The relationship between exercise‐induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days local muscle unloading

• DOI: 10.1111/cpf.12087
• Publication Date: 2013-10-12T02:05:12Z
• Authors: Tobias Weber; Michel Ducos; Edwin Mulder; Åsa Beijer; Frankyn Herrera; Jochen Zange; Hans Degens; Wilhelm Bloch; Jörn Rittweger
• Keywords: Muscle Fatigue; Plantar flexion

Summary In the light of dynamic nature habitual plantar flexor activity, we utilized an incremental isokinetic exercise test ( IIET ) to assess work‐related power deficit W o RPD as a measure for exercise‐induced muscle fatigue before and after prolonged calf unloading in relation arterial blood flow perfusion. Eleven male subjects (31 ± 6 years) wore HEPHAISTOS orthosis unilaterally 56 days. It allows ambulation while greatly reducing activity torque production. Endpoint measurements encompassed flow, measured femoral artery using D oppler ultrasound, oxygenation soleus assessed by near‐infrared spectroscopy, lactate concentrations determined capillary surface electromyography. Furthermore, biopsies were taken investigate morphological changes. After intervention, maximal was reduced 23·4 8·2% P <0·001) fibre size 8·5 13% = 0·016). However, Wo remained unaffected indicated unchanged loss relative between pre‐ postexperiments 0·88). Blood tissue oxygenation, EMG median frequency kinematics during comparable whereas increase RMS response less following intervention 0·03). conclusion, submaximal work is local unloading. The observation that maintained may underlie fatigability.