The purpose of this study was to determine the functional role of six prominent leg muscles during knee extension. Changes in muscle-tendon length and EMG activity were looked at in conjunction with the results from an inverse dynamics analysis. The muscles investigated were the monoarticular vastus lateralis, soleus, gluteus maximus and the biarticular biceps femoris, rectus femoris and gastrocnemius. Four female and five male elite rowers performed on a Gjessing rowing ergometer while kinematic information was recorded on cinefilm. The force applied to the stretcher, the force applied to the oar handle and the EMG activity were sampled simultaneously. Through inverse dynamics, net moments of force at the ankle, knee and hip joints and powers from these moments were computed for one drive. The results showed a difference in the use of knee extensors by female and male rowers. For the females, the power produced originated exclusively from the hip extensors. This contrasts with the results obtained from the male subjects where power was produced by hip and knee extensors. Plausible explanations include differences in anatomical structures between both sexes (skeletal dimensions, tendon attachments location, muscle mass distribution), differences in rowing technique and deficiency in the knee extensor strength. Paradoxical activity appeared to take place in the recruitment of the biarticular gastrocnemius and biceps femoris during the extension of the knee. More intriguing was the detection of paradoxical activity from the action of m. rectus femoris at the hip which it seemed to extend.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/6617 |
| Date | January 1994 |
| Creators | Fortin, Yves D. |
| Contributors | Robertson, Gordon, |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 112 p. |
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