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Is rat soleus muscle recruited during swimming?
1Department of Physiology, Oral Roberts University School of Medicine, 7777 South Lewis, Tulsa, OK 74171, USA.
Brain Research
|September 10, 2013
Summary
This study reveals differential muscle blood flow (BF) in rat ankle plantar flexors during swimming versus running. Soleus muscle shows reduced BF during swimming, suggesting unique recruitment patterns not seen in terrestrial locomotion.
Area of Science:
- Exercise Physiology
- Skeletal Muscle Physiology
- Comparative Locomotion
Background:
- Understanding muscle recruitment patterns is crucial for exercise physiology.
- Differential activation of slow-twitch and fast-twitch muscle fibers influences performance and fatigue.
- Previous research has primarily focused on terrestrial locomotion, leaving aquatic locomotion patterns less understood.
Purpose of the Study:
- To investigate and compare blood flow (BF) distribution in rat ankle plantar flexor muscles during swimming and treadmill running.
- To determine if the soleus muscle, a predominantly slow-twitch muscle, is recruited during aquatic locomotion.
- To explore the implications of differential muscle recruitment for understanding exercise physiology.
Main Methods:
- Utilized radiolabeled microspheres to quantify blood flow within specific ankle plantar flexor muscles.
- Measured blood flow during swimming and treadmill running at a standardized speed (60 m/min).
- Assessed muscle glycogen utilization to corroborate blood flow data and muscle activity.
Main Results:
- During swimming, blood flow increased in plantaris and gastrocnemius (red and middle portions) but decreased in soleus muscle compared to resting levels.
- During treadmill running, soleus muscle blood flow remained unchanged, while plantaris and gastrocnemius showed increased blood flow.
- Glycogen use data supported the interpretation that soleus muscle was less active during swimming.
Conclusions:
- The soleus muscle exhibits distinct recruitment patterns during swimming compared to terrestrial locomotion.
- Contraction cycling time alone does not explain the lack of soleus muscle recruitment during swimming.
- The swimming rat model offers a valuable tool for studying differential slow and fast muscle recruitment.
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