A synthetic undergarment increases physiological strain

2019 ◽  
Vol 28 (4) ◽  
pp. 275 ◽  
Author(s):  
Matthew C. Dorton ◽  
Brent C. Ruby ◽  
Charles L. Dumke
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Perceived Exertion ◽  
Sweat Rate ◽  
Rest Period ◽  
Time Trial ◽  
Rating Of Perceived Exertion ◽  
Physiological Strain ◽  
Physiological Factors ◽  
Increased Risk

Our aim was to examine the effect of a synthetic material undergarment on heat stress during exercise in a hot environment. Ten active males completed two trials of intermittent (50min walking, 10min sitting) treadmill walking over 3h in 35°C and 30% relative humidity. Subjects wore wildland firefighter flame-resistant meta-aramid blend pants and shirt with either a 100% cotton (C) or flame-retardant modacrylic undergarment (S), while carrying a 16-kg pack, helmet and leather gloves. Exercise was followed by a 30-min rest period without pack, helmet, gloves, and outerwear shirt. Rectal temperature and physiological strain were greater in S than C (P=0.04). No significant differences were found for heart rate, rating of perceived exertion, energy expenditure or skin temperature between C and S. Skin blood flow increased significantly in S following the second hour of exercise, resulting in a time×trial interaction (P=0.001). No significant differences for skin blood flow were found post exercise. Sweat rate and percent dehydration were not different between C and S. These data indicate that, of the two undergarments investigated, the synthetic undergarment negatively affected physiological factors that have been shown to indicate an increased risk of heat-related injuries.

scholarly journals Protection Against Spikes in Workload With Aerobic Fitness and Playing Experience: The Role of the Acute:Chronic Workload Ratio on Injury Risk in Elite Gaelic Football

2017 ◽  
Vol 12 (3) ◽  
pp. 393-401 ◽  
Author(s):  
Shane Malone ◽  
Mark Roe ◽  
Dominic A. Doran ◽  
Tim J. Gabbett ◽  
Kieran D. Collins
Keyword(s):  
Aerobic Fitness ◽  
Injury Risk ◽  
Perceived Exertion ◽  
Reference Group ◽  
Time Trial ◽  
Rating Of Perceived Exertion ◽  
Football Players ◽  
Risk Of Injury ◽  
Increased Risk ◽  
Injury Protection

Purpose:To examine the association between combined session rating of perceived exertion (RPE) workload measures and injury risk in elite Gaelic footballers.Methods:Thirty-seven elite Gaelic footballers (mean ± SD age 24.2 ± 2.9 y) from 1 elite squad were involved in a single-season study. Weekly workload (session RPE multiplied by duration) and all time-loss injuries (including subsequent-wk injuries) were recorded during the period. Rolling weekly sums and wk-to-wk changes in workload were measured, enabling the calculation of the acute:chronic workload ratio by dividing acute workload (ie, 1-weekly workload) by chronic workload (ie, rolling-average 4-weekly workload). Workload measures were then modeled against data for all injuries sustained using a logistic-regression model. Odds ratios (ORs) were reported against a reference group.Results:High 1-weekly workloads (≥2770 arbitrary units [AU], OR = 1.63–6.75) were associated with significantly higher risk of injury than in a low-training-load reference group (<1250 AU). When exposed to spikes in workload (acute:chronic workload ratio >1.5), players with 1 y experience had a higher risk of injury (OR = 2.22) and players with 2–3 (OR = 0.20) and 4–6 y (OR = 0.24) of experience had a lower risk of injury. Players with poorer aerobic fitness (estimated from a 1-km time trial) had a higher injury risk than those with higher aerobic fitness (OR = 1.50–2.50). An acute:chronic workload ratio of (≥2.0) demonstrated the greatest risk of injury.Conclusions:These findings highlight an increased risk of injury for elite Gaelic football players with high (>2.0) acute:chronic workload ratios and high weekly workloads. A high aerobic capacity and playing experience appears to offer injury protection against rapid changes in workload and high acute:chronic workload ratios. Moderate workloads, coupled with moderate to high changes in the acute:chronic workload ratio, appear to be protective for Gaelic football players.

