There is a lack of evidence about the ventilatory efficiency in resistance exercises despite the key role played in endurance exercises. This study aimed to compare the cardiorespiratory, metabolic ...responses and ventilatory efficiency between half-squat (HS) and cycle ergometer exercises during a constant-load test at the lactate threshold (LT) intensity. Eighteen healthy male participants were randomly assigned in a crossover design to carry out HS or cycle ergometer tests. For the three HS tests, a one repetition maximum (1RM) test was performed first to determine the load (kg) corresponding to the 1RM percentages. In the second test, the incremental HS exercise was carried out to establish the load (kg) at the LT intensity. Finally, a constant-load HS test was performed at the LT intensity. The first cycle ergometer test was incremental loading to determine the intensity in watts corresponding to the LT, followed by a constant-load test at the LT intensity. A recovery time of 48 hours between each test was established. During both constant-load test, cardiorespiratory and metabolic responses were monitored. A significant exercise mode x time interaction effect was only detected in oxygen uptake (VO2), heart rate, and blood lactate (p < 0.001). No differences were found between the two types of exercise in ventilatory efficiency (p >0.05). Ventilation (VE) and carbon dioxide were highly correlated (p <0.001) in the cycle ergometer (r = 0.892) and HS (r = 0.915) exercises. In the VO2 efficiency slope (OUES), similarly significant and high correlations (p <0.001) were found between VO2 and log10 VE in the cycle ergometer (r = 0.875) and in the HS (r = 0.853) exercise. Although the cardioventilatory responses were greater in the cycle ergometer test as compared to HS exercise, ventilatory efficiency was very similar between the two exercise modalities in a predominantly aerobic metabolism.
There is a lack of information regarding the slow component of oxygen uptake (VO
sc) and efficiency/economy in resistance exercises despite the crucial role played in endurance performance.
this ...study aimed to compare the VO
sc, efficiency/economy, metabolic, cardiorespiratory responses, rating of perceived effort and mechanical fatigue between cycling and half-squat (HS) exercises during a constant-load test at lactate threshold (LT
) intensity.
Twenty-one healthy men were randomly assigned in a crossover design to perform cycle-ergometer or HS tests. The order of the two cycle ergometer tests was an incremental test for determining load-intensity in watts (W) at LT
, followed by a constant-load test at the LT
intensity. For the three HS tests, the order was a 1RM test to determine the load (kg) corresponding to the 1RM percentages to be used during the second test, incremental HS exercise to establish the load (kg) at the LT
intensity, and finally, a constant-load HS test at the LT
intensity. A rest period of 48 h between each test was established. During the HS and cycle-ergometer constant-load tests, cardiorespiratory and metabolic responses were recorded. Lower limbs fatigue was determined by a jump test before and after the constant-load tests.
A significant exercise mode × time interaction effect was detected in VO
, heart rate, energy expenditure (EE), gross efficiency (GE), and economy (
< 0.05). A significant and sustained VO
raise was confirmed in HS exercise (
< 0.05) and a steady-state VO
was revealed in cycle-ergometer. A higher GE and economy were obtained in HS test than in cycle-ergometer exercise (
< 0.001). In both exercises, a non-significant decrease was observed in GE and economy (
> 0.05). Lower limbs fatigue was only detected after constant-load HS test.
Although the VO
, heart rate and EE responses were higher in cycling exercise, the constant-load HS test induced a greater VO
sc and EE raise than the cycling test in a predominantly aerobic metabolism. These results could explain a decrease observed in jump performance only after HS test. GE and economy could benefit from the eccentric phase of the HS exercise.
This study aimed to determine the effects of circulating nitrate plus nitrite (NOx) concentrations on resistance exercise performance, VO
and biomarkers of muscle damage. Eleven well-trained male ...CrossFit athletes (29.2 ± 3.7 years, 78.9 ± 5.4 kg, 175.1 ± 6.3 cm) carried out a resistance exercise test after drinking 140 mL of beetroot juice (BJ) or placebo. The test consisted of repeating the same resistance exercise routine twice: wall ball shots plus full back squat with 3-min rest (1st routine) or without rest (2nd routine) between the two exercises. Higher NO
plasma levels were verified after BJ than placebo in the pretest and post-test (p < 0.001). A higher number of repetitions was observed after BJ intake compared to placebo in the full back squat exercise during the first routine (p = 0.004). A significantly reduced VO
was detected after BJ intake compared to placebo during rest and full back squat execution in the first routine (p < 0.05). Plasma myoglobin concentrations were significantly increased with BJ compared to placebo (p = 0.036). These results showed that plasma NOx levels reduced VO
after BJ intake during rest time. These reduced VO
was a key factor for improving full back squat performance during the first routine.
