Repeated Short-Term Bouts of Hyperoxia Improve Aerobic Performance in Acute Hypoxia.

ABSTRACT: Faulhaber, M, Schneider, S, Rausch, LK, Dünnwald, T, Menz, V, Gatterer, H, Kennedy, MD, and Schobersberger, W. Repeated short-term bouts of hyperoxia improve aerobic performance in acute hypoxia. J Strength Cond Res 37(10): 2016-2022, 2023-This study aimed to test the effects of repeated short-term bouts of hyperoxia on maximal 5-minute cycling performance under acute hypoxic conditions (3,200 m). Seventeen healthy and recreationally trained individuals (7 women and 10 men) participated in this randomized placebo-controlled cross-over trial. The procedures included a maximal cycle ergometer test and 3 maximal 5-minute cycling time trials (TTs). TT1 took place in normoxia and served for habituation and reference. TT2 and TT3 were conducted in normobaric hypoxia (15.0% inspiratory fraction of oxygen). During TT2 and TT3, the subjects were breathing through a face mask during five 15-second periods. The face mask was connected through a nonrebreathing T valve to a 300-L bag filled with 100% oxygen (intermittent hyperoxia) or ambient hypoxic air (placebo). The main outcome was the mean power output during the TT. Statistical significance level was set at p < 0.05. The mean power output was higher in the intermittent hyperoxia compared with the placebo condition (255.5 ± 49.6 W vs. 247.4 ± 48.2 W, p = 0.001). Blood lactate concentration and ratings of perceived exertion were significantly lower by about 9.7 and 7.3%, respectively, in the intermittent hyperoxia compared with the placebo condition, whereas heart rate values were unchanged. IH application increased arterial oxygen saturation (82.9 ± 2.6% to 92.4 ± 3.3%, p < 0.001). Repeated 15-second bouts of hyperoxia, applied during high-intensity exercise in hypoxia, are sufficient to increase power output. Future studies should focus on potential dose-response effects and the involved mechanisms.

Long-Term Athlete Development: Seasonal and Longitudinal Fitness Changes in Female University Rugby Players.

ABSTRACT: Falk Neto, JH, Parent, E, and Kennedy, MD. Long-term athlete development: Seasonal and longitudinal fitness changes in female university rugby players. J Strength Cond Res 35(12): 3459-3465, 2021-The Long-Term Athlete Development model is used by organizations to determine the expected improvements from athletes at different stages of their careers. For female rugby athletes, university sports should provide continued support for athlete development during the Training to Perform stage (18-21 years old). However, little evidence exists for longitudinal changes across years of participation in university sports in this group. The purpose of this study was to assess changes in anthropometric and fitness characteristics in female university rugby players across different seasons. Seventeen players were divided into forwards (n = 9, 21.1 ± 2.6 years) and backs (n = 8, 19.62 ± 0.9 years) and assessed across 5 points over 3 years: preseason 1, postseason 1, preseason 2, postseason 2, and preseason 3. Anthropometric (height, body mass, and body mass index) and performance measurements (grip strength, flexibility, trunk muscular endurance, upper-body muscular endurance, 40-m sprint, vertical jump, and 20-m shuttle run) were collected. V̇o2max was higher at preseason 2 compared with postseason 1 (p = 0.02), postseason 2 (p = 0.01), and preseason 3 (p = 0.015), and trunk muscular endurance was higher at preseason 3 (p = 0.02). Performance in the first 5 m of the sprint test decreased at postseason 1 (p = 0.018) and preseason 2 (p = 0.016) when compared with preseason 1. The results indicate that these female athletes did not improve their fitness across the Training to Perform stage when participating in university sports. These female rugby players likely developed their fitness at earlier stages and, at this stage, already possessed well-developed fitness levels, which were merely maintained throughout years.

Effects of a heat and moisture exchanger on respiratory function and symptoms post-cold air exercise.

