Author(s): VUKAJ, X., TOMMASINI, E.1, MISSAGLIA, S.1, MARTEGANI, E.1, BOSIO, A.2, RAMPININI, E.2, VAGO, P.1, MALLARDO, M.3, DANIELE, A.3, NIGRO, E.3, TAVIAN, D.1, Institution: CATHOLIC UNIVERSITY OF THE SACRED HEART OF MILAN, Country: ITALY, Abstract-ID: 1995

INTRODUCTION:
Exercise is a key factor for health and prevention of metabolic disorders (1), partially mediated by the secretion of exerkines such as adiponectin. This hormone displays key anti-hyperglycemic, anti-atherogenic, and anti-inflammatory properties (2). Neuromuscular electrical stimulation (NMES) has been shown to amplify an acute metabolic and hormonal response by increasing motor unit recruitment (3). Although the effects of NMES during cycling have been studied, its specific impact on adiponectin levels remains unexplored. Therefore, this study aimed to investigate the acute and chronic effects of cycling with and without synchronous superimposed NMES on plasma adiponectin expression levels.
METHODS:
Sixteen active male participants (age 39 ±10 years, V̇O2peak 47.9 ±4.6 mL·kg-1·min-1) were randomly assigned to the control (CTRL) or the electrically stimulated (EXP) group. Both groups performed a 4x5min interval at 60% peak power output (PPO), interspersed with 3min recovery at 40% PPO (14 training sessions over 6 weeks). Adaptive Functional Electrical Stimulation Kinesitherapy (AFESK), delivered through the VIK8 device, was adopted to trigger NMES in synchrony with voluntary contraction of the lower limb muscles during all the training sessions for the EXP group. Plasma adiponectin, analysed by ELISA assay, was evaluated at baseline, 15min, 24h, and 48h after the first (S1) and last (S14) training sessions. Friedman and Mann-Whitney tests were used for statistical analyses.
RESULTS:
After the S1, a slight increase in plasma adiponectin was detected in both the CRTL (+8.6%) and EXP groups (+9.6%). At S14, both groups showed a significant rise in adiponectin levels at 15min, and 24h post-exercise, returning to basal levels after 48h. However, within-group analysis showed that the EXP group exhibited a greater increase from baseline (+15.6% and +15.0%; p<0.005) in comparison to the CTRL group (+8.8% and +8.4%; p<0.005). Moreover, after 13 training sessions, the analysis between-groups revealed that EXP displayed significantly higher adiponectin levels than CTRL at baseline (p<0.05), as well as after 15min (p<0.005), and 24h (p<0.005).
CONCLUSION:
While both protocols induced acute adiponectin release, the EXP group exhibited higher chronic effects at basal levels and a greater transient response. Such data suggest that the synchronous recruitment of additional motor units via AFESK may potentiate the adipose tissue response by increasing adiponectin secretion, offering superior metabolic health outcomes than cycling alone.