ABSTRACTGarnacho-Castaño, MV, Albesa-Albiol, L, Serra-Payá, N, Gomis Bataller, M, Pleguezuelos Cobo, E, Guirao Cano, L, Guodemar-Pérez, J, Carbonell, T, Domínguez, R, and Maté-Muñoz, JL. Oxygen ...uptake slow component and the efficiency of resistance exercises. J Strength Cond Res XX(X)000–000, 2018—This study aimed to evaluate oxygen uptake slow component (VCombining Dot AboveO2sc) and mechanical economy/efficiency in half squat (HS) exercise during constant-load tests conducted at lactate threshold (LT) intensity. Nineteen healthy young men completed 3 HS exercise tests separated by 48-hour rest periods1 repetition maximum (1RM), incremental-load HS test to establish the %1RM corresponding to the LT, and constant-load HS test at the LT. During the last test, cardiorespiratory, lactate, and mechanical responses were monitored. Fatigue in the lower limbs was assessed before and after the constant-load test using a countermovement jump test. A slight and sustained increase of the VCombining Dot AboveO2sc and energy expended (EE) was observed (p < 0.001). In blood lactate, no differences were observed between set 3 to set 21 (p > 0.05). A slight and sustained decrease of half squat efficiency and gross mechanical efficiency (GME) was detected (p < 0.001). Significant inverse correlations were observed between VCombining Dot AboveO2 and GME (r = −0.93, p < 0.001). Inverse correlations were detected between EE and GME (r = −0.94, p < 0.001). Significant losses were observed in jump height ability and in mean power output (p < 0.001) in response to the constant-load HS test. In conclusion, VCombining Dot AboveO2sc and EE tended to rise slowly during constant-load HS exercise testing. This slight increase was associated with lowered efficiency throughout constant-load test and a decrease in jump capacity after testing. These findings would allow to elucidate the underlying fatigue mechanisms produced by resistance exercises in a constant-load test at LT intensity.
Background Acute beetroot juice (BJ) intake has shown to enhance aerobic and anaerobic performance. However, no studies have evaluated the effects of BJ intake on CrossFit (CF) performance by linking ...hormonal, metabolic, and mechanical responses. The purpose of this study was to determine the causal physiological association between hormonal, metabolic and mechanical responses, and CF workouts performance after acute BJ intake. Methods Twelve well-trained male practitioners undertook a CF workout after drinking 140 mL of BJ (~ 12.8 mmol NO.sub.3.sup.-) or placebo. The two experimental conditions (BJ or placebo) were administered using a randomized, double-blind, crossover design. The CF workout consisted of repeating the same exercise routine twice: Wall ball (WB) shots plus full back squat (FBS) with 3-min rest (1st routine) or without rest (2nd routine) between the two exercises. A 3-min rest was established between the two exercise routines. Results An interaction effect was observed in the number of repetitions performed (p = 0.04). The Bonferroni test determined a higher number of repetitions after BJ than placebo intake when a 3-min rest between WB and FBS (1st routine) was established (p = 0.007). An interaction effect was detected in cortisol response (p = 0.04). Cortisol showed a higher increase after BJ compared to placebo intake (76% vs. 36%, respectively). No interaction effect was observed in the testosterone and testosterone/cortisol ratio (p > 0.05). A significant interaction effect was found in oxygen saturation (p = 0.01). A greater oxygen saturation drop was observed in BJ compared to placebo (p < 0.05). An interaction effect was verified in muscular fatigue (p = 0.03) with a higher muscular fatigue being observed with BJ than placebo (p = 0.02). Conclusions BJ intake improved anaerobic performance only after the recovery time between exercises. This increase in performance in the first routine probably generated greater hypoxia in the muscle mass involved, possibly conditioning post-exercise performance. This was observed with a fall in oxygen saturation and in muscle fatigue measured at the end of the CF workout. The greatest perceived changes in cortisol levels after BJ intake could be attributed to the nitrate-nitrite-nitric oxide pathway. Keywords: Workouts of the day, Testosterone, Cortisol, Testosterone/cortisol ratio, Lactate, Anaerobic performance, Oxygen saturation, Muscular fatigue, Countermovement jump
