Aerobic power and insulin action improve in response to endurance exercise training in healthy 77-87 yr olds.

Previous studies have demonstrated that frail octogenarians have an attenuated capacity for cardiovascular adaptations to endurance exercise training. In the present study, we determined the magnitude of cardiovascular and metabolic adaptations to high-intensity endurance exercise training in healthy, nonfrail elderly subjects. Ten subjects [8 men, 2 women, 80.3 yr (SD2.5)] completed 10-12 mo (108 exercise sessions) of a supervised endurance exercise training program consisting of 2.5 sessions/wk (SD 0.2), 58 min/session (SD 6), at an intensity of 83% (SD 5) of peak heart rate. Primary outcomes were maximal attainable aerobic power [peak aerobic capacity (Vo(2peak))]; serum lipids, oral glucose tolerance, and insulin action during a hyperglycemic clamp; body composition by dual-energy X-ray absorptiometry, and energy expenditure using doubly labeled water and indirect calorimetry. The training program resulted in an increase in Vo(2peak) of 15% (SD 7) [22.9 (SD 3.3) to 26.2 ml.kg(-1).min(-1) (SD 4.0); P < 0.0001]. Favorable lipid changes included reductions in total cholesterol (-8%; P = 0.002) and LDL cholesterol (-10%; P = 0.003), with no significant change in HDL cholesterol or triglycerides. Insulin action improved, as evidenced by a 29% increase in glucose disposal rate relative to insulin concentration during the hyperglycemic clamp. Fat mass decreased by 1.8 kg (SD 1.4) (P = 0.003); lean mass did not change. Total energy expenditure increased by 400 kcal/day because of an increase in physical activity. No change occurred in resting metabolism. In summary, healthy nonfrail octogenarians can adapt to high-intensity endurance exercise training with improvements in aerobic power, insulin action, and serum lipid and lipoprotein risk factors for coronary heart disease; however, the adaptations in aerobic power and insulin action are attenuated compared with middle-aged individuals.     

Endurance training and sprint performance in elite junior cross-country skiers

The purpose of the present study was to investigate the relationship between aerobic characteristics and sprint skiing performance, and the effects of high-intensity endurance training on sprint skiing performance and aerobic characteristics. Ten male and 5 female elite junior cross-country skiers performed an 8-week intervention training period. The intervention group (IG, n = 7) increased the volume of high-intensity endurance training performed in level terrain, whereas the control group (CG, n = 8) continued their baseline training. Before and after the intervention period, the skiers were tested for 1.5-km time-trial performance on roller skis outdoors in the skating technique. Maximal oxygen uptake (VO?max) and oxygen uptake at the ventilatory threshold (VO?VT) were measured during treadmill running. VO?max and VO?VT were closely related to sprint performance (r = ~0.75, both p < 0.008). The IG improved sprint performance, VO?max, and VO?VT from pre to posttesting and improved sprint performance and VO?VT when compared to the CG (all p < 0.01). This study shows a close relationship between aerobic power and sprint performance in cross-country skiing and highlights the positive effects of high-intensity endurance training in level terrain.     

Changes evaluated in soccer-specific power endurance either with or without a 10-week,in-season,intermittent, high-intensity training protocol

The purpose of this study was to evaluate changes in soccer-specific power endurance of 34 female high school soccer players throughout a season either with or without an intermittent, high-intensity exercise protocol. Thirty-four female high school soccer players were tested prior to the 2000 fall season and again 10 weeks later. The tests included an abridged 45-minute shuttle test (LIST), hydrostatic weighing, vertical jump, 20-m running-start sprint, and 30-second Wingate test. The experimental group (EG; n = 17, age 16.5 +/- 0.9 years) completed a 10-week in-season plyometric, resistive training, and high-intensity anaerobic program. The control group (n = 17, age 16.3 +/- 1.4 years) completed only traditional aerobic soccer conditioning. Statistical significance was set at alpha < 0.05. The experimental group showed significant improvements in the LIST (EG = delta 394 seconds +/- 124 seconds), 20-m sprint (EG = Delta-0.10 seconds +/- 0.10 seconds), increase in fat-free mass (EG = delta 1.14 kg +/- 1.22 kg), and decreases in fat mass (EG = Delta-1.40 kg +/- 1.47 kg) comparing pre- to postseason. This study indicates that a strength and plyometric program improved power endurance and speed over aerobic training only. Soccer-specific power endurance training may improve match performance and decrease fatigue in young female soccer players.     