PURPOSE: Exercise at temperatures below -15°C induces drying and cooling of lung airways which causes exercise-induced bronchoconstriction (EIB) and respiratory symptoms, especially in winter sport athletes. The objective of this study was to evaluate whether a heat and moisture exchanger (HME) worn during intense cold air exercise improves lung function and reduces respiratory symptoms in healthy winter sport athletes. METHODS: Seven active males and six active females (maximum oxygen uptake 61.9 ± 6.9 and 52.2 ± 5.3 mL/kg/min), all active or former winter sport athletes, completed running trials with and without HME in random order on 2 days in an environmental chamber (-20°C temperature, humidity 46.2%). Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1 ), forced expiratory flow at 25%-75% (FEF25%-75% ), and FEF at 50% (FEF50% ) were measured pre- and post-exercise (3, 6, 10, 15, and 20 minutes). Respiratory symptoms were reported after exercise. RESULTS: Significant interaction effects were observed for FEV1 and FEF25%-75% . Mean decrease of FVC (-5.9%, P ≤ .001) and FEV1 (-4.2%, P = .003) was largest 3 minutes post-exercise without HME. There was an increase of FEV1 , FEF25%-75% , and FEF50% post-exercise compared to pre-exercise with HME. More respiratory symptoms overall were reported without HME (P = .046). CONCLUSION: Intense cold air exercise likely causes transient acute bronchoconstriction and symptoms of cough in individuals participating in winter sports. However, this study finds that the application of an HME during intense cold air exercise improves lung function and reduces prevalence of EIB-associated symptoms compared to unprotected intense cold air exercise.

Field versus race pace conditions to provoke exercise-induced bronchoconstriction in elite swimmers: Influence of training background.

BACKGROUND: Diagnosing Airway hyper-responsiveness (AHR) requires bronchial provocation tests that are performed at rest and after exercise or hyperventilation in either a lab or field setting. Presently, it is unclear whether the proposed AHR field test for swimming induces sufficient provocation due to lack of intensity. Thus we aimed to examine how the 8 minute field swim test compared to all out racing and a lower intensity practice exposure affected AHR. We hypothesized that the race would affect AHR the most thereby highlighting the importance of maximal effort in swim AHR. METHODS: 10 female and 15 male swimmers completed three conditions (sanctioned race of different distances, 8 min field swim challenge and swim practice). Forced vital capacity (FVC), forced expired volume in 1 second (FEV1) and forced expiratory flow (FEF25-75) were measured at rest and after each exercise condition (at 6 and 10 min) in accordance with standard protocols. AHR was defined as a decrease in FEV1 of ≥10% post exercise. RESULTS: A significant increase in FEV1 and FEF25-75 was observed for both post swim field test and post-race. The practice condition reduced FEV1 in 44% of swimmers although the magnitude of change was small. There was a wide variability in the individual responses to the 3 conditions and AHR was diagnosed in one swimmer (race condition). CONCLUSION: All conditions have poor sensitivity to diagnose EIB and total accumulated ventilation (distance swum) did not influence AHR. These results also indicate that elite swimmers, despite many risk factors, are not limited by respiratory function in race conditions. It is proposed that the swim field test not be used for AHR assessment in swimmers due to too high relative humidity.

Quadriceps effort during squat exercise depends on hip extensor muscle strategy.

Hip extensor strategy, specifically relative contribution of gluteus maximus versus hamstrings, will influence quadriceps effort required during squat exercise, as hamstrings and quadriceps co-contract at the knee. This research examined the effects of hip extensor strategy on quadriceps relative muscular effort (RME) during barbell squat. Inverse dynamics-based torque-driven musculoskeletal models were developed to account for hamstrings co-contraction. Net joint moments were calculated using 3D motion analysis and force platform data. Hamstrings co-contraction was modelled under two assumptions: (1) equivalent gluteus maximus and hamstrings activation (Model 1) and (2) preferential gluteus maximus activation (Model 2). Quadriceps RME, the ratio of quadriceps moment to maximum knee extensor strength, was determined using inverse dynamics only, Model 1 and Model 2. Quadriceps RME was greater in both Models 1 and 2 than inverse dynamics only at barbell loads of 50-90% one repetition maximum. The highest quadriceps RMEs were 120 ± 36% and 87 ± 28% in Models 1 and 2, respectively, which suggests that barbell squats are only feasible using the Model 2 strategy prioritising gluteus maximus versus hamstrings activation. These results indicate that developing strength in both gluteus maximus and quadriceps is essential for lifting heavy loads in squat exercise.

