Can ten days of heat acclimation training improve temperate-condition rowing performance in national-level rowers?

This study investigated whether heat acclimation (HA) could improve rowing performance in temperate conditions in national-level rowers. Using a parallel-group design, eleven rowers (3 female, 8 male, age: 21±3 years, height: 182.3±6.8cm, mass: 79.2±9.0kg, [Formula: see text]: 61.4±5.1ml·kg·min-1) completed either a HA intervention (HEAT, n = 5) or acted as controls (CON, n = 6). The intervention replaced usual cross-training sessions and consisted of an hour of submaximal cycling or rowing ergometry in either 34±0°C for HEAT or 14±1°C for CON daily over two five-day blocks (10 sessions total), separated by 72h. Participants performed the '10+4' test that consists of 10-min submaximal rowing and a 4-min time-trial (TT) in temperate conditions (20±0°C) before and after the intervention. Heat acclimation following the 10-session intervention was evidenced by large significant (p<0.05) decreases in maximum tympanic temperature (d = -1.68) and rate of perceived exertion (RPE) (d = -2.26), and a large significant increase in sweat loss (d = 0.91). Large non-significant (p>0.05) decreases were seen in average tympanic temperature (d = -3.08) and average heart rate (d = -1.53) in HEAT from session 2 to session 10 of the intervention. Furthermore, a large significant increase was seen in plasma volume (d = 3.74), with large significant decreases in haemoglobin concentration (d = -1.78) and hematocrit (d = -12.9). Following the intervention, large non-significant increases in respiratory exchange ratio (d = 0.87) and blood lactate (d = 1.40) as well as a large non-significant decrease in RPE (d = -1.23) were seen in HEAT during the 10-min submaximal rowing. A large significant decrease in peak heart rate (d = -2.27), as well as a large non-significant decrease in relative [Formula: see text] (d = -0.90) and large non-significant increases in respiratory exchange ratio (d = 1.18), blood lactate concentration (d = 1.25) and power output (d = 0.96) were seen in HEAT during the 4-min TT. This study suggests that a 10-session HA intervention may elicit HA in national-level rowers, with potential to improve 4-min TT performance in temperate conditions.

Hot water immersion; potential to improve intermittent running performance and perception of in-game running ability in semi-professional Australian Rules Footballers?

This study investigated whether hot water immersion (HWI) could heat acclimate athletes and improve intermittent running performance and perception of in-game running ability, during a competitive Australian Rules Football (ARF) season. Fifteen male semi-professional ARF athletes (Mean (SD); age: 22 (3) years, height: 182.3 (6.5) cm, mass: 80.5 (5.1) kg) completed either HWI (HEAT, N = 8, 13 (2) sessions, 322 (69) min exposure, 39.5 (0.3) °C) or acted as a control (CON, N = 7, no water immersion) over 6-weeks. Athletes completed a 30-15 Intermittent Fitness Test pre and post-intervention to assess intermittent running performance (VIFT), with perception of in-game running ability measured. Heat acclimation was determined via change in resting plasma volume, as well as physiological and perceptual responses during HWI. HEAT elicited large PV expansion (mean ± 90% CI: d = 1.03 ± 0.73), large decreases in heart rate (d = -0.89 ± 0.70), thermal sensation (d = -2.30 ± 1.15) and tympanic temperature (d = -1.18 ± 0.77). Large improvements in VIFT were seen in HEAT (d = 1.67 ± 0.93), with HEAT showing a greater improvement in VIFT when compared to CON (d = 0.81 ± 0.88). HEAT also showed greater belief that in-game running ability improved post-intervention (d = 2.15 ± 1.09) compared to CON. A 6-week HWI intervention can elicit heat acclimation, improve perception of in-game running ability, and potentially improve VIFT in semi-professional ARF athletes.

Compression Socks Reduce Running-Induced Intestinal Damage.

