Electromyographic Examination of Hip and Knee Extension Hex Bar Exercises Varied by Starting Knee and Torso Angles.
Int J Exerc Sci
; 15(1): 541-551, 2022.
Article
em En
| MEDLINE
| ID: mdl-35520010
ABSTRACT
Variations of the deadlift can be executed using the hexagonal (hex) bar by altering, for instance, the knee and torso angles while maintaining a constant hip angle at the start position. PURPOSE:
To examine muscle activation patterns of the biceps femoris, rectus femoris, and erector spinae during three deadlift variations using the hex bar.METHODS:
Twenty resistance-trained male and female subjects performed hex bar deadlift variations in three different starting knee flexion positions 128.4 ± 8.5°, 111.9 ± 8.7°, and 98.3 ± 6.5°. Subjects performed three repetitions at 75% of their three-repetition maximum. Electromyography sensors were placed on the dominant biceps femoris, rectus femoris, and lumbar erector spinae. A one-way repeated measures ANOVA was used to detect differences in mean and peak EMG values normalized to maximum voluntary isometric contraction (MVIC) (p < 0.05).RESULTS:
As knee flexion increased at the starting position, mean activation of the rectus femoris increased (24.7 ± 21.5 â 35.5 ± 25.4 â 62.1 ± 31.3% MVIC, p < 0.001), while biceps femoris (40.6 ± 17.9 â 34.0 ± 16.4 â 28.1 ± 14.5% MVIC, p = 0.003) and erector spinae (73.0 ± 27.6 â 65.9 ± 34.4 â 54.9 ± 32.5% MVIC, p = 0.009) activation decreased. Peak activation of the rectus femoris increased (46.9 ± 33.0 â 60.9 ± 38.7 â 99.3 ± 41.6% MVIC, p < 0.001) while decreasing in the erector spinae (118.6 ± 47.1 â 105.9 ± 49.4 â 89.1 ± 40.1% MVIC, p = 0.008). The rectus femoris experienced the greatest mean differences of the three muscles.CONCLUSIONS:
Practitioners should consider the muscular goals when adjusting the starting position of a hex bar deadlift as posterior chain recruitment diminished and quadriceps activation increased as knee flexion increased.
Texto completo:
1
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article