The present study investigated changes in acute serum hormone responses to a resistance exercise bout following a prolonged period of hypertrophic resistance training in young (YM) and older men (OM). Subjects performed a 5 × 10RM leg press exercise protocol before and after 20 weeks of hypertrophic resistance training. In YM, the acute responses in growth hormone were greater compared with before training (p < .05), and cortisol concentration did not increase after training. Endocrine responses in OM were similar before and after training. Greater acute growth hormone responses after training were associated with larger gains in lean mass in the entire subject group (r = .596, p = .019). These findings suggest that, in general, YM demonstrate greater adaptability within the endocrine system compared with OM. However, adaptability in growth hormone response was associated with larger training-induced gains independent of age.
Simon Walker, Fabrizio Santolamazza, William Kraemer and Keijo Häkkinen
Kirsty J. Elliott-Sale, Adam S. Tenforde, Allyson L. Parziale, Bryan Holtzman and Kathryn E. Ackerman
; Mountjoy et al., 2014 ). RED-S was proposed to expand upon the Triad and to include both female and male athletes. It suggests 10 physiological and 10 performance-related effects of low EA ( Mountjoy et al., 2014 ). In this paper, we will focus specifically on the endocrine effects of RED-S, or what the
Dean J. McNamara, Tim J. Gabbett, Geraldine Naughton, Patrick Farhart and Paul Chapman
This study investigated key fatigue and workload variables of cricket fast bowlers and nonfast bowlers during a 7-wk physical-preparation period and 10-d intensified competition period.
Twenty-six elite junior cricketers (mean ± SD age 17.7 ± 1.1 y) were classified as fast bowlers (n = 9) or nonfast bowlers (n = 17). Individual workloads were measured via global positioning system technology, and neuromuscular function (countermovement jump [relative power and flight time]), endocrine (salivary testosterone and cortisol concentrations), and perceptual well-being (soreness, mood, stress, sleep quality, and fatigue) markers were recorded.
Fast bowlers performed greater competition total distance (median [interquartile range] 7049  m vs 5062  m), including greater distances at low and high speeds, and more accelerations (40  vs 19 ) and had a higher player load (912  arbitrary units vs 697  arbitrary units) than nonfast bowlers. Cortisol concentrations were higher in the physical-preparation (mean ± 90% confidence intervals, % likelihood; d = –0.88 ± 0.39, 100%) and competition phases (d = –0.39 ± 0.30, 85%), and testosterone concentrations, lower (d = 0.56 ± 0.29, 98%), in the competition phase in fast bowlers. Perceptual well-being was poorer in nonfast bowlers during competition only (d = 0.36 ± 0.22, 88%). Differences in neuromuscular function between groups were unclear during physical preparation and competition.
These findings demonstrate differences in the physical demands of cricket fast bowlers and nonfast bowlers and suggest that these external workloads differentially affect the neuromuscular, endocrine, and perceptual fatigue responses of these players.
In recent years there has been a remarkable enhancement in the knowledge and understanding of endocrine responses to exercise and exercise training in children and adolescents who participate in sports. This includes, for example, exercise-associated changes in growth factors that regulate muscle adaptations to exercise training, the use of hormonal changes to assess training intensity, as well as deleterious effects of competitive sports, in particularly if associated with inadequate nutrition, on growth and the reproductive system. However, major scientific gaps still exist in our understanding of the application and translation of this knowledge to the everyday use of young athletes and their coaches. These gaps include the translation of laboratory research to “real-life” training setting to optimize training efficiency, mainly due to the lack of “real-life” exercise studies; and the use of genetic endocrinology for sports selection, the prediction of excellence in sports and to improve training.
