Detrended fluctuation analysis to determine physiologic thresholds, investigation and evidence from incremental cycling test.

PURPOSE: Training zones are generally assessed by gas-exchange thresholds (GET). Several mathematical analyses of heart rate variability (HRV) are proposed for indirect GET determination. Our study aimed to investigate the accordance of the detrend fluctuation analysis (DFA α1) for determining GET with first (VT1) and second ventilatory (VT2) thresholds in well-trained subjects. METHODS: Eighteen female and 38 male sub-elite cyclists performed a maximal incremental cycling test of 2-min stage duration with continuous gas exchange and HR measurements. Power output (PO), Oxygen uptake ( V ˙ O2) and HR at VT1 and VT2 were compared with DFA α1 0.75 (HRVT1) and 0.50 (HRVT2). Agreements between PO, V ˙ O2 and HR values were analyzed using Bland-Altman analysis. RESULTS: Large limits of agreement between VT1 and HRVT1 were observed for measures of V ˙ O2 expressed in mL.min-1.kg-1 [- 21.3; + 14.1], HR [ 39.2; + 26.9] bpm and PO [- 118; + 83] watts. Indeed, agreements were also low between VT2 and HRVT2 for measures of V ˙ O2 [- 26.7; + 4.3] mL.min-1.kg-1, HR [- 45.5; + 10.6] bpm and PO [- 157; + 35] watts. Our results also showed a sex effect: women obtained worst predictions based on DFA α1 than men for HR (p = 0.014), PO (p = 0.044) at VT1 and V ˙ O 2 (p = 0.045), HR (p = 0.003) and PO (p = 0.004) at VT2. CONCLUSION: There was unsatisfactory agreement between the GET and DFA α1 methods for VT1 and VT2 determination in both sex well-trained cyclists. Trial registration number 2233534 on 2024/03/05 retrospectively registered.

Determinants of V̇+O2peak Changes After Aerobic Training in Coronary Heart Disease Patients.

This study aimed to highlight the ventilatory and circulatory determinants of changes in ˙VO2peak after exercise-based cardiac rehabilitation (ECR) in patients with coronary heart disease (CHD). Eighty-two CHD patients performed, before and after a 3-month ECR, a cardiopulmonary exercise testing (CPET) on a bike with gas exchanges measurements (˙VO2peak, minute ventilation, i. e., ˙VE), and cardiac output (Q˙c). The arteriovenous difference in O2 (C(a-v¯)O2) and the alveolar capillary gradient in O2 (PAi-aO2) were calculated using Fick's laws. Oxygen uptake efficiency slope (OUES) was calculated. A 5.0% cut off was applied for differentiating non- (NR: ˙VO2<0.0%), low (LR: 0.0≤ ∆˙VO2<5.0%), moderate (MR: 5.0≤∆˙VO2 < 10.0%), and high responders (HR: ∆˙VO2≥10.0%) to ECR. A total of 44% of patients were HR (n=36), 20% MR (n=16), 23% LR (n=19), and 13% NR (n=11). For HR, the ˙VO2peak increase (p<0.01) was associated with increases in ˙VE (+12.8±13.0 L/min, p<0.01), (+1.0±0.9 L/min, p<0.01), and C(a-v¯)O2 (+2.3±2.5 mLO2/100 mL, p<0.01). MR patients were characterized by+6.7±19.7 L/min increase in ˙VE (p=0.04) and+0.7±1.0 L/min of Q˙c (p<0.01). ECR induced decreases in ˙VE (p=0.04) and C(a-v¯)O2 (p<0.01) and a Q˙c increase in LR and NR patients (p<0.01). Peripheral and ventilatory responses more than central adaptations could be responsible for the ˙VO2peak change with ECR in CHD patients.

Acute effects of aerobic continuous, intermittent, and resistance exercise on glycemia in adolescents males with type 1 diabetes.

