Robert P Weatherby

Two Emerging Concepts for Elite Athletes The Short-Term Effects of Testosterone and Cortisol on the Neuromuscular System and the Dose-Response Training Role of these Endogenous Hormones

The aim of this review is to highlight two emerging concepts for the elite athlete using the resistance-training model: (i) the short-term effects of testosterone (T) and cortisol (C) on the neuromuscular system; and (ii) the dose-response training role of these endogenous hormones. Exogenous evidence confirms that T and C can regulate long-term changes in muscle growth and performance, especially with resistance training. This evidence also confirms that changes in T or C concentrations can moderate or support neuromuscular performance through various short-term mechanisms (e.g. second messengers, lipid/protein pathways, neuronal activity, behaviour, cognition, motor-system function, muscle properties and energy metabolism). The possibility of dual T and C effects on the neuromuscular system offers a new paradigm for understanding resistance-training performance and adaptations.Endogenous evidence supports the short-term T and C effects on human performance. Several factors (e.g. workout design, nutrition, genetics, training status and type) can acutely modify T and/or C concentrations and thereby potentially influence resistance-training performance and the adaptive outcomes. This novel short-term pathway appears to be more prominent in athletes (vs non-athletes), possibly due to the training of the neuromuscular and endocrine systems. However, the exact contribution of these endogenous hormones to the training process is still unclear. Research also confirms a dose-response training role for basal changes in endogenous T and C, again, especially for elite athletes. Although full proof within the physiological range is lacking, this athlete model reconciles a proposed permissive role for endogenous hormones in untrained individuals. It is also clear that the steroid receptors (cell bound) mediate target tissue effects by adapting to exercise and training, but the response patterns of the membrane-bound receptors remain highly speculative.This information provides a new perspective for examining, interpreting and utilizing T and C within the elite sporting environment. For example, individual hormonal data may be used to better prescribe resistance exercise and training programmes or to assess the trainability of elite athletes. Possible strategies for acutely modifying the hormonal milieu and, thereafter, the performance/training outcomes were also identified (see above). The limitations and challenges associated with the analysis and interpretation of hormonal research in sport (e.g. procedural issues, analytical methods, research design) were another discussion point. Finally, this review highlights the need for more experimental research on humans, in particular athletes, to specifically address the concept of dual steroid effects on the neuromuscular system.

Muscular strength, body composition and health responses to the use of testosterone enanthate: a double blind study

To determine the effect the steroid, testosterone enanthate (TE) had on upper body strength, body composition and health. Twenty one male weight training subjects were randomly assigned in a double blind method to either a 3.5 mg(-1) x kg(-1) TE (n=11) or placebo (n=10) weight training group. The subjects were monitored during a 12 week administration phase and a subsequent 12 week follow up phase. Subjects were tested on a number of strength and size measurements, whilst having their health monitored. The results from the study revealed that the testosterone/weight training group improved significantly (p<0.05) more than the placebo/weight training group during and immediately after the administration phase on a 1 repetition maximum bench press. With regards to body composition, body weight, arm girth and rectus femoris circumference all increased significantly greater in the TE group compared to the placebo. Furthermore, the abdomen skinfold showed significant decreases in the TE group compared to the placebo group at post testing, follow up mid testing and the follow up post testing occasions. With the exception of the abdomen skinfold no within or between group differences were evident following a cycling off period of 12 weeks. Changes to baseline health indicators were reported in some subjects following testosterone usage. This included an average elevation in systolic blood pressure in all TE subjects by 10 mm Hg, a mild increase in hereditary frontal alopecia, increased muscle tightness (hamstrings and pectorals), a mild increase in libido over the first two weeks with a subsequent fall to normal, mild acne, subjective changes to personality including an increase in aggression, irritability and positive mood responses. Consequently, moderate doses of TE combined with weight training can result in short term significant changes in upper body strength and body composition, with corresponding changes to baseline health in some individuals.

