Architectural Changes of the Biceps Femoris Long Head after Concentric or Eccentric Training

Ryan G Timmins, Joshua D. Ruddy, Joel Presland, Nirav Maniar, Anthony J Shield, Morgan D Williams, David A Opar

Research output: Contribution to journalArticlepeer-review

135 Downloads (Pure)


PURPOSE: To determine the architectural adaptations of the biceps femoris long head (BFlh) after concentric or eccentric strength training interventions and the time course of adaptation during training and detraining.

METHODS: Participants in this intervention (concentric training group [n = 14], eccentric training group [n = 14], male subjects) completed a 4-wk control period, followed by 6 wk of either concentric- or eccentric-only knee flexor training on an isokinetic dynamometer and finished with 28 d of detraining. Architectural characteristics of BFlh were assessed at rest and during graded isometric contractions using two-dimensional ultrasonography at 28 d prebaseline; baseline; and days 14, 21, and 42 of the intervention and then again after 28 d of detraining.

RESULTS: BFlh fascicle length was significantly longer in the eccentric training group (P < 0.05; d range, 2.65-2.98) and shorter in the concentric training group (P < 0.05; d range, -1.62 to -0.96) after 42 d of training compared with baseline at all isometric contraction intensities. After the 28-d detraining period, BFlh fascicle length was significantly reduced in the eccentric training group at all contraction intensities compared with the end of the intervention (P < 0.05; d range, -1.73 to -1.55). There was no significant change in fascicle length of the concentric training group after the detraining period.

CONCLUSIONS: These results provide evidence that short-term resistance training can lead to architectural alterations in the BFlh. In addition, the eccentric training-induced lengthening of BFlh fascicle length was reversed and returned to baseline values after 28 d of detraining. The contraction mode specific adaptations in this study may have implications for injury prevention and rehabilitation.

Original languageEnglish
Pages (from-to)499-508
Number of pages10
JournalMedicine and Science in Sports and Exercise
Issue number3
Publication statusPublished - 31 Mar 2016


  • Adaptation, Physiological
  • Adult
  • Hamstring Muscles
  • Humans
  • Isometric Contraction
  • Knee
  • Male
  • Muscle Strength
  • Resistance Training
  • Ultrasonography
  • Young Adult
  • Randomized Controlled Trial


Dive into the research topics of 'Architectural Changes of the Biceps Femoris Long Head after Concentric or Eccentric Training'. Together they form a unique fingerprint.

Cite this