Performance changes following training in junior rugby league players

The purpose of this study was to investigate the time course of adaptations to training in young (i.e., <15 years) and older (i.e., <18 years) junior rugby league players. Fourteen young (14.1 +/- 0.2 years) and 21 older (16.9 +/- 0.3 years) junior rugby league players participated in a 10-week preseason strength, conditioning, and skills program that included 3 sessions each week. Subjects performed measurements of standard anthropometry (i.e., height, body mass, and sum of 7 skinfolds), muscular power (i.e., vertical jump), speed (i.e., 10-m, 20-m, and 40-m sprint), agility (505 test), and estimated maximal aerobic power (i.e., multistage fitness test) before and after training. In addition, players underwent a smaller battery of fitness tests every 3 weeks to assess the time course of adaptation to the prescribed training stimulus. During the triweekly testing sessions, players completed assessments of upper-body (i.e., 60-second push-up, sit-up, and chin-up test) and lower-body (i.e., multiple-effort vertical jump test) muscular endurance. Improvements in maximal aerobic power and muscular endurance were observed in both the young and the older junior players following training. The improvements in speed, muscular power, maximal aerobic power, and upper-body muscular endurance were greatest in the young junior players, while improvements in lower-body muscular endurance were greatest in the older junior players. These findings demonstrate that young (i.e., <15 years) and older (i.e., <18 years) junior rugby league players adapt differently to a given training stimulus and that training programs should be modified to accommodate differences in maturational and training age. In addition, the results of this study provide conditioning coaches with realistic performance improvements following a 10-week preseason strength and conditioning program in junior rugby league players.     

The Positive Effects of Priming Exercise on Oxygen Uptake Kinetics and High-Intensity Exercise Performance Are Not Magnified by a Fast-Start Pacing Strategy in Trained Cyclists

The purpose of this study was to determine both the independent and additive effects of prior heavy-intensity exercise and pacing strategies on the VO2 kinetics and performance during high-intensity exercise. Fourteen endurance cyclists (VO₂max  = 62.8±8.5 mL.kg⁻¹.min⁻¹) volunteered to participate in the present study with the following protocols: 1) incremental test to determine lactate threshold and VO₂max; 2) four maximal constant-load tests to estimate critical power; 3) six bouts of exercise, using a fast-start (FS), even-start (ES) or slow-start (SS) pacing strategy, with and without a preceding heavy-intensity exercise session (i.e., 90% critical power). In all conditions, the subjects completed an all-out sprint during the final 60 s of the test as a measure of the performance. For the control condition, the mean response time was significantly shorter (p<0.001) for FS (27±4 s) than for ES (32±5 s) and SS (32±6 s). After the prior exercise, the mean response time was not significantly different among the paced conditions (FS = 24±5 s; ES = 25±5 s; SS = 26±5 s). The end-sprint performance (i.e., mean power output) was only improved (∼3.2%, p<0.01) by prior exercise. Thus, in trained endurance cyclists, an FS pacing strategy does not magnify the positive effects of priming exercise on the overall VO2 kinetics and short-term high-intensity performance.     

Effect of nutritionally enriched coffee consumption on aerobic and anaerobic exercise performance

The purpose of this study was to compare nutritionally enriched JavaFit coffee (JF) to commercially available decaffeinated coffee (P) with regard to impact on endurance and anaerobic power performance in a physically active, college-aged population. Ten subjects (8 men, 2 women) performed two 30-second Wingate anaerobic power tests and 2 cycle ergometer tests (75% VO2 max) to exhaustion. Mean VO2 was measured during each endurance exercise protocol. Excess postexercise oxygen consumption (EPOC) and respiratory exchange ratio (RER) were recorded for 30 minutes following all exercise sessions. Area under the curve analysis was used to compare EPOC between JF and P for all exercise sessions. No differences were seen between JF and P in any of the power performance measures. However, time to exhaustion was significantly (p = 0.05) higher in JF (35.3 +/- 15.2 minutes) compared with P (27.3 +/- 10.7 minutes). No difference between JF and P were seen in EPOC in either the aerobic or anaerobic exercise sessions. A significant (p < 0.05) difference in average 30-minute postanaerobic power exercise RER was seen between JF (0.87 +/- 0.04) and P (0.83 +/- 0.03), but not following endurance exercise. A nutritionally-enriched coffee beverage appears to enhance time to exhaustion during aerobic exercise, but does not provide an ergogenic benefit during anaerobic exercise.     

