Author(s): NINE, I., RIAL-VÁZQUEZ, J.1, FARIÑAS, J.1, RÚA-ALONSO, M.1, REVUELTA-LERA, B.1, RIVERA-MEJÍA, S.L.1, CLAVEL, I.1, MÁRQUEZ, G.2, IGLESIAS-SOLER, E.1, Institution: UNIVERSITY OF A CORUNA / Q6550005J, Country: SPAIN, Abstract-ID: 1885

INTRODUCTION:
Postmenopausal women are more susceptible to encountering diverse metabolic disorders, often with changes in body composition, energy metabolism, muscle mass and strength reduction (1). Manipulation of set configuration modulates acute responses to resistance exercise (2) modifying the intensity of effort, by the redistributing of the repetitions and rest periods (3). This study aimed to compare acute metabolic responses to training sessions differing in set configuration in a sample of postmenopausal women.
METHODS:
50 physically active postmenopausal women participated in this study funded by the Spanish Ministry of Science and Innovation (PID2021-124277OB). Three resistance training (4 exercises) and a control session (CON) were randomized. The exercises were performed using a 12RM load, differing in set configuration while maintaining the same volume (36 repetitions): 9 sets of 4 reps (4S), 6 sets of 6 reps (6S), and 4 sets of 9 reps (9S). Inter-set rest intervals were 45, 72 and 120 seconds, respectively, ensuring an equivalent work-to-rest ratio.
Oxygen uptake (VO2), carbon dioxide production (VCO2) and respiratory exchange ratio (RER) were recorded before (PRE: 15min) and after (POST: 60min) each session and averaged over 10min intervals. Blood lactate concentration (La) was sampled before and 1min after session. A 4x7 ANOVA analyzed set configuration effects on energy expenditure responses over time (PRE: 5-10min; and POST: 0-10, 10-20, 20-30, 30-40, 40-50, 50-60min), and a 3x2 ANOVA assessed lactate levels (PRE and POST).
RESULTS:
The analysis showed a main effect of session, moment and session×moment interaction (p=0.005) for VO2, RER and La.
Greater VO2 values were observed in 9S and 6S compared with CON (p=0.006), with a tendency of 4S to be higher than CON (p=0.059). Higher VO2 was recorded in the first 10min POST compared to PRE and subsequent intervals (p=0.002). VO2 was only increased after 9S (POST 0-10) compared with PRE (p<0.001). Compared to CON, VO2 POST remained higher in 9S until 40-50min of recovery (p=0.039); in 6S until 30-40min (p=0.014) and in 4S only for the first 10min (p=0.002).
Baseline RER values were similar across all sessions, with PRE > POST (p<0.001). Overall, CON showed higher values (p=0.036) than experimental sessions, with 9S recording the lowest values (p=0.037). La POST was significantly higher than PRE in all sessions, with greater values in 9S compared to 6S and 4S (9S>6S>4S) (p<0.001). For VCO2 only a time effect (p<0.001) was detected (POST 0-10 > the rest of periods).
CONCLUSION:
By maintaining the same volume and work-to-rest ratio, no differences in total energy expenditure were found, however only long set configuration (9S) promoted VO2 increase immediately after exercise. Set configuration may modulate the metabolic response after strength exercise, with shorter sets promoting lower La compared with longer sets.
1) Ko et al., Nutrients, 2021
2) Kraemer et al., Curr Sports Med Rep, 2002
3) Iglesias-Soler et al., J Sports Sci