Beetroot juice (BRJ) intake has been considered a practical nutritional strategy among well-trained athletes. This study aimed to assess the effects of BRJ intake on performance, cardiorespiratory ...and metabolic variables during a simulated 2000-meter rowing ergometer test in well-trained master rowers.BACKGROUNDBeetroot juice (BRJ) intake has been considered a practical nutritional strategy among well-trained athletes. This study aimed to assess the effects of BRJ intake on performance, cardiorespiratory and metabolic variables during a simulated 2000-meter rowing ergometer test in well-trained master rowers.Ten well-trained male master rowers (30-48 years) participated in a randomized, double-blind, crossover design for 3 weeks. In the first week, a researcher explained all the experimental procedures to the participants. In the next two weeks, the participants were tested in 2 rowing ergometer sessions, separated from each other by a 7-day washout period. In both strictly identical sessions, the participants randomly drank BRJ or placebo (PL) 3 hours before the start of the tests. Subsequently, the participants carried out the 2000-meter rowing ergometer tests. Oxygen saturation and blood lactate measurements were performed before starting (pretest) and at the end of the test (posttest). Performance parameters and cardiorespiratory variables were recorded during the rowing ergometer test.METHODTen well-trained male master rowers (30-48 years) participated in a randomized, double-blind, crossover design for 3 weeks. In the first week, a researcher explained all the experimental procedures to the participants. In the next two weeks, the participants were tested in 2 rowing ergometer sessions, separated from each other by a 7-day washout period. In both strictly identical sessions, the participants randomly drank BRJ or placebo (PL) 3 hours before the start of the tests. Subsequently, the participants carried out the 2000-meter rowing ergometer tests. Oxygen saturation and blood lactate measurements were performed before starting (pretest) and at the end of the test (posttest). Performance parameters and cardiorespiratory variables were recorded during the rowing ergometer test.An improvement in time trial performance was observed, with a mean difference of 4 seconds (90% confidence limits ± 3.10; p ≤ 0.05) compared to PL. Relative and absolute maximaloxygenuptakeV˙O2max increased (mean difference of 2.10 mL·kg-1·min-1, 90% confidence limits ± 1.80; mean difference of 0.16 L·min-1 90% confidence limits ± 0.11, respectively; p ≤ 0.05) compared to PL. No ergogenic effect was observed on ventilatory efficiency and blood lactate concentrations after BRJ intake.RESULTSAn improvement in time trial performance was observed, with a mean difference of 4 seconds (90% confidence limits ± 3.10; p ≤ 0.05) compared to PL. Relative and absolute maximaloxygenuptakeV˙O2max increased (mean difference of 2.10 mL·kg-1·min-1, 90% confidence limits ± 1.80; mean difference of 0.16 L·min-1 90% confidence limits ± 0.11, respectively; p ≤ 0.05) compared to PL. No ergogenic effect was observed on ventilatory efficiency and blood lactate concentrations after BRJ intake.Acute BRJ intake may improve time trial performance as well as V˙O2max in well-trained master rowers. However, BRJ does not appear to improve ventilatory efficiency.CONCLUSIONAcute BRJ intake may improve time trial performance as well as V˙O2max in well-trained master rowers. However, BRJ does not appear to improve ventilatory efficiency.
Purpose: The Spanish Activity Questionnaire in COPD (SAQ-COPD) is a short, simple physical activity (PA) measurement instrument for patients with chronic obstructive pulmonary disease (COPD). In this ...study, we analyzed its validity and sensitivity to change. Methods: Prospective scale validation study. An accelerometer (DynaPort MoveMonitorR) and the Yale Physical Activity Survey (YPAS) were used as reference standards. The analyses examined the criterion validity (Spearman correlations), internal consistency (Cronbach's alpha), factorial structure, test-retest reliability (intraclass correlation coefficient, ICC), sensitivity to change and receiver operating characteristic (ROC) curve to classify patients with low PA. Results: A total of 300 patients diagnosed with COPD were analyzed (73% males, mean age 66 + or - 8 years, 40.3% with severe airflow limitation). Cronbach's alpha was 0.60 and Spearman's correlations with accelerometer measurements of PA number of steps, metabolic equivalents (MET), physical activity level (PAL) and YPAS ranged from 0.37 to 0.53 (all p < 0.001). ICC was 0.69 (95% CI 0.61-0.74) and the area under the ROC curve to identify low PA was 0.65 (95% confidence interval: 0.58- 0.73). Significant variations in SAQ-COPD scores were found between groups defined by YPAS for change. Conclusion: The SAQ-COPD questionnaire is a valid instrument for classifying PA in patients with COPD. Correlations with other instruments provide criterion validity and also demonstrate good sensitivity to change. Keywords: physical activity, chronic obstructive pulmonary disease, SAQ-COPD, validity, reliability
Quantifying physical activity in chronic obstructive pulmonary disease (COPD) is important as physical inactivity is related to poor health outcomes. This study analyzed the relationship between ...patients' self-reported daily walking time and relevant characteristics related to COPD severity.
