Validation of a six second cycle test for the determination of peak power output.

The present study examined the agreement between peak power output during a standard Wingate anaerobic test (WAnT) and a six second 'all-out' test on a Wattbike Pro. Nine males (40.7 ± 19.4 yrs, 1.76 ± 0.03 cm, 82.11 ± 8.9 kg) underwent three testing protocols on separate days. The protocols consisted 30 second WAnT (WAnT30), a modified WAnT over 6 seconds (WAnT6) and a 6 second peak power test (PPT6). PPT6 was correlated with WAnT30 (r = 0.9; p < 0.001) with a mean bias of 105 W. PPT6 correlated with WAnT6 (r = 0.95; p < 0.001) with a mean bias of 74 W. WAnT6 correlated with WAnT30 (r = 0.99; p < 0.001) with a mean bias of 31 W. There was no difference in time to peak power between any trial. PPT6 resulted in significantly greater power outputs than in WAnT30 and WAnT6 (p < 0.001). We conclude that PPT6 and WAnT6 are valid measures of peak power output compared with WAnT30. This identifies that PPT6 and WAnT6 as short duration 'all-out' tests that have practical applications for researchers and coaches who wish to assess peak power output without the fatiguing effects associated with a standard WAnT.

Partial heat acclimation of athletes with spinal cord lesion.

Heat acclimation (HA) can improve thermoregulatory stability in able-bodied athletes in part by an enhanced sweat response. Athletes with spinal cord lesion are unable to sweat below the lesion and it is unknown if they can HA. Five paralympic shooting athletes with spinal cord lesion completed seven consecutive days HA in hot conditions (33.4 ± 0.6 °C, 64.8 ± 3.7 %rh). Each HA session consisted of 20 min arm crank exercise at 50 % [Formula: see text] followed by 40 min rest, or simulated shooting. Aural temperature (T (aur)) was recorded throughout. Body mass was assessed before and after each session and a sweat collection swab was fixed to T12 of the spine. Fingertip whole blood was sampled at rest on days 1 and 7 for estimation of the change in plasma volume. Resting T (aur) declined from 36.3 ± 0.2 °C on day 1 to 36.0 ± 0.2 °C by day 6 (P < 0.05). During the HA sessions mean, T (aur) declined from 37.2 ± 0.2 °C on day 1, to 36.7 ± 0.3 °C on day 7 (P < 0.05). Plasma volume increased from day 1 by 1.5 ± 0.6 % on day 7 (P < 0.05). No sweat secretion was detected or changes in body mass observed from any participant. Repeated hyperthermia combined with limited evaporative heat loss was sufficient to increase plasma volume, probably by alterations in fluid regulatory hormones. In conclusion, we found that although no sweat response was observed, athletes with spinal cord lesion could partially HA.

Does chronic exercise attenuate age-related physiological decline in males?

Alteration in body composition, physical function, and substrate metabolism occur with advancing age. These changes can be attenuated by exercise. This study evaluated whether master athletes (MA [n = 20]) would have improved exercise capabilities, anthropometry, and hormone profiles when compared with age-matched sedentary counterparts (S [n = 28]). The MA group was predominantly aerobically trained with some resistance exercise incorporated in their routine. The VO(2max), peak power output, and salivary testosterone was significantly higher (p < 0.05) in the MA group, while diastolic blood pressure, systolic blood pressure, and body fat percentage were lower (p < 0.05). Cortisol, fat free mass, (FFM) and total body mass were not significantly different between groups. Salivary testosterone correlated positively with VO(2max) (r² = .320), suggesting that increased aerobic capacity is linked with higher concentrations of testosterone. These results suggest that life-long exercise is associated with favorable body composition and attenuation of the age related decline in testosterone.

A new VO2max protocol allowing self-pacing in maximal incremental exercise.

INTRODUCTION: The traditional maximal oxygen uptake (VO(2max)) protocol has received criticism for being an unnatural form of exercise, lacking ecological validity and producing different VO(2max) responses depending on protocol duration and work rate increments. PURPOSE: The purpose of this investigation was to design and test a new VO(2max) protocol allowing subjects to self-pace their work rate while maintaining an incremental test structure. METHODS: 16 untrained subjects completed a self-paced VO(2max) protocol (SPV) and a traditional VO(2max) test in a counter-balanced, crossover design. The SPV used incremental 'clamps' of ratings of perceived exertion (RPE) over 5 × 2-min stages (10-min duration) while allowing subjects to vary their power output (PO) according to the required RPE. RESULTS: Subjects achieved significantly higher (p < 0.05) VO(2max) values (40 ± 10 ml/kg/min vs 37 ± 8 ml/kg/min) and peak POs (273 ± 58 W vs 238 ± 55 W) in the SPV. Higher VO(2max) values were observed in the SPV even when a plateau (VO(2)-time slope <0.05 l/min) occurred in the traditional test. No differences were found between any other measured physiological variable (minute ventilation, heart rate and respiratory exchange ratio). CONCLUSIONS: As SPV is a closed-loop test (10-min duration) that allows subjects to self-pace their work rate, it disregards the need for experimenters to estimate starting work rates, stage lengths and increments in order to bring about volitional exhaustion in 8-10 min. The observation that the SPV may also elicit higher VO(2max) values than a traditional test warrants further research in this area and its consideration as standard measure to elicit VO(2max).

Performance enhancing drug abuse and cardiovascular risk in athletes: implications for the clinician.

The use of performance-enhancing and social drugs by athletes raises a number of ethical and health concerns. The World Anti-Doping Agency was constituted to address both of these issues as well as publishing a list of, and testing for, banned substances in athletes. Despite continuing methodological developments to detect drug use and associated punishments for positive dope tests, there are still many athletes who choose to use performance and image enhancing drugs. Of primary concern to this review are the health consequences of drug use by athletes. For such a large topic we must put in place delimitations. Specifically, we will address current knowledge, controversies and emerging evidence in relation to cardiovascular (CV) health of athletes taking drugs. Further, we delimit our discussion to the CV consequences of anabolic steroids and stimulant (including amphetamines and cocaine) use. These drugs are reported in the majority of adverse findings in athlete drug screenings and thus are more likely to be relevant to the healthcare professionals responsible for the well-being of athletes. In detailing CV health issues related to anabolic steroid and stimulant abuse by athletes we critique current research evidence, present exemplar case studies and suggest important avenues for on-going research. Specifically we prompt the need for awareness of clinical staff when assessing the potential CV consequences of drug use in athletes.

The effects of a formal exercise training programme on salivary hormone concentrations and body composition in previously sedentary aging men.

Alteration in body composition, physical function, and substrate metabolism occur with advancing age. These changes may be attenuated by exercise. This study examined whether twenty eight, previously sedentary males (62.5 ± 5.3 years of age; body mass of 89.7 ± 16.4 kg) adhering to the ACSM minimum guidelines for aerobic exercise for six weeks would improve exercise capabilities, body composition and salivary hormone profiles. After six weeks of adhering to the guidelines, salivary testosterone and vo(2max) (absolute and relative) increased (p < 0.05), whilst body fat percentage and body mass decreased (p < 0.05). Peak power output, fat free mass and cortisol values were not significantly different. Interestingly, salivary testosterone correlated inversely with body fat percentage (R(2) = .285, p = 0.011). These results suggest that despite previous inactivity, older males can achieve improvements in cardiorespiratory fitness, body composition and anabolism by adhering to simple lifestyle changes.

Androgens affect myogenesis in vitro and increase local IGF-1 expression.

PURPOSE: The mechanism whereby anabolic androgens are associated with hypertrophy of skeletal muscle is incompletely understood but may involve an interaction with locally generated insulin-like growth factor (IGF) 1. The present investigation utilized a cell culture model of human skeletal muscle-derived cell maturation to test the hypothesis that androgens increase differentiation of human muscle precursor cells in vitro and to assess effects of androgen with or without IGF-1 on IGF-1 messenger RNA (mRNA) expression in human muscle precursor cells. METHODS: Differentiation of muscle-derived cells was induced under standard low-serum conditions. Cultures were then exposed to androgen (testosterone (T)) at 50, 100, and 500 nM or IGF-1 (10-50 ng·mL⁻¹). Immunocytochemistry and real-time polymerase chain reaction (RT-PCR) were used to assess effects of androgens and IGF-1 after 3- (early) or 7-d (late) muscle differentiation, respectively; RT-PCR was used to quantify the effects on androgen receptor expression. RESULTS: Under low-serum conditions, 3-d exposure to androgens or IGF-1 or both resulted in no significant increase in cellular myogenic commitment. After 7-d exposure, however, T and IGF-1 were both found to increase fusion index with no observable synergistic effect. T also increased IGF-1 mRNA generation (P < 0.0001), whereas exogenous IGF-1 (P < 0.001) reduced IGF-1 mRNA transcription relative to control. The T effect was reversible after treatment with flutamide, an androgen receptor antagonist. CONCLUSIONS: Both T and IGF-1 increase myogenic commitment after 7-d exposure to a differentiation medium. With T causing a concomitant increase in IGF-1 mRNA underpinning IGF-1 as a central mediator in the cellular pathways associated with muscle hypertrophy, including those affected by androgens. The novel system described has the potential for elucidating the pattern of growth factor effects associated with androgens in skeletal muscle.

WITHDRAWN:A New VO2maxProtocolAllowing Self-Pacing in Maximal Incremental Exercise.

INTRODUCTION: Ahead of Print article withdrawn by publisher. The traditional VO2max protocol has received criticism for being an unnatural form of exercise, lacking ecological validity and producing different VO2max responses depending on protocol duration and work rate increments. PURPOSE: The purpose of this investigation was to design and test a new VO2max protocol that allowed subjects to regulate and self-pace their work rate, whilst maintaining an incremental structure. METHODS: 16 untrained subjects completed the new Mauger-Sculthorpe test (MSP) and a traditional VO2max test in a counter-balanced, cross-over design. The MSP used incremental 'clamps' of RPE over 5×2 minute stages (10 minute duration), whilst allowing subjects to vary their power output according to the required RPE. RESULTS: Subjects achieved significantly higher (p < 0.05) VO2max values (40 ± 10 mL·kg·min vs. 37 ± 8 mL·kg·min) and peak power outputs (273 ± 58 W vs. 238 ± 55 W) in the MSP. Higher VO2max values were observed in the MSP, even when a plateau (VO2-time slope < 0.05 L·min) occurred in the traditional test. No differences were found between any other measured physiological variable (VE, HR, RER). CONCLUSIONS: As the MSP is a closed-loop test (10 minute duration) that allows subjects to self-pace their work rate, it disregards the need for experimenters to estimate starting work rates, stage lengths and increments in order to bring about volitional exhaustion in 8-10 minutes. The observation that the MSP may also elicit higher VO2max values than a traditional test warrants further research in this area and its considerationas standard measure to elicit VO2max.