The Effect of Training Modalities on Bicep Femoris Fascicle Length Adaptations: A Systematic Review and Meta-analyses

Ripley, Nicholas; Ross, Steve; Cuthbert, Matthew; Comfort, Paul; McMahon, John

Abstract

Bicep femoris long head (BFLH) fascicle length (FL) is a modifiable risk factor of hamstring strain injury (HSI) and is extremely adaptable to imposed demands. The aim was to conduct a systematic review and meta-analysis to estimate the effects of different exercise-based training modalities on BFLH FL. A systematic search of the literature was conducted in several databases, with controlled vocabulary. Data extraction included: population, intervention prescription, ultrasonographic methods and architecture measures. Twenty-six studies were included. Study quality assessments demonstrated moderate-high quality, with a low risk of bias and publication bias (N=46; p<0.001). Moderate heterogeneity among the effects reported in the individual studies was observed (I2=59.32%). Main effects for in BFLH FL was (0.62 (95% CI 0.32 to 0.92), Z = 4.11, p < 0.001). Sprinting and eccentrics increased BFLH FL (g=1.04 & 0.97, respectively). Short length, knee dominant concentric training (g= -0.66) and cycling endurance training dosed independently or concurrently decreased in BFLH FL (g=-1.71&-1.40, respectively). Adaptations to BFLH FL are modality specific, able to enhance, diminish or even have no observed effect BFLH FL. The prescription of training needs to carefully implemented to maximise the desired response, such as improved contractile functioning, potentially reducing the risk of HSI.

• Journal Article Type: Article
• Acceptance Date: Jul 22, 2024
• Deposit Date: Aug 1, 2024
• Journal: International Journal of Strength and Conditioning
• Electronic ISSN: 2634-2235
• Peer Reviewed: Peer Reviewed
• Volume: 1
• Pages: 1-19
• DOI: https://doi.org/10.47206/ijsc.v4i1.291