OBJECTIVE: Increased levels of physical activity is often associated with reduced HbA1c in individuals with diabetes. However, the effect on glycemic control differs between different programs of exercise. The aim of this study was to compare the acute effects on glycemia of resistance and two aerobic continuous and intermittent exercise bouts in adolescent males with type 1 diabetes. RESEARCH DESIGN AND METHODS: Eight active males with type 1 diabetes (17.5 ± 0.8 years, BMI: 20.8 ± 2.2 kg/m2 , HbA1c: 7.2 ± 0.5% [54.9 ± 5.3 mmol/mol]) performed four experimental sessions-nonexercise (control), resistance exercise (RE) and two isocaloric continuous (CE) and intermittent (IE) cycling exercise trials-in a randomized order. Each session consisted of 45 min of exercise (except for the control modality) and 60 min of passive recovery. Venous blood was drawn for assessment of plasma glucose (PG). A two-way repeated-measures ANOVA was used for statistical comparisons. RESULTS: A significant time-to-exercise interaction effect on PG was detected. PG significantly decreased during IE (-5.1 ± 1.6 mmol/L) and CE (-5.4 ± 1.8 mmol/L) but not during RE (-1.0 ± 1.4 mmol/L, ns). Additionally, decreases in PG after IE and CE were sustained throughout the recovery period. CONCLUSIONS: While intermittent and continuous aerobic exercises are associated with a lowering of glycemia in male adolescents with type 1 diabetes, glycemia remained stable without significant alterations after resistance exercise. These findings hold important implications related to clinical exercise advice and disease management in adolescents with type 1 diabetes.

Post-exercise Heart Rate Variability: Whole-body Cryotherapy vs. Contrast Water Therapy.

High-intensity training sessions are known to alter cardiac autonomic modulation. The purpose of this study was to compare the effects of whole-body cryotherapy, contrast water therapy and passive recovery on the time course of cardiac autonomic markers following a standardized HIT session. Eleven runners completed a high intensity session followed by one of the following recovery interventions: whole-body cryotherapy, contrast water therapy or passive recovery. Changes in cardiac autonomic modulation were assessed in supine and standing positions during an active tilt test at pre-, post-14 h and post-38 h. In supine, high-frequency power increased from pre- to post-14 h following whole-body cryotherapy (1661.1±914.5 vs. 2799.0±948.4 ms2, respectively; p=0.023) and contrast water therapy (1906.1±1327.9 vs. 4174.3±2762.9 ms2, respectively; p=0.004) whereas high frequency power decreased in response to passive recovery (p=0.009). In standing, low-frequency power increased from pre-to post-38 h (1784.3 ± 953.7 vs. 3339.8±1862.7 ms2, respectively; p=0.017) leading to an increase in total power from pre- to post-38 h (1990.8 ± 1089.4 vs. 3606.1±1992.0 ms2, respectively; p=0.017). Spectral analysis revealed that contrast water therapy appears to be a more efficient recovery strategy than whole-body cryotherapy in restoring cardiac autonomic homeostasis.

Effects of a short-term Interval Aerobic Training Programme with active Recovery bouts (IATP-R) on cognitive and mental health, functional performance and quality of life: A randomised controlled trial in sedentary seniors.

BACKGROUND: Interval aerobic training programme with active recovery bouts (IATP-R) has shown to improve tolerance to IATP among seniors. However, data concerning its benefits for seniors' health are still limited. PURPOSE: The purpose of this study was to examine the effects of IATP-R on seniors' health status. METHODS: Sedentary volunteers (n = 60, aged ≥70 years) were randomly assigned to either IATP-R or maintained sedentary lifestyle for 9.5 weeks. IATP-R consisted of 30-minute cycling (6 × 4 minutes at first ventilatory threshold (VT1 ) intensity + 1 minute at 40% of VT1 ) twice a week. Cognitive and functional performances were assessed with the Trail Making Test (TMT-A; TMT-B); Paced Auditory Serial Addition Test (PASAT); Timed Up and Go (TUG) test; 6-Minute Walk Test (6-MWT); one-leg balance test; and the Short Physical Performance Battery (SPPB) tests, respectively. QoL and anxiety/depression status were measured by the Short Form-12 and the Goldberg's Scale, respectively. All participants were assessed at baseline and 9.5 weeks later. RESULTS: Compared to controls, IATP-R improved cognitive functions (TMT-A: +1.5% vs -21.5%; TMT-B: +0.9% vs -13.3%; PASAT: +1.4% vs -14.6%; semantic fluency: -1.1% vs +11.7%), functional performance (TUG: +5.4% vs -16.5%; 6-MWT: -3.2% vs +11.5%; SPPB: -3.2% vs +14.6%; One-leg balance: -16.3% vs +25.0%); QoL (physical health: -13.3% vs +23.1%; mental health: -7.1% vs +8.2%); and depressive symptoms (+26.3% vs -42.8%). Significant impacts were measured neither on letter modality of fluency tasks nor on anxiety score. CONCLUSION: These data showed that IATP-R is an effective training programme to improve functional and cognitive performances, mental health and well-being in sedentary seniors. Trial registration ClinicalTrials.gov NCT02263573. Registered October 1, 2014.

Effects of Interval Aerobic Training Program with Recovery bouts on cardiorespiratory and endurance fitness in seniors.

Interval aerobic training programs (IATP) improve cardiorespiratory and endurance parameters. They are, however, unsuitable to seniors as frequently associated with occurrence of exhaustion and muscle pain. The purpose of this study was to measure the benefits of an IATP designed with recovery bouts (IATP-R) in terms of cardiorespiratory and endurance parameters and its acceptability among seniors (≥70 years). Sedentary healthy volunteers were randomly assigned either to IATP-R or sedentary lifestyle. All participants performed an incremental cycle exercise and 6-minute walk test (6-MWT) at baseline and 9.5 weeks later. The first ventilatory threshold (VT1 ); maximal tolerated power (MTP); peak of oxygen uptake (VO2peak ); maximal heart rate (HRmax ); and distance walked at 6-MWT were thus measured. IATP-R consisted of 19 sessions of 30-minute (6 × 4-min at VT1  + 1-minute at 40% of VT1 ) cycling exercise over 9.5 weeks. With an adherence rate of 94.7% without any significant adverse events, 9.5 weeks of IATP-R, compared to controls, enhanced endurance (VT1 : +18.3 vs -4.6%; HR at baseline VT1 : -5.9 vs +0.2%) and cardiorespiratory parameters (VO2peak : +14.1 vs -2.7%; HRmax : +1.6 vs -1.7%; MTP: +19.2 vs -2.3%). The walk distance at the 6-MWT was also significantly lengthened (+11.6 vs. -3.1%). While these findings resulted from an interim analysis planned when 30 volunteers were enrolled in both groups, IATP-R appeared as effective, safe, and applicable among sedentary healthy seniors. These characteristics are decisive for exercise training prescription and adherence.

Effects of pre-exercise alkalosis on the decrease in VO2 at the end of all-out exercise.

PURPOSE: This study determined the effects of pre-exercise sodium bicarbonate ingestion (ALK) on changes in oxygen uptake (VO2) at the end of a supramaximal exercise test (SXT). METHODS: Eleven well-trained cyclists completed a 70-s all-out cycling effort, in double-blind trials, after oral ingestion of either 0.3 g kg(-1) of sodium bicarbonate (NaHCO3) or 0.2 g kg(-1) body mass of calcium carbonate (PLA). Blood samples were taken to assess changes in acid-base balance before the start of the supramaximal exercise, and 0, 5 and 8 min after the exercise; ventilatory parameters were also measured at rest and during the SXT. RESULTS: At the end of the PLA trial, which induced mild acidosis (blood pH = 7.20), subjects presented a significant decrease in VO2 (P < 0.05), which was related to the amplitude of the decrease in minute ventilation (VE) during the SXT (r = 0.70, P < 0.01, n = 11). Pre-exercise metabolic alkalosis significantly prevented the exercise-induced decrease in VO2 in eleven well-trained participants (PLA:12.5 ± 2.1 % and ALK: 4.9 ± 0.9 %, P < 0.05) and the decrease in mean power output was significantly less pronounced in ALK (P < 0.05). Changes in the VO2 decrease between PLA and ALK trials were positively related to changes in the VE decrease (r = 0.74, P < 0.001), but not to changes in power output (P > 0.05). CONCLUSIONS: Pre-exercise alkalosis counteracted the VO2 decrease related to mild acidosis, potentially as a result of changes in VE and in muscle acid-base status during the all-out supramaximal exercise.

Signal-morphology impedance cardiography is a non-invasive tool for predicting responses to exercise-based cardiac rehabilitation.

Exercise Based Cardiac Rehabilitation (EBCR) is highly beneficial to improve the outcome and quality of life of patients suffering from cardiac diseases. Most of the time, it increases cardiorespiratory and muscle capacity. However, not all patients elicit these benefits because of the high variability in their response to EBCR. In this context, the present study aimed to determine the potential of a specific parameter, the Contractility index (CTi), to predict the response of cardiac patients to EBCR. This parameter is acquired during the baseline Cardiopulmonary Exercise Test (CPET), using Signal-Morphology based Impedance Cardiography (SM-ICGTM). METHODS: 58 cardiac patients (59.7 ± 10.2 years old) were retrospectively enrolled in this study and admitted to EBCR, and 57 could be analyzed. RESULTS: The patients were divided into 2 groups based on their CTi response during CPET (normal versus altered or compromised). After the EBCR program, there was an overall increase in peak oxygen uptake (VO2peak) (+13.6 ± 22.9 %). EBCR induced a higher VO2peak improvement in patients with normal CTi response compared to their counterparts with altered or compromised CTi profiles (+24.1 ± 21.4 % vs. + 3.36 ± 19.5 %, p < 0.01) Patients with a normal CTi response during the baseline CPET were more likely to have a greater than 5% improvement in VO2peak (odds ratio 8.7, p = 0.012) and benefit from EBCR, as compared to the patients in the altered or compromised CTi group. CONCLUSION: This study demonstrated the predictive potential of the CTi profile observed during the baseline CPET to anticipate the response to EBCR in cardiac patients.

Influence of dorsiflexion shoes on neuromuscular fatigue of the plantar flexors after combined tapping-jumping exercises in volleyball players.

Dorsiflexion shoes could be useful to increase jumping performance. The aim of the present study was to investigate the impact of wearing shoes inducing moderate dorsiflexion (2°) on neuromuscular fatigue induced by volleyball exercises involving multiple stretch-shortening cycles. Squat jump (SJ) and countermovement jump (CMJ) performance, and plantar flexors isometric voluntary and evoked contractile properties were assessed in 10 unfamiliarized trained volleyball players before and after a 10-minute intensive combined tapping-jumping volleyball exercise performed, in blinded randomized conditions, with neutral (0°) or moderate dorsiflexion (2°). No significant difference was observed on SJ performance in neutral and moderate dorsiflexion conditions. However, CMJ height was initially lower with 2° dorsiflexion compared with 0° (p < 0.05). Height in CMJ was increased after exercise with 2° dorsiflexion shoes and remained unchanged in neutral 0° condition. Combined tapping-jumping volleyball exercise also induced a significant decrease in maximal voluntary contraction (p < 0.001), peak-twitch torque (p = 0.009), contraction time (p < 0.001) and twitch relaxation rate (p = 0.001) values without any significant difference between neutral and dorsiflexion conditions. Voluntary activation level (p = 0.014) and rate of force development (p = 0.05) were also decreased in both conditions. In conclusion, acute moderate dorsiflexion had no effect on jumping performance and neuromuscular fatigue in unfamiliarized trained subjects and altered the elastic energy store in plyometric condition (CMJ). Future studies are necessary to investigate the chronic effect of moderate dorsiflexion on jumping performance and neuromuscular fatigue in trained volleyball players.

Effects of pre-exercise, endurance, and recovery designer sports drinks on performance during tennis tournament simulation.

Sports drinks are often used before, during, and after tennis tournaments, but their ability to influence physiological and psychological variables and the characteristics of tennis match play remains uncertain. The objective of this study was to evaluate the impact of ingesting specially formulated pre-exercise, endurance, and recovery sports drinks on glycemia and performance indices during a simulated tennis tournament. Eight well-trained male tennis players performed two 3-match round-robin tennis tournaments although ingesting sports drinks (SPDs) or placebos (PLAs) before, during, and after each match (crossover study design). Before the first tournament, match and drink order were randomized (SPDs or PLAs first) and players were placed under controlled nutritional and hydration conditions. Glycemia, heart rate response, rate of perceived exertion, and notational/match analysis were assessed during each match. Sports drinks maintained higher glycemia levels during match 2 and 3 of the tennis tournament compared with PLAs (p < 0.01). Moreover, higher mean heart rates (p < 0.01) and stroke frequencies (p < 0.01) concomitantly with lower rates of perceived exertion (p < 0.01) were recorded throughout the duration of the tournament, when players used the SPDs. During a 3-match tennis tournament, SPDs allow higher stroke frequency during play, with decreased rates of perceived exertion.

Changes in cardiac tone regulation with fatigue after supra-maximal running exercise.

To investigate the effects of fatigue and metabolite accumulation on the postexercicse parasympathetic reactivation, 11 long-sprint runners performed on an outdoor track an exhaustive 400 m long sprint event and a 300 m with the same 400 m pacing strategy. Time constant of heart rate recovery (HRRτ), time (RMSSD), and frequency (HF, and LF) varying vagal-related heart rate variability indexes were assessed during the 7 min period immediately following exercise. Biochemical parameters (blood lactate, pH, PO2, PCO2, SaO2, and HCO3⁻) were measured at 1, 4 and 7 min after exercise. Time to perform 300 m was not significantly different between both running trials. HHRτ measured after the 400 m running exercise was longer compared to 300 m running bouts (183.7 ± 11.6 versus 132.1 ± 9.8 s, P < 0.01). Absolute power density in the LF and HF bands was also lower after 400 m compared to the 300 m trial (P < 0.05). No correlation was found between biochemical and cardiac recovery responses except for the PO2 values which were significantly correlated with HF levels measured 4 min after both bouts. Thus, it appears that fatigue rather than metabolic stresses occurring during a supramaximal exercise could explain the delayed postexercise parasympathetic reactivation in longer sprint runs.

Benefits of a Supervised Ambulatory Outpatient Program in a Cardiovascular Rehabilitation Unit Prior to a Heart Transplant: A Case Study.

Preoperative peak oxygen uptake ( V . O2peak ) and ventilatory efficiency ( V . E / V . CO2slope) are related to the vital prognosis after cardiac transplantation (HTx). The objective of our study was to evaluate the effects of exercise-based cardiac rehabilitation (ECR) program on the preoperative exercise capacity of a HTx candidate. A male patient, aged 50-55 years, with chronic heart failure was placed on the HTx list and performed 12 weeks of intensive ECR (5 sessions-a-week). Our results showed that the cardiac index continuously increased between the onset and the end of ECR (1.40 vs. 2.53 L.min-1.m2). The first 20 sessions of ECR induced a V . O2peak increase (15.0 vs. 19.3 ml.min-1.kg-1, corresponding to 42.0 and 53.0% of its maximal predicted values, respectively). The peak V . O2 plateaued between the 20th and the 40th ECR session (19.3 vs. 19.4 ml.min-1.kg-1) then progressively increased until the 60th ECR session to reach 25.7 ml.min-1.kg-1, i.e., 71.0% of the maximal predicted values. The slope of V . E/ V . CO2 showed a biphasic response during the ECR program, with an increase between the onset and the 20th ECR session (58.02 vs. 70.48) and a decrease between the 20th and the 40th ECR session (70.48 vs. 40.94) to reach its minimal value at the 60th ECR session (31.97). After the first 40 sessions of the ECR program, the Seattle Heart Failure Model score predicted median survival time was estimated at 7.2 years. In conclusion, the improvement in exercise capacity and cardiorespiratory function following the ECR helped delay the heart transplant surgery in our patient awaiting heart transplantation.

Short term effects of various water immersions on recovery from exhaustive intermittent exercise.

In order to investigate the effectiveness of different techniques of water immersion recovery on maximal strength, power and the post-exercise inflammatory response in elite athletes, 41 highly trained (Football, Rugby, Volleyball) male subjects (age = 21.5 ± 4.6 years, mass = 73.1 ± 9.7 kg and height = 176.7 ± 9.7 cm) performed 20 min of exhaustive, intermittent exercise followed by a 15 min recovery intervention. The recovery intervention consisted of different water immersion techniques, including: temperate water immersion (36°C; TWI), cold water immersion (10°C; CWI), contrast water temperature (10-42°C; CWT) and a passive recovery (PAS). Performances during a maximal 30-s rowing test (P(30 s)), a maximal vertical counter-movement jump (CMJ) and a maximal isometric voluntary contraction (MVC) of the knee extensor muscles were measured at rest (Pre-exercise), immediately after the exercise (Post-exercise), 1 h after (Post 1 h) and 24 h later (Post 24 h). Leukocyte profile and venous blood markers of muscle damage (creatine kinase (CK) and lactate dehydrogenase (LDH)) were also measured Pre-exercise, Post 1 h and Post 24 h. A significant time effect was observed to indicate a reduction in performance (Pre-exercise vs. Post-exercise) following the exercise bout in all conditions (P < 0.05). Indeed, at 1 h post exercise, a significant improvement in MVC and P(30 s) was respectively observed in the CWI and CWT groups compared to pre-exercise. Further, for the CWI group, this result was associated with a comparative blunting of the rise in total number of leucocytes at 1 h post and of plasma concentration of CK at 24 h post. The results indicate that the practice of cold water immersion and contrast water therapy are more effective immersion modalities to promote a faster acute recovery of maximal anaerobic performances (MVC and 30″ all-out respectively) after an intermittent exhaustive exercise. These results may be explained by the suppression of plasma concentrations of markers of inflammation and damage, suggesting reduced passive leakage from disrupted skeletal muscle, which may result in the increase in force production during ensuing bouts of exercise.

Oxygen uptake and blood metabolic responses to a 400-m run.

This study aimed to investigate the oxygen uptake and metabolic responses during a 400-m run reproducing the pacing strategy used in competition. A portable gas analyser was used to measure the oxygen uptake (VO2) of ten specifically trained runners racing on an outdoor track. The tests included (1) an incremental test to determine maximal VO2 (VO2max) and the velocity associated with VO2(max) (v - VO2max), (2) a maximal 400-m (400T) and 3) a 300-m running test (300T) reproducing the exact pacing pattern of the 400T. Blood lactate, bicarbonate concentrations [HCO3(-)], pH and arterial oxygen saturation were analysed at rest and 1, 4, 7, 10 min after the end of the 400 and 300T. The peak VO2 recorded during the 400T corresponded to 93.9 +/- 3.9% of VO2max and was reached at 24.4 +/- 3.2 s (192 +/- 22 m). A significant decrease in VO2 (P < 0.05) was observed in all subjects during the last 100 m, although the velocity did not decrease below v - VO2max. The VO2 in the last 5 s was correlated with the pH (r = 0.86, P < 0.0005) and [HCO3(-)] (r = 0.70, P < 0.05) measured at the end of 300T. Additionally, the velocity decrease observed in the last 100 m was inversely correlated with [HCO3(-)] and pH at 300T (r = -0.83, P < 0.001, r = -0.69, P < 0.05, respectively). These track running data demonstrate that acidosis at 300 m was related to both the VO2 response and the velocity decrease during the final 100 m of a 400-m run.

Effect of cold water immersion on 100-m sprint performance in well-trained swimmers.

The aim of the present study was to examine the effect of cold water immersion (CWI) on sprint swimming performance in simulated competition conditions. Ten well-trained swimmers (5 males, 5 females; 19.0 +/- 3.9 years) performed two 100-m swimming sprints (S1 and S2) interspersed with a 30-min passive recovery period, during which athletes were randomly assigned to 5 min of CWI (14 degrees C) or an out-of-water control condition (CON 28 degrees C). During tests, sprint times, heart rate (HR), pre- and post-race parasympathetic activity via HR variability (natural logarithm of the square root of the mean of the sum of the squares of differences between adjacent normal R-R intervals; Ln rMSSD) and blood lactate accumulation ([La](ac)) and clearance ([La](cle)) were recorded. Rates of perceived recovery (RPR) and exertion (RPE) were evaluated before and after each sprint. CWI was associated with a 'likely' decrease in swimming performance [1.8% (90% CI 0.2, 3.5)], as well as 'likely' lower peak HR [-1.9% (-3.6, -0.2)]. CWI was also associated with a 'likely' smaller decrease in Ln rMSSD after the first sprint [-16.7% (-30.9, -4.1)]. RPR was 'likely' better [+27.2% (-3.7, 68.0)] following CWI. 'unclear' effects were observed for [La](ac) [+24.7% (-13.4, 79.5)], [La](cle) [-7.6% (-24.2, 12.7)] or RPE [+2.0% (-12.3, 18.5)]. Following CWI, changes in sprint times were 'largely' correlated with changes in peak HR (r = 0.80). Despite a subjective perception of improved recovery following CWI, this recovery intervention resulted in slower swimming times in well-trained athletes swimming in simulated competition conditions.

Effect of in- versus out-of-water recovery on repeated swimming sprint performance.

The aim of this study was to compare the effect of passive in- (IN) versus out-of-(OUT) water recovery on performance during repeated maximal sprint swimming. Nine well-trained male swimmers (21 +/- 3.5 years) performed six repeated maximal 50-m sprints (RS), departing every 2 min, interspersed with either IN or OUT recovery. Best (RS(b)) and mean (RS(m)) RS times, percentage speed decrement (%Dec) and between-sprint heart rate recovery (HRR(80s)) were calculated for both conditions. Blood lactate was measured after the third ([La](b) S3) and sixth sprints (post [La](b)). Rating of perceived recovery level (REC) and exertion (RPE) were collected before and after each sprint. Repeated sprint performance was significantly lower in the OUT condition (i.e., for RS(m), P = 0.02, +1.3%, 90% CI -0.7, 3.2%). OUT was also associated with poorer HRR(80s) (P < 0.001, -23%, 90% CI -34, -10%) and higher [La](b) S3 (P < 0.01, +13%, 90% CI -1, 29%). Post [La](b), however, was similar (P = 0.44, +1%, 90% CI -7, 10%). RPE and REC were not significantly different between the two conditions (all P > 0.43). To conclude, present results confirm the beneficial effect of the IN condition on repeated swim sprint performance, but also suggest that the OUT recovery modality could be an effective training practice for eliciting a low intramuscular energy status.

Cardiorespiratory and cardiac autonomic responses to 30-15 intermittent fitness test in team sport players.

The 30-15 Intermittent Fitness Test (30-15IFT) is an attractive alternative to classic continuous incremental field tests for defining a reference velocity for interval training prescription in team sport athletes. The aim of the present study was to compare cardiorespiratory and autonomic responses to 30-15IFT with those observed during a standard continuous test (CT). In 20 team sport players (20.9 +/- 2.2 years), cardiopulmonary parameters were measured during exercise and for 10 minutes after both tests. Final running velocity, peak lactate ([La]peak), and rating of perceived exertion (RPE) were also measured. Parasympathetic function was assessed during the postexercise recovery phase via heart rate (HR) recovery time constant (HRR[tau]) and HR variability (HRV) vagal-related indices. At exhaustion, no difference was observed in peak oxygen uptake VO2peak), respiratory exchange ratio, HR, or RPE between 30-15IFT and CT. In contrast, 30-15IFT led to significantly higher minute ventilation, [La]peak, and final velocity than CT (p < 0.05 for all parameters). All maximal cardiorespiratory variables observed during both tests were moderately to well correlated (e.g., r = 0.76, p = 0.001 for [latin capital VO2peak). Regarding ventilatory thresholds (VThs), all cardiorespiratory measurements were similar and well correlated between the 2 tests. Parasympathetic function was lower after 30-15IFT than after CT, as indicated by significantly longer HHR[tau] (81.9 +/- 18.2 vs. 60.5 +/- 19.5 for 30-15IFT and CT, respectively, p < 0.001) and lower HRV vagal-related indices (i.e., the root mean square of successive R-R intervals differences [rMSSD]: 4.1 +/- 2.4 and 7.0 +/- 4.9 milliseconds, p < 0.05). In conclusion, the 30-15IFT is accurate for assessing VThs and VO2peak, but it alters postexercise parasympathetic function more than a continuous incremental protocol.

Does the direct anterior approach allow earlier recovery of walking following total hip arthroplasty? A randomized prospective trial using accelerometry.

INTRODUCTION: In total hip arthroplasty (THA), the anterior approach is attractive, being intermuscular, with theoretic functional benefit. Such benefit has been frequently claimed, but there are few data from randomized comparative studies using more precise metrics than patient satisfaction. We therefore conducted a randomized trial comparing early functional results between anterior and posterior approaches on gait analysis and functional scores. HYPOTHESIS: The study hypothesis was that there is no difference between the two approaches in terms of early recovery of walking. MATERIALS AND METHOD: A single-center single-surgeon prospective randomized study was conducted between February 2017 and April 2018. Inclusion criteria comprised: age<85 years, body-mass index (BMI)<32, and hip osteoarthritis with indication for THA. Preoperatively, the 2 groups were comparable for age, gender, BMI, Charnley, Harris, Postel-Merle-d'Aubigné and Oxford-12 scores and locomotor parameters (triaxial acceleration, step regularity and walking power). Preoperative and 3-, 6- and 12-week assessment comprised triaxial acceleration in walking and Postel-Merle-d'Aubigné, Harris and Oxford SF-12 scores. RESULTS: One hundred patients were randomized to the anterior approach (AA: n=50) and posterior approach (PA: n=50) groups. Hospital stay was comparable between groups: PA, 2.8±1.78 days [range, 2.29-3.31 days]; AA, 2.84±1.25 days [range, 2.48-3.2 days] (p=0.8). Operative time was significantly longer in AA: 70.1±11 minutes vs. 56.7±11.79 (p<0.0001). There were no significant differences in locomotor parameters (p 0.122 to 0.987) or functional scores (p 0.052 to 0.968) over the 3-month follow-up. There was no difference in cup inclination: PA, 39.6±6.87° [range, 37.65-41.55°] vs. AA, 37.74±4.2° [range, 36.55-38.93°] (p=0.09). There were 8/50 cases (16%) of neurapraxia of the lateral cutaneous nerve of the thigh in the AA group; rates for other complications did not differ between groups. CONCLUSION: Early functional results and especially objective locomotor parameters following THA were comparable between anterior and posterior approaches at 3 to 12 weeks. The approach should be chosen according to the surgeon's experience. LEVEL OF EVIDENCE: II, low-power prospective randomized study.

Effects of a short-term interval aerobic training program with recovery bouts on vascular function in sedentary aged 70 or over: A randomized controlled trial.

BACKGROUND: Interval aerobic training programs with active recovery bouts (IATP-R) are reported as being more adapted to seniors while improving cardiorespiratory and endurance parameters. Report of benefits on vascular function is still limited. PURPOSE: To measure the impact of IATP-R on vascular function among seniors. METHODS: Sedentary volunteers (≥70 years of age) were randomly assigned to either IATP-R (n = 30) or control group (n = 30). The IATP-R consisted of 2 weekly sessions of 30-min (6 × 4-min at first ventilatory threshold (VT1) intensity + 1-min at 40% of VT1) cycling exercise over 9.5-week. Controls remained their sedentary life over the same period. In all participants, the endothelial function was measured by flow-mediated dilation (FMD) in brachial artery and arterial stiffness through the carotid/radial and carotid/femoral pulse wave velocity (PWV). Systolic (SBP) and diastolic blood pressure (DBP) were measured at baseline and 9.5 weeks later. RESULTS: Resulting from a planned interim analysis, IATP-R improved SBP (IATP-R: from 133.7 ± 9.8 to 122.6 ± 9.4 mmHg vs. Controls: from 128.9 ± 12.5 to 132.6 ± 14.7 mmHg), DBP (IATP-R: from 80.2 ± 7.0 to 74.1 ± 6.7 mmHg vs. Controls: from 77.1 ± 6.8 to 80.3 ± 7.5 mmHg), and FMD (IATP-R: from 6.7 ± 2.0 to 7.5 ± 2.7% vs. Controls: from 7.9 ± 2.7 to 7.5 ± 2.5%). No significant impact on PWV was measured. CONCLUSION: Although these findings resulted from an interim analysis, IATP-R might be effective in regulating BP and improving endothelial function among sedentary seniors.