Neural control of the forearm cutaneous vasoconstrictor response to dynamic exercise

1991 ◽  
Vol 71 (5) ◽  
pp. 1892-1896 ◽  
Author(s):  
D. B. Friedman ◽  
J. M. Johnson ◽  
J. H. Mitchell ◽  
N. H. Secher
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Perceived Exertion ◽  
Dynamic Exercise ◽  
Rating Of Perceived Exertion ◽  
Doppler Flowmetry ◽  
Low Intensity ◽  
Vasoconstrictor Response ◽  
Low Intensity Exercise ◽  
Exercise In Humans

This study was designed to evaluate the relative importance of intended effort (“central command”) and of the absolute intensity of dynamic exercise to the cutaneous vasoconstrictor response to the onset of exercise in humans. Skin blood flow (laser-Doppler flowmetry) was measured from the forearm in six healthy individuals during 3-min periods of high- and low-intensity exercise with and without partial neuromuscular blockade. Cutaneous vascular conductance (CVC) was calculated from the ratio of skin blood flow to mean arterial pressure and expressed as a percent change from rest. A rating of perceived exertion (RPE) was expressed as a subjective measure of intended effort. Under control conditions, CVC decreased by 22% (median; range 7–42%, P less than 0.05) during high-intensity exercise [218 (186–268) W; RPE 16 (14–19) exertion units]. In contrast, during control low-intensity exercise [106 (88–128) W; RPE 10 (9–14) exertion units], during low-level exercise with curare [77 (54–98) W; RPE 13 (11–16) exertion units], and during maximal exercise with curare [106 (88–124) W; RPE 19 (18–20) exertion units], CVC did not change significantly. These results suggest that factors related to the activity of the exercising muscle and its metabolism rather than intended effort determine the cutaneous vasoconstrictor response to the initiation of intense dynamic exercise in humans.

Warm-Up Intensity and Duration’s Effect on Traditional Rowing Time-Trial Performance

2012 ◽  
Vol 7 (2) ◽  
pp. 186-188 ◽  
Author(s):  
Iñigo Mujika ◽  
Rafa González de Txabarri ◽  
Sara Maldonado-Martín ◽  
David B. Pyne
Keyword(s):  
Heart Rate ◽  
Blood Lactate ◽  
Perceived Exertion ◽  
Time Trial ◽  
Rating Of Perceived Exertion ◽  
Lower Intensity ◽  
Physiological Strain ◽  
Warm Up ◽  
Time Trial Performance ◽  
Trial Performance

The warm-up procedure in traditional rowing usually involves continuous low-intensity rowing and short bouts of intense exercise, lasting about 60 min.Purpose:To compare the effects of a traditional and an experimental 30-min warm-up of lower intensity on indoor rowing time-trial performance.Methods:Fourteen highly trained male rowers (age 25.9 ± 5.3 y, height 1.86 ± 0.06 m, mass 80.4 ± 5.2 kg, peak aerobic power 352.0 ± 24.4 W; mean ± SD) performed 2 indoor rowing trials 12 d apart. Rowers were randomly assigned to either LONG or SHORT warm-ups using a crossover design, each followed by a 10-min all-out fixed-seat rowing-ergometer time trial.Results:Mean power output during the time trial was substantially higher after SHORT (322 ± 18 vs 316 ± 17 W), with rowers generating substantially more power in the initial 7.5 min of the time trial after SHORT. LONG elicited substantially higher mean warm-up heart rate than SHORT (134 ± 11 vs 121 ± 13 beats/min), higher pre–time-trial rating of perceived exertion (10.2 ± 1.4 vs 7.6 ± 1.7) and blood lactate (1.7 ± 0.4 mM vs 1.2 ± 0.2 mM), but similar heart rate (100 ± 14 vs 102 ± 9 beats/min). No substantial differences were observed between LONG and SHORT in stroke rate (39.4 ± 2.0 vs 39.4 ± 2.2 strokes/min) or mean heart rate (171 ± 6 vs 171 ± 8 beats/min) during the time trial, nor in blood lactate after it (11.8 ± 2.5 vs 12.1 ± 2.0 mM).Conclusion:A warm-up characterized by lower intensity and shorter duration should elicit less physiological strain and promote substantially higher power production in the initial stages of a rowing time trial.