Henry Davis IV, Sari M. van Anders, Elton T. Ngan, Todd S. Woodward, Jared X. Van Snellenberg, Helen S. Mayberg and Mario Liotti
In this follow-up study, self-referential videos of success and failure were used for mood provocation to investigate mood, neural, and endocrine activity among 26 internationally competitive athletes using functional Magnetic Resonance Imaging (fMRI) and salivary hormone measures. The initial sample of 14 athletes who had experienced career-threatening failure was contrasted to 12 athletes with exceptional success. Endocrine data were added to the preliminary report to round
Jay Hoffman, Nicholas Ratamess, Jie Kang, Gerald Mangine, Avery Faigenbaum and Jeffrey Stout
The effects of creatine and creatine plus β-alanine on strength, power, body composition, and endocrine changes were examined during a 10-wk resistance training program in collegiate football players. Thirty-three male subjects were randomly assigned to either a placebo (P), creatine (C), or creatine plus β-alanine (CA) group. During each testing session subjects were assessed for strength (maximum bench press and squat), power (Wingate anaerobic power test, 20-jump test), and body composition. Resting blood samples were analyzed for total testosterone, cortisol, growth hormone, IGF-1, and sex hormone binding globulin. Changes in lean body mass and percent body fat were greater (P < 0.05) in CA compared to C or P. Significantly greater strength improvements were seen in CA and C compared to P. Resting testosterone concentrations were elevated in C, however, no other significant endocrine changes were noted. Results of this study demonstrate the efficacy of creatine and creatine plus β-alanine on strength performance. Creatine plus β-alanine supplementation appeared to have the greatest effect on lean tissue accruement and body fat composition.
James A. Betts, Milou Beelen, Keith A. Stokes, Wim H.M. Saris and Luc J.C. van Loon
Nocturnal endocrine responses to exercise performed in the evening and the potential role of nutrition are poorly understood. To gain novel insight, 10 healthy men ingested carbohydrate with (C+P) and without (C) protein in a randomized order and double-blind manner during 2 hr of interval cycling followed by resistancetype exercise and into early postexercise recovery. Blood samples were obtained hourly throughout 9 hr of postexercise overnight recovery for analysis of key hormones. Muscle samples were taken from the vastus lateralis before and after exercise and then again the next morning (7 a.m.) to calculate mixed-muscle protein fractional synthetic rate (FSR). Overnight plasma hormone concentrations were converted into overall responses (expressed as area under the concentration curve) and did not differ between treatments for either growth hormone (1,464 ± 257 vs. 1,432 ± 164 pg/ml · 540 min) or total testosterone (18.3 ± 1.2 vs. 17.9 ± 1.2 nmol/L · 540 min, C and C+P, respectively). In contrast, the overnight cortisol response was higher with C+P (102 ± 11 nmol/L · 540 min) than with C (81 ± 8 nmol/L · 540 min; p = .02). Mixed-muscle FSR did not differ between C and C+P during overnight recovery (0.062% ± 0.006% and 0.062% ± 0.009%/hr, respectively) and correlated significantly with the plasma total testosterone response (r = .7, p < .01). No correlations with FSR were apparent for the response of growth hormone (r = –.2, p = .4), cortisol (r = .1, p = .6), or the ratio of testosterone to cortisol (r = .2, p = .5). In conclusion, protein ingestion during and shortly after exercise does not modulate the endocrine response or muscle protein synthesis during overnight recovery.
Tony Adebero, Brandon John McKinlay, Alexandros Theocharidis, Zach Root, Andrea R. Josse, Panagiota Klentrou and Bareket Falk
Intense exercise has been shown to increase circulating hormonal concentrations in both athletic adults ( 13 , 17 , 22 ) and youth ( 23 , 28 , 33 , 37 ). An intense exercise session alters the homeostasis of the endocrine system by elevating both catabolic (eg, cortisol, adrenaline, glucagon) and
Andrew C. Fry, William J. Kraemer, Michael H. Stone, Beverly J. Warren, Jay T. Kearney, Carl M. Maresh, Cheryl A. Weseman and Steven J. Fleck
To examine the effects of 1 week of high volume weightlifting and amino acid supplementation, 28 elite junior male weightlifting received either amino acid (protein) or lactose (placebo) capsules using double-blind procedures. weightlifting test sessions were performed before and after 7 days of high volume training sessions. Serum concentrations of testosterone (Tes), cortisol (Cort), and growth hormone (GH) as well as whole blood iactate (HLa) were determined from blood draws. Lifting performance was not altered for either group after training, although vertical jump performance decreased for both groups. Both tests elicited significantly elevated exercise-induced hormonal and HLa concentrations. Significant decreases in postexercise hormonal and HLa concentrations from Test 1 to Test 2 were observed for both groups. Tes concentrations at 7 a.m. and preexercise decreased for both groups from Test 1 to Test 2, while the placebo group exhibited a decreased 7 a.m. Tes/ Cort. These data suggest that amino acid supplementation does not influence resting or exercise-induced hormonal responses to 1 week of high volume weight training, but endocrine responses did suggest an impending overtraining syndrome.