• Title/Summary/Keyword: Endurance holding time

Search Result 2, Processing Time 0.016 seconds

The Effect of Visual Biofeedback on EMG Activity of Trunk Muscles and Endurance Holding Time for Correct Position During Whole-Body Tilt Exercise (전신 기울기 운동 시 시각적 바이오피드백이 올바른 자세 유지 시간과 체간 근육의 근활성도에 미치는 영향)

  • Kang, Min-Hyeok;Yoon, Ji-Yeon;Yang, Jae-Lak;Jang, Jun-Hyeok;Jung, Doh-Heon;Oh, Jae-Seop
    • Physical Therapy Korea
    • /
    • v.18 no.1
    • /
    • pp.9-17
    • /
    • 2011
  • The purpose of this study was to assess visual biofeedback's influence on trunk muscles' (EMG) activity and endurance holding time for correct position during whole-body tilt exercise. For the study, we recruited 14 volunteers who showed no symptom of lumbar disease during medical tests. We measured the EMG activity of their rectus abdominis, external abdominal oblique, internal abdominal oblique and erector spinae muscles, and their endurance holding time for correct position during $40^{\circ}$ anterior and posterior whole-body tilt under two conditions: whole-body tilt with and without visual biofeedback. Resistance with gravitational force on the trunk during whole-body tilt was applied by using a device that had a monitor on which the subjects could check their alignment and that sounded an alarm if a subject's alignment collapsed. The study showed an increase in the EMG activity of external abdominal oblique, internal abdominal oblique/rectus abdominis ratio and endurance holding time for correct position during both $40^{\circ}$ anterior and posterior whole-body tilt with visual biofeedback compared with without visual biofeedback (p<.05). We suggest that the whole-body tilt exercise with visual biofeedback could be a beneficial strategy for selectively strengthening the internal abdominal oblique muscle and minimizing the rectus abdominis muscle's activity while maintaining correct alignment during whole-body tilt exercise.

Muscle Fatigue according to Joint Angle and the Transfer Effect with Isometric Training (관절각도에 따른 근 피로도와 등척성 훈련 전이효과)

  • Song, Young-Hee;Kwon, Oh‐Yun
    • Journal of the Ergonomics Society of Korea
    • /
    • v.25 no.4
    • /
    • pp.93-101
    • /
    • 2006
  • This study examined whether there is a transfer effect to other joint angles and the angular specificity of muscle fatigue after 6 weeks of isometric training of the vastus medialis. Twenty subjects were randomly assigned to 30° and 90° knee flexion groups and were trained at 80% maximal voluntary isometric contraction(MVIC) three times a week for 6 weeks. The pre-and post-training values of the 80% holding time(endurance time) of MVIC, the Fatigue Index(FI), and the MVIC at 30°, 60°, and 90° were compared. After isometric training for 6 weeks, in the 30° knee flexion group, FI decreased significantly(p<0.05) only at 30°, which was the training angle; there was no change at other angles. By contrast, in the 90° knee flexion group, FI decreased significantly(p<0.05) at both the trained angle and at the other angles, indicating a transfer effect of training. MVIC did not increase significantly(p<0.05) at any trained angle in either the 30° or 90° knee flexion groups after 6 weeks of isometric training, neither did the 80% holding time of MVIC differ significantly compared with pre-training in either group. These findings suggest that training at 90° of knee flexion is more effective than training at 30° of knee flexion for obtaining a training transfer effect on muscle fatigue in the vastus medialis.