EMG Results
The EMG data were analyzed only for the cross country DWR condition (C1). During the second condition of DWR, water leaked into the seal and corrupted the signal. Although the area was dried off during the TMR condition, the resulting signal was not satisfactory, and therefore was dropped from the analysis.
The activity of the biceps femoris (BF) and rectus femoris (RF) during DWR C1 for each level of intensity are illustrated in figures 13-15. Because the EMG and kinematic data were not synchronized, discrete events defining different phases have been estimated.
The pattern of muscle activity changes dramatically between levels of intensity. During level 1 (RPE 11, stride rate 58.3 st/min), the BF and RF were active at different portions of the stride. Also, the BF demonstrate a bi-phasic response during what is believed to be the support phase during DWR. As the intensity of exercise increased, the RF also demonstrated a bi-phasic response. This is most likely due to the dual role of the RF, which function to flex the hip and extend the knee.
As intensity of exercise increased, the bi-phasic response of the BF was reduced. Also, the RF and BF tended to be co-contracting to a greater degree than the lower levels of intensity.
During TMR, the RF are typically active just prior to heel contact and throughout mid support (Elliott & Blanksby, 1979; Mann, Moran, & Dougherty, 1986). During support, the RF generally function to control knee flexion. The BF tend to be active during the later portion of swing to control knee extension, and throughout mid support to assist in hip flexion (Elliott & Blanksby 1979, Mann, et al. 1986).
EMG Conclusion
Due to the problems identified with collecting EMG during TMR, there a comparison of muscle activity during DWR and TMR can be made for the subject tested during this study. However, the comparison of the DWR data to muscle activity levels of published data indicate that at lower levels of intensity, the muscle pattern appears to be different during DWR and TMR. However, during higher levels of intensity, the EMG pattern appears to be similar during the two modes of exercise. This observation should be confirmed through further research.
Proceed to next section- Limitations
Back to Deep Water Running