Neuromuscular performance of elite rugby union players and relationships with salivary hormones

Crewther, BT, Lowe, T, Weatherby, RP, Gill, N, and Keogh, J. Neuromuscular performance of elite rugby union players and relationships with salivary hormones. J Strength Cond Res 23(7): 2046-2053, 2009-This study compared the neuromuscular performance (speed, power, strength) of elite rugby union players, by position, and examined the relationship between player performance and salivary hormones, by squad and position. Thirty-four professional male rugby players were assessed for running speed (10-m, 20-m or 30-m sprints), concentric mean (MP) and peak power (PP) during a 70-kg squat jump (SJ) and 50-kg bench press throw (BT), and estimated 1 repetition maximum (1RM) strength for a box squat (BS) and bench press (BP). Tests were performed on separate days with absolute and normalized (power and strength only) values computed. Saliva was collected before each test and assayed for testosterone (Sal-T) and cortisol (Sal-C). In absolute terms, the backs demonstrated greater speed and BT MP, whereas the forwards produced greater SJ PP and MP and BS 1RM (p < 0.01). However, BT, SJ and BS performances were no different when normalized for body mass in kg0.67 (p > 0.05). A comparison (absolute and normalized) of BT PP showed no positional differences (p > 0.05), whereas BP 1RM was greater for the forwards (p < 0.05). These results may be attributed to genetic and/or training factors relating to the positional demands of rugby. The Sal-T and/or Sal-C concentrations of players correlated to speed, power, and strength, especially for the backs (p < 0.05), thereby confirming relationships between neuromuscular performance and hormone secretion patterns. Based on these findings, it was suggested that training to increase whole-body and muscle mass might facilitate general performance improvements. Training prescription might also benefit from acute and chronic hormone monitoring to identify those individuals likely to respond more to hormonal change.

The effect of five weeks of Tribulus terrestris supplementation on muscle strength and body composition during preseason training in elite rugby league players.

Tribulus terrestris is an herbal nutritional supplement that is promoted to produce large gains in strength and lean muscle mass in 5–28 days (15, 18). Although some manufacturers claim T. terrestris will not lead to a positive drug test, others have suggested that T. terrestris may increase the urinary testosterone/epitestosterone (T/E) ratio, which may place athletes at risk of a positive drug test. The purpose of the study was to determine the effect of T. terrestris on strength, fat free mass, and the urinary T/E ratio during 5 weeks of preseason training in elite rugby league players. Twenty-two Australian elite male rugby league players (mean ± SD; age = 19.8 ± 2.9 years; weight = 88.0 ± 9.5 kg) were match-paired and randomly assigned in a double-blind manner to either a T. terrestris (n = 11) or placebo (n = 11) group. All subjects performed structured heavy resistance training as part of the clubs preseason preparations. A T. terrestris extract (450 mg·d-1) or placebo capsules were consumed once daily for 5 weeks. Muscular strength, body composition, and the urinary T/E ratio were monitored prior to and after supplementation. After 5 weeks of training, strength and fat free mass increased significantly without any between-group differences. No between-group differences were noted in the urinary T/E ratio. It was concluded that T. terrestris did not produce the large gains in strength or lean muscle mass that many manufacturers claim can be experienced within 5–28 days. Furthermore, T. terrestris did not alter the urinary T/E ratio and would not place an athlete at risk of testing positive based on the World Anti-Doping Agencys urinary T/E ratio limit of 4:1.

The effect of short-term use of testosterone enanthate on muscular strength and power in healthy young men

Use of testosterone enanthate has been shown to significantly increase strength within 6–12 weeks of administration (2, 9), however, it is unclear if the ergogenic benefits are evident in less than 6 weeks. Testosterone enanthate is classified as a prohibited substance by the World Anti- Doping Agency (WADA) and its use may be detected by way of the urinary testosterone/epitestosterone (T/E) ratio (16). The two objectives of this study were to establish (a) if injection of 3.5 mg·kg-1 testosterone enanthate once per week could increase muscular strength and cycle sprint performance in 3–6 weeks; and (b) if the WADA-imposed urinary T/E ratio of 4:1 could identify all subjects being administered 3.5 mg·kg-1 testosterone enanthate. Sixteen healthy young men were match-paired and were assigned randomly in a double-blind manner to either a testosterone enanthate or a placebo group. All subjects performed a structured heavy resistance training program while receiving either testosterone enanthate (3.5 mg·kg-1) or saline injections once weekly for 6 weeks. One repetition maximum (1RM) strength measures and 10-second cycle sprint performance were monitored at the pre (week 0), mid (week 3), and post (week 6) time points. Body mass and the urinary T/E ratio were measured at the pre (week 0) and post (week 6) time points. When compared with baseline (pre), 1RM bench press strength and total work during the cycle sprint increased significantly at week 3 (p < 0.01) and week 6 (p < 0.01) in the testosterone enanthate group, but not in the placebo group. Body mass at week 6 was significantly greater than at baseline in the testosterone enanthate group (p < 0.01), but not in the placebo group. Despite the clear ergogenic effects of testosterone enanthate in as little as 3 weeks, 4 of the 9 subjects in the testosterone enanthate group (−44%) did not test positive to testosterone under current WADA urinary T/E ratio criteria.

A comparison of ratio and allometric scaling methods for normalizing power and strength in elite rugby union players.

Abstract In this study, we compared the effectiveness of ratio and allometric scaling for normalizing power and strength in elite male rugby union players. Rugby union forwards (n = 18) and backs (n = 20) were assessed for squat jump and bench throw peak power, and box squat and bench press one-repetition maximum strength. The performance data for the forwards and backs were compared using ratio (P/BM) and allometric scaling (P/BMb ), where P represents performance, BM is body mass in kilograms, and b is a power exponent. A proposed allometric exponent (0.67) and exponents (±95% confidence intervals) derived for the box squat (0.33 ± 0.31), bench press (0.45 ± 0.30), bench throw (0.46 ± 0.36), and squat jump (0.64 ± 0.31) exercises were used. In general, the absolute expression of power and strength was superior for the heavier forwards, but after ratio scaling these performance measures then favoured the lighter backs. There were no performance differences between the forwards and backs after allometric scaling using either the proposed or the derived exponents. Thus, allometric scaling may provide a more effective method for normalizing power and strength in elite athletes when body size is a confounding variable.

The effect of a high-carbohydrate diet on the skill performance of midfield soccer players after intermittent treadmill exercise

This study examined the effect of a high-carbohydrate diet on the performance of dribbling and shooting skills of recreational soccer players. Six male midfield soccer players first completed 60 minutes of intermittent treadmill exercise, followed either by a mixed or a high-carbohydrate diet for 48 hours. A modified Zelenka Functional Performance Test was then administered, followed by the intermittent treadmill exercise and another skills test. Subjects then repeated the protocol two weeks later under the alternative dietary regime. Blood samples were obtained pre exercise and after each procedure for Hematocrit and concentrations of hemoglobin, plasma glucose and lactate. Heart rate was recorded during and after each procedure. Repeated measures MANOVA revealed (1) the skill performance was not impaired by the intermittent treadmill exercise (p > 0.05); (2) the high-carbohydrate diet did not increase the ability of players to shoot or dribble (p > 0.05); (3) a significant increase in heart rate during the post treadmill exercise skill test compared with that during the pre treadmill exercise test (p < 0.05); (4) a significant order by time effect for hematocrit (p < 0.05); (5) no significant differences in plasma glucose, plasma lactate or hemoglobin concentrations between tests (p > 0.05); and (6) a significant decrease in body mass from pre to post dietary regime within both conditions (p < 0.05). It is speculated that either (1) muscle glycogen depletion may not impair the ability of the player to execute game skills; (2) an alternative fatigue mechanism such as dehydration or increased lactate production may be causative factors in the reduction in skill performance; or (3) the treadmill protocol employed failed to induce a degree of glycogen depletion or fatigue large enough to cause a significant fall in skill performance.

The effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players.

Crewther, BT, Cook, CJ, Lowe, TE, Weatherby, RP, and Gill, N. The effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players. J Strength Cond Res 25(1): 32-39, 2011-This study examined the effects of short-cycle sprints on power, strength, and salivary hormones in elite rugby players. Thirty male rugby players performed an upper-body power and lower-body strength (UPLS) and/or a lower-body power and upper-body strength (LPUS) workout using a crossover design (sprint vs. control). A 40-second upper-body or lower-body cycle sprint was performed before the UPLS and LPUS workouts, respectively, with the control sessions performed without the sprints. Bench throw (BT) power and box squat (BS) 1 repetition maximum (1RM) strength were assessed in the UPLS workout, and squat jump (SJ) power and bench press (BP) 1RM strength were assessed in the LPUS workout. Saliva was collected across each workout and assayed for testosterone (Sal-T) and cortisol (Sal-C). The cycle sprints improved BS (2.6 ± 1.2%) and BP (2.8 ± 1.0%) 1RM but did not affect BT and SJ power. The lower-body cycle sprint produced a favorable environment for the BS by elevating Sal-T concentrations. The upper-body cycle sprint had no hormonal effect, but the workout differences (%) in Sal-T (r = −0.59) and Sal-C (r = 0.42) concentrations correlated to the BP, along with the Sal-T/C ratio (r = −0.49 to −0.66). In conclusion, the cycle sprints improved the BP and BS 1RM strength of elite rugby players but not power output in the current format. The improvements noted may be explained, in part, by the changes in absolute or relative hormone concentrations. These findings have practical implications for prescribing warm-up and training exercises.

Anabolic androgenic steroids effects on the immune system: a review

Androgenic anabolic steroids (AAS) are synthetic derivatives of the male hormone testosterone. AAS are used by athletes and recreational users of all ages to enhance their athletic performance and/or physical appearance. While several adverse effects of AAS abuse have been described, their effect on the immune system has not been clearly elucidated. The literature generally indicates that supraphysiologic doses of AAS with an intact steroid nucleus are immunosuppressive, that is they reduce immune cell number and function. While those with alterations to the steroid nucleus are immunostimulatory as they induce the proliferation of T cells and other immune cells. Specifically, several common AAS have been shown to adversely influence lymphocyte differentiation and proliferation, antibody production, Natural Killer Cytotoxic activity and the production of certain cytokines, thereby altering the immune reaction. These effects may be profound and long lasting depending on the dosing regime, types or combinations of AAS used and the extent and duration of AAS abuse. Nevertheless, the effects of long term use of supraphysiologic doses of AAS on the immune system remain uncertain.

Profiling of urinary testosterone and luteinizing hormone in exercise-stressed male athletes, using gas chromatography-mass spectrometry and enzyme immunoassay techniques

Knowledge of the effects of episodic or short-term exercise-stress on endogenous testosterone and luteinizing hormone levels still remains fragmentary and inconclusive. In this study, an approach based on the absolute concentrations of urinary total testosterone (T), luteinizing hormone (LH) and the T/LH concentration ratios, was used to profile short-term exercise-stress responses in healthy drug-free male athletes. Testosterone and luteinizing hormone concentrations were measured using gas chromatography-mass spectrometry (GC-MS) and microparticle enzyme immunoassay (MEIA) techniques, respectively. Stress profiles derived from exercise-stress at VO2max, 68.1% VO2max and 51.6% VO2max were plotted using the concentrations of T, LH and the ratios of T/LH found under non-stressed and stressed conditions. Significant changes in LH concentrations (p < 0.005) and T/LH ratios (p < 0.005) levels were observed between the pre-stress and post-exercise conditions during acute exercise-stress at VO2max but the T concentration did not show any marked change relative to the non-stressed condition. Whilst exercise-stress appeared to reduce the change in T concentrations between the pre- and post-exercise states compared to that in the non-stressed control condition, the change in LH concentrations showed a moderate increase at submaximal oxygen uptake values. The stress profiles derived from this study facilitated an assessment of the relationship between the endogenous T, LH and T/LH ratio stress-responses over a short period of applied exercise-stress.