Intrarater and interrater reliability of the modified Thomas Test

KIRSTY HOPGOOD, Kate Cady*, Molly Powis

*Corresponding author for this work

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The modified Thomas Test (MTT) is a method of assessing flexibility of the iliopsoas, rectus femoris and tensor fascia Latae. The aim of this study is to identify the intraand inter-rater reliability of the pass/fail scoring for the Modified Thomas Test (MTT) using digital photographs.

Six raters varying between 1-13years of clinical experience were used to review digital photographs of 20 semi-professional rugby players performing the /MTT. Raters were asked to score each muscle of the MTT either with 0 (fail) or 1 (pass). Digital photographs were allocated in a randomized order. Each rater reviewed each photograph three times at two week intervals.

Cronbach's alpha (Cα) revealed a mean result of high reliability for both iliopsoas (Cα = 0.95) and rectus femoris (Cα = 1.00) flexibility. TFL flexibility values ranged from 0.64- 0.95, demonstrating some inconsistencies within some of the 6 raters. Fleiss kappa (Fк) revealed a high mean reliability result across the 3 testing sessions for both iliopsoas (Fк = 0.78) and rectus femoris (Fк = 0.80) flexibility, along with a moderate reliability mean result for TFL (Fк = 0.56).

High intra and inter rater reliability was found for iliopsoas and rectus femoris flexibility with those for TFL found to be moderately reliable.
Original languageEnglish
JournalJournal of Bodywork and Movement Therapies
Early online date12 Oct 2021
Publication statusE-pub ahead of print - 12 Oct 2021


  • modified Thomas Test
  • inter-rater reliability


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