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Terbutaline is a prohibited drug except for athletes with a therapeutic use exemption certificate; terbutaline's effects on endurance performance are relatively unknown. Purpose: To investigate the effects of 2 therapeutic (2 and 4 mg) inhaled doses of terbutaline on 3-km running time-trial performance. Methods: A total of 8 men (age 24.3 [2.4] y; weight 77.6 [8] kg; and height 179.5 [4.3] cm) and 8 women (age 22.4 [3] y; weight 58.6 [6] kg; and height 163 [9.2] cm) free from respiratory disease and illness provided written informed consent. Participants completed 3-km running time trials on a nonmotorized treadmill on 3 separate occasions following placebo and 2- and 4-mg inhaled terbutaline in a single-blind, repeated-measures design. Urine samples (15 min postexercise) were analyzed for terbutaline concentration. Data were analyzed using 1-way repeated-measures analysis of variance, and significance was set at P < .05 for all analyses. Results: No differences were observed for completion times (1103 [201] s, 1106 [195] s, 1098 [165] s; P = .913) for the placebo or 2- and 4-mg inhaled trials, respectively. Lactate values were higher (P = .02) after 4 mg terbutaline (10.7 [2.3] mmol⋅L-1) vs placebo (8.9 [1.8] mmol⋅L-1). Values of forced expiratory volume in the first second of expiration (FEV1) were greater after inhalation of 2 mg (5.08 [0.2]; P = .01) and 4 mg terbutaline (5.07 [0.2]; P = .02) compared with placebo (4.83 [0.5] L) postinhalalion. Urinary terbutaline concentrations were mean 306 (288) ng⋅mL-1 and 435 (410) ng⋅mL-1 (P = .2) and peak 956 ng⋅mL-1 and 1244 ng⋅mL-1 after 2 and 4 mg inhaled terbutaline, respectively. No differences were observed between the male and female participants. Conclusions: Therapeutic dosing of terbutaline does not lead to an improvement in 3-km running performance despite significantly increased FEV1. The findings suggest that athletes using inhaled terbutaline at high therapeutic doses to treat asthma will not gain an ergogenic advantage during 3-km running performance. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses the clinical significance of functional changes and cardiac changes in the left ventricular function after prolonged exercise. It relates that there is a need to understand the clinical issues of the changes that occurred and resolving issues such as whether extended exercise can produce cardiac stress and the need to educate people responsible for the medical care of athletes about the occurrence of the disease. In addition, it states that further studies are needed to support the notion that upper limit of exercise can cause cardiac problems.

The article presents a study which summarizes the findings of studies being conducted in relation to the topic of whether prolonged exercise can lead to transient depression in left ventricular (LV) functions. It presents several research studies which utilized various techniques as evidences including echocardiographic technology, tissue Doppler imaging (TDI) and assessment on myocardial strain rate. In conclusion, it notes the growing evidence which indicates that extended exercise may cause reduction in both systolic and diastolic LV functions.

The article presents a study which examines the impact of low-intensity and a mixture of low and high-intensity training on physiological and performance responses in rowing training. The subjects of the study were eighteen experienced rowers that undertook a 12-week program of lactate threshold (LT) training (LOW) in which the responses were assessed by a progressive exercise test to exhaustion. Results indicate that LOW training programs improved performance and attenuated the blood lactate response to a given exercise intensity.

The article presents a study which compares the oxygen uptake response between Olympic champion rowers and club standard rowers. The subject of the study were eight Olympic champion (ELITE) rowers and eight club standard (CLUB) oarsmen. Here, the participants completed a progressive exercise test to exhaustion which were repeated 6 minutes moderate and heavy square-wave transitions with a maximum of 2000-meter ergometer time trial. Results revealed that there were no differences noted relative to the work rate performed by both parties although ELITE rowers have a shorter time constant response to oxygen uptake compared to CLUB oarsmen.

Multiday ultra-endurance races present athletes with a significant number of physiological and psychological challenges. We examined emotions, the perceived functionality (optimal-dysfunctional) of emotions, strategies to regulate emotions, sleep quality, and energy intakeexpenditure in a four-man team participating in the Race Across AMerica (RAAM); a 4856km continuous cycle race. Cyclists reported experiencing an optimal emotional state for less than 50% of total competition, with emotional states differing significantly between each cyclist over time. Coupled with this emotional disturbance, each cyclist experienced progressively worsening sleep deprivation and daily negative energy balances throughout the RAAM. Cyclists managed less than one hour of continuous sleep per sleep episode, high sleep latency and high percentage moving time. Of note, actual sleep and sleep efficiency were better maintained during longer rest periods, highlighting the importance of a race strategy that seeks to optimise the balance between average cycling velocity and sleep time. Our data suggests that future RAAM cyclists and crew should: 1) identify beliefs on the perceived functionality of emotions in relation to best (functional-optimal) and worst (dysfunctional) performance as the starting point to intervention work; 2) create a plan for support sufficient sleep and recovery; 3) create nutritional strategies that maintain energy intake and thus reduce energy deficits; and 4) prepare for the deleterious effects of sleep deprivation so that they are able to appropriately respond to unexpected stressors and foster functional working interpersonal relationships. [ABSTRACT FROM AUTHOR]

Regular physical exercise is recommended for the primary prevention of cardiovascular disease. Although the high prevalence of physical inactivity remains a formidable public health issue, participation in exercise programs and recreational sporting events, such as marathons and triathlons, is on the rise. Although regular exercise training reduces cardiovascular disease risk, recent studies have documented elevations in cardiac troponin (cTn) consistent with cardiac damage after bouts of exercise in apparently healthy individuals. At present, the prevalence, mechanism(s), and clinical significance of exercise-induced cTn release remains incompletely understood. This paper will review the biochemistry, prevalence, potential mechanisms, and management of patients with exercise-induced cTn elevations. [Copyright &y& Elsevier]

The article presents sports medicine research that describes the impact of repetitive prolonged sixty-minute exercise bouts on heart biochemical markers and left ventricle function in athletes. Participants were assessed before, immediately after, an hour after, and 20 hours after a 15.3-mile hill run on three consecutive days. Biochemical markers include cardiac troponin T, ejection fraction, systolic blood pressure/end systolic volume ratio, and diastolic filling ratio. Results suggest physiological alterations have minimal functional or clinical impact.