Coagulation activity and thrombotic risk following high-volume endurance exercise in recreationally active cyclists.

Despite the prognostic effect of physical activity, acute bouts of high-volume endurance exercise can induce cardiac stress and postexercise hypercoagulation associated with increased thrombotic risk. The aim of this study was to explore the effect of high-volume endurance exercise on coagulation and thrombotic activity in recreational cyclists. Thirty-four recreational cyclists completed 4.8 ± 0.3 h of cycling at 45 ± 5% of maximal power output on a bicycle ergometer. Intravenous blood samples were collected preexercise, immediately postexercise, 24 and 48 h postexercise, and analyzed for brain natriuretic peptide (BNP), cardiac troponin (cTn), C-reactive protein (CRP), D-dimer, thrombin-antithrombin (TAT) complex, tissue factor (TF), tissue factor pathway inhibitor (TFPI), and TF-to-TFPI ratio (TF:TFPI). An increase in cTn was observed postexercise (P < 0.001). CRP concentrations were increased at 24 and 48 h postexercise compared with preexercise concentrations (P ≤ 0.001). TF was elevated at 24 h postexercise (P < 0.031) and TFPI was higher immediately postexercise (P < 0.044) compared with all other time points. TF:TFPI was increased at 24 and 48 h postexercise compared with preexercise (P < 0.025). TAT complex was reduced at 48 h postexercise compared with preexercise (P = 0.015), D-dimer was higher immediately postexercise compared with all other time points (P ≤ 0.013). No significant differences were observed in BNP (P > 0.05). High-volume endurance cycling induced markers of cardiac stress among recreational cyclists. However, plasma coagulation and fibrinolytic activity suggest no increase in thrombotic risk after high-volume endurance exercise.NEW & NOTEWORTHY In this study, a high-volume endurance exercise protocol induced markers of cardiac stress and altered plasma coagulation and fibrinolytic activity for up to 48 h in recreationally active cyclists. However, analysis of coagulation biomarkers indicates no increase in thrombotic risk when appropriate hydration and rest protocols are implemented.

The influence of considering individual resistance training variables as a whole on muscle strength: A systematic review and meta-analysis protocol.

Examinations of the effect of resistance training (RT) on muscle strength have attempted to determine differences between prescriptions, mostly examining individual training variables. The broad interaction of variables does not appear to be completely considered, nor has a dose-response function been determined. This registered (doi.org/10.17605/OSF.IO/EH94V) systematic review with meta-analysis aims to determine if the interaction of individual training variables to derive RT dose, dosing, and dosage can influence muscle strength and determine if an optimal prescription range exists for developing muscle strength. To derive RT dose, the following calculation will be implemented: number of sets × number of repetitions × number of exercises × exercise intensity, while RT dosing factors in frequency and RT dosage considers program duration. A keyword search strategy utilising interchangeable terms for population (adult), intervention (resistance training), and outcomes (strength) will be conducted across three databases (CINAHL, MEDLINE, and SPORTDiscus). Novel to the field of exercise prescription, an analytical approach to determine the dose-response function for continuous outcomes will be used. The pooled standardised mean differences for muscle strength will be estimated using DerSimonian and Laird random effects method. Linear and non-linear dose-response relationships will be estimated by fitting fixed effects and random effects models using the one-stage approach to evaluate if there is a relationship between exercise dose, dosing and dosage and the effect on muscle strength. Maximised log-likelihood and the Akaike Information Criteria will be used to compare alternative best fitting models. Meta regressions will investigate between-study variances and a funnel plot and Egger's test will assess publication bias. The results from this study will identify if an optimal prescription range for dose, dosing and dosage exists to develop muscle strength.

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.

Effects of Sports Compression Socks on Performance, Physiological, and Hematological Alterations After Long-Haul Air Travel in Elite Female Volleyballers.

Broatch, JR, Bishop, DJ, Zadow, EK, and Halson, S. Effects of sports compression socks on performance, physiological, and hematological alterations after long-haul air travel in elite female volleyballers. J Strength Cond Res 33(2): 492-501, 2019-The purpose of this investigation was to assess the merit of sports compression socks in minimizing travel-induced performance, physiological, and hematological alterations in elite female volleyball athletes. Twelve elite female volleyballers (age, 25 ± 2 years) traveled from Canberra (Australia) to Manila (Philippines), and were assigned to 1 of 2 conditions; compression socks (COMP, n = 6) worn during travel or a passive control (CON, n = 6). Dependent measures included countermovement jump (CMJ) performance, subjective ratings of well-being, cardiovascular function, calf girth, and markers of blood clotting, collected before (-24 hours, CMJ; -12 hours, all measures), during (+6.5 and +9 hours, subjective ratings and cardiovascular function), and after (+12 hours, all measures except CMJ; +24 hours and +48 hours, CMJ) travel. When compared with CON, small-to-large effects were observed for COMP to improve heart rate (+9 hours), oxygen saturation (+6.5 hours and +9 hours), alertness (+6.5 hours), fatigue (+6.5 hours), muscle soreness (+6.5 hours and +9 hours), and overall health (+6.5 hours) during travel. After travel, small-to-moderate effects were observed for COMP to improve systolic blood pressure (+12 hours), right calf girth (+12 hours), CMJ height (+24 hours), mean velocity (+24 hours), and relative power (+48 hours), compared with CON. COMP had no effect on the markers of blood clotting. This study suggests that compression socks are beneficial in combating the stressors imposed by long-haul travel in elite athletes, and may have merit for individuals frequenting long-haul travel or competing soon after flying.

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.

Validity of Power Settings of the Wahoo KICKR Power Trainer.

PURPOSE: To assess the validity of power output settings of the Wahoo KICKR Power Trainer (KICKR) using a dynamic calibration rig (CALRIG) over a range of power outputs and cadences. METHODS: Using the KICKR to set power outputs, powers of 100-999 W were assessed at cadences (controlled by the CALRIG) of 80, 90, 100, 110, and 120 rpm. RESULTS: The KICKR displayed accurate measurements of power of 250-700 W at cadences of 80-120 rpm with a bias of -1.1% (95% limits of agreement [LoA] -3.6% to 1.4%). A larger mean bias in power was observed across the full range of power tested, 100-999 W (4.2%, 95% LoA -20.1% to 28.6%), due to larger biases of 100-200 and 750-999 W (4.5%, 95% LoA -2.3% to 11.3%, and 13.0%, 95% LoA -24.4% to 50.3%), respectively. CONCLUSIONS: Compared with a CALRIG, the KICKR has acceptable accuracy reporting a small mean bias and narrow LoA in the measurement of power output of 250-700 W at cadences of 80-120 rpm. Caution should be applied by coaches and sports scientists when using the KICKR at power outputs of <200 W and >750 W due to the greater variability in recorded power.