ABSTRACT: Zadow, EK, Edwards, KH, Kitic, CM, Fell, JW, Adams, MJ, Singh, I, Kundur, A, Johnstone, ANB, Crilly, J, Bulmer, AC, Halson, SL, and, and Wu, SSX. Compression socks reduce running-induced intestinal damage. J Strength Cond Res 36(9): 2461-2464, 2022-Exercise is associated with a reduction in splanchnic blood flow that leads to the disruption of intestinal epithelium integrity, contributing to exercise-induced gastrointestinal syndrome. Strategies that promote intestinal blood flow during exercise may reduce intestinal damage, which may be advantageous for subsequent recovery and performance. This study aimed to explore if exercise-associated intestinal damage was influenced by wearing compression garments, which may improve central blood flow. Subjects were randomly allocated to wear compression socks ( n = 23) or no compression socks (control, n = 23) during a marathon race. Blood samples were collected 24 hours before and immediately after marathon and analyzed for intestinal fatty acid-binding protein (I-FABP) concentration as a marker of intestinal damage. The magnitude of increase in postmarathon plasma I-FABP concentration was significantly greater in control group (107%; 95% confidence interval [CI], 72-428%) when compared with runners wearing compression socks (38%; 95% CI, 20-120%; p = 0.046; d = 0.59). Wearing compression socks during a marathon run reduced exercise-associated intestinal damage. Compression socks may prove an effective strategy to minimize the intestinal damage component of exercise-induced gastrointestinal syndrome.

Effects of Time of Day on Pacing in a 4-km Time Trial in Trained Cyclists.

CONTEXT: Time of day has been shown to impact athletic performance, with improved performance observed in the late afternoon-early evening. Diurnal variations in physiological factors may contribute to variations in pacing selection; however, research investigating time-of-day influence on pacing is limited. PURPOSE: To investigate the influence of time-of-day on pacing selection in a 4-km cycling time trial (TT). METHODS: Nineteen trained male cyclists (mean [SD] age 39.0 [10.7] y, height 1.8 [0.1] m, body mass 78.0 [9.4] kg, VO2max 62.1 [8.7] mL·kg-1·min-1) completed a 4-km TT on 5 separate occasions at 08:30, 11:30, 14:30, 17:30, and 20:30. All TTs were completed in a randomized order, separated by a minimum of 2 d and maximum of 7 d. RESULTS: No time-of-day effects were observed in pacing as demonstrated by similar power outputs over 0.5-km intervals (P = .78) or overall mean power output (333.0 [38.9], 339.8 [37.2], 335.5 [31.2], 336.7 [35.2], and 334.9 [35.7] W; P = .45) when TTs were performed at 08:30, 11:30, 14:30, 17:30, and 20:30. Preexercise tympanic temperature demonstrated a time-of-day effect (P < .001), with tympanic temperature higher at 14:30 and 17:30 than at 08:30 and 11:30. CONCLUSION: While a biological rhythm was present in tympanic temperature, pacing selection and performance when completing a 4-km cycling TT were not influenced by time of day. The findings suggest that well-trained cyclists can maintain a robust pacing strategy for a 4-km TT regardless of time of the day.

Acute Physical Exercise Can Influence the Accuracy of Metacognitive Judgments.

Acute exercise generally benefits memory but little research has examined how exercise affects metacognition (knowledge of memory performance). We show that a single bout of exercise can influence metacognition in paired-associate learning. Participants completed 30-min of moderate-intensity exercise before or after studying a series of word pairs (cloud-ivory), and completed cued-recall (cloud-?; Experiments 1 & 2) and recognition memory tests (cloud-? spoon; ivory; drill; choir; Experiment 2). Participants made judgments of learning prior to cued-recall tests (JOLs; predicted likelihood of recalling the second word of each pair when shown the first) and feeling-of-knowing judgments prior to recognition tests (FOK; predicted likelihood of recognizing the second word from four alternatives). Compared to no-exercise control conditions, exercise before encoding enhanced cued-recall in Experiment 1 but not Experiment 2 and did not affect recognition. Exercise after encoding did not influence memory. In conditions where exercise did not benefit memory, it increased JOLs and FOK judgments relative to accuracy (Experiments 1 & 2) and impaired the relative accuracy of JOLs (ability to distinguish remembered from non-remembered items; Experiment 2). Acute exercise seems to signal likely remembering; this has implications for understanding the effects of exercise on metacognition, and for incorporating exercise into study routines.

The effect of an ultra-endurance running race on heart rate variability.

