Cross-country Race Research Articles

Liberation and Containment: Re-visualising the Eugenic and Evolutionary Ideal of the Fizkul'turnitsa in 1944

In July 1944 cross-country races and parades of physical culturists were prominently used to celebrate Soviet liberation from German occupation. While journalistic accounts stressed the manly health and vigour of the victorious Red Army, press photographs in Pravda and Red Sport, and Aleksandr Deneika's monumental painting ‘Liberation’, emphasised images of the young female physical culturist. This essay explores what a contextualised analysis of these images may have to tell historians about the connections between women, physical culture and liberation being projected. The argument suggests that, on one level, the images straightforwardly symbolised and celebrated the liberation of the Soviet ‘Motherland’. On another, more complex level, the images represented a particularly nuanced notion of constricted liberation for Soviet women deriving from 1920s eugenic and evolutionary discourse, inscribed into the contemporary imperative for engagement with physical culture as a necessary stage of healthful body discipline on the path to hygienic and successful motherhood.

Investigation into a new method for monitoring snow temperature on cross-country ski tracks

Accurate predictions of snow surface temperature on cross-country race courses are crucial for optimal race ski preparation. This study investigates an easy and inexpensive method to monitor snow temperature at strategic locations on a racing track (e.g., southerly aspects, shaded areas and the stadium). Small self-contained temperature sensor dataloggers collect the average subsurface temperature between 1 and 2 cm, often where a skating ski rides. Temperature, temperature changes and trends are monitored the day, or days, prior to competition and examined to aid in ski preparation for upcoming events. Solar absorption of the sensors was the primary challenge and techniques to mitigate this issue were tested and are discussed. Results from a field study are presented, which give insight into the benefits and limitations for the usefulness of iButton temperature data for ski teams.

Psychological Analysis on Students’ Participation in Orienteering

In order to help the development of “Sports in Sunshine”, this paper sets about analyzing the current phenomena of more participation in orienteering and students’ better behavior in sports, then compares the different features between the middle-distance race, cross-country race and orienteering. After applying the cognitive psychology, sports psychology and biopsychology and exploring the factors of the mental drive and the function process, the paper concludes that orienteering is a perfect sport of stamina containing mental superiority. Combining the analysis results in students’ participation in the orienteering, more scientific practice in training could be offered for the PE teaching and “Sports in Sunshine”.

Effects of Prolonged Exercise on Left Ventricular Mechanical Synchrony in Long-Distance Runners: Importance of Previous Exposure to Endurance Races

Prolonged exercise has been shown to lead to elevated levels of cardiac troponin and altered cardiac function on echocardiography. It is not known if cardiac synchrony is altered by prolonged exercise. The aims of this study were to assess changes in intra-left ventricular mechanical synchrony and circulating levels of cardiac troponin following prolonged exercise and to evaluate the importance of prior exposure to endurance racing. Forty-three male participants in a 30-km cross-country race (20 new participants at this event [median, 3 previous endurance races] age matched against 23 repeat participants [median, 31 previous endurance events]) were assessed prospectively 1 to 2 days before and 24 hours after the race using troponin T and Doppler tissue imaging analyzing the standard deviation of time to peak myocardial systolic velocity (T(s)-SD) in a six-basal, six-midventricular segment model measuring myocardial synchrony. The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene was also analyzed, as I allele carriers reportedly have superior endurance performance, while the D allele predisposes to renin-angiotensin system-induced cardiac remodeling. Prerace troponin T was undetectable in all runners, and postrace levels were higher in new runners (median, 0.03 microg/L; interquartile range [IQR], 0.01-0.04 microg/L) than in repeat runners (median, 0.01 microg/L; IQR, 0.01-0.02 microg/L) (P = .03). Although new and repeat runners had similar T(s)-SD at baseline (32 msec [IQR, 22-43 msec] vs 34 msec [IQR, 29-45 msec], P = .13), dyssynchrony increased only in new runners (40 msec [IQR, 31-47 msec], P < .001; in repeat runners, median, 38 msec [IQR, 29-43 msec], P = .30; median relative difference, +13% vs +5%, P = .02). ACE genotype distribution was similar in both groups. Multivariate analysis showed that (1) a lack of prior endurance exposure; (2) more copies of the ACE D allele; and (3) lower peak systolic velocity were independent predictors of postrace dyssynchrony (P < .05 for all). Prolonged exertion increased ventricular mechanical dyssynchrony in new endurance participants and in ACE D allele carriers. The long-term impact of such changes warrants future study.