scholarly journals Effects of mode of exercise recovery on thermoregulatory and cardiovascular responses

2002 ◽  
Vol 93 (6) ◽  
pp. 1918-1924 ◽  
Author(s):  
Robert Carter ◽  
Thad E. Wilson ◽  
Donald E. Watenpaugh ◽  
Michael L. Smith ◽  
Craig G. Crandall
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Heat Dissipation ◽  
Sweat Rate ◽  
Local Heating ◽  
Cardiovascular Responses ◽  
Maximal Heart Rate ◽  
Exercise Recovery ◽  
Active Recovery ◽  
Arterial Blood

To identify the effects of exercise recovery mode on cutaneous vascular conductance (CVC) and sweat rate, eight healthy adults performed two 15-min bouts of upright cycle ergometry at 60% of maximal heart rate followed by either inactive or active (loadless pedaling) recovery. An index of CVC was calculated from the ratio of laser-Doppler flux to mean arterial pressure. CVC was then expressed as a percentage of maximum (%max) as determined from local heating. At 3 min postexercise, CVC was greater during active recovery (chest: 40 ± 3, forearm: 48 ± 3%max) compared with during inactive recovery (chest: 21 ± 2, forearm: 25 ± 4%max); all P < 0.05. Moreover, at the same time point sweat rate was greater during active recovery (chest: 0.47 ± 0.10, forearm: 0.46 ± 0.10 mg · cm−2 · min−1) compared with during inactive recovery (chest: 0.28 ± 0.10, forearm: 0.14 ± 0.20 mg · cm−2 · min−1); all P < 0.05. Mean arterial blood pressure, esophageal temperature, and skin temperature were not different between recovery modes. These data suggest that skin blood flow and sweat rate during recovery from exercise may be modulated by nonthermoregulatory mechanisms and that sustained elevations in skin blood flow and sweat rate during mild active recovery may be important for postexertional heat dissipation.

On- Versus Off-Bike Power Training in Professional Cyclists: A Randomized Controlled Trial

2020 ◽  
pp. 1-8 ◽  
Author(s):  
Pedro L. Valenzuela ◽  
Jaime Gil-Cabrera ◽  
Eduardo Talavera ◽  
Lidia B. Alejo ◽  
Almudena Montalvo-Pérez ◽  
...  
Keyword(s):  
Body Composition ◽  
Muscle Strength ◽  
Perceived Exertion ◽  
Ventilatory Threshold ◽  
Controlled Trial ◽  
Time Trial ◽  
Endurance Performance ◽  
Rating Of Perceived Exertion ◽  
Power Training ◽  
Sprint Training

Purpose: To compare the effectiveness of resistance power training (RPT, training with the individualized load and repetitions that maximize power output) and cycling power training (CPT, short sprint training) in professional cyclists. Methods: The participants (20 [2] y, peak oxygen uptake 78.0 [4.4] mL·kg−1·min−1) were randomly assigned to perform CPT (n = 8) or RPT (n = 10) in addition to their usual training regime for 7 weeks (2 sessions/wk). The training loads were continuously registered using the session rating of perceived exertion. The outcomes included endurance performance (8-min time trial and incremental test), as well as measures of muscle strength/power (1-repetition maximum and mean maximum propulsive power on the squat, hip thrust, and lunge exercises) and body composition (assessed by dual-energy X-ray absorptiometry). Results: No between-group differences were found for training loads or for any outcome (P > .05). Both interventions resulted in increased time-trial performance, as well as in improvements in other endurance-related outcomes (ie, ventilatory threshold, respiratory compensation point; P < .05). A significant or quasi-significant increase (P = .068 and .047 for CPT and RPT, respectively) in bone mineral content was observed after both interventions. A significant reduction in fat mass (P = .017), along with a trend (P = .059) toward a reduced body mass, was observed after RPT, but not CPT (P = .076 for the group × time interaction effect). Significant benefits (P < .05) were also observed for most strength-related outcomes after RPT, but not CPT. Conclusion: CPT and RPT are both effective strategies for the improvement of endurance performance and bone health in professional cyclists, although the latter tends to result in greater improvements in body composition and muscle strength/power.

