Sedentary behavior and compensatory mechanisms in response to different doses of exercise-a randomized controlled trial in overweight and obese adults.

BACKGROUND/OBJECTIVES: To examine compensatory changes in sedentary behavior (SB) and light-intensity physical activities (LIPA) in response to a 22-week exercise training program in overweight/obese adults; and to determine if different forms of exercise training and physical activity recommendations interact with these compensatory changes. SUBJECTS/METHODS: Eighty-nine overweight and obese individuals (body mass index (BMI): 25-34.9 kg/m2, 48% males), aged 18-50 years, were randomized into four intervention groups (strength, endurance, combined strength + endurance and physical activity recommendations) with a 25-30% caloric restriction of total daily energy expenditure for 22 weeks. Energy expenditure was measured by accelerometry before, during and after the program. RESULTS: LIPA increased significantly (P<0.001) after three months and at the end of intervention compared to baseline (pre: 281±9 min; 3 months: 303±9 min; post: 312±8 min). SB percentage decreased by 5.3 at the end of the intervention (P=0.002). No interactions were observed between groups or sexes. Significant correlations were found between SB and body weight, fat mass, android fat mass and lean body mass before and after the intervention (P<0.05). LIPA was also significantly correlated with all these body composition variables in the pre-intervention, but only correlated with body weight at the end of intervention. CONCLUSIONS: There were no compensatory changes after a combined exercise and diet program; where minutes in LIPA increased and %SB decreased after the program, without differences among exercise modes. Greater physical activity levels can contribute to a better percentage and distribution of body tissues.

The midpoint between ventilatory thresholds approaches maximal lactate steady state intensity in amateur cyclists.

The aim was to determine whether the midpoint between ventilatory thresholds (MPVT) corresponds to maximal lactate steady state (MLSS). Twelve amateur cyclists (21.0 ± 2.6 years old; 72.2 ± 9.0 kg; 179.8 ± 7.5 cm) performed an incremental test (25 W·min-1) until exhaustion and several constant load tests of 30 minutes to determine MLSS, on different occasions. Using MLSS determination as the reference method, the agreement with five other parameters (MPVT; first and second ventilatory thresholds: VT1 and VT2; respiratory exchange ratio equal to 1: RER = 1.00; and Maximum) was analysed by the Bland-Altman method. The difference between workload at MLSS and VT1, VT2, RER=1.00 and Maximum was 31.1 ± 20.0, -86.0 ± 18.3, -63.6 ± 26.3 and -192.3 ± 48.6 W, respectively. MLSS was underestimated from VT1 and overestimated from VT2, RER = 1.00 and Maximum. The smallest difference (-27.5 ± 15.1 W) between workload at MLSS and MPVT was in better agreement than other analysed parameters of intensity in cycling. The main finding is that MPVT approached the workload at MLSS in amateur cyclists, and can be used to estimate maximal steady state.

Reliability of infrared thermography in skin temperature evaluation of wheelchair users.

STUDY DESIGN: Test-retest reliability analysis segmented by body parts. OBJECTIVES: To examine the reliability of infrared thermography (IRT) in wheelchair users (WCUs), as a noninvasive and risk-free technique to detect the natural thermal radiation emitted by human skin and to allow subsequent interpretations of temperature distributions. SETTING: Research Center on Physical Disability of Valladolid, ASPAYM Castilla y León Foundation, Spain. METHODS: Twenty-four manual WCUs (22 men, 2 women) participated in this study. Skin temperature (Tsk) of 16 and 20 areas of the front and rear upper body, respectively, were measured using an infrared camera. Two thermographic images were recorded in each session during two days separated by 24 h. Results were analyzed using descriptive statistics, intraclass correlation coefficients, coefficients of variation and side-to-side skin temperature differences (δTsk). RESULTS: The intraclass correlation coefficient produced values ranging from 15 to 95 for the various regions of interest. The coefficient of variation ranged between 1.05-6.18%. The mean Tsk of the front upper body was 31.92 °C, and that of the rear upper body was 31.77 °C. The total δTsk was 0.09±0.44°C, r=0.583. CONCLUSION: The reliability of IRT varies depending on the analyzed areas. IRT is a noninvasive and noncontact technique that allows measuring the temperature of the skin, with which to advance in WCU research.

Heart rate recovery in elite Spanish male athletes.

