Dataset Information

Biceps Femoris Activation during Hamstring Strength Exercises: A Systematic Review.

ABSTRACT:

Background

The aim of the study was to systematically evaluate the biceps femoris long head activation across cross-sectional hamstring strength exercise studies.

Methods

A systematic review design was followed. The search strategy conducted in PubMed, Cochrane Library, and Web of Sciences databases found a total of 3643 studies. Once inclusion and exclusion criteria were applied, 29 studies were finally included in this systematic review. A total of 507 participants and 114 different exercises were analyzed. Exercises were evaluated individually and grouped into several categories: Nordics, isokinetic exercises, lunges, squats, deadlifts, good mornings, hip thrusts, bridges, leg curls, swings, hip and back extensions, and others.

Results

Results showed the isokinetic and Nordic exercises as the categories with highest biceps femoris activation (>60% of Maximal Voluntary Isometric Contraction). Nordic hamstring exercise ankle dorsiflexion was the exercise that achieved the highest biceps femoris long head activation (128.1% of its Maximal Voluntary Isometric Contraction).

Conclusions

The results from this systematic review suggest that isokinetic and Nordic exercises seem to be the best option to activate biceps femoris long head. Future studies evaluating the implementation of these exercises in prevention programs are needed.

SUBMITTER: Llurda-Almuzara L

PROVIDER: S-EPMC8393607 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Current debate exists around whether a presumed eccentric exercise, the Nordic hamstring exercise (NHE), actually causes active hamstring muscle lengthening. This is because of the decoupling that can occur between the muscle fascicle and muscle-tendon unit (MTU) length changes in relatively compliant human lower-limb MTUs, which results in MTU lengthening not necessarily causing muscle fascicle lengthening. This missing knowledge complicates the interpretation of why the NHE is effective at reducing running-related hamstring muscle injury risk in athletes previously unfamiliar with performing this exercise. The purpose of the study was therefore to investigate if the most-commonly injured hamstring muscle, the biceps femoris long head (BF), exhibits active muscle lengthening (i.e. an eccentric muscle action) during the NHE up until peak force in Nordic novices. External reaction force at the ankle, knee flexion angle, and BF and semitendinosus muscle activities were recorded from the left leg of 14 participants during the NHE. Simultaneously, BF muscle architecture was imaged using B-mode ultrasound imaging, and muscle architecture changes were tracked using two different tracking algorithms. From ~85 to 100% of peak NHE force, both tracking algorithms detected that BF muscle fascicles (n = 10) significantly lengthened (p < 0.01) and had a mean positive lengthening velocity (p ≤ 0.02), while knee extension velocity remained positive (17°·s-1) over knee flexion angles from 53 to 37° and a duration of 1.6 s. Despite some individual cases of brief isometric fascicle behavior and brief fascicle shortening during BF MTU lengthening, the predominant muscle action was eccentric under a relatively high muscle activity level (59% of maximum). Eccentric hamstring muscle action therefore does occur during the NHE in relatively strong (429 N) Nordic novices, which might contribute to the increase in resting BF muscle fascicle length and reduction in running-related injury risk, which have previously been reported following NHE training. Whether an eccentric BF muscle action occurs in individuals accustomed to the NHE remains to be tested.