Dynamic measurement of pennation angle of gastrocnemius muscles during contractions based on ultrasound imaging

Yongjin Zhou, Ji Zhou Li, Guangquan Zhou, Yongping Zheng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

42 Citations (Scopus)


Background: Muscle fascicle pennation angle (PA) is an important parameter related to musculoskeletal functions, and ultrasound imaging has been widely used for measuring PA, but manually and frame by frame in most cases. We have earlier reported an automatic method to estimate aponeurosis orientation based on Gabor transform and Revoting Hough Transform (RVHT).Methods: In this paper, we proposed a method to estimate the overall orientation of muscle fascicles in a region of interest, in order to complete computing the orientation of the other side of the pennation angle, but the side found by RVHT. The measurements for orientations of both fascicles and aponeurosis were conducted in each frame of ultrasound images, and then the dynamic change of pennation angle during muscle contraction was obtained automatically. The method for fascicle orientation estimation was evaluated using synthetic images with different noise levels and later on 500 ultrasound images of human gastrocnemius muscles during isometric plantarflexion.Results: The muscle fascicle orientations were also estimated manually by two operators. From the results it's found that the proposed automatic method demonstrated a comparable performance to the manual method.Conclusions: With the proposed methods, ultrasound measurement for muscle pennation angles can be more widely used for functional assessment of muscles.
Original languageEnglish
Article number63
JournalBioMedical Engineering Online
Publication statusPublished - 3 Sept 2012


  • Electromyography
  • EMG
  • Gastrocnemius muscle
  • Hough transform
  • Orientation
  • Pennation angle
  • SMG
  • Sonomyography
  • Ultrasound image

ASJC Scopus subject areas

  • Biomedical Engineering
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Biomaterials


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