Acute postexercise effects of concentric and eccentric exercise on glucose tolerance

Area of Science:

• Exercise Physiology
• Metabolic Health
• Glucose Homeostasis

Background:

• Eccentric exercise is known to cause muscle damage and has been previously linked to impaired glucose tolerance.
• The immediate metabolic effects of muscle-damaging eccentric exercise on glucose tolerance require further investigation.

Purpose of the Study:

• To investigate the acute effects of muscle-damaging eccentric exercise versus concentric exercise on glucose tolerance.
• To compare the immediate insulin response to an oral glucose tolerance test (OGTT) following matched-intensity concentric and eccentric exercise protocols.

Main Methods:

• Ten healthy men underwent three conditions: rest, concentric exercise (level running), and eccentric exercise (downhill running), all matched for intensity.
• Muscle damage was assessed via isometric force deficits in the quadriceps femoris.
• Participants completed a 2-hour, 75-gram oral glucose tolerance test (OGTT) after each condition, with plasma glucose and insulin levels measured.

Main Results:

• Eccentric exercise induced significantly greater isometric force deficits, confirming muscle damage.
• Despite muscle damage, there were no significant differences in the area under the curve for plasma glucose or insulin during the OGTT across conditions.
• Peak glucose and insulin levels following the OGTT were also similar between rest, concentric, and eccentric exercise conditions.

Conclusions:

• Acute muscle-damaging eccentric exercise does not impair glucose tolerance or alter the immediate insulin response to an oral glucose tolerance test.
• Glucose regulation mechanisms appear resilient to the immediate metabolic perturbations caused by strenuous eccentric exercise.