The Characteristics of Endurance Events with a Variable Pacing Profile-Time to Embrace the Concept of "Intermittent Endurance Events"?

A variable pacing profile is common in different endurance events. In these races, several factors, such as changes in elevation or race dynamics, lead participants to perform numerous surges in intensity. These surges are so frequent that certain events, such as cross-country (XC) skiing, mountain biking (MTB), triathlon, and road cycling, have been termed "intermittent endurance events". The characteristics of these surges vary depending on the sport: MTB and triathlon require athletes to perform numerous short (<10 s) bouts; XC skiing require periods of short- and moderate-(30 s to 2 min) duration efforts, while road cycling is comprised of a mix of short-, moderate-, and long-duration (>2 min) bouts. These bouts occur at intensities above the maximal metabolic steady state (MMSS), with many efforts performed at intensities above the athletes' maximal aerobic power or speed (MAP/MAS) (i.e., supramaximal intensities). Given the factors that influence the requirement to perform surges in these events, athletes must be prepared to always engage in a race with a highly stochastic pace. The aim of this review is to characterize the variable pacing profile seen in endurance events and to discuss how the performance of multiple maximal and supramaximal surges in intensity can affect how athletes fatigue during a race and influence training strategies that can lead to success in these races.

Influence of an Exercise-Specific Face Mask on Physiological and Perceptual Responses to Graded Exercise.

The impact of exercise-specific face masks (ESFMs) in aerobically fit individuals on physiological, perceptual, respiratory, and performance responses remains unclear. How ESFMs mitigate exercise-induced bronchoconstriction (EIB) is also unknown. Thus, this study aimed to determine how an ESFM altered within-exercise physiological, perceptual, respiratory, and performance responses to graded treadmill exercise. Twenty-four individuals (11 females) completed a discontinuous graded exercise test on a treadmill under two conditions (ESFM and unmasked). Physiological, respiratory function, and perceptual measures were assessed. Performance was determined by time to exhaustion. Statistical analyses included linear mixed-effects modeling, repeated measures analysis of variance, and pairwise comparisons using an alpha value of 0.05. ESFM use significantly impaired performance (median = -150.5 s) and decreased arterial oxygen saturation at maximal intensity (mean = -3.7%). Perceptions of air hunger and work of breathing were elevated across submaximal and maximal intensities. Perceived exertion and breathing discomfort were significantly elevated submaximally but not maximally. Spirometry measures were not significantly different at termination but were significantly improved at submaximal intensities in participants with and without EIB. ESFM use in fit individuals increased perceptual discomfort, impaired performance, and augmented arterial desaturation. Respiratory function improvements were observed but were accompanied by adverse perceptual sensations. Despite this, performance impairments may limit the real-world utility of ESFMs for athletes.

Factors that influence fatigue status in Canadian university swimmers.

The overall purpose of this two-part study was to examine factors that influenced fatigue status in university level swimmers. Participants were 25 swimmers (14 male, 11 female) from one university swim team. A mixed methods approach was used. Quantitative data were collected using an orthostatic heart rate test and self-report questionnaire at multiple time points throughout a competitive season. Qualitative data were collected via focus groups conducted at the end of the season. Analysis of the quantitative data indicated high levels of accumulated physiological and psychological fatigue that improved with increased recovery. Specifically, heart rate indices, form, feeling, and energy level improved during taper periods and worsened during and immediately after intensive training blocks. Analysis of the qualitative data revealed that one factor (flexible structure of training programme) had a positive influence on athletes' fatigue while two factors (teammate expectations and balancing school, work, and sleep) had a negative influence on athletes' fatigue.

Time-motion analysis, heart rate, and physiological characteristics of international canoe polo athletes.

To evaluate the time international canoe polo players spend performing various game activities, measure heart rate (HR) responses during games, and describe the physiological profile of elite players. Eight national canoe polo players were videotaped and wore HR monitors during 3 games at a World Championship and underwent fitness testing. The mean age, height, and weight were 25 ± 1 years, 1.82 ± 0.04 m, and 81.9 ± 10.9 kg, respectively. Time-motion analysis of 3 games indicated that the players spent 29 ± 3% of the game slow and moderate forward paddling, 28 ± 5% contesting, 27 ± 5% resting and gliding, 7 ± 1% turning, 5 ± 1% backward paddling, 2 ± 1% sprinting, and 2 ± 1% dribbling. Sixty-nine (±20)% of the game time was played at an HR intensity above the HR that corresponded to the ventilatory threshold (VT) that was determined during the peak V[Combining Dot Above]O2 test. Peak oxygen uptake and VT were 3.3 ± 0.3 and 2.2 ± 0.3 L·min, respectively, on a modified Monark arm crank ergometer. Arm crank peak 5-second anaerobic power was 379 W. The majority of the time spent during international canoe polo games involved slow-to-moderate forward paddling, contesting for the ball, and resting and gliding. Canoe polo games are played at a high intensity indicated by the HR responses, and the physiological characteristics suggest that these athletes had high levels of upper body aerobic and anaerobic fitness levels.

Do Female University Varsity Athletes Have a Greater Risk of Injury Within a Competitive Varsity Season?

Previous varsity sport injury research has analyzed how acute and chronic injury severity, type, and location differs between sport and sexes, with limited research in time to injury. Canadian university varsity sport injury research is especially sparse and mostly retrospective. Thus, we aimed to understand injury differences in male and female competitive university athletes competing in the same sport. Athletes who competed on the basketball, volleyball, soccer, ice hockey, football (male), rugby (female), and wrestling teams were eligible for the study. There were 182 male and 113 female athletes who provided informed consent to be prospectively followed over a season. Injury date, type, location, chronicity, and events missed due to injury were recorded on a weekly basis. Overall, the percentage of male (68.7%) and female (68.1%) athletes injured was not different. No overall sex differences (variables collapsed) were observed in injury chronicity, location, type, events lost, mean number of injuries, or time to injury. Within sport differences existed for mean number of injuries, injury location, type of injury, and events missed. Mean time to injury in female basketball (28 days) and volleyball athletes (14 days) was significantly shorter compared to male basketball (67 days) and volleyball (65 days). Time to a concussion was significantly shorter in females overall compared to males. These results indicate that Canadian female university age athletes are not inherently more susceptible to injury, but female athletes within certain sports may have increased injury risk which could shorten time to injury (basketball, volleyball) and increase the number of events missed due to injury (hockey).

Effect of incline versus block heel-raise exercise on foot muscle strength and vertical jump performance - an 11-week randomized resistance training study.

Strengthening the toe flexors and ankle plantar flexors may improve vertical jump performance. One exercise that may be effective for concurrently strengthening these muscles is heel-raises performed on an incline. The purpose of this study was to investigate the effects of incline versus conventional (block) heel-raise exercise on hallux and II-V digit flexor strength, vertical jump performance, and ankle plantar flexor strength. Thirty-three female volleyball players were randomly allocated to perform incline (n = 17) or block (n = 16) heel-raise exercise for 11-weeks. Participants' toe flexor strength, countermovement jump, approach jump, and ankle plantar flexor strength were assessed before, after 7 weeks, and after 11 weeks of exercise. There were no significant time-by-group interactions for any variable (p > 0.05). However, both groups improved their hallux flexor strength (Δ0.27 ± 0.50 N·kg-1; p < 0.05), and vertical countermovement (Δ1.2 ± 2.3 cm; p < 0.05) and approach (Δ1.9 ± 2.6 cm; p < 0.05) jump height from pre- to post-test. No changes were observed in the ankle plantar flexor or II-V digit flexor strength (n > 0.05). Both incline and conventional heel-raises improve toe flexor strength. Practitioners seeking to improve individuals' foot function may consider incorporating incline or block heel-raises.

Association of personal and equipment-related factors on ACL injury risk in alpine skiers with cautious or risk-taking behaviour: A case-control study.

Background: In recreational alpine skiing ACL injury risk depends on the interaction of individual characteristics and behaviours as well as on equipment-related factors. Aim: to evaluate if and to what extent personal characteristics and equipment-related parameters are associated with ACL injury risk in cautious and risk-taking recreational alpine skiers. Methods: A retrospective questionnaire-based, case-control study of ACL-injured and uninjured in a cohort of cautious as well as risk-taking recreational skiers was conducted. Participants self-reported their demographics, skiing skill level, and risk-taking behaviour. Ski length, side-cut radius, widths of the tip, waist, and tail were recorded from each participant's skis. Standing heights at the front and rear components of the ski binding were measured with a digital sliding caliper, and a standing height ratio between the front and rear components was calculated. Ski boot sole abrasion at the toe and heel pieces was also measured with the digital sliding caliper. Results: In total, 1068 recreational skiers (50.8% females) with a mean age of 37.8 ± 12.3 years participated, of whom 193 (22.0%) sustained an ACL injury, and 330 (30.9%) participants reported a risk-taking behaviour. Results of the multiple logistic regression analyses revealed that a higher age, a lower skill level, a higher standing height ratio, and greater ski boot sole abrasion at the toe as well as heel pieces were independently associated with an increased ACL injury risk in both the cautious and the risk-taking group. Among cautious skiers, a longer ski length was an additional significant risk factor for sustaining an ACL injury. In conclusion, the same personal and equipment related characteristics contribute to an increase in the ACL injury risk regardless of risk-taking behaviour, with the only difference that longer skis represent an additional risk factor in cautious skiers.

Creatine supplementation and endurance performance: surges and sprints to win the race.

Creatine supplementation is an effective ergogenic aid to augment resistance training and improve intense, short duration, intermittent performance. The effects on endurance performance are less known. The purpose of this brief narrative review is to discuss the potential mechanisms of how creatine can affect endurance performance, defined as large muscle mass activities that are cyclical in nature and are >~3 min in duration, and to highlight specific nuances within the literature. Mechanistically, creatine supplementation elevates skeletal muscle phosphocreatine (PCr) stores facilitating a greater capacity to rapidly resynthesize ATP and buffer hydrogen ion accumulation. When co-ingested with carbohydrates, creatine enhances glycogen resynthesis and content, an important fuel to support high-intensity aerobic exercise. In addition, creatine lowers inflammation and oxidative stress and has the potential to increase mitochondrial biogenesis. In contrast, creatine supplementation increases body mass, which may offset the potential positive effects, particularly in weight-bearing activities. Overall, creatine supplementation increases time to exhaustion during high-intensity endurance activities, likely due to increasing anaerobic work capacity. In terms of time trial performances, results are mixed; however, creatine supplementation appears to be more effective at improving performances that require multiple surges in intensity and/or during end spurts, which are often key race-defining moments. Given creatines ability to enhance anaerobic work capacity and performance through repeated surges in intensity, creatine supplementation may be beneficial for sports, such as cross-country skiing, mountain biking, cycling, triathlon, and for short-duration events where end-spurts are critical for performance, such as rowing, kayaking, and track cycling.

Effect of squat depth and barbell load on relative muscular effort in squatting.

Resistance training is used to develop muscular strength and hypertrophy. Large muscle forces, in relation to the muscle's maximum force-generating ability, are required to elicit these adaptations. Previous biomechanical analyses of multi-joint resistance exercises provide estimates of muscle force but not relative muscular effort (RME). The purpose of this investigation was to determine the RME during the squat exercise. Specifically, the effects of barbell load and squat depth on hip extensor, knee extensor, and ankle plantar flexor RME were examined. Ten strength-trained women performed squats (50-90% 1 repetition maximum) in a motion analysis laboratory to determine hip extensor, knee extensor, and ankle plantar flexor net joint moment (NJM). Maximum isometric strength in relation to joint angle for these muscle groups was also determined. Relative muscular effect was determined as the ratio of NJM to maximum voluntary torque matched for joint angle. Barbell load and squat depth had significant interaction effects on hip extensor, knee extensor, and ankle plantar flexor RME (p < 0.05). Knee extensor RME increased with greater squat depth but not barbell load, whereas the opposite was found for the ankle plantar flexors. Both greater squat depth and barbell load increased hip extensor RME. These data suggest that training for the knee extensors can be performed with low relative intensities but require a deep squat depth. Heavier barbell loads are required to train the hip extensors and ankle plantar flexors. In designing resistance training programs with multi-joint exercises, how external factors influence RME of different muscle groups should be considered to meet training objectives.

Participant Exercise-Session Attendance in Community-Based, Bridging, and Hospital-Based Cardiac Rehabilitation: A Retrospective Case-Control Study.

Background: A paucity of studies have investigated participant attendance in community-based and hybrid cardiac rehabilitation programs in the Canadian setting. We compared exercise-session attendance of community-based, bridging (hospital plus community-based), and hospital-based participants who attended a high-volume cardiac rehabilitation program in Alberta, Canada. Methods: Exercise sessions attended and participant characteristics were collected and analyzed from 230 records of patients who attended cardiac rehabilitation between 2016 and 2019. Community-based (n = 74) and bridging (n = 41) program participants were age- and sex-matched in a 1:1 ratio to hospital-based participants. The number of exercise sessions attended was compared among program groups, between female and male patients, and for patients with vs without cardiac surgery. The percentage of exercise sessions attended was also compared among program groups. Results: Bridging participants attended the greatest number of exercise sessions (median = 10.0 sessions) and demonstrated a significantly higher percentage of sessions attended (91%, 25th and 75th percentile interquartile range [IQR] = 64, 100%) than matched hospital participants (median = 6.0 sessions; 63%, 25, 75 IQR = 13, 94%; P = 0.01). Percentage of sessions attended did not differ for bridging and community-based participants (P = 0.30). Exercise-session attendance was similar for community-based participants (median = 6.0 sessions; 75%, 25, 75 IQR = 38%, 88%) vs their hospital matches (median = 6.0 sessions; 81%, 25, 75 IQR = 38%, 100%; P ≥ 0.37), as well as for female vs male patients (median = 7.0 sessions for both sexes; P = 0.66), and for surgical vs nonsurgical patients (median = 7.0 sessions; P = 0.48). Female patients in the bridging program attended significantly more exercise sessions in the community, compared with male patients in the bridging program (P = 0.02). Conclusions: Bridging participants attended the most exercise sessions overall and demonstrated a higher percentage attendance than hospital-based participants. These results suggest that a hybrid program consisting of hospital and community-based exercise was favourable for exercise-session attendance. Given modern approaches to de-medicalize cardiac rehabilitation, our findings further support the provision of community program offerings, without detriment to patient session attendance.

Introduction: Peu d'études ont porté sur la participation des patients aux programmes communautaires ou hydrides de réadaptation cardiaque du Canada. Nous avons comparé la participation des patients aux séances d'entraînement en milieu communautaire, de transition (en milieu hospitalier et milieu communautaire) et en milieu hospitalier d'un programme de réadaptation cardiaque à volume élevé de l'Alberta, au Canada. Méthodes: Nous avons collecté et analysé les données sur les séances d'entraînement suivies et les caractéristiques des participants provenant de 230 dossiers de patients qui avaient participé à la réadaptation cardiaque entre 2016 et 2019. Les participants du programme en milieu communautaire (n = 74) et du programme de transition (n = 41) ont été appariés par âge et sexe aux participants du programme en milieu hospitalier selon un ratio 1:1. Le nombre de séances d'entraînement suivies a été comparé entre les groupes du programme, entre les patientes et les patients, et entre les patients qui avaient subi ou non une chirurgie cardiaque. Le pourcentage des séances d'entraînement suivies a aussi été comparé entre les groupes du programme. Résultats: Les participants du programme de transition ont assisté au plus grand nombre de séances d'entraînement (médiane = 10,0 séances) et ont démontré un pourcentage significativement plus élevé de séances suivies (91 %, 25e et 75e percentile [25, 75] intervalle interquartile [IIQ] = 64, 100 %) que les participants appariés du programme en milieu hospitalier (médiane = 6,0 séances; 63 %, 25, 75 IIQ = 13, 94 %; P = 0,01). Le pourcentage de séances suivies ne différait pas entre les participants du programme de transition et les participants du programme en milieu communautaire (P = 0,30). La participation aux séances d'entraînement était similaire entre les participants du programme en milieu communautaire (médiane = 6,0 séances; 75 %, 25, 75 IIQ = 38 %, 88 %) et les participants appariés du programme en milieu hospitalier (médiane = 6,0 séances; 81 %, 25, 75 IIQ = 38 %, 100 %; P ≥ 0,37), de même qu'entre les patientes et les patients (médiane = 7,0 séances pour les deux sexes; P = 0,66), et les patients opérés et les patients non opérés (médiane = 7,0 séances; P = 0,48). Les patientes du programme de transition ont participé à un nombre plus important de séances d'entraînement en milieu communautaire que les patients du programme de transition (P = 0,02). Conclusions: Les participants du programme de transition ont dans l'ensemble assisté à la plupart des séances d'entraînement et ont démontré un pourcentage plus élevé de participation que les participants du programme en milieu hospitalier. Ces résultats indiquent qu'un programme hybride qui consiste en un entraînement en milieu hospitalier et en milieu communautaire favorisait la participation aux séances d'entraînement. Compte tenu des approches contemporaines de démédicalisation de la réadaptation cardiaque, nos conclusions justifient d'autant plus la mise à disposition de programmes en milieu communautaire, et ce, sans compromettre la participation des patients aux séances.

