講演・口頭発表等

2022年12月11日

Differences in the activity of hip abductor muscles during clam exercises at different femoral anteversion and hip flexion angles in females

第9回日本スポーツ理学療法学会学術大会
  • Sho Mitomo
  • ,
  • Junya Aizawa
  • ,
  • Kenji Hirohata
  • ,
  • Takehiro Ohmi
  • ,
  • Shunsuke Ohji
  • ,
  • Hidetaka Furuya
  • ,
  • Tomoko Kawasaki
  • ,
  • Yayoi Sakai
  • ,
  • Kazuyoshi Yagishita

開催年月日
2022年12月10日 - 2022年12月11日

【Background/Purpose】
Clam exercise(Clam-Ex), prescribed for the prevention of
sports injuries, can increase the activity of the gluteus medius
(GMed)and the superior portion of the gluteus maximus(SUPGMax), while minimizing the activity of the tensor fascia latae
(TFL)muscle. While previous reports have shown that the
activity of the GMed does not increase in those with excessive
femoral anteversion, the optimal position that can increase
the activity of the GMed, even in those with excessive femoral
anteversion, is not known. Therefore, the purpose of this study
was to classify the subjects based on femoral anteversion and
to determine differences in the activity of the hip abductor
muscles during Clam-Ex at different hip flexion angles.
【Methods】
The subjects comprised 30 healthy women without back pain
or lower-limb disability. The exercise task consisted of ClamEx at different hip flexion angles(60°, 45°, and 30°). TFL,
GMed, and SUP-GMax activities were measured during the
exercise task. Exercise intensity was set at 50% of the torque
value at maximum voluntary contraction(MVC), for each
exercise task, and the subjects were given visual feedback
using a computer display. The order of the exercise tasks was
randomized. The obtained muscle activity was normalized by
activity during MVC, and the gluteal-to-TFL muscle activation
(GTA)index was calculated using the following formula: GTA
index = {[ (GMed/TFL) × GMed] + [ (SUP-GMax/TFL) × SUPGMax]}/2. Higher GTA index values indicated higher levels of
GMed and SUP-GMax activity relative to TFL activity. Subjects
were divided into two groups based on the femoral anteversion
measured by the Craig test: the excessive anteversion group
(EAG), for those with an angle of 30° or more, and the
normal group (NG) , for those with an angle between 8° and 20
°. Statistical analysis was conducted using an unpaired t-test
to compare basic demographics between groups, analysis of
variance for split-plot factorial design to examine differences
in muscle activity and the GTA index, and Bonferroni test as a
post-hoc test if main effects and interactions were found. The
significance level was set at 5%.
【Results】
The subjects were divided into groups of 15 in the EAG(age,
median [interquartile range], 26.0 [4.3] years)and 15 in the
NG(age, 27.0 [2.0] years). There were no differences in the
basic demographics between the groups. There were no main
effects and interactions between the factors for TFL and GMed
activities. There was no interaction between the factors for
SUP-GMax activity, but a main effect was found for the exercise
task. Post-hoc tests showed that hip flexion at 60° and 45° was
significantly higher than that at 30 °(p<0.001 and p=0.011,
respectively). There was no interaction between the factors
in the GTA index, but there were main effects of the exercise
task and group factors. Post-hoc tests indicated that EAG was
lower than NG(p=0.044), hip flexion at 60° was significantly
higher than that at 45 °(p=0.042), and hip flexion at 60 °
and 45 ° was significantly higher than that at 30 °(p<0.001,
p=0.022).
【Conclusions】
Subjects with excessive femoral anteversion showed a lower
activity ratio of GMed and SUP-GMax relative to the TFL during
Clam-Ex. Clam-Ex with an increased hip flexion angle also
increased the activity ratio of GMed and SUP-GMax relative to
TFL, and the activity of SUP-GMax. Therefore, the hip flexion
angle of the Clam-Ex should be adjusted to increase the activity
of the gluteal muscles. For those with excessive femoral
anteversion, it was suggested that it is important to increase
the exercise load of the Clam-Ex to increase the activity of the
gluteal muscles relative to the TFL.
【Ethical Considerations】
This study was conducted in accordance with the principles of
the Declaration of Helsinki. Ethical approval was obtained from
the Ethics Committee of Tokyo Medical and Dental University
(approval number: M2020-259). All participants provided
written informed consent prior to participation and consented
on the publication of their data.