Effects of trunk extensor eccentric exercise on lipid profile and glycaemic response

Abstract

Objectives: A number of previous studies reported physiological responses and adaptations after eccentric muscle contraction of limb muscles. In contrast, no study has determined physiological response after eccentric contraction of trunk muscles. The purpose of the present study was to compare the functional and metabolic changes after eccentric or concentric exercises of trunk extensor muscles.

Methods: In this randomised, crossover study, 10 men performed a single bout of 50 maximal voluntary concentric and eccentric contractions of the trunk extensor with an interval of 2 weeks between bouts. The activities of the paraspinal muscles were recorded during concentric and eccentric contractions. Muscle soreness, muscle function, blood lipid profiles and glycaemic responses were measured before, immediately after and at 24, 48, 72 and 96 hours after each bout.

Results: The lumbar multifidus and iliocostalis lumborum activities during eccentric contractions were significantly higher than those during concentric contractions (p<0.05). The maximal strength and muscle endurance of the trunk extensor were not decreased even after the eccentric contractions. Compared with concentric contractions, muscle soreness was significantly increased at 24, 48, 72 and 96 hours after eccentric contractions (p<0.05). The TG, TC and LDL-C were significantly lower at 48, 72 and 96 hours after eccentric contractions (p<0.05), while blood glucose levels and HOMA-IR were significantly greater at 48 and 72 hours after eccentric contractions (p<0.05).

Conclusion: This study indicated that eccentric contractions of the trunk extensor had positive effects on the lipid profile and the glycaemic response.

Keywords: Glucose; Lipids; Metabolism; Muscle damage/injuries.

Figure 1

Schematic presentation of the experimental protocol. The figure shows the timing of physical characteristics (●), muscle soreness (▲), muscle function (■) and blood samples (♠) assessments. Muscle activity (★) was measured during each bout of exercise.

Figure 2

Maximal voluntary contraction measured before (pre), immediately after (0) and 24, 48, 72 and 96 hours after concentric and eccentric contractions. Values are means ± SD. CON, concentric; ECC, eccentric; MVC, maximal voluntary contraction.

Figure 3

Results of the Sørensen test performed before (pre), immediately after (0) and 24, 48, 72 and 96 hours after eccentric and concentric contractions. Values are means ± SD. CON, concentric; ECC, eccentric.

Figure 4

Activities of paraspinal muscles during concentric and eccentric contractions. Muscle activities are presented as the per cent maximal voluntary contraction following each contraction type. Values are means ± SD. * p<0.05 versus CON. CON, concentric; ECC, eccentric; GM, gluteus maximus; LD, latissimus dorsi; ILL, iliocostalis lumborum pars lumborum; ILT, iliocostalis lumborum pars thoracic; LM, lumbar multifidus; LTL, longissimus thoracis pars lumborum; LTT, longissimus thoracis pars thoracic.