Impact of Different Low-Volume Concurrent Training Regimens on Cardiometabolic Health, Inflammation, and Fitness in Obese Metabolic Syndrome Patients

Abstract

Background/objectives: Evidence supports the benefits of concurrent training (CT), which combines endurance and resistance exercises, for enhancing health and physical fitness. Recently, low-volume, time-efficient exercise approaches such as low-volume high-intensity interval training (LOW-HIIT), whole-body electromyostimulation (WB-EMS), and single-set resistance training (1-RT) have gained popularity for their feasibility and efficacy in improving various health outcomes. This study investigated the effects of low-volume CT, focusing on (1) whether exercise order affects cardiometabolic health, inflammation, and fitness adaptations and (2) which combination, LOW-HIIT plus WB-EMS or LOW-HIIT plus 1-RT, yields better results.

Methods: Ninety-three obese metabolic syndrome (MetS) patients undergoing caloric restriction were randomly assigned to four groups performing the different low-volume CT protocols over 12 weeks. Outcomes included cardiometabolic, inflammatory, and fitness parameters.

Results: In both combinations, no significant differences were found regarding exercise order. However, the pooled LOW-HIIT and 1-RT group achieved superior improvements in blood pressure, blood lipids, inflammation markers (CRP, hsCRP), the MetS severity score, and overall fitness compared to the LOW-HIIT and WB-EMS combination. Compared to previous studies using these modalities individually, LOW-HIIT plus 1-RT appeared to further reduce inflammation, whereas LOW-HIIT combined with WB-EMS was less effective for cardiometabolic health, potentially due to interference effects between modalities.

Conclusions: While LOW-HIIT plus WB-EMS appears to be a viable option for individuals unable to perform traditional resistance training, the findings suggest prioritizing LOW-HIIT plus 1-RT to maximize health outcomes. These findings highlight the importance of tailored exercise prescriptions and the need for further research into optimizing CT protocols for diverse populations.

Keywords: WB-EMS; interference effect; low-volume HIIT; low-volume concurrent training; obesity; single-set resistance training.

Figure 1

Study flow chart.

Figure 2

Changes in (A) serum C-reactive protein (CRP), (B) serum high-sensitivity C-reactive protein (hsCRP), (C) serum triglycerides, (D) serum high-density lipoprotein cholesterol (HDL), (E) mean arterial blood pressure (MAB), (F) metabolic syndrome severity z-score (MetS z-score). * (p < 0.01), *** (p < 0.001): significant change between T-1 and T-2. ^# (p < 0.05), ^## (p < 0.01), ^### (p < 0.001): significant difference between LOW-HIIT and 1-RT and LOW-HIIT and WB-EMS.

Figure 3

Changes in (A) maximum power output (W_max), (B) power output at ventilatory threshold (W_VT), (C) abdominals 1-RM, (D) lower back 1-RM, (E) overall physical fitness score (Fit-score). *** (p < 0.001): significant change between T-1 and T-2. ^# (p < 0.05), ^## (p < 0.01): significant difference between LOW-HIIT and 1-RT versus LOW-HIIT and WB-EMS.

Figure 4

Changes in (A) serum C-reactive protein (CRP), (B) serum high-sensitivity C-reactive protein (hsCRP), (C) mean arterial blood pressure (MAB), and (D) metabolic syndrome severity z-score (MetS z-score) observed in the present trial in the pooled LOW-HIIT and WB-EMS and LOW-HIIT and 1-RT groups, respectively, compared to a previous study investigating the changes following LOW-HIIT, WB-EMS, 1-RT alone, or a non-active control condition (CON) [20]. Note: No statistical comparisons were performed as the results originate from different studies.