PURPOSE: The aim of this study was to investigate the effect of an ultra-marathon on heart rate variability (HRV) and psychometric indices in endurance runners. In addition, we aimed to determine the magnitude of change and subsequent recovery for 7 days following the race. METHODS: Recreationally trained runners (n = 13 (8M); age = 36.6 ± 7.6 years; height = 174 ± 9 cm; weight = 70.5 ± 9.3 kg) completed measures of HRV upon waking in the morning for 1 week prior to and 1 week following a 64-km running race. Profile of mood states, wellbeing, and muscular soreness were also measured throughout the study period to further contextualise recovery. RESULTS: An increase in heart rate accompanied by decreased LnSDNN, LnRMSSD, LnLF, LnHF, and LnLF/HF from baseline were observed 1 day post-race (p < 0.05). Indices of HRV had returned to baseline on day 2 of recovery. Perceptual fatigue and muscle soreness increased post-race (immediately following and on day 1 of recovery) (p < 0.05) and took until day 5 of recovery to return to baseline. CONCLUSION: The results indicate that cardiac autonomic control is significantly altered in response to a 64 km ultra-marathon. Specifically, parasympathetic activity is suppressed. The change in autonomic control was relatively short-lived, and parasympathetic-related indices had returned to baseline 2 days after the event. Subjective measures of fatigue and wellbeing suggest that athletes were not completely recovered until day 5 post-event, with muscular soreness remaining prominent during this period. A combination of physiological and psychological parameters is important to contextualise recovery in ultra-endurance runners.

Shoulder extension strength: a potential risk factor for shoulder pain in young swimmers?

OBJECTIVES: To determine the relationship and predictive value of isometric shoulder strength in the development of shoulder pain in young swimmers. DESIGN: Prospective, cohort study. METHODS: Shoulder flexion, extension, external and internal rotation strength tests were performed in elevation on 85 swimmers (14-20 years; 48 females) without current shoulder pain using a hand-held dynamometer. Following testing, swimmers were emailed questionnaires to determine if significant shoulder pain developed within 24 months subsequent to testing. The differences between shoulders that did and did not develop pain and the predictive ability of shoulder strength and strength ratios were investigated using Mann Whitney U tests and receiver operating characteristic curves. RESULTS: Thirty-seven swimmers (47%) returned questionnaires and 18 reported shoulder pain. A comparison of individual shoulders (27 with pain reported and 47 without) determined that shoulder extension strength was lower and flexion:extension strength ratio was higher for male swimmers (n=36 shoulders) who reported shoulder pain compared to those who did not (p=0.04). The predictive value of extension strength was fair (0.72; p=0.03) for males with a cut-off value for extension strength calculated at 13.5% body mass. There were no differences between the two groups in shoulder rotation strength, age, training hours or previous pain history. CONCLUSIONS: Shoulder extension strength, a functional test for swimmers, was associated with and predictive of the development of shoulder pain in male swimmers. Low shoulder extension strength may be a risk factor for the development of shoulder pain in swimmers, proposing a direction for injury prevention and future investigation.

Central-to-brachial blood pressure amplification in type 2 diabetes: a systematic review and meta-analysis.

Due to systolic blood pressure (SBP) amplification, brachial SBP may not accurately reflect central SBP, the pressure the organs are exposed to. Patients with type 2 diabetes (T2D) have vascular irregularities that may affect blood pressure (BP) amplification and central BP indices (i.e. augmentation index [AIx] and augmentation pressure [AP]). By systematic review and meta-analysis, this study aimed firstly to determine the magnitude of central-to-brachial SBP and pulse pressure (PP) amplification in T2D compared to healthy controls and secondly, the difference in AIx and AP between the groups. Online databases were searched for published studies reporting invasive or non-invasive central and brachial SBP in T2D and healthy controls up to the 20th of February 2018. Random effects meta-analyses and meta-regression were used to analyze the studies. Eighteen studies (all non-invasive: 17 radial tonometry, 1 carotid tonometry, 2 brachial oscillometry) with a total of 2758 patients with T2D and 10,561 healthy controls were identified. There was no significant difference in SBP amplification between groups (T2D = 9.9 ± 4.7, healthy controls = 9.6 ± 4.5 mmHg, p = 0.84; pooled difference = 0.64 mmHg, 95%CI -0.27 1.54, p = 0.17) or PP amplification ratio (p = 0.16). However, among these studies, central BP indices (AIx corrected for heart rate and AP) were significantly higher in T2D (p < 0.05 for both). Despite a similar magnitude of central-to-brachial SBP amplification, patients with T2D have increased central systolic loading (AIx and AP) that cannot be discerned from brachial BP alone.

