Often the approach to investigating muscular coordination during transitions entailed conducting tests at speeds held constant. This study investigated muscular activity during continuously changing speeds in order to further detail and quantify neuromuscular changes during gait transitions. Twelve healthy adults, 18-41 years of age, were recruited as participants. Informed consent was obtained. Gait transitions were induced by the speed of the treadmill changing with constant acceleration. Reflective markers were placed on anatomical landmarks of the hip, knee,ankle, heel, and 5 th metatarsal joint. Bipolar surface electrodes were positioned on the subjectsskin over the muscular bellies of the gluteus maximus (GM), rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), gastrocnemius (GAS), and soleus (SOL). Electromyographic (EMG) data were collected at 960 Hz. Five transition trials were conducted for both progression modes: walk-to-run (WR) and run-to-walk (RW), and five interval trials were collected for both gaits at constant speeds. Five steps preceding the gait transitions were analyzed. The mean of recorded transition speeds (MTS) was calculated from the prior transition trials. There were five different constant speed trials for walking (WC) and running (RC); the speeds were MTS - 0.6, MTS - 0.3, MTS, MTS + 0.3, and MTS + 0.6 mph. Cross-correlation comparisons and discrete parameters of the EMG activity ensemble curves were examined across trials and conditions. Two factor (condition and trial) repeated measures ANOVA was employed for statistical analysis (รก = .05). For the correlation parameters, significant running condition/trial interactions were observed for all muscles. Significant condition/trial interactions were revealed for the discrete parameters concerning activation magnitude (GM, RF, VL, TA, GAS, and SOL)and duration (RF, GAS, and SOL) for both walking and running. EMG activity intensity and duration in some muscles changed with the locomotion speed in a quadratic fashion, which was only observed in transition related trials. These results indicate that neuromuscular changes occurred steps before the observed gait transition and that changing velocity induces gait transition related behavior that cannot be observed with constant velocity in the same range.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-0415102-134111 |
| Date | 17 April 2002 |
| Creators | Ogden, Lorna Louise |
| Contributors | Dennis Landin, Richard Magill, Li Li |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-0415102-134111/ |
| Rights | unrestricted, I hereby grant to LSU or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. |
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