AIM: During postexercise recovery, heart rate (HR) initially falls rapidly, followed by a period of slower decrease, until resting values are reached. The aim of the present work was to examine the differences in the recovery heart rate (RHR) between athletes engaged in static and dynamic sports. METHODS: The study subjects were 294 federated sportsmen competing at the national and international level in sports classified using the criteria of Mitchell et al. as either prevalently static (N.=89) or prevalently dynamic (N.=205). Within the dynamic group, the subjects who practised the most dynamic sports were assigned to further subgroups: triathlon (N.=20), long distance running (N.=58), cycling (N.=28) and swimming (N.=12). All athletes were subjected to a maximum exertion stress test and their HR recorded at 1, 2, 3 and 4 min (RHR1,2,3,4) into the HR recovery period. The following indices of recovery (IR) were then calculated: IR1=(HRpeak-RHR1,2,3,4)/(HRmax-HRrest)*100, IR2=(HRpeak-RHR1,2,3,4)/(HRmax/HRpeak), and IR3=HRpeak-RHR1,2,3,4. The differences in the RHR and IR for the static and dynamic groups were examined using two way ANOVA. RESULTS: The RHR at minutes 2 (138.7±15.2 vs. 134.8±14.4 beats·min⁻¹) and 3 (128.5±15.2 vs. 123.3±14.4 beats·min⁻¹) were significantly higher for the static group (Group S) than the dynamic group (Group D), respectively. Significant differences were seen between Group D and S with respect to IR1 at minutes 1 (26.4±8.7 vs. 24.8±8.4%), 2 (43.8±8.1 vs. 41.5±7.8%), 3 (52.1±8.3 vs. 49.1±8%) and 4 (56.8±8.6 vs. 55.4±7.4%) of recovery. For IR2, significant differences were seen between the same groups at minutes 2 (59.7±12.5 vs. 55.9±10.8 beats·min⁻¹) and 3 (71.0±13.5 vs. 66.1±11.4 beats·min⁻¹) of recovery. Finally, for IR3, the only significant difference between Group D and S was recorded at minute 3 of recovery (72.2±12.5 vs. 66.2±11.5 beats·min⁻¹). CONCLUSION: This work provides information on RHR of a large population of elite Spanish athletes, and shows marked differences in the way that HR recovers in dynamic and static sports.

Effects of dietary restriction combined with different exercise programs or physical activity recommendations on blood lipids in overweight adults.

BACKGROUND AND AIM: Many exercise studies, although generally showing the beneficial effects of supervised aerobic, resistance or combined exercise on blood lipids, have sometimes reached equivocal conclusions. The aim of this study is to evaluate the impact of different programs that combined exercise and dietary restriction on blood lipids versus a clinical practice intervention for weight loss, in overweight adults. METHODS: For this study 66 subjects participated in a supervised 22 weeks training program, composed of three sessions per week and they were randomized in three groups: strength training (S; n = 19), endurance training (E; n = 25), a combination of E and S (SE; n = 22). Eighteen subjects served as physical activity group (PA) that followed a clinical intervention consisted of physical activity recommendations. All groups followed the same dietary treatment, and blood samples were obtained for lipids measurements, at the beginning and end of the study. RESULTS: Lipid profile improved in all groups. No significant differences for baseline and post-training values were observed between groups. In general, SE and PA decreased low-density lipoprotein cholesterol (LDL-C) values (p < 0.01). S decreased triglyceride levels (p < 0.01) and E, SE, and PA decreased total cholesterol levels (p < 0.05, p < 0.01 and p < 0.01, respectively). CONCLUSIONS: These results suggest that an intervention program of supervised exercise combined with diet restriction did not achieved further improvements in blood lipid profile than diet restriction and physical activity recommendations, in overweight adults. (Clinical Trials gov number: NCT01116856).

Validation of the SenseWear armband in circuit resistance training with different loads.

The use of the SenseWear™ armband (SWA), an objective monitor of physical activity, is a relatively new device used by researchers to measure energy expenditure. These monitors are practical, relatively inexpensive and easy-to-use. The aim of the present study was to assess the validity of SWAs for the measurement of energy expenditure (EE) in circuit resistance training (CRT) at three different intensities in moderately active, healthy subjects. The study subjects (17 females, 12 males) undertook CRT at 30, 50 and 70% of the 15 repetition maximum for each exercise component wearing an SWA as well as an Oxycon Mobile (OM) portable metabolic system (a gold standard method for measuring EE). The EE rose as exercise intensity increased, but was underestimated by the SWAs. For women, Bland-Altman plots showed a bias of 1.13 ± 1.48 METs and 32.1 ± 34.0 kcal in favour of the OM system, while for men values of 2.33 ± 1.82 METs and 75.8 ± 50.8 kcal were recorded.