The current state of personal training: managers' perspectives

Fitness managers play an integral role in the day-to-day operation of the facilities in which they work. One of the most critical responsibilities is that of hiring, training, and supervising personal trainers. Research studies have identified a number of qualities and competencies that an effective exercise leader is required to have, but there is little scholarly work addressing managers' attitudes surrounding the performance of personal trainers. Using focus group methodology, managers of personal trainers were recruited to provide viewpoints related to desirable qualities of personal trainers and opinions regarding certification and academic preparation. Responses of the participants were transcribed, coded, and analyzed for themes. Two global themes, Selection Rationale and Negative Characteristics, emerged. Selection Rationale consisted of qualities that influence a manager's decision to hire a particular trainer (e.g., physique, education, social skills). Negative characteristics referred to qualities considered unethical or unprofessional (e.g., sexual comments, misuse of power) and the consequences of those behaviors (e.g., loss of clients, potential for litigation). The results suggest that undergraduate exercise science programs devote additional time toward the development of the affective qualities of future fitness trainers. Managers also recommended licensure for employees.     

Hybrid lecture-online format increases student grades in an undergraduate exercise physiology course at a large urban university

Hybrid courses allow students additional exposure to course content that is not possible in a traditional classroom environment. This exposure may lead to an improvement in academic performance. In this report, I describe the transition of a large undergraduate exercise physiology course from a traditional lecture format to a hybrid lecture-online format. A total of 658 final grades (traditional = 346, hybrid = 312) was used to evaluate the effect of course format on academic performance. The hybrid online portion was delivered using WebCT Vista, enhanced with various instructional technologies. The hybrid lecture portion was enhanced with an in-class response system. PowerPoint files were used to distribute in-class lectures in both formats of the course. Final student grades were 9.9% higher (83% of the increase due to an increase in the exam grade) when the course was administered in a hybrid format (P = 0.01), which translated to a one letter grade increase on a standard grading scale. Transition from a traditional lecture format to a hybrid format significantly enhanced student learning; presumably, this increase is due to the fact that students were able to increase their exposure to course content via access to material on WebCT.     

Test battery designed to quickly and safely assess diverse indices of neuromuscular function after unweighting

Adequately describing the functional consequences of unweighting (e.g., bed rest, immobilization, spaceflight) requires assessing diverse indices of neuromuscular function (i.e., strength, power, endurance, central activation, force steadiness). Additionally, because unweighting increases the susceptibility of muscle to damage, testing should consider supplementary safety features. The purpose of this study was to develop a test battery for quickly assessing diverse indices of neuromuscular function. Commercially available exercise equipment was modified to include data acquisition hardware (e.g., force plates, position transducers) and auxiliary safety hardware (e.g., magnetic brakes). Ten healthy, ambulatory subjects (31 ± 5 years, 173 ± 11 cm, 73 ± 14 kg) completed a battery of lower- and upper-body neuromuscular function tests on 3 occasions separated by at least 48 hours. The battery consisted of the following tests, in order: (1) knee extension central activation, (2) knee extension force steadiness, (3) leg press maximal strength, (4) leg press maximal power, (5) leg press power endurance, (6) bench press maximal strength, (7) bench press force steadiness, (8) bench press maximal power, and (9) bench press power endurance. Central activation, strength, rate of force development, maximal power, and power endurance (total work) demonstrated good-to-excellent measurement reliability (SEM = 3-14%; intraclass correlation coefficient [ICC] = 0.87-0.99). The SEM of the force steadiness variables was 20-35% (ICC = 0.20-0.60). After familiarization, the test battery required 49 ± 6 minutes to complete. In conclusion, we successfully developed a test battery that could be used to quickly and reliably assess diverse indices of neuromuscular function. Because the test battery involves minimal eccentric muscle actions and impact forces, the potential for muscle injury has likely been reduced.     

Impact of problem-based learning in a large classroom setting: student perception and problem-solving skills

Problem-based learning (PBL) can be described as a learning environment where the problem drives the learning. This technique usually involves learning in small groups, which are supervised by tutors. It is becoming evident that PBL in a small-group setting has a robust positive effect on student learning and skills, including better problem-solving skills and an increase in overall motivation. However, very little research has been done on the educational benefits of PBL in a large classroom setting. Here, we describe a PBL approach (using tutorless groups) that was introduced as a supplement to standard didactic lectures in University of British Columbia Okanagan undergraduate biochemistry classes consisting of 45-85 students. PBL was chosen as an effective method to assist students in learning biochemical and physiological processes. By monitoring student attendance and using informal and formal surveys, we demonstrated that PBL has a significant positive impact on student motivation to attend and participate in the course work. Student responses indicated that PBL is superior to traditional lecture format with regard to the understanding of course content and retention of information. We also demonstrated that student problem-solving skills are significantly improved, but additional controlled studies are needed to determine how much PBL exercises contribute to this improvement. These preliminary data indicated several positive outcomes of using PBL in a large classroom setting, although further studies aimed at assessing student learning are needed to further justify implementation of this technique in courses delivered to large undergraduate classes.     