Increased Cardiorespiratory Stress During Submaximal Cycling After Ketone Monoester Ingestion in Endurance-Trained Adults

2021 ◽  
Author(s):  
Devin Goddard McCarthy ◽  
William Bostad ◽  
Fiona Jane Powley ◽  
Jonathan P. Little ◽  
Douglas Richards ◽  
...  
Keyword(s):  
Body Mass ◽  
Ketone Body ◽  
Perceived Exertion ◽  
Bolus Dose ◽  
Ventilatory Threshold ◽  
Time Trial ◽  
Rating Of Perceived Exertion ◽  
Threshold Intensity ◽  
Double Blind ◽  
And Performance

There is growing interest in the effect of exogenous ketone body supplementation on exercise responses and performance. The limited studies to date have yielded equivocal data, likely due in part to differences in dosing strategy, increase in blood ketones, and participant training status. Using a randomized, double-blind, counterbalanced design, we examined the effect of ingesting a ketone monoester (KE) supplement (600 mg/kg body mass) or flavour-matched placebo in endurance-trained adults (n=10 males, n=9 females; VO2peak=57±8 ml/kg/min). Participants performed a 30-min cycling bout at ventilatory threshold intensity (71±3% VO2peak), followed 15 min later by a 3 kJ/kg body mass time-trial. KE versus placebo ingestion increased plasma [β-hydroxybutyrate] before exercise (3.9±1.0 vs 0.2±0.3 mM, p<0.0001, dz=3.4), ventilation (77±17 vs 71±15 L/min, p<0.0001, dz=1.3) and heart rate (155±11 vs 150±11 beats/min, p<0.001, dz=1.2) during exercise, and rating of perceived exertion at the end of exercise (15.4±1.6 vs 14.5±1.2, p<0.01, dz=0.85). Plasma [β-hydroxybutyrate] remained higher after KE vs placebo ingestion before the time-trial (3.5±1.0 vs 0.3±0.2 mM, p<0.0001, dz=3.1), but performance was not different (KE: 16:25±2:50 vs placebo: 16:06±2:40 min:s, p=0.20; dz=0.31). We conclude that acute ingestion of a relatively large KE bolus dose increased markers of cardiorespiratory stress during submaximal exercise in endurance-trained participants. Novelty bullets: •Limited studies have yielded equivocal data regarding exercise responses after acute ketone body supplementation. •Using a randomized, double-blind, placebo-controlled, counterbalanced design, we found that ingestion of a large bolus dose of a commercial ketone monoester supplement increased markers of cardiorespiratory stress during cycling at ventilatory threshold intensity in endurance-trained adults.

Various Workload Models and the Preseason Are Associated With Injuries in Professional Female Cyclists

2021 ◽  
pp. 1-6
Author(s):  
Teun van Erp ◽  
Taco van der Hoorn ◽  
Marco J.M. Hoozemans ◽  
Carl Foster ◽  
Jos J. de Koning
Keyword(s):  
Generalized Estimating Equations ◽  
Perceived Exertion ◽  
Estimating Equations ◽  
Rating Of Perceived Exertion ◽  
Moving Averages ◽  
The Third ◽  
Increased Risk ◽  
The Difference ◽  
Workload Models ◽  
Exponentially Weighted

