Background: Advanced magnetic resonance imaging (MRI) is capable of identifying subtle effects of exercise. However, it is unclear whether it is sensitive enough to differentiate between different contractions. Purpose: To compare the acute and delayed effects of concentric and eccentric exercise on quantitative MRI in hamstring muscles. Material and Methods: Participants performed eccentric and concentric leg curls. Quantitative T2 and magnetization transfer ratio (MTR) maps were calculated in the hamstring complex before exercise, 30 minutes, 24 hours, 7 days, and 14 days after exercise. Results: Compared to baseline, significant MTR reduction (–7.3%) and T2 elevation (72.2%) were observed in the semitendinosus muscle (ST) at 24 hours after eccentric exercise (P = 0.04). Concentric contractions induced T2 elevation in the ST (20.8%) and biceps femoris (5.1%) muscles at 30 minutes after exercise (P = 0.04) which normalized within 24 hours. Conclusions: Longitudinal effects of concentric and eccentric exercise can be detected by both T2 and MTR, but T2 is more sensitive to subtle alterations.
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Radiology Nuclear Medicine and imaging