Sun-dried raisins are a cost-effective alternative to Sports Jelly Beans in prolonged cycling

The purpose of this study was to examine the effects of a natural carbohydrate (CHO) source in the form of sun-dried raisins (SDRs) vs. Sports Jelly Beans? (SJBs) on endurance performance in trained cyclists and triathletes. Ten healthy men (18-33 years) completed 1 water-only acclimatization exercise trial and 2 randomized exercise trials administered in a crossover fashion. Each trial consisted of a 120-minute constant-intensity glycogen depletion period followed by a 10-km time trial (TT). During each experimental trial, participants consumed isocaloric amounts of SDRs or SJBs in 20-minute intervals. Measurements included time to complete 10-km TT, power output during 10-km TT, blood glucose levels and respiratory exchange ratio during glycogen depletion period, rate of perceived exertion (RPE), 'flow' questionnaire responses, and a hedonic (i.e., pleasantness) sensory acceptance test. There were no significant differences in endurance performance for TT time (SDRs vs. SJBs, 17.3 ± 0.4 vs. 17.3 ± 0.4 seconds) or power (229.3 ± 13.0 vs. 232.0 ± 13.6 W), resting blood glucose levels (5.8 ± 04 mmol·L(-1) for SDRs and 5.4 ± 0.2 mmol·L(-1) for SJBs), RPE, or flow experiences between SDR and SJB trials. However, the mean sensory acceptance scores were significantly higher for the SDRs compared to the SJBs (50.7 ± 1.7 vs. 44.3 ± 2.7). Consuming SDRs or SJBs during 120 minutes of intense cycling results in similar subsequent TT performances and are equally effective in maintaining blood glucose levels during exercise. Therefore, SDRs are a natural, pleasant, cost-effective CHO alternative to commercial SJBs that can be used during moderate- to high-intensity endurance exercise.     

Please pass the cauliflower: a recipe for introducing undergraduate students to brain structure and function

Neurophysiology/pathophysiology content is a frequent source of anxiety for undergraduate students and their instructors. This learning module supplements traditional lecture and overhead presentations to offer a novel, nonthreatening, and entertaining introduction to neuropathology. The module is based on a ridiculous analogy between the human brain and the cauliflower. This module has been used with both underclassmen and more advanced health science undergraduate students and has produced enthusiastic student responses while deescalating both student and instructor anxiety.     

Characteristics influencing changes in aerobic performance of children aged 7-9

Interpretation of the actual level of aerobic endurance in a growing child is difficult. Endurance capacity per se is influenced by a number of factors, e.g. by genetic endowment, developmental rate, body composition and habitual physical activity. The respective effects of these factors cannot be distinctly separated from one another, so their particular role is not clearly definable in the various age periods. The aim of our investigation was to define the actual level of aerobic endurance performance in children aged 7-9, and to analyse the relevant factors that may affect this kind of performance according to the different level of sport activities. Two primary school classes (N=42) were selected for the experiment. Both groups had physical education classes every day (five times a week). One group (AG, N=31) consisted of children taking part in regular sport courses at least twice a week (e.g. basket ball, karate, triathlon swimming and gymnastics), as well, the other group (NAG, N=11) served as comparison group. Aerobic performance was estimated by measuring cardiorespiratory response during a Jaeger treadmill run using a "vita maxima" (all-out) testing protocol. The subjects were measured in the Laboratory for Spiroergometry of the Hungarian University of Physical Education twice, in 1997 and 1998. Body composition was assessed by the Drinkwater-Ross [4] body mass fractionation technique. Robustness of the body was described by using the plastic index (PLX) of Conrad's growth type [2], morphological age (MORF AGE) was estimated by using the method of Mészáros and Mohácsi [5]. Exercise performance was studied in the laboratory by using a Jaeger 6000 LE model treadmill and a Jaeger mu-DATASPIR model gas analyser. The functional status of the subjects' cardiopulmonary system was estimated by spiroergometric parameters and total mechanical work (WORK). The AG group had a better endurance performance in 1998 than that of non-athletic group. A factor analytic study (principal component method) of the employed variables revealed that the higher level of endurance fitness in the athletic group was not only affected by growth in size, but also by an increased level of cardiorespiratory performance capacity.     