Purpose: To determine if workload and seasonal periods (preseason vs in season) are associated with the incidence of injuries and illnesses in female professional cyclists. Methods: Session rating of perceived exertion was used to quantify internal workload and was collected from 15 professional female cyclists, from 33 athlete seasons. One week (acute) workload, 4 weeks (chronic) workload, and 3 acute:chronic workload models were analyzed. Two workload models are based on moving averages of the ratios, the acute:chronic workload ratio (ACWR), and the ACWR uncoupled (ACWRuncoup). The difference between both is the chronic load; in ACWR, the acute load is part of the chronic load, and in ACWRuncoup, the acute and chronic load are uncoupled. The third workload model is based on exponentially weighted moving averages of the ratios. In addition, the athlete season is divided into the preseason and in season. Results: Generalized estimating equations analysis was used to assess the associations between the workload ratios and the occurrence of injuries and illnesses. High values of acute workload (P = .048), ACWR (P = .02), ACWRuncoup (P = .02), exponentially weighted moving averages of the ratios (P = .01), and the in season (P = .0001) are significantly associated with the occurrence of injury. No significant associations were found between the workload models, the seasonal periods, and the occurrence of illnesses. Conclusions: These findings suggest the importance of monitoring workload and workload ratios in female professional cyclists to lower the risk of injuries and therefore improve their performances. Furthermore, these results indicate that, in the preseason, additional stressors occur, which could lead to an increased risk of injuries.

The Effect of Self-Paced and Prescribed Interset Rest Strategies on Performance in Strength Training

2019 ◽  
Vol 14 (7) ◽  
pp. 980-986
Author(s):  
Peter Ibbott ◽  
Nick Ball ◽  
Marijke Welvaert ◽  
Kevin G. Thompson
Keyword(s):  
Strength Training ◽  
Perceived Exertion ◽  
Mechanical Performance ◽  
Rest Period ◽  
Rating Of Perceived Exertion ◽  
Subjective Rating ◽  
Male Athletes ◽  
Rest Periods ◽  
Pacing Strategies ◽  
Feasible Alternative

Purpose: To assess pacing strategies using prescribed and self-selected interset rest periods and their influence on performance in strength-trained athletes. Methods: A total of 16 strength-trained male athletes completed 3 randomized heavy strength-training sessions (5 sets and 5 repetitions) with different interset rest periods. The interset rest periods were 3 min (3MIN), 5 min (5MIN), and self-selected (SS). Mechanical (power, velocity, work, and displacement), surface electromyography (sEMG), and subjective (rating of perceived exertion) and readiness-to-lift data were recorded for each set. Results: SS-condition interset rest periods increased from sets 1 to 4 (from 207.52 to 277.71 s; P = .01). No differences in mechanical performance were shown between the different interset rest-period conditions. Power output (210 W; 8.03%) and velocity (0.03 m·s−1; 6.73%) decreased as sets progressed for all conditions (P < .001) from set 1 to set 5. No differences in sEMG activity between conditions were shown; however, vastus medialis sEMG decreased as the sets progressed for each condition (1.75%; P = .005). All conditions showed increases in rating of perceived exertion as sets progressed (set 1 = 6.1, set 5 = 7.9; P < .001). Participants reported greater readiness to lift in the 5MIN condition (7.81) than in the 3MIN (7.09) and SS (7.20) conditions (P < .001). Conclusions: Self-selecting interset rest periods does not significantly change performance compared with 3MIN and 5MIN conditions. Given the opportunity, athletes will vary their interset rest periods to complete multiple sets of heavy strength training. Self-selection of interset rest periods may be a feasible alternative to prescribed interset rest periods.

scholarly journals Acute Caffeine and Coconut Oil Intake, Isolated or Combined, Does Not Improve Running Times of Recreational Runners: A Randomized, Placebo-Controlled and Crossover Study

Nutrients ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1661
Author(s):  
Gabrielle de Lima Borba ◽  
Julianne Soares de Freitas Batista ◽  
Ludmilla Marques Queiroz Novais ◽  
Myrnzzia Beatriz Silva ◽  
João Batista da Silva Júnior ◽  
...  
Keyword(s):  
Crossover Study ◽  
Perceived Exertion ◽  
Coconut Oil ◽  
Time Trial ◽  
Rating Of Perceived Exertion ◽  
Soy Oil ◽  
Borg Scale ◽  
Virgin Coconut Oil ◽  
Decaffeinated Coffee ◽  
Recreational Runners

The aim was to evaluate the effect of caffeine (CAF) and extra virgin coconut oil (CO), isolated or combined, on running performance in runners. Methods: A randomized, placebo-controlled, and crossover study was conducted with thirteen recreational runners aged 18–40. All volunteers performed a 1600 m time trial at a 400 m track, each ingesting four different substances: (1) placebo (water), (2) decaffeinated coffee plus isolated CAF (DECAF + CAF), (3) decaffeinated coffee plus isolated CAF plus soy oil (DECAF + CAF + SO), and (4) decaffeinated coffee plus isolated CAF plus extra virgin coconut oil (DECAF + CAF + CO). The substances were ingested 60 min before the trials, the order of the situations was randomized, and there were one-week intervals between them. At the end of the trials, the Borg scale was applied to evaluate the rating of perceived exertion (RPE) and the time was measured. Results: Our data did not show differences in running time among the trials (placebo: 7.64 ± 0.80, DECAF + CAF: 7.61 ± 1.02, DECAF + CAF + SO: 7.66 ± 0.89, and DECAF + CAF + CO: 7.58 ± 0.74 min; p = 0.93), nor RPE (placebo: 6.15 ± 2.03, DECAF + CAF: 6.00 ± 2.27, DECAF + CAF + SO: 6.54 ± 2.73, and DECAF + CAF + CO: 6.00 ± 2.45 score; p = 0.99). Lactate concentrations (placebo: 6.23 ± 2.72, DECAF + CAF: 4.43 ± 3.77, DECAF + CAF + SO: 5.29 ± 3.77, and DECAF + CAF + CO: 6.17 ± 4.18 mmol/L; p = 0.55) also was not modified. Conclusion: Our study shows that ingestion of decaffeinated coffee with the addition of isolated CAF and extra virgin CO, either isolated or combined, does not improve 1600 m running times, nor influence RPE and lactate concentrations in recreational runners. Thus, combination of coffee with CO as a pre-workout supplement seems to be unsubstantiated for a short-distance race.

scholarly journals The effect of low- vs high-cadence interval training on the freely chosen cadence and performance in endurance-trained cyclists

2016 ◽  
Vol 41 (6) ◽  
pp. 666-673 ◽  
Author(s):  
Anthony G. Whitty ◽  
Aron J. Murphy ◽  
Aaron J. Coutts ◽  
Mark L. Watsford
Keyword(s):  
Perceived Exertion ◽  
Average Power ◽  
Time Trial ◽  
Interval Training ◽  
Performance Measure ◽  
Rating Of Perceived Exertion ◽  
Superior Performance ◽  
Strength Development ◽  
And Performance ◽  
High Cadence

The aim of this study was to determine the effects of high- and low-cadence interval training on the freely chosen cadence (FCC) and performance in endurance-trained cyclists. Sixteen male endurance-trained cyclists completed a series of submaximal rides at 60% maximal power (Wmax) at cadences of 50, 70, 90, and 110 r·min−1, and their FCC to determine their preferred cadence, gross efficiency (GE), rating of perceived exertion, and crank torque profile. Performance was measured via a 15-min time trial, which was preloaded with a cycle at 60% Wmax. Following the testing, the participants were randomly assigned to a high-cadence (HC) (20% above FCC) or a low-cadence (LC) (20% below FCC) group for 18 interval-based training sessions over 6 weeks. The HC group increased their FCC from 92 to 101 r·min−1 after the intervention (p = 0.01), whereas the LC group remained unchanged (93 r·min−1). GE increased from 22.7% to 23.6% in the HC group at 90 r·min−1 (p = 0.05), from 20.0% to 20.9% at 110 r·min−1 (p = 0.05), and from 22.8% to 23.2% at their FCC. Both groups significantly increased their total distance and average power output following training, with the LC group recording a superior performance measure. There were minimal changes to the crank torque profile in both groups following training. This study demonstrated that the FCC can be altered with HC interval training and that the determinants of the optimal cycling cadence are multifactorial and not completely understood. Furthermore, LC interval training may significantly improve time-trial results of short duration as a result of an increase in strength development or possible neuromuscular adaptations.

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