Hip Muscle Activity during Isometric Contraction of Hip Abduction.
Level 4 - case-series / case-control
Repeated-measures laboratory biomechanical study in healthy volunteers
PubMed 24648628 · doi:10.1589/jpts.26.187
What was done
Surface electromyography (EMG) was measured in 27 healthy young men (mean age 21.5 ± 1.2 years) to evaluate the effect of hip flexion angle on muscle recruitment during isometric hip abduction. Participants performed isometric hip abduction across five hip flexion angles (0°, 20°, 40°, 60°, and 80°) and four contraction intensities (20%, 40%, 60%, and 80% maximum strength). Integrated EMG (IEMG) normalized to maximum voluntary contraction (%MVC) was recorded from the upper gluteus maximus (UGM), lower gluteus maximus (LGM), tensor fasciae latae (TFL), and gluteus medius (GMed).
What was found
IEMG of both the UGM and LGM increased significantly with increasing hip flexion angle, peaking at 80° of flexion (UGM: 85.7 ± 80.8% MVC; LGM: 38.2 ± 32.9% MVC). TFL activity decreased significantly as flexion angle increased, showing maximum activity at 40° of hip flexion (71.0 ± 39.0% MVC). GMed IEMG did not change with increases in hip flexion angle.
Why it matters
Selecting specific hip flexion angles during hip abduction exercises allows targeted recruitment of gluteus maximus subdivisions while suppressing tensor fasciae latae activation, which may assist in prescribing targeted hip rehabilitation exercises.
Limits
The study included only 27 young healthy males, precluding generalization to females, older individuals, or clinical populations with hip pathology. Measurements were restricted to static isometric tasks rather than functional dynamic movements, and standard deviations for EMG activity were very large.
Cited by
- context When seated upright or leaning forward during hip abduction, the gluteus maximus is more involved, with slightly less involvement of the gluteus medius.