Effect of different knee flexion angles with a constant hip and knee torque on the muscle forces and neuromuscular activities of hamstrings and gluteus maximus muscles.
Eur J Appl Physiol
; 119(2): 399-407, 2019 Feb.
Article
em En
| MEDLINE
| ID: mdl-30430278
ABSTRACT
PURPOSE:
This study examined the effect of different knee flexion angles with a constant hip and knee torque on the muscle force and neuromuscular activity of the hamstrings and gluteus maximus.METHODS:
Twenty healthy males lay in prone position and held their lower limb with hip flexion at 45° and knee flexion at either 10° or 80°. At these angles, the hip and knee torques are identical. Under three load conditions passive (referred to as Unloaded), active (Loaded), and active with 3-kg weight added to the shank (Loaded + 3 kg), the muscle stiffness (i.e., an indicator of muscle force) and neuromuscular activity of the hamstrings and gluteus maximus were measured using shear wave elastography and surface electromyography.RESULTS:
The muscle stiffness and neuromuscular activity of the hamstrings and gluteus maximus increased significantly with the load. Muscle stiffness in the hamstrings was significantly lower at knee flexion of 80° than at 10° for Unloaded, but not for either Loaded or Loaded + 3 kg. The neuromuscular activity of the hamstrings was significantly greater at knee flexion of 80° than at 10° for both Loaded and Loaded + 3 kg. The muscle stiffness or neuromuscular activity of the gluteus maximus showed no significant differences between knee angles.CONCLUSIONS:
When the passive force in the hamstrings decreases with knee flexion, sufficient muscle force to maintain the hip and knee torques against an external load is generated by preferentially increasing the neuromuscular activity of the hamstrings, rather than increasing the synergetic muscle force.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Músculo Esquelético
/
Músculos Isquiossurais
/
Articulação do Joelho
Limite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
Eur J Appl Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Japão