Heel pain lasting more than one month
• Pain during the first steps in the morning or after rest
• Tenderness at the medial calcaneal tubercle
• Plantar fascia thickness greater than 4.0 mm (confirmed by ultrasound)

Exclusion Criteria:

• History of back or lower limb surgery within 6 months
• Recent trauma or corticosteroid injections (within 6 months)
• Leg length discrepancy greater than 1 cm
• Pregnancy
• Inability to perform the exercise program
• Receiving other ongoing treatments or performing other foot-specific exercises

• Coexisting conditions including:

  • Achilles tendinopathy
  • Acute ankle sprain
  • Tarsal tunnel syndrome
  • Patellofemoral syndrome
  • Calcaneal spurs
  • Heel pad syndrome

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Strengthening group; Individuals with PF who received strengthening exercises. (study 3)	Procedure: Strengthening exercises; Conservative physical therapy treatment with home-based strengthening exercises (study 3)
Active Comparator: Stretching group; Individuals with PF who received stretching exercises. (study 3)	Procedure: Stretching exercises; Conservative physical therapy treatment with home-based stretching exercises (study 3)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Worst Pain	Worst pain was assessed using the Visual analog scale (VAS), where 0 indicates "no pain" and 10 indicates "pain as bad as participants can imagine". Participants were asked to report their worst pain level over the past 24 hours. Higher scores indicate more severe pain. Unit of Measure: scores	Baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up
Morning Pain	Morning pain intensity upon waking was assessed using a 10 cm Visual Analog Scale (VAS), where participants mark a point along a continuous line anchored by "no pain" (0) and "worst imaginable pain" (10), with higher values indicating more severe morning pain. Unit of Measure: scores	Baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cadence	Cadence refers to the number of steps taken per minute during walking. It is a critical parameter in gait analysis, influencing both performance and injury risk, and the effectiveness of rehabilitation programs. Unit of Measure: steps/minute	Baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up
Stride Length	Stride length is the distance covered between two consecutive placements of the same foot during walking. It represents the length of a full gait cycle, encompassing both the stance and swing phases of the same limb. In clinical assessments, stride length is measured to evaluate gait efficiency, balance, and the effectiveness of rehabilitation program. Unit of Measure: meter	Baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up
Stride Time	Time spend during walking over one gait cycle (s) Stride time refers to the duration of one full gait cycle, measured from the initial contact of one foot to the subsequent initial contact of the same foot. It encompasses both the stance and swing phases of the limb's movement. Stride time is a critical temporal parameter in gait analysis, providing insights into the rhythm and coordination of walking. Unit of Measure: second	Baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up
Gait Speed	Distance of walking over time (m/s) Gait speed refers to the rate at which an individual walks. It serves as a crucial indicator of mobility and overall physical fitness, playing a significant role in assessing an individual's balance, endurance, and functional abilities. Unit of Measure: meter/second	Baseline, 2 weeks after the intervention, 4 weeks after the intervention, 1-month follow-up, and 2-month follow-up

Collaborators and Investigators

• Sponsor: Mahidol University
• Collaborators: Thailand Research Fund
• Investigators: Principal Investigator: Sunee Bovonsunthonchai, PhD, Mahidol University

Publications and helpful links

General Publications

• Lemont H, Ammirati KM, Usen N. Plantar fasciitis: a degenerative process (fasciosis) without inflammation. J Am Podiatr Med Assoc. 2003 May-Jun;93(3):234-7. doi: 10.7547/87507315-93-3-234.
• Martin RL, Davenport TE, Reischl SF, McPoil TG, Matheson JW, Wukich DK, McDonough CM; American Physical Therapy Association. Heel pain-plantar fasciitis: revision 2014. J Orthop Sports Phys Ther. 2014 Nov;44(11):A1-33. doi: 10.2519/jospt.2014.0303.
• Cole C, Seto C, Gazewood J. Plantar fasciitis: evidence-based review of diagnosis and therapy. Am Fam Physician. 2005 Dec 1;72(11):2237-42.
• Chang R, Rodrigues PA, Van Emmerik RE, Hamill J. Multi-segment foot kinematics and ground reaction forces during gait of individuals with plantar fasciitis. J Biomech. 2014 Aug 22;47(11):2571-7. doi: 10.1016/j.jbiomech.2014.06.003. Epub 2014 Jun 11.
• Wearing SC, Smeathers JE, Yates B, Sullivan PM, Urry SR, Dubois P. Sagittal movement of the medial longitudinal arch is unchanged in plantar fasciitis. Med Sci Sports Exerc. 2004 Oct;36(10):1761-7. doi: 10.1249/01.mss.0000142297.10881.11.
• Budiman-Mak E, Conrad KJ, Mazza J, Stuck RM. A review of the foot function index and the foot function index - revised. J Foot Ankle Res. 2013 Feb 1;6(1):5. doi: 10.1186/1757-1146-6-5.
• Hill CL, Gill TK, Menz HB, Taylor AW. Prevalence and correlates of foot pain in a population-based study: the North West Adelaide health study. J Foot Ankle Res. 2008 Jul 28;1(1):2. doi: 10.1186/1757-1146-1-2.
• Sullivan J, Burns J, Adams R, Pappas E, Crosbie J. Musculoskeletal and activity-related factors associated with plantar heel pain. Foot Ankle Int. 2015 Jan;36(1):37-45. doi: 10.1177/1071100714551021. Epub 2014 Sep 18.
• Rathleff MS, Moelgaard C, Lykkegaard Olesen J. Intra- and interobserver reliability of quantitative ultrasound measurement of the plantar fascia. J Clin Ultrasound. 2011 Mar-Apr;39(3):128-34. doi: 10.1002/jcu.20787. Epub 2011 Jan 10.
• Digiovanni BF, Nawoczenski DA, Malay DP, Graci PA, Williams TT, Wilding GE, Baumhauer JF. Plantar fascia-specific stretching exercise improves outcomes in patients with chronic plantar fasciitis. A prospective clinical trial with two-year follow-up. J Bone Joint Surg Am. 2006 Aug;88(8):1775-81. doi: 10.2106/JBJS.E.01281.
• Rathleff MS, Molgaard CM, Fredberg U, Kaalund S, Andersen KB, Jensen TT, Aaskov S, Olesen JL. High-load strength training improves outcome in patients with plantar fasciitis: A randomized controlled trial with 12-month follow-up. Scand J Med Sci Sports. 2015 Jun;25(3):e292-300. doi: 10.1111/sms.12313. Epub 2014 Aug 21.
• Bovonsunthonchai S, Thong-On S, Vachalathiti R, Intiravoranont W, Suwannarat S, Smith R. Thai version of the foot function index: a cross-cultural adaptation with reliability and validity evaluation. BMC Sports Sci Med Rehabil. 2020 Sep 10;12:56. doi: 10.1186/s13102-020-00206-8. eCollection 2020.

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2017
• Primary Completion (Actual): February 1, 2019
• Study Completion (Actual): March 1, 2019

Study Registration Dates

• First Submitted: May 8, 2017
• First Submitted That Met QC Criteria: May 17, 2017
• First Posted (Actual): May 19, 2017

Study Record Updates

• Last Update Posted (Actual): July 4, 2025
• Last Update Submitted That Met QC Criteria: June 13, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: exercise; gait; physical therapy; stretching; strengthening; plantar fasciitis; translation; plantar heel pain; multisegment foot motion
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Foot Diseases; Fasciitis; Fasciitis, Plantar
• Other Study ID Numbers: MU-CIRB 2016/182.0211

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No