Wearing compression socks during exercise aids subsequent performance.

OBJECTIVES: To assess the effect of wearing compression socks on immediate and subsequent 5km running time trials, with particular attention to the influences on physiological, perceptual and performance-based parameters. DESIGN: Counter-balanced cross-over experiment. METHODS: Twelve male runners (mean±SD 5km run time 19:29±1:18min:s) each completed two experimental sessions. Sessions consisted of a standardised running warm-up, followed by a 5km time trial (TT1), a one hour recovery period, then a repeat of the warm-up and 5km time trial (TT2). One session required the use of sports compression socks during the first warm-up and time trial (COMP), while the other did not (CON). RESULTS: The decline in run performance in CON from TT1 to TT2 was moderate and significantly greater than that experienced by runners in COMP (9.6s, d=0.67, p<0.01). No difference was found between experimental conditions for oxygen consumption, blood lactate or calf volume (p=0.61, 0.54, 0.64, respectively). Perceptual measures of muscle soreness, fatigue and recovery were also similar between trials (p=0.56, 1.00 & 0.61, respectively). CONCLUSIONS: Wearing sports compression socks during high intensity running has a positive impact on subsequent running performance. The underlying mechanism of such performance enhancement remains unclear, but may relate to improved oxygen delivery, reduced muscle oscillation, superior running mechanics and athlete beliefs.

Deep vein thrombosis in a well-trained masters cyclist, is popliteal vein entrapment syndrome to blame?

Whilst athletes are the epitome of health, venous thromboembolisms (VTE) including deep vein thrombosis and pulmonary embolism have been demonstrated to occur in well-trained athletes. VTE is frequently misdiagnosed and poorly treated within this population, often resulting in career or life-threatening ramifications. Furthermore, VTE risk rises with increasing age (> 40 years), potentially affecting masters athletes. A 44-year-old well-trained male cyclist volunteered to participate in a research project investigating the influence of exercise on haemostasis in well-trained athletes. The cyclist presented with elevated D-Dimer levels both pre- (2251 ng/mL) and post-exercise (2653 ng/mL). The cyclist reported constant mild-pain in the left mid-calf region, with a cold tingling sensation in their left foot. Diagnosis of DVT was confirmed via a DVT squeeze test and Doppler ultrasound, with the clot located in the left popliteal vein. During the research project, the cyclist was exposed to numerous thrombogenic risk factors including travel, dehydration, prolonged sitting and exercise. The DVT in the popliteal vein may have resulted from repetitive movements associated with cycling. Additionally, hypertrophy of the gastrocnemius muscle may have impinged the vein. When diagnosing DVT within a cycling population, PVES should not be overlooked as a contributing factor.

Intestinal damage following short-duration exercise at the same relative intensity is similar in temperate and hot environments.

Increasing temperature and exercise disrupt tight junctions of the gastrointestinal tract although the contribution of environmental temperature to intestinal damage when exercising is unknown. This study investigated the effect of 2 different environmental temperatures on intestinal damage when exercising at the same relative intensity. Twelve men (mean ± SD; body mass, 81.98 ± 7.95 kg; height, 182.6 ± 7.4 cm) completed randomised cycling trials (45 min, 70% maximal oxygen uptake) in 30 °C/40% relative humidity (RH) and 20 °C/40%RH. A subset of participants (n = 5) also completed a seated passive trial (30 °C/40%RH). Rectal temperature and thermal sensation (TSS) were recorded during each trial and venous blood samples collected at pre- and post-trial for the analysis of intestinal fatty acid-binding protein (I-FABP) level as a marker of intestinal damage. Oxygen uptake was similar between 30 °C and 20 °C exercise trials, as intended (p = 0.94). I-FABP increased after exercise at 30 °C (pre-exercise: 585 ± 188 pg·mL-1; postexercise: 954 ± 411 pg·mL-1) and 20 °C (pre-exercise: 571 ± 175 pg·mL-1; postexercise: 852 ± 317 pg·mL-1) (p < 0.0001) but the magnitude of damage was similar between temperatures (p = 0.58). There was no significant increase in I-FABP concentration following passive heat exposure (p = 0.59). Rectal temperature increased during exercise trials (p < 0.001), but not the passive trial (p = 0.084). TSS increased more when exercising in 30 °C compared with 20 °C (p < 0.001). There was an increase in TSS during the passive heat trial (p = 0.03). Intestinal damage, as measured by I-FABP, following exercise in the heat was similar to when exercising in a cooler environment at the same relative intensity. Passive heat exposure did not increase I-FABP. It is suggested that when exercising in conditions of compensable heat stress, the increase in intestinal damage is predominantly attributable to the exercise component, rather than environmental conditions.