运动训练和停训对鲈鲤幼鱼游泳能力的影响

为探讨运动训练和停训对鲈鲤Percocypris pingi幼鱼运动能力的影响,将480尾(体质量为2.18g±0.12g,体长为5.33cm±0.09cm)鲈鲤幼鱼随机分为4组(每组120尾):对照组(C)、无氧训练组(An)、4BL·s^-1组(BL为体长)(H)和2BL·s^-1组(L)(H组和L组每天均训练8h),在15℃±2℃条件下持续训练30d后停训。分别在训练前(T0)、训练30d后(T30)、停训20d后(DT20)和停训50d后(DT50)测定鲈鲤幼鱼的临界游泳速度(Ucrit)和1.5Ucrit条件下的耐受时间。结果显示:(1)持续运动训练显著提高了鲈鲤幼鱼的有氧和无氧运动能力,而力竭运动训练只提高了鲈鲤幼鱼的无氧运动能力;(2)停训20d后,L组的Ucrit显著高于An组和C组,An组、H组和C组间的差异无统计学意义,而An组和H组的耐受时间仍显著高于对照组,L组和C组间的差异无统计学意义;(3)停训50d后,实验组和C组间Ucrit和耐受时间的差异均无统计学意义。因此,运动训练显著提高了鲈鲤幼鱼的有氧和无氧运动能力,但不同训练方式的提升效果及其维持时间不同。     

A theoretical analysis of the effect of altitude on running performance

A theoretical analysis of the effect of altitude on running performance is presented using a mathematical model we have recently described and validated (J. Appl. Physiol. 67: 453-465, 1989). This model relates the average power output available over a given running time for a given combination of anaerobic capacity, maximal aerobic power, and endurance capability. For short sprinting distances, the contribution of aerobic metabolism to the energy requirement is small and the speed sustained is high. The reduction of maximal aerobic power with altitude is, thus, negligible, whereas the reduction of aerodynamic resistance is beneficial. Accordingly the performance steadily increases with altitude (e.g., average speed for 100 m at Mexico City is 101.9% of the average speed at sea level). On the other hand, the reduction in maximal aerobic power with altitude is associated with a reduction in performance over middle and long distances (800 m to marathon). For 400 m an improvement in performance is observed up to an altitude of approximately 2,400-2,500 m (average speed approximately 101.4% of sea level speed). Beyond this altitude the reduction in air density cannot compensate for the reduction in maximal aerobic power, and the performance deteriorates. Tables of performances equivalent to the current world records for selected altitudes ranging from 0 to 4,000 m are proposed.     

Influence of training status on maximal accumulated oxygen deficit during all-out cycle exercise

The influence of training status on the maximal accumulated oxygen deficit (MAOD) was used to assess the validity of the MAOD method during supramaximal all-out cycle exercise. Sprint trained (ST; n = 6), endurance trained (ET; n = 8), and active untrained controls (UT; n = 8) completed a 90 s all-out variable resistance test on a modified Monark cycle ergometer. Pretests included the determination of peak oxygen uptake ( O_2peak) and a series (5–8) of 5-min discontinuous rides at submaximal exercise intensities. The regression of steady-state oxygen uptake on power output to establish individual efficiency relationships was extrapolated to determine the theoretical oxygen cost of the supramaximal power output achieved in the 90 s all-out test. Total work output in 90 s was significantly greater in the trained groups (P<0.05), although no differences existed between ET and ST. Anaerobic capacity, as assessed by MAOD, was larger in ST compared to ET and UT. While the relative contributions of the aerobic and anaerobic energy systems were not significantly different among the groups, ET were able to achieve significantly more aerobic work than the other two groups, while ST were able to achieve significantly more anaerobic work. Peak power and peak pedalling rate were significantly higher in ST. The results suggested that MAOD determined during all-out exercise was sensitive to training status and provided a useful assessment of anaerobic capacity. In our study sprint training, compared with endurance training, appeared to enhance significantly power output and high intensity performance over brief periods (up to 60 s), yet few overall differences in performance (i.e. total work) existed during 90 s of all-out exercise.     