Physiological Adaptations to Taper in Competitive Distance Runners

Little is known about the physiological response to taper in distance runners. The aim of this study was to examine the effects of a 3-wk taper (progressive reduction in training volume with no change in intensity) on performance and physiology of competitive distance runners. We implemented a 'whole body to gene' approach to study seven collegiate distance runners (20 ± 1 yr, 66 ± 1 kg) before and after taper. The primary measures included 8-km cross country race performance, gastrocnemius single muscle fiber size and function (peak force, shortening velocity, and power), resting and run-induced gene expression 4 hrs after a standardized 8-km indoor track run [pre-30:18 (min:sec), post-30:20], citrate synthase activity, and maximal and submaximal cardiovascular physiology (Vo2, VE, HR, and RER) before and after taper. The taper was successful at enhancing cross country race performance (-3%, P<0.05). MHC IIa fiber diameter (+7%, P<0.05), force (+11%, P=0.06), and absolute power (+9%, P<0.05) were elevated following taper. In addition to the MHC IIa fiber adaptations, taper elicited a distinct post-run gene response. Specifically, the induction of MuRF-1 was attenuated following taper, whereas MRF-4, HSP 72, and MT-2A displayed an exaggerated response to the standardized run (P<0.05). No changes were observed in MHC I size/function, resting gene expression, citrate synthase activity, or cardiovascular function. Our findings show that tapered training in competitive runners promoted MHC IIa fiber remodeling and a differential transcriptional response following the same exercise perturbation, while having no adverse effects on aerobic physiology. These data suggest that myocellular remodeling is a key ingredient for taper induced gains in running performance.

Myocellular basis for tapering in competitive distance runners

The purpose of this study was to examine the effects of a 3-wk taper on the physiology of competitive distance runners. We studied seven collegiate distance runners (20+/-1 yr, 66+/-1 kg) before and after a 3-wk taper. The primary measures included 8-km cross-country race performance, gastrocnemius single muscle fiber size and function (peak force, shortening velocity, and power), baseline and exercise-induced gene expression 4 h after a standardized 8-km run, citrate synthase activity, and maximal and submaximal cardiovascular physiology (oxygen consumption, ventilation, heart rate, and respiratory exchange ratio). Race performance improved by 3% following taper (P<0.05). Myosin heavy chain (MHC) IIa fiber diameter (+7%, P<0.05), peak force (+11%, P=0.06), and absolute power (+9%, P<0.05) increased following taper. In addition to the MHC IIa adaptations, taper elicited a distinct postexercise gene response. Specifically, the induction of MuRF-1 was attenuated following taper, whereas MRF4, HSP 72, and MT-2A displayed an exaggerated response (P<0.05). No changes were observed in MHC I size or function, baseline gene expression, citrate synthase activity, or cardiovascular function. Our findings show that tapered training in competitive runners promoted MHC IIa fiber remodeling and an altered transcriptional response following the same exercise perturbation, with no adverse affects on aerobic fitness. Together, these results provide a myocellular basis for distance runners to taper in preparation for peak performance.

Diagonal Technique of Cross-country Skiing on Different Slopes in a Classical 10 km Race

Purpose: The purpose of this study was to investigate the kinematic difference in the skiing motion of the diagonal technique between different slopes during classical style cross-country 10 km official race. Methods: Data were collected from two official men 10 km cross-country races of classical technique on the same 5 km circuit course. Skiers passing in the uphill sections of the course were videotaped with a VTR camera (60 Hz) positioned at 0.4 km point (3.8 degree slope) in one race, and at 1 km point (12.4 degree slope) in another race. To reconstruct the two dimensional coordinates of the motion of subjects, a two dimensional direct linear transformation technique was used. Seven skiers including national class junior and collegiate skiers of Japan were selected as subjects on each race. Results: The time from the instant of the heel contact on the ski to the instant of the ski detaching the snow on the moderate slope was almost same as that on the steep slope. However, the gliding length after heel contact on the ski on the moderate slope was larger than that on the steep slope. The length of ski gliding resulted in the large skiing speed on the moderate slope.