Reliability of Power Settings of the Wahoo KICKR Power Trainer After 60 Hours of Use.

PURPOSE: To assess the reliability of power-output measurements of a Wahoo KICKR Power Trainer (KICKR) on 2 separate occasions separated by 14 mo of regular use (∼1 h/wk). METHODS: Using the KICKR to set power outputs, powers of 100-600 W in increments of 50 W were assessed at cadences of 80, 90, and 100 rpm that were controlled and validated by a dynamic calibration rig. RESULTS: A small ratio bias of 1.002 (95% limits of agreement [LoA] 0.992-1.011) was observed over 100-600 W at 80-100 rpm between trials 1 and 2. Similar ratio biases with acceptable limits of agreement were observed at 80 rpm (1.003 [95% LoA 0.987-1.018]), 90 rpm (1.000 [0.996-1.005]), and 100 rpm (1.002 [0.997-1.007]). The intraclass correlation coefficient with 95% confidence interval (CI) for mean power between trials was 1.00 (95% CI 1.00-1.00) with a typical error (TE) of 3.1 W and 1.6% observed between trials 1 and 2. CONCLUSION: When assessed at 2 separate time points 14 mo apart, the KICKR has acceptable reliability for combined power outputs of 100-600 W at 80-100 rpm, reporting overall small ratio biases with acceptable LoA and low TE. Coaches and sport scientists should feel confident in the power output measured by the KICKR over an extended period of time when performing laboratory training and performance assessments.

Combined Carbohydrate and Protein Ingestion During Australian Rules Football Matches and Training Sessions Does Not Reduce Fatigue or Accelerate Recovery Throughout a Weeklong Junior Tournament.

Lee, NA, Fell, JW, Pitchford, NW, Hall, AH, Leveritt, MD, and Kitic, CM. Combined carbohydrate and protein ingestion during Australian rules football matches and training sessions does not reduce fatigue or accelerate recovery throughout a weeklong junior tournament. J Strength Cond Res 32(2): 344-355, 2018-Australian rules football (ARF) is a physically demanding sport that can induce high levels of fatigue. Fatigue may be intensified during periods where multiple matches are played with limited recovery time. Combined carbohydrate and protein (CHO + PRO) intake during physical activity may provide performance and recovery benefits. The aim of this study was to investigate whether CHO + PRO ingestion during ARF matches and training sessions throughout a tournament would enhance performance or recovery in comparison with CHO-only ingestion. Australian rules football players (n = 21) competing in a 7-day national tournament participated in this randomized and double-blinded study. Beverages containing either CHO (n = 10) or CHO + PRO (n = 11) were provided during matches (day 1, day 4, and day 7) and training sessions (day 2 and day 3). Countermovement jumps (CMJs), ratings of muscle soreness, and autonomic function were assessed throughout the tournament. Gastrointestinal tract (GI) discomfort was measured after matches. Countermovement jump peak velocity increased in the CHO + PRO group (p = 0.01) but not in the CHO group. There were no differences in the other CMJ variables. In both groups, muscle soreness increased from days 0 and 1 to day 2 (p ≤ 0.05) but did not remain elevated. R-R intervals (time elapsed between successive peaks in QRS complexes) increased in both groups from day 1 to day 7 (mean difference = 59.85 ms, p < 0.01). Postmatch GI discomfort was not different (p > 0.05) between groups. When daily dietary protein is adequate (>1.8 g·kg·d), the ingestion of CHO + PRO during matches and training sessions throughout a tournament does not reduce muscle soreness nor have clear benefits for neuromuscular recovery or modulate autonomic function in junior ARF athletes, compared with that of CHO alone.

Low FODMAP: A Preliminary Strategy to Reduce Gastrointestinal Distress in Athletes.

