Exercise training at the crossover point improves bodily and cardiorespiratory data but not quality of life in women with metabolic syndrome.

BACKGROUND: This study investigated the effects of an exercise program at the intensity corresponding to the crossover point of substrate utilization (COP) on anthropometric measures, health-related quality of life (HRQoL) and cardiorespiratory fitness (i.e., peak oxygen uptake [V̇O2peak] and peak power output [Ppeak]) in women with metabolic syndrome (MetS). METHODS: Nineteen obese and post-menopausal women with MetS (age: 54.8±8.1 years, body mass: 89.0±12.2 kg, Body Mass Index: 34.5±4.0 kg/m2) followed a 12-week program consisting of three 45-minute sessions per week of cycle ergometer exercise. The imposed exercise intensity corresponded to COP. Before and after the program, HRQoL, V̇O2peak and Ppeak were measured and then compared. RESULTS: Body mass (89.0±12.2 vs. 86.2±11.0 kg), Body Mass Index (34.5±4.0 vs. 33.4±3.6 kg/m2), waist (106±10 vs. 100±9 cm) and hip (117±11 vs. 114±11 cm) circumferences, waist-to-hip ratio (0.91±0.07 vs. 0.88±0.07), fat mass (43.3±4.6 vs. 41.9±4.6%), fat-free mass (56.7±4.6 vs. 58.2±4.6%), V̇O2peak (16.6±3.4 vs. 18.1±4.1 mL/min/kg) and Ppeak (102±22 vs. 125±27 W) were significantly improved after the exercise program (P<0.05), but HRQoL showed no significant improvement on any subscale (i.e., physical functioning: performance limitation for physical activities including bathing and dressing, role physical: problems with work or other daily activities, bodily pain, general health, vitality, social functioning, role emotional and mental health; P>0.05). CONCLUSIONS: Although a 12-week exercise program at COP improved anthropometric measures and cardiorespiratory fitness in women with MetS, self-perceived HRQoL did not significantly improve. This finding may be linked to a significant but still insufficient reduction in body mass, probably because COP is too weak exercise intensity to induce important energy expenditure.

Effects of Endurance Training at the Crossover Point in Women with Metabolic Syndrome.

INTRODUCTION: On the basis of theoretical evidence, intensity at the crossover point (COP) of substrate utilization could be considered as potential exercise intensity for metabolic syndrome (MetS). This study aimed to examine the effects of a training program at COP on exercise capacity parameters in women with MetS and to compare two metabolic indices (COP and the maximal fat oxidation rate point LIPOXmax®) with ventilatory threshold (VT). METHODS: Nineteen women with MetS volunteered to perform a 12-wk training program on a cycle ergometer, with intensity corresponding to COP. Pre- and posttraining values of anthropometric and exercise capacity parameters were compared to determine the effects of exercise training. The pre-post training change of COP, LIPOXmax®, and VT were also investigated. RESULTS: After training, anthropometric parameters were significantly modified, with reduction of body mass (3.0% ± 3.0%, P < 0.001), fat mass (3.3% ± 3.4%, P < 0.001), and body mass index (3.2% ± 3.4%, P < 0.001). Exercise capacity was improved after the training program, with significant increase of maximal power output (25.0% ± 18.4%, P < 0.001) and maximal oxygen uptake (V˙O2max, 9.0% ± 11.2%; P < 0.01). Lastly, when expressed in terms of power output, COP, LIPOXmax®, and VT occurred at a similar exercise intensity, but the occurrence of these three indices is different when expressed in terms of oxygen uptake, HR, or RPE. CONCLUSIONS: This study highlights the effectiveness of a 12-wk training program at COP to improve physical fitness in women with MetS. The relations between metabolic indices and VT in terms of power output highlight the determination of VT from a shorter maximal exercise as a useful method for determining metabolic indices in MetS.

Influence of kick frequency on metabolic efficiency and performance at a severe intensity in international monofin-swimmers.

The aim of this study was to examine the effect of kick frequency on metabolic efficiency and performance in elite monofin-swimmers at the surface. Seven participants of international calibre were requested to perform three separate time limit exercises conducted at an intensity corresponding to 97.5% of the velocity at the maximal oxygen uptake. The first Time Limit exercise was systematically conducted at a freely chosen kick frequency (FCK(F)) and the other Time Limit exercises were performed in random order at FCK(F)-10% and FCK(F) + 10%. The slow component of oxygen uptake (VO2sc) was identified independently of the Time Limit exercise (ranging from 180 to 243 ml · min(-1), P < 0.05). No significant change in energy cost of aquatic locomotion (ranging from 565 to (596 J · m(-1)) and [VO2sc) responses was observed between the three Time Limit exercises. An increase or decrease of 10% of the FCK(F) was associated with a significant reduction in Time Limit of -47.3% and -49.1%, respectively (P < 0.05). The analysis of the Time Limit exercise indicates that the selection of kick frequency other than FCK(F) is detrimental to overall monofin-swimming performance. Furthermore, the study results showed that the indicators of metabolic efficiency such as energy cost or [VO2sc) do not determine the performance response in elite monofin-swimmers at a severe intensity.

Kick frequency affects the energy cost of aquatic locomotion in elite monofin swimmers.

The aim of this study was to evaluate the influence of kick frequency (K(F)) on the energy cost of aquatic locomotion in elite monofin (Mf) swimmers at the surface. Eight subjects of international calibre (4 females, 4 males) were requested to perform in a 50-m outdoor swimming pool: (1) a continuous multi-stage incremental test to determine maximal physiological responses and (2) a submaximal exercise composed of five constant Mf-swimming tests (600-m exercise, 5-min rest) at an intensity corresponding to 90% of the velocity at the maximal oxygen uptake (VO2max). The first submaximal Mf-swimming test was systematically conducted at a freely chosen K(F) (FCK(F)) and the other tests were performed at FCK(F) - 15%, FCK(F) - 10%, FCK(F) + 10% and FCK(F) + 20% in a random order. No significant effect of K(F) on ventilation, heart rate and blood lactate concentration was observed throughout the submaximal Mf-swimming tests. However, mean values in Ec or fraction of VO2max were significantly lower during the FCK(F) + 10% condition as compared to those observed during the FCK(F) - 15% (-11.5 and -9.6%, respectively, P < 0.05) and FCK(F) - 10% (-10.4 and -9.3%, respectively, P < 0.05) conditions. In conclusion, the lack of significant differences between FCK(F) + 10% and FCK(F) or FCK(F) + 20% does not allow to identify a specific trend, but suggests the occurrence of an energetically optimal K(F) close to that freely chosen by the Mf swimmers. Variations in muscle activity level and active drag have been hypothesized to explain the observed differences in Ec consecutive to the selection of various K(F).