High-intensity interval training vs. repeated-sprint training in tennis

The aim of this study was to compare the effects of high-intensity interval training (HIIT) and repeated-sprint training (RST) on aerobic fitness, tennis-specific endurance, linear and repeated-sprint ability (RSA), and jumping ability. Thirty-one competitive male tennis players took part in a training intervention of 6 weeks. The players were matched into 3 groups, HIIT (n = 11), RST (n = 12), or control group (CON, n = 9). The results showed significant time × intervention interactions for VO(2)peak, with a significant increase in the VO(2)peak level of 6.0% in HIIT (p = 0.008) and 4.9% in RST (p = 0.010), whereas no changes occurred in CON. However, the following differences were found between the intervention groups: The HIIT-induced greater improvements in tennis-specific endurance (HIIT 28.9% vs. RST 14.5%; p < 0.05) and RST led to a significant improvement in RSA (i.e., reduction in the mean sprint time of 3.8%; p < 0.05). Neither training strategy induced any effects on jumping and sprinting abilities. Both training interventions showed similar improvements in general aerobic fitness. Also, the present results suggest that RST represents a time-efficient stimulus for a simultaneous improvement of general and tennis-specific aerobic fitness as well for RSA.     

Intensity-dependent tolerance to exercise after attaining V(O2) max in humans.

The tolerable duration of high-intensity, constant-load cycle ergometry is a hyperbolic function of power, with an asymptote termed critical power (CP) and a curvature constant (W') with units of work. It has been suggested that continued exercise after exhaustion may only be performed below CP, where predominantly aerobic energy transfer can occur and W' can be partially replenished. To test this hypothesis, six volunteers each performed cycle-ergometer exercise with breath-by-breath determination of ventilatory and pulmonary gas exchange variables. Initially, four exercise tests to exhaustion were made: 1). a ramp-incremental and 2). three high-intensity constant-load bouts at different work rates, to estimate lactate (theta(L)) and CP thresholds, W', and maximum oxygen uptake (Vo2 max). Subsequently, subjects cycled to the limit of tolerance (for approximately 360 s) on three occasions, each followed by a work rate reduction to 1). 110% CP, 2). 90% CP, and 3). 80% theta(L) for a 20-min target. W' averaged 20.9 +/- 2.35 kJ or 246 +/- 30 J/kg. After initial fatigue, 110% CP was tolerated for only 30 +/- 12 s. Each subject completed 20 min at 80% theta(L), but only two sustained 20 min at 90% CP; the remaining four subjects fatigued at 577 +/- 306 s, with oxygen consumption at 89 +/- 8% Vo2 max. The results support the suggestion that replenishing W' after fatigue necessitates a sub-CP work rate. The variation in subjects' responses during 90% CP was unexpected but consistent with mechanisms such as reduced CP consequent to prior high-intensity exercise, variation in lactate handling, and/or regional depletion of energy substrates, e.g., muscle glycogen.     

An outreach activity to enhance biochemistry pedagogy

Students are self-motivated to learn when provided opportunities that connect theory and real-world applications. Here, we describe for biochemistry majors a newborn screening–focused outreach activity that seeks to develop students’ mastery of disciplinary content and soft skills (e.g., critical thinking, teamwork, effective communication, community engagement) and to enhance student engagement.     

Frequency of the C34T mutation of the AMPD1 gene in world-class endurance athletes: does this mutation impair performance?

The C34T mutation in the gene encoding for the skeletal muscle-specific isoform of AMP deaminase (AMPD1) is a common mutation among Caucasians (i.e., one of five individuals) that can impair exercise capacity. The purpose of this study was twofold. First, we determined the frequency distribution of the C34T mutation in a group of top-level Caucasian (Spanish) male endurance athletes (cyclists and runners, n = 104). This group was compared with randomly selected Caucasian (Spanish) healthy (asymptomatic) nonathletes (n = 100). The second aim of this study was to compare common laboratory indexes of endurance performance (maximal oxygen uptake or ventilatory thresholds) within the group of athletes depending on their C34T AMPD1 genotype. The frequency of the mutant T allele was lower (P < 0.05) in the group of athletes (4.3%) compared with controls (8.5%). On the other hand, indexes of endurance performance did not differ (P > 0.05) between athlete carriers or noncarriers of the C34T mutation (e.g., maximal oxygen uptake 72.3 +/- 4.6 vs. 73.5 +/- 5.9 ml.kg(-1).min(-1), respectively). In conclusion, although the frequency distribution of the mutant T allele of the AMPD1 genotype is lower in Caucasian elite endurance athletes than in controls, the C34T mutation does not significantly impair endurance performance once the elite-level status has been reached in sports.