Activity profile of elite goalkeepers during football match-play.

AIM: The purpose of this study was to analyse the activities of a goalkeeper during a match and to identify the distances covered at different velocities between the first and second halves. METHODS: Sixty-two goalkeepers belonging to 28 teams in the English Premier League were monitored over 109 matches using the Prozone(R) system. All values are averages and standard deviations. Pearson product moment correlation was used to examine selected bivariate correlation. To analyze the differences in averages, the paired Student t-test was used. The analyses were performed using SPSS (v.13.0; SPSS, Inc. Chicago, IL). The significance level was set at P<0.05. RESULTS: Mean total distance covered by the goalkeeper during the match was 5 611+/-613 m. There were no differences between distances covered in the first and second halves. The distance covered at high-intensity was 56+/-34 m, while the distance covered sprinting was 11+/-12 m. The average number of high speed actions was 10+/-6, with a total range between 0 and 40. The goalkeeper walked during 73% of the match, while spending just 2% moving at high-intensity. CONCLUSION: The goalkeeper's physical activity was not as great as that of the field players, but the high-intensity actions carried out will be very decisive in the final result of the match.

Evolution of physiological and haematological parameters with training load in elite male road cyclists: a longitudinal study.

AIM: The aim of this study was to describe and evaluate physiological parameters as a control tool for the monitoring of training in a group of elite cyclists during one season of training. METHODS: The study is divided into two periods (winter or ''volume'' mesocycle and spring or ''intensity'' mesocycle) between the tests that they carried out in the laboratory, consisting of a ramp test to exhaustion (work load increases 25 W X min(-1)) and a maximal lactate steady state (MLSS) test on a cycle ergometer. Macronutrients and hematological variables were recorded during the test periods as were the volume and the intensity of training sessions during the whole period of the study. RESULTS: The physiological data were similar to those previously reported for professional cyclists (approximately 450 Watts, approximately 78 mL x kg(-1) x min(-1)) and the values for the MLSS also agree with previous studies (approximately 250 Watts). Subjects improved the first ventilatory threshold (VT(1)) (approximately 52% to approximately 60% VO(2max)) and the second ventilatory threshold (VT(2)) (approximately 82% to approximately 87% VO(2max)) after the first period of training even though its low intensity focused on the performance of VT(1) (77% training in ''zone 1'', under VT(1)). The MLSS improved after the first period (approximately 225 to approximately 250 Watts) and remained high in the second (approximately 255 Watts). High levels of creatine kinase (approximately 230 U x L(-1)) and urea (37 mg x L(-1)) were found, also a decrease in hemoglobin values (approximately 15.4 to approximately 14.7g x dL(-1)). CONCLUSION: The high level reached by the subjects after the first period of training suggests that two effort tests could be enough to plan training. On the other hand, the decrease in some red blood cell and nutrition parameters suggests that there should be greater control over them during the season.

[Response of tidal volume to inspiratory time ratio during incremental exercise]. / Respuesta de la relación volumen corriente-tiempo inspiratorio durante un esfuerzo incremental.

OBJECTIVE: There is some debate about the participation of the Hering-Breuer reflex during exercise in human beings. This study aimed to investigate breathing pattern response during an incremental exercise test with a cycle ergometer. Participation of the Hering-Breuer reflex in the control of breathing was to be indirectly investigated by analyzing the ratio of tidal volume (VT) to inspiratory time (tI). SUBJECTS AND METHODS: The 9 active subjects who participated the study followed an incremental protocol on a cycle ergometer until peak criteria were reached. During exercise, VT/ti can be described in 2 phases, separated by activation of the Hering-Breuer reflex (inspiratory off-switch threshold). In phase 1, ventilation increases because VT increases, resulting in a slight decrease in tI, whereas, in phase 2, increased ventilation is due to both an increase in VT and a decrease in tI. RESULTS: The mean (SD) inspiratory off-switch threshold was 84.6% (6.3%) when expressed relative to peak VT (mean, 3065 [566.8] mL) and 48% (7.2%) relative to the forced vital capacity measured by resting spirometry. The inspiratory off-switch threshold correlated positively (r=0.93) with the second ventilatory threshold, or respiratory compensation point. CONCLUSIONS: The inspiratory off-switch threshold and VT/ti are directly related to one another. The inspiratory off-switch threshold was related to the second ventilatory threshold, suggesting that the Hering-Breuer reflex participates in control of the breathing pattern during exercise. Activation of the reflex could contribute by signaling the respiratory centers to change the breathing pattern.