Predisposing Factors and Consequences of Elevated Biomarker Levels in Long-Distance Runners Aged ≥55 Years

Cardiac biomarkers play an important role in the diagnosis of cardiovascular disease. Elevated levels can be seen in the context of strenuous exercise. We studied this phenomenon in senior endurance runners. We included 185 participants (61.1 +/- 5 years; 29% women) at a 30-km cross-country race who were self-reportedly in excellent health. Before and after the race, the creatinine, N-terminal pro-brain natriuretic peptide (NT-proBNP), and troponin T were analyzed, and participation in the number of previous races and the race duration were recorded. NT-proBNP increased from 53 ng/L (interquartile range 31 to 89) to 121 ng/L (interquartile range 79 to 184) and troponin T from undetectable to 0.01 microg/L (interquartile range 0.01 to 0.04). The independent predictors of a large NT-proBNP increase were (1) greater levels present at baseline, (2) a greater increase in creatinine (both p <0.001), (3) older age (p = 0.01), and (4) a longer race duration (p <0.05). Troponin T elevation was independently predicted by (1) older age (p = 0.01), (2) a greater increase in creatinine, and (3) participation in fewer previous races (both p <0.05). Of the 15 runners with an elevated (>194 ng/L) baseline NT-proBNP level (8.1% of 185), 4 were found to have serious cardiovascular disease (2.2% of whole sample). Of these 4 patients, 1 died from sudden cardiac death within months after the race. In conclusion, biomarker elevation occurs commonly in senior runners. A high baseline NT-proBNP is predictive of a large release during exercise, suggesting that the factors that control the at rest levels also determine its release with exertion. Troponin T elevation was seen in less-experienced participants. A small group of very ill runners were identified by NT-proBNP analysis.

Cardiac fatigue in long-distance runners is associated with ventricular repolarization abnormalities

Prolonged exercise can induce cardiac fatigue, which is characterized by biomarker release and impaired myocardial function. The impact on ventricular electrophysiology is largely unknown. The objective of this study was to examine changes in ventricular repolarization after a 30-km cross-country race in runners aged >or=55 years. Fifteen healthy participants (62 +/- 5 years) were assessed using biomarkers (N-terminal pro-brain natriuretic peptide [NT-proBNP], troponin T [TnT]), tissue Doppler echocardiography, and vectorcardiography at baseline, within 1 hour postrace and on days 1 and 6 postrace. During the race, NT-proBNP increased from 42 ng/L (interquartile range 25-117) to 187 ng/L (113-464), and TnT increased from undetectable levels to 0.03 microg/L (0.015-0.05). Global strain (19.1% +/- 2.2%) decreased on day 1 (17.2% +/- 1.8%) and day 6 (17.9% +/- 1.5%; P <.01). QT(c) increased from 431 +/- 15 ms prerace to 445 +/- 22 ms postrace and 445 +/- 15 ms on day 1 (P <.05), mainly because of an increased T(peak-end) interval (prerace 108 +/- 13 ms, postrace 127 +/- 43 ms, day 1 127 +/- 43 ms; P <.05). Postrace, T(area) (baseline 75 +/- 26 microVs) peaked on day 1 (105 +/- 42 microVs) and remained high on day 6 (89 +/- 37 microVs; P <.05). Runners with higher baseline NT-proBNP developed greater impairment of myocardial velocities (rho = -0.68 to -0.54; P <.05) and a larger increase in T(area) (rho = 0.73; P <.01). Cardiac fatigue induced by prolonged exertion is associated with sustained abnormalities in ventricular repolarization. Runners with higher baseline NT-proBNP are especially liable to such alterations of cardiac function.

Magnitude, Reproducibility, and Association With Baseline Cardiac Function of Cardiac Biomarker Release in Long-Distance Runners Aged ≥55 Years

Cardiac biomarker release after endurance exercise has been described in young athletes. Although older athletes are increasingly active in such sports, they have not previously been studied. Therefore, the aim of this study was to assess the magnitude and reproducibility of biomarker release in athletes aged > or =55 years. Forty-three healthy athletes (mean age 61 +/- 3.6 years) were assessed before and immediately after a 30-km cross-country race and studied with echocardiography at rest. The median N-terminal pro-brain natriuretic peptide (NT-proBNP; normal <194 ng/L) level was 42 ng/L (interquartile range 30 to 95) at baseline and 191 ng/L (interquartile range 114 to 308) after the race. Troponin T (normal <0.03 microg/L) was elevated in 19 subjects (44%) after the race. Twenty-two subjects had also been studied 3 years before at the same race, using an identical test protocol. Between the 2 races, strong correlations were seen for individual runners' postrace biomarker levels (NT-proBNP: r = 0.82, log transformed data; troponin T: Spearman's rho = 0.84; p <0.001 for both). The coefficient of variation for NT-proBNP release was 8.1%. Levels of NT-proBNP after the race were correlated with levels at baseline (r = 0.93, p <0.001) and with left ventricular mass index (r = 0.32, p = 0.03). Moreover, participants with elevated postrace NT-proBNP were significantly older (62.0 vs 59.8 years, p = 0.04). In conclusion, long-distance runners aged > or =55 years released NT-proBNP and troponin T in a reproducible fashion. The magnitude of NT-proBNP release during the race was correlated strongly with NT-proBNP baseline levels and was associated with left ventricular mass and age. These findings may suggest a potential adverse effect of long-distance running on cardiac function in certain participants in this age group.

Osteoporotic fracture in an elite male Kenyan athlete

An elite Kenyan runner presented with a tibial fracture sustained during an international cross-country race. There was no clear history of symptoms suggestive of preceding overload and no radiological features...

IMPACT OF TRAINING INTENSITY DISTRIBUTION ON PERFORMANCE IN ENDURANCE ATHLETES

The purpose of this study was to compare the effect of 2 training programs differing in the relative contribution of training volume, clearly below vs. within the lactate threshold/maximal lactate steady state region on performance in endurance runners. Twelve subelite endurance runners (who are specialists in track events, mostly the 5,000-m race usually held during spring-summer months and who also participate in cross-country races [9–12 km] during fall and winter months) were randomly assigned to a training program emphasizing low-intensity (subthreshold) (Z1) or moderately high-intensity (between thresholds) (Z2) training intensities. At the start of the study, the subjects performed a maximal exercise test to determine ventilatory (VT) and respiratory compensation thresholds (RCT), which allowed training to be controlled based on heart rate during each training session over a 5-month training period. Subjects performed a simulated 10.4-km cross-country race before and after the training period. Training was quantified based on the cumulative time spent in 3 intensity zones: zone 1 (low intensity; VT), zone 2 (moderate intensity; between VT and RCT), and zone 3 (high intensity; RCT). The contribution of total training time spent in zones 1 and 2 was controlled to have relatively more low-intensity training in Z1 (80.5 ± 1.8% and 11.8 ± 2.0%, respectively) than in Z2 (66.8 ± 1.1% and 24.7 ± 1.5%, respectively), whereas the contribution of high-intensity (zone 3) training was similar (8.3 ± 0.7% [Z1] and 8.5 ± 1.0% [Z2]). The magnitude of the improvement in running performance was significantly greater (p = 0.03) in Z1 (−157 ± 13 seconds) than in Z2 (−121.5 ± 7.1 seconds). These results provide experimental evidence supporting the value of a relatively large percentage of low-intensity training over a long period (−5 months), provided that the contribution of high-intensity training remains sufficient.

Field and laboratory correlates of performance in competitive cross-country mountain bikers

We designed a laboratory test with variable fixed intensities to simulate cross-country mountain biking and compared this to more commonly used laboratory tests and mountain bike performance. Eight competitive male mountain bikers participated in a cross-country race and subsequently did six performance tests: an individual outdoor time trial on the same course as the race and five laboratory tests. The laboratory tests were as follows: an incremental cycle test to fatigue to determine peak power output; a 26-min variable fixed-intensity protocol using an electronically braked ergometer followed immediately by a 1-km time trial using the cyclist's own bike on an electronically braked roller ergometer; two 52-min variable fixed-intensity protocols each followed by a 1-km time trial; and a 1-km time trial done on its own. Outdoor competition time and outdoor time trial time correlated significantly (r = 0.79, P < 0.05). Both outdoor tests correlated better with peak power output relative to body mass (both r = −0.83, P < 0.05) than absolute peak power output (outdoor competition: r = −0.65; outdoor time trial: r = −0.66; non-significant). Outdoor performance times did not correlate with the laboratory tests. We conclude that cross-country mountain biking is similar to uphill or hilly road cycling. Further research is required to design sport-specific tests to determine the remaining unexplained variance in performance.

Endurance running and digit ratio (2D:4D): Implications for fetal testosterone effects on running speed and vascular health

There is anatomical and physiological evidence that endurance running (ER), i.e., