The effects of an acute bout of eccentric, concentric, and traditional resistance exercise on adiponectin concentrations

Introduction. Adiponectin is a protein secreted from adipose tissue which displays both anti-diabetic and anti-atherogenic properties. Studies have found that with resistance exercise, adiponectin concentrations can be increased. Purpose. The primary aim of the study was to examine the effects of a single session of eccentric, concentric, and traditional resistance exercise on total adiponectin and high molecular weight adiponectin (HMWA) concentrations. Methods. Forty-three overweight (BMI 32.3 +/- 0.6 kg/m2), untrained participants (15 males and 28 females) were randomly assigned to either eccentric (ECC), concentric (CON), or traditional resistance exercise (TRE). Subjects in the study participated in a one repetition maximum (1RM) session which was immediately followed up by an acute exercise session. Subjects initially performed a 1RM using the non dominant leg for CON, ECC, or TRE. Immediately following the 1RM testing, subjects performed three sets of 10 repetitions of bilateral leg extensions and leg curls, with both legs together, at 75% of the respective two legged-1RM (2L-1RM). The 2L-1RM was calculated by doubling the weight of the 1RM and then 75% 2L-1RM was used for the exercise session. Baseline characteristics were taken prior to exercise testing and included height, weight, dual energy X-Ray absorptiometry (DEXA) body composition, heart rate, and blood pressure. Outcome measurements were assessed at baseline, and 1 h, 24 h, and 48 h post exercise and include blood collection and muscle soreness assessments. Blood samples were analyzed for total adiponectin, high molecular weight adiponectin (HMWA), glucose, and insulin. Results. There was no significant difference among groups at baseline for total adiponectin (CON- 10.9 +/- 0.6 ng/mL; ECC- 11.8 +/- 1.3 ng/mL; TRE- 12.6 +/- 1.3 ng/mL) or HMWA (CON- 13.9 +/- 2.1 ng/mL; ECC- 20.1 +/- 3.0 ng/mL; TRE- 20.1 +/- 3.0 ng/mL). A single session of CON exercise elicited a significant increase in total adiponectin concentrations by ∼15% from baseline to 1 h post exercise (10.9 +/- 0.6 ng/mL to 12.5 +/- 0.8 ng/mL) while no changes were observed with ECC or TRE exercise 1 h post resistance exercise. ECC and TRE groups had significant decreases in total adiponectin concentration from baseline at 24 h and 48 h post exercise. ECC, CON, and TRE had no influence on HMWA or insulin sensitivity following an acute bout of resistance exercise. Conclusion. The results of the current investigation suggest that the concentric phase of resistance exercise can stimulate an increase in total adiponectin concentrations 1 h post exercise while ECC and TRE had no significant influence on total adiponectin concentrations 1 h post exercise period. However, since total adiponectin levels significantly decreased from baseline 24 h and 48 h post exercise, this may suggest that the eccentric component of resistance exercise could inhibit changes in adiponectin concentrations. The results from the study also indicate that an acute bout of resistance exercise, regardless of the mode, does not elicit a significant change in HMWA or in insulin sensitivity in these specific populations.