Eccentric exercise decreases glucose transporter GLUT4 protein in human skeletal muscle.

Abstract

1. Eccentric exercise causes impaired postexercise glycogen resynthesis. To study whether changes in muscle concentration of the glucose transporter (GLUT4) protein might be involved, seven healthy young men performed one-legged eccentric exercise by resisting knee flexion enforced by a motor-driven device. 2. The GLUT4 protein concentration in the exercised and in the control thigh was unchanged immediately after exercise. On days 1 and 2 after exercise, the GLUT4 protein concentration in the exercised muscle was 68 + 10 and 64 + 10% (means + S.E.M.; P < 0 05), respectively, of the concentration in the control muscle, and had returned to control values on days 4 and 7.3. The muscle glycogen concentration decreased from 404 + 44 to 336 + 44 mmol (kg dry wtf1 (P < 0 05) during exercise. The glycogen concentration remained significantly lower than in the control thigh on days 1 and 2 after exercise but on days 4 and 7 no differences were found. 4. Although no cause-effect relationship was established, these findings may suggest that decreased muscle concentrations of GLUT4 protein, and, hence, a decreased rate of glucose transport into muscle cells, may concentration seen after eccentric exercise.Eccentric exercise has been shown to cause muscle damage and impaired postexercise glycogen resynthesis (O'Reilly,

Metabolic Consequences of Exercise-Induced Muscle Damage

“…This initial disruption is followed by degeneration during which the damaged myofibrillar proteins are acted on by proteases. A number of studies have reported the infiltration of immune cells within 2 to 3 days following injury [14,17] , but other researchers have failed to show an immune response [2,10,20] . Regeneration follows with satellite cells becoming centrally located and replacing the damaged myofibrils.…”

“…Researchers have used a number of eccentric exercise models to induce and study EIMD. A rather artificial method of inducing EIMD has been the use of protocols in which the exercise component is purely eccentric; these protocols involve resisting the action of a weight or lever [2,4,6] , as in eccentric cycling [7,14] . Other protocols have combined concentric and eccentric actions but placed the greater emphasis on the eccentric component.…”

“…The symptoms of EIMD are common and easily characterised, and include; stiffness and swelling, decreased force of muscular contraction and delayed onset muscular soreness (DOMS) [1] . In addition, EIMD is often characterised by the presence of the intramuscular enzyme creatine kinase (CK) in the blood [2][3][4][5][6][7][8][9][10][11] .…”

Indirect measures of substrate utilisation following exercise‐induced muscle damage

“…Furthermore, it has been demonstrated that glycogen resynthesis is impaired following EIMD (Asp, Daugaard, Kristiansen, Kiens, & Richter, 1998;Asp, Daugaard, & Richter, 1995;Costill et al, 1990;Widrick et al, 1992). Pre-exercise availability of intramuscular glycogen and triglycerides largely dictates fuel selection during exercise (Coyle, Jeukendrup, Oseto, Hodgkinson, & Zderic, 2001;Johnson et al, 2003).…”

The effect of glycogen reduction on cardiorespiratory and metabolic responses during downhill running

“…Prolonged, intense or unaccustomed exercise is known to induce muscle damage, leading to force loss, muscle soreness (Clarkson and Sayers 1999 ) and impaired glucose metabolism (Asp et al 1995; Krishnan et al 2003. After prolonged eccentric exercise, glycogen stores remain depleted up to 10 days (O'Reilly et al 1987 ).…”