INTRODUCTION: Gastrointestinal (GI) distress in endurance athletes is prevalent and detrimental to performance. Adverse GI symptomatology can be analogous with irritable bowel syndrome, where fermentable oligosaccharide, disaccharide, monosaccharide, and polyols (FODMAP) reduction has demonstrated efficacy. This study investigated the effects of low FODMAP (LFOD) diet on GI distress parameters in runners with a history of nonclinical exercise-associated GI symptoms. METHODS: Eleven recreationally competitive runners (five men, six women; 5-km personal best 23:00 ± 4:02 min:s) participated in the study. Runners were allocated to a randomized 6-d LFOD or high FODMAP (HFOD) diet separated by a 1-d wash-out in a controlled, single-blinded cross-over study. In each period participants completed two strenuous running sessions consisting of 5 × 1000 m and a 7-km threshold run. GI symptoms (during-exercise and daily) and the Daily Analysis of Life Demand for Athletes questionnaires were completed. Area under the curve was calculated for daily GI symptoms across each dietary period and analysis was conducted using multilevel mixed-effects linear regression for comparison between the two diets. RESULTS: A significantly smaller area under the curve for daily GI symptoms 6 d during the LFOD compared with HFOD (mean difference, -13.4; 95% confidence interval, -22 to -4.60; P = 0.003) was observed. The daily GI symptoms that were significantly lower during LFOD were flatulence (P < 0.001), urge to defecate (P = 0.04), loose stool (P = 0.03), and diarrhea (P = 0.004). No significant differences in during exercise symptoms or Daily Analysis of Life Demand for Athletes responses were observed between diets (P > 0.05). CONCLUSIONS: Preliminary findings suggest that short-term FODMAP reduction may be a beneficial intervention to minimize daily GI symptoms in runners with exercise-related GI distress.

Isometric shoulder strength in young swimmers.

OBJECTIVES: The prevalence of shoulder pain in young swimmers is high. Shoulder rotation strength and the ratio of internal to external rotation strength have been reported as potential modifiable risk factors associated with shoulder pain. However, relative strength measures in elevated positions, which include flexion and extension, have not been established for the young swimmer. The aim of this study was to establish clinically useful, normative shoulder strength measures and ratios for swimmers (14-20 years) without shoulder pain. DESIGN: Cross-sectional, observational study. METHODS: Swimmers (N=85) without a recent history of shoulder pain underwent strength testing of shoulder flexion and extension (in 140° abduction); and internal and external rotation (in 90° abduction). Strength tests were performed in supine using a hand-held dynamometer and values normalised to body weight. Descriptive statistics were calculated for strength and strength ratios (flexion:extension and internal:external rotation). Differences between groups (based on gender, history of pain, test and arm dominance) were explored using independent and paired t tests. RESULTS: Normative shoulder strength values and ratios were established for young swimmers. There was a significant difference (p<0.002) in relative strength between males and females for all tests with no differences in strength ratios. Relative strength of the dominant and non-dominant shoulders (except for extension); and for swimmers with and without a history of shoulder pain was not significantly different. CONCLUSIONS: A normal shoulder strength profile for the young swimmer has been established which provides a valuable reference for the clinician assessing shoulder strength in this population.

Scapular upward rotation position is symmetrical in swimmers without current shoulder pain.

OBJECTIVES: A history of shoulder pain is common in swimmers and may influence scapular position, possibly increasing the risk of shoulder pain recurring. The aim of this study was to establish and compare bilateral static measures of scapular upward rotation in swimmers (14-20 years), some with a history of shoulder pain but all currently pain free, in two different elevated positions of shoulder abduction. DESIGN: Cross-sectional, observational study. PARTICIPANTS: Eighty-five swimmers without current shoulder pain. METHODS: Scapular upward rotation position was measured on both shoulders using a digital inclinometer in 90° and 140° shoulder abduction. Descriptive statistics were calculated for degrees of scapular upward rotation in both shoulder positions. Differences between shoulders (dominant, non-dominant, history and no history of pain) were explored using one-way ANOVA and paired t tests. RESULTS: A large range of values for scapular upward rotation was found at both positions of shoulder abduction but there were no significant differences between the shoulders: with and without a history of shoulder pain for the dominant and non-dominant sides. CONCLUSIONS: A history of shoulder pain and arm dominance did not influence scapular upward rotation position when measured in shoulder abduction in swimmers without current shoulder pain.

Does Short-Duration Heat Exposure at a Matched Cardiovascular Intensity Improve Intermittent-Running Performance in a Cool Environment?

PURPOSE: To investigate whether a 5-d cycling training block in the heat (35°C) in Australian Rules footballers was superior to exercising at the same relative intensity in cool conditions (15°C) for improving intermittent-running performance in a cool environment (<18°C). METHODS: Using a parallel-group design, 12 semiprofessional football players performed 5 d of cycling exercise (70% heart-rate reserve [HRR] for 45 min [5 × 50-min sessions in total]) in a hot (HEAT, 35°C ± 1°C, 56% ± 9% RH) or cool environment (COOL, 15°C ± 3°C, 81% ± 10% RH). A 30-15 Intermittent Fitness Test to assess intermittent running performance (VIFT) was conducted in a cool environment (17°C ± 2°C, 58 ± 5% RH) before and twice after (1 and 3 d) the intervention. RESULTS: There was a likely small increase in VIFT in each group (HEAT, 0.5 ± 0.3 km/h, 1.5 ± 0.8 × smallest worthwhile change [SWC]; COOL, 0.4 ± 0.4 km/h, 1.6 ± 1.2 × SWC) 3 d postintervention, with no difference in change between the groups (0.5% ± 1.9%, 0.4 ± 1.4 × SWC). Cycle power output during the intervention was almost certainly lower in the HEAT group (HEAT 1.8 ± 0.2 W/kg vs COOL 2.5 ± 0.3 W/kg, -21.7 ± 3.2 × SWC, 100/0/0). CONCLUSIONS: When cardiovascularexercise intensity is matched (ie, 70% HRR) between environmental conditions, there is no additional performance benefit from short-duration moderate-intensity heat exposure (5 × 50 min) for semiprofessional footballers exercising in cool conditions. However, the similar positive adaptations may occur in HEAT with 30% lower mechanical load, which may be of interest for load management during intense training or rehabilitation phases.

Effect of Compression Socks Worn Between Repeated Maximal Running Bouts.

PURPOSE: To determine the effect of wearing compression socks between repeated running bouts on perceptual, physiological, and performance-based parameters. METHODS: Twelve well-trained male runners (mean ± SD 5-km time 19:24 ± 1:19 [min:s]) recorded their perceptions of the efficacy of compression socks for recovery before completion of 2 experimental sessions. Each session consisted of two 5-km running time trials (TT1 and TT2) on a treadmill, with a 1-h recovery period between. In a randomized crossover design, 1 session required participants to wear compression socks during the recovery period, and no compression socks were worn between TTs in the other session (control). RESULTS: Running performance between TT1 and TT2 for runners wearing compression socks was similar between TTs (mean Δ 5.3 ± 20.7 s, d = 0.07, P = .20), whereas for control runners, performance significantly decreased in the second TT (mean Δ 15.9 ± 13.3 s, d = 0.19, P < .01). When grouped by perception of efficacy for compression socks, participants with strong beliefs (n = 7) experienced improved subsequent running performance with compression socks (mean Δ -3.6 ± 19.2 s, d = 0.05, P = .32) compared with those with neutral or negative perceptions (n = 5; mean Δ 17.9 ± 17.0 s, d = 0.19, P = .04). Cross-sectional area of the calf and muscle soreness were significantly reduced during the recovery period with the use of compression socks (P < .01), whereas ratings of fatigue showed no difference between conditions. CONCLUSIONS: Wearing compression socks between repeated running bouts can aid recovery and subsequent performance. Furthermore, subsequent exercise performance may be even further enhanced when athletes believe in the efficacy of compression socks to assist in recovery between exercise bouts.

Commercial Hype Versus Reality: Our Current Scientific Understanding of Gluten and Athletic Performance.

Recent explosion in the prevalence of gluten-free athletes, exacerbated by unsubstantiated commercial health claims, has led to some professional athletes touting gluten-free diet as the secret to their success. Forty-one percent of athletes report adhering to a gluten-free diet (GFD), which is four-fold higher than the population-based clinical requirements. Many nonceliac athletes believe that gluten avoidance improves gastrointestinal well-being, reduces inflammation, and provides an ergogenic edge, despite the fact that limited data yet exist to support any of these benefits. There are several plausible associations between endurance-based exercise and gastrointestinal permeability whereby a GFD may be beneficial. However, the implications of confounding factors, including the risks of unnecessary dietary restriction, financial burden, food availability, psychosocial implications, alterations in short-chain carbohydrates (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols), and other wheat constituents emphasize the need for further evaluation.