کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6208221 1265680 2012 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The effects of grade and speed on leg muscle activations during walking
موضوعات مرتبط
علوم پزشکی و سلامت پزشکی و دندانپزشکی ارتوپدی، پزشکی ورزشی و توانبخشی
پیش نمایش صفحه اول مقاله
The effects of grade and speed on leg muscle activations during walking
چکیده انگلیسی

Compared to level walking, additional muscle actions are required to raise and lower the center of mass during uphill and downhill walking, respectively. However, it remains unclear which muscle recruitment strategies are employed at typical grades when walking over a range of speeds. Based on previous reports, we hypothesized that, across a range of walking speeds, hip, knee, and ankle extensor muscle activations would increase with steeper uphill grade, but only knee extensor muscle activations would increase with steeper downhill grade. We also hypothesized that these changes in muscle activations with grade would become more pronounced at faster walking speeds. To test these hypotheses, 10 young adults (5M/5F) walked on a standard treadmill at seven grades (0°, ±3°, ±6°, and ±9°) and three speeds (0.75, 1.25, and 1.75 m s−1). We quantified the stance phase electromyographic activities of the gluteus maximus (GMAX), biceps femoris (BF), rectus femoris (RF), vastus medialis (VM), medial gastrocnemius (MG), and soleus (SOL) muscles. On average, compared to level walking, hip (BF: 635%, GMAX: 345%), knee (RF: 165%, VM: 366%), and ankle (MG: 175%, SOL: 136%) extensor muscle activities increased to walk up 9°, but only knee (RF: 310%, VM: 246%) extensor muscle activities increased to walk down 9°. Further, these changes in muscle activations with grade became greater with faster walking speed. We conclude that people employ distinct uphill (hip, knee, and ankle extensors) and downhill (knee extensors) muscle recruitment strategies generally across walking speeds and progressively with steeper grade.

► Leg muscle activities during level, uphill, and downhill walking at various speeds. ► Hip, knee, and ankle extensor muscle activities increase with steeper uphill grade. ► Only knee extensor muscle activities increase with steeper downhill grade. ► Changes in muscle activity with grade are more pronounced at faster walking speeds

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Gait & Posture - Volume 35, Issue 1, January 2012, Pages 143-147
نویسندگان
, ,