Pooled analysis was performed on data from four observational studies on which daily walking time was gathered from a personal interview. Patients were classified as physically inactive if walking time was <30 min/day. Walking times were described and compared according to several markers of disease severity.
The mean daily walking time of 5,969 patients was 66 (standard deviation SD 47) min/day; 893 (15%) patients were inactive. A linear dose-response relationship was observed between walking time and the modified Medical Research Council (mMRC) dyspnea score, admissions, COPD assessment test (CAT), body mass index, airway obstruction, dyspnea, exacerbation (BODEx) index, and Charlson index (
<0.001). Daily walking times were lower in patients classified as Global Initiative for Chronic Obstructive Lung Disease (GOLD) B and D (
<0.001). Often, inactive patients had mMRC or Charlson index >3, post-bronchodilator forced expiratory volume in the first second <30% predicted, at least one hospitalization for COPD, classified as GOLD B or D, BODEx >4, and CAT score >30.
Lower self-reported walking times are related to worse markers of disease severity in COPD.
Prospective longitudinal study.
To identify prognosis factors that allow us to identify patients with risk of developing chronic symptoms and disabilities after a whiplash injury.
The prognosis ...factors for poor recovery in acute whiplash are not conclusive.
We included 557 patients who suffered whiplash injury after road traffic accident and visited the Department of Physical Medicine and Rehabilitation of Mataró Hospital (Spain) for medical evaluation and rehabilitation treatment. The variables were collected following a protocol designed for the study, and all patients were assessed through the Visual Analogue Scale (VAS) for the intensity of neck pain, the Goldberg Depression and Anxiety Scale and the Northwick Park Neck Pain Questionnaire (NPH) for cervical column functionality at initial evaluation and 6 months later.
Factors related with VAS 6 months after the whiplash injury were women, age, number of days of cervical column immobilization, previous neck pain, self-employed workers, housewives, pensioners, students, presence of headache or dizziness, and VAS, Goldberg Depression and Anxiety scale, and NPH scores at initial evaluation. In multivaried analysis, it had been found that the variables that had influence on VAS 6 months after the whiplash injury were statistically significant for age, presence of dizziness, self-employed workers, and VAS and NPH scores at initial evaluation.
Our findings indicate that factors that allow us to identify patients at risk for poor recovery are age, dizziness, and initial evaluation of neck pain with VAS and cervical column functionality with NPH.
Purpose: The Spanish Activity Questionnaire in COPD (SAQ-COPD) is a short, simple physical activity (PA) measurement instrument for patients with chronic obstructive pulmonary disease (COPD). In this ...study, we analyzed its validity and sensitivity to change. Methods: Prospective scale validation study. An accelerometer (DynaPort MoveMonitorR) and the Yale Physical Activity Survey (YPAS) were used as reference standards. The analyses examined the criterion validity (Spearman correlations), internal consistency (Cronbach's alpha), factorial structure, test-retest reliability (intraclass correlation coefficient, ICC), sensitivity to change and receiver operating characteristic (ROC) curve to classify patients with low PA. Results: A total of 300 patients diagnosed with COPD were analyzed (73% males, mean age 66 + or - 8 years, 40.3% with severe airflow limitation). Cronbach's alpha was 0.60 and Spearman's correlations with accelerometer measurements of PA number of steps, metabolic equivalents (MET), physical activity level (PAL) and YPAS ranged from 0.37 to 0.53 (all p < 0.001). ICC was 0.69 (95% CI 0.61-0.74) and the area under the ROC curve to identify low PA was 0.65 (95% confidence interval: 0.58- 0.73). Significant variations in SAQ-COPD scores were found between groups defined by YPAS for change. Conclusion: The SAQ-COPD questionnaire is a valid instrument for classifying PA in patients with COPD. Correlations with other instruments provide criterion validity and also demonstrate good sensitivity to change. Keywords: physical activity, chronic obstructive pulmonary disease, SAQ-COPD, validity, reliability
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