Time-course effects of functional fitness sessions performed at different intensities on the metabolic, hormonal, and BDNF responses in trained men.

BACKGROUND: To investigate the time-course effects of a self-regulated training session (performed at an rating perceived exertion of 6/10), all-out session, and a control session on the metabolic, hormonal, and brain derived neurotrophic factor (BDNF) responses in Functional-Fitness (FFT) participants. METHODS: In a randomized, crossover fashion, eight healthy males (age 28.1 ± 5.4 years old; body mass 77.2 ± 4.4 kg; VO2max: 52.6 ± 4.6 mL.(kg.min)-1; 2000 m rowing test 7.35 ± 0.18 min; 1RM back squat 135.6 ± 21.9 kg) performed a FFT session under two different conditions: all-out, or with the intensity controlled to elicit an rating perceived exertion (RPE) of 6 in the Borg 10-point scale (RPE6). A control session (no exercise) was also completed. Metabolic (lactate and creatine kinase), hormonal (testosterone and cortisol), and BDNF responses were assessed pre, post-0 h, 1 h, 2 h and 24 h after the sessions. RESULTS: Creatine kinase concentrations were significantly higher (p ≤ 0.05) after 24 h for both training sessions. Total and free testosterone concentrations were lower post-2 h for all-out when compared to the RPE6 session (p ≤ 0.05). Serum cortisol concentration increased post-0 h (p = 0.011) for RPE6 and post-0 h (p = 0.003) and post-1 h (p = 0.030) for all-out session when comparing to baseline concentrations. BDNF was significantly higher (p = 0.002) post-0 h only for the all-out session when compared to baseline. A positive correlation between blood lactate concentrations and BDNF (r = 0.51; p = 0.01) was found for both effort interventions. CONCLUSIONS: A single FFT session when performed in all-out format acutely increases the concentrations of serum BDNF. However, physiological stress markers show that the all-out session requires a longer recovery period when compared to the RPE6 protocol. These findings can be helpful to coaches and practitioners design FFT session.

Effect of different bicycle body positions on power output in aerobically trained females.

Aerodynamic bicycle positioning reduces drag but also reduces power output (PO) in males. The effect of aerodynamic bicycle positioning in trained endurance females is unknown. Eighteen females participants (VO2max 49.7 ± 6.3 ml · kg(-1) · min(-1)) all with competitive experience performed cycling trials at ventilatory threshold 1 and 2 (VT-1, VT-2) in both an aerodynamic and an upright position. There was a significant difference in PO between the aerodynamic and upright positions at VT-1 (152.7 ± 28.0 Watts and 159.7 ± 33.1 Watts, respectively) but not at VT-2 (191.2 ± 39.1 Watts and 192.4 ± 40.0 Watts, respectively). There were no significant differences in heart rate, oxygen consumption, or cadence between positions at either intensity. At both intensities the individual response was varied and no trends due to years of experience or background (triathlete or cyclist) explained this variability. Therefore, despite the significant mean difference in PO at VT-1, these results indicate that in trained females the effect of aerodynamic positioning is individual.

The Training Characteristics of Recreational-Level Triathletes: Influence on Fatigue and Health.

