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This study sought to investigate the effect of cold ambient temperature on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and blood flow during steady-state endurance exercise in endurance-trained cyclists. Ten males (age: 23 ± 3 years; peak oxygen consumption: 60.60 ± 4.84 ml·kg−1·min−1; body fat: 18.4% ± 3.5%) participated in baseline lactate threshold (LT) and peak oxygen consumption testing, two familiarization trials, and two experimental trials. Experimental trials consisted of cycling in COLD (3 °C; 42% relative humidity) and neutral (NEU; 19 °C; 39% relative humidity) temperatures. Exercise consisted of 25 min cycling at 70% LT and 25 min at 90% LT. In situ SCAAT lipolysis and blood flow were measured via microdialysis. Heart rate, core temperature, carbohydrate and fat oxidation, blood glucose, and blood lactate were also measured. Heart rate, core temperature, oxygen consumption, and blood lactate increased with exercise but were not different between COLD and NEU. SCAAT blood flow did not change from rest to exercise or between COLD and NEU. Interstitial glycerol increased during exercise (p <.001) with no difference between COLD and NEU. Fat oxidation increased (p <.001) at the onset of exercise and remained elevated thereafter with no difference between COLD and NEU. Carbohydrate oxidation increased with increasing exercise intensity and was greater at 70% LT in COLD compared to NEU (p =.030). No differences were observed between conditions for any other variable. Cycling exercise increased SCAAT lipolysis but not blood flow. Ambient temperature did not alter SCAAT metabolism, SCAAT blood flow, or fat oxidation in well-trained cyclists, though cold exposure increased whole-body carbohydrate oxidation at lower exercise intensities. [ABSTRACT FROM AUTHOR]

Purpose: Changes in biophysiological markers related to perceived burnout and self-comfort were tested in this study. Method: Forty-two student-athletes from middle and high school grades were evaluated for burnout, salivary cortisol levels, measures of arousal-related physiological markers (i.e., blood volume pulse; BVP), galvanic skin response (GSR), and respiratory rate, and self-comfort variables during the last two weeks of the season. Using self-comfort theory as its conceptual framework, we examined burnout through a conceptual model in which feeling of discomfort with the self was related to biophysiological markers affecting perceived burnout. The proposed model was tested by using a partial least squares structural equation modeling (PLS-SEM). Results: The main findings indicate that increased self-discomfort is significantly (p < 0.001) associated with increased salivary cortisol ([beta] = - 0.189) along with a significant (p = 0.050) decrease in GSR ([beta] = - 0.259). Increased salivary cortisol is significantly (p < 0.001) associated with increased burnout ([beta] = 0.242). Conclusion: The findings partially support the model and encourage further effort to capture the burnout syndrome through the integration of biological and psychological markers.

The relationship between sleep duration, sleep quality, and race completion time during each stage of a 3-day ultra-endurance triathlon (stage 1: 10-km swim, 146-km cycle; stage 2: 276-km cycle; and stage 3: 84.4-km run) was investigated. Seventeen triathletes partook in sleep analysis throughout the ultra-endurance multiday triathlon using an actigraphy wristband. The participants wore the band to record objective sleep outcomes for approximately 4 days (1–2 d prerace, 3 race days, and 1 d postrace), except while racing. The total sleep time (TST; prerace: 414.1 [95.3] min, prestage 1: 392.2 [138.3] min, prestage 2: 355.6 [62.5] min, and prestage 3: 299.7 [107.0] min) significantly decreased over time (P <.05). Significant Pearson moment–product correlations were found between TST and subsequent race–day performance for race stage 1 (r = −.577; P =.019) and stage 3 (r = −.546; P =.035), with further analysis revealing that TST explained 33% and 30% of the variation in performance for stages 1 and 3, respectively. During a 3-day ultra-endurance triathlon, the TST was reduced and had a significant negative correlation to exercise performance, indicating that sleep loss was associated with slower performances. Sleep onset latency, wake episodes, and sleep efficiency did not significantly change over the course of this investigation, which may stem from the close proximity of exercise to sleep. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Baur, DA, Johnson, JB, Giron-Molina, LG, Caterisano, M, Shaner, C, Caterisano, A, and Gentry, M. Career-best changes in body mass and physical fitness test performance among Division 1 college football players encompassing 28 years at the same institution. J Strength Cond Res 37(4): 806–815, 2023—Understanding typical changes induced by collegiate American football strength and conditioning programs is essential for optimizing program design and athletic development. The purpose of the study was to evaluate body mass and physical fitness test performance changes at a Division 1 program with 28 years of coaching stability. Initial and personal record results were collected from 1,102 players who were subdivided into 3 position groups: combination players (COMBO), skill players (SKILL), and line of scrimmage players. Players followed a linear periodized training program with biannual body mass and performance testing. Tested variables included body mass, strength (bench press, back squat, and front squat), impulse (power clean, push jerk, and vertical jump [VJ]), and speed/agility (10-yard dash [10YD], 40-yard dash, and 20-yard shuttle). The fixed effect of time and position group on the dependent variables was assessed using linear mixed models. If appropriate, post hoc tests using the estimated marginal means were used to evaluate the source of any significant effects. Significance was accepted as p < 0.05. Normative values were produced by descriptive statistics (i.e., weighted means). All players and position groups increased/improved across all tested variables (p < 0.05). Improvements were 8.2%, 11.9–18.3%, 13.5–17.5%, and 3.6–6.0% for body mass, strength, impulse, and speed/agility, respectively. Line of scrimmage improvements were absolutely larger across most tested variables and relatively larger for back squat, VJ, and 10YD vs. SKILL and with VJ vs. COMBO/SKILL (p < 0.05). These results reveal typical expectations for 4–5 years performance improvements and that position group differences in trainability may influence game readiness and training needs. [ABSTRACT FROM AUTHOR]

Previous studies reported that adding protein (PRO) to carbohydrate (CHO) solutions enhances endurance performance. The ergogenic effect may be a function of additional protein/amino acid calories, but this has not been examined. In addition, although supplemental L-alanine (ALA) is readily oxidized during exercise, the subsequent impact on metabolism and prolonged endurance performance is unknown. The purpose of this investigation was to independently gauge the impact of whey PRO hydrolysate and ALA supplementation on performance and various physiological parameters. Eight cyclists (age: 22.3 ± 5.6 yr, weight: 70.0 ± 8.0 kg, VO2max: 59.4 ± 4.9 ml·kg–1·min–1) performed 120 min of constant-load cycling (55% of peak power) followed by a 30-km time trial (TT) under placebo (PLA), PRO, and ALA conditions. Magnitude-based qualitative inferences were applied to evaluate treatment differences and data are presented as percent difference between treatments ± 90% confidence limit. Both ALA (–2.1 ± 2.7%) and PRO intake (–2.1 ± 2.2%) possibly harmed performance compared with PLA. Of interest, heart rate was possibly lower with ALA than PLA at 20– (–2.7 ± 3.4%) and 120-min (–1.7 ± 2.9%) of constant-load cycling and the serum interleukin-6 (IL-6) response to 120 min of cycling was likely attenuated with PRO compared with PLA (PLA, 6.6 ± 3.7 fold vs. PRO, 2.9 ± 1.8 fold). In addition, blood glucose levels were lower with PRO than PLA at 20– (–8.8 ± 2.3%; very likely) and 120-min (–4.9 ± 4.6%; likely) of constant-load cycling. Although ALA intake appears to lower HR and PRO ingestion dampens the IL-6 response to exercise, the ingestion of PRO (without CHO) or ALA does not enhance, and may actually impair, performance following prolonged cycling. [ABSTRACT FROM AUTHOR]