Exercise & Training

Morphological and mechanical properties of the knee extensors between strength training and cross-training practitioners: A cross-sectional study.

TL;DR

Cross-training practitioners demonstrated higher knee extensor peak torque at all tested velocities and higher 1RM squat compared to strength training practitioners, despite no differences in fascicle length, muscle thickness, stiffness, or specific tension between groups.

Key Findings

Cross-training practitioners showed higher pennation angle compared to strength training practitioners, with no differences in fascicle length or muscle thickness.

  • Pennation angle was higher in the CT group with an effect size of ES = 0.66
  • No significant differences were found between groups for fascicle length (FL) or muscle thickness (MT) (p > 0.05)
  • Sample consisted of 20 strength training and 17 cross-training male practitioners with at least 2 years of experience in their respective modality
  • Muscle architecture was assessed via vastus lateralis ultrasound imaging

Cross-training practitioners demonstrated higher knee extensor peak torque at all tested isokinetic velocities compared to strength training practitioners.

  • Peak torque was higher for CT compared to ST at 60°/s, 180°/s, and 300°/s (p < 0.05)
  • Effect sizes ranged from ES = 1.03 to 1.38 across the tested velocities
  • Peak torque was measured using an isokinetic dynamometer and normalized to maximum voluntary isometric contraction

Cross-training practitioners had higher estimated one-repetition maximum in the barbell back squat compared to strength training practitioners.

  • 1RM was higher for CT compared to ST (p < 0.05) with effect sizes ranging ES = 1.03–1.38
  • 1RM was estimated within three trials with knee flexion standardized at 120° (0° = full extension)
  • 1RM was normalized to body mass

No differences in vastus lateralis stiffness or specific tension were found between strength training and cross-training practitioners.

  • Stiffness was assessed via shear-wave velocity measurement
  • Specific tension was calculated based on muscle thickness and peak torque
  • Both stiffness and specific tension showed p > 0.05 between groups

Strength training practitioners had higher training experience and weekly training volume compared to cross-training practitioners, while cross-training practitioners were older.

  • ST group had higher training experience (ES = 1.02) and higher weekly training volume (ES = 0.88; p < 0.05)
  • CT group showed higher age (ES = 1.09)
  • These differences represent important covariates in the cross-sectional design

Interrater reliability for muscle architecture measurements was good to excellent.

  • Intraclass correlation coefficient (ICC) ranged from 0.841 to 0.992 (p < 0.05)
  • Reliability was classified as ranging from 'good to excellent'
  • ICC was used to assess muscle architecture reliability across raters

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Citation

Viera H, Gidiel-Machado L, Pinto R, Lanferdini F. (2026). Morphological and mechanical properties of the knee extensors between strength training and cross-training practitioners: A cross-sectional study.. Clinical physiology and functional imaging. https://doi.org/10.1111/cpf.70054