Little is known about how recreational triathletes prepare for an Olympic distance event. The aim of this study was to identify the training characteristics of recreational-level triathletes within the competition period and assess how their preparation for a triathlon influences their health and their levels of fatigue. During the 6 weeks prior to, and the 2 weeks after, an Olympic distance triathlon, nine recreational athletes (five males, four females) completed a daily training log. Participants answered the Daily Analysis of Life Demands Questionnaire (DALDA), the Training Distress Scale (TDS) and the Alberta Swim Fatigue and Health Questionnaire weekly. The Recovery-Stress Questionnaire (REST-Q) was completed at the beginning of the study, on the day before the competition, and at the end of week 8. Training loads were calculated using session-based rating of perceived exertion (sRPE). The data from every week of training was compared to week 1 to determine how athletes' training and health changed throughout the study. No changes in training loads, duration or training intensity distribution were seen in the weeks leading up to the competition. Training duration was significantly reduced in week 6 (p = 0.041, d = 1.58, 95% CI = 6.9, 421.9), while the number of sessions was reduced in week 6 (Z = 2.32, p = 0.02, ES = 0.88) and week 7 (Z = 2.31, p = 0.02, ES = 0.87). Training was characterized by large weekly variations in training loads and a high training intensity. No significant changes were seen in the DALDA, TDS or REST-Q questionnaire scores throughout the 8 weeks. Despite large spikes in training load and a high overall training intensity, these recreational-level triathletes were able to maintain their health in the 6 weeks of training prior to an Olympic distance triathlon.

Effect of Elevated Ambient Temperature on Simulator-Derived Oscillometric Blood Pressure Measurement.

BACKGROUND: Oscillometric blood pressure (BP) devices are typically labeled for use up to 40 °C. Many geographic regions have ambient temperatures exceeding 40 °C. We assessed the effect of increased ambient temperature (40-55 °C) on simulator-derived oscillometric BP measurement. METHODS: Three Omron BP769CAN devices, 3 A&D Medical UA-651BLE devices, and accompanying cuffs were used. A custom heat chamber heated each device to the specified temperature. A noninvasive BP simulator was used to take 3 measurements with each device at differing temperatures (22, 40, 45, 50, and 55 °C) and BP thresholds: 80/50, 100/60, 120/80, 140/90, 160/110, and 180/130 mm Hg. Using each device as its own control (22 °C), we determined the relative differences in mean BP for each device at each temperature and BP setting, assessed graphical trends with increasing temperature, and examined variability. RESULTS: Graphical trends of mean simulator-subtracted BP differences from room temperature showed no discernable pattern, with differences clustered around zero. Overall mean difference in BP (combined elevated temperatures minus room temperature) was -0.8 ± 2.1 (systolic ± SD)/1.2 ± 3.5 (diastolic ± SD) mm Hg for the A&D device and 0.2 ± 0.4 (systolic ± SD)/-0.1 ± 0.1 (diastolic ± SD) mm Hg for the Omron. All individual elevated temperature differences (elevated temperature minus room temperature) except A&D diastolic BP at 50 °C were within 5 mm Hg. CONCLUSIONS: In this simulator-based study assessing within-device differences, higher ambient temperatures resulted in oscillometric BP measurements that were comparable to those performed at room temperature.

Practicing Sport in Cold Environments: Practical Recommendations to Improve Sport Performance and Reduce Negative Health Outcomes.

Although not a barrier to perform sport, cold weather environments (low ambient temperature, high wind speeds, and increased precipitation, i.e., rain/water/snow) may influence sport performance. Despite the obvious requirement for practical recommendations and guidelines to better facilitate training and competition in such cold environments, the current scientific evidence-base is lacking. Nonetheless, this review summarizes the current available knowledge specifically related to the physiological impact of cold exposure, in an attempt to provide practitioners and coaches alike with practical recommendations to minimize any potential negative performance effects, mitigate health issues, and best optimize athlete preparation across various sporting disciplines. Herein, the review is split into sections which explore some of the key physiological effects of cold exposure on performance (i.e., endurance exercise capacity and explosive athletic power), potential health issues (short-term and long-term), and what is currently known with regard to best preparation or mitigation strategies considered to negate the potential negative effects of cold on performance. Specific focus is given to "winter" sports that are usually completed in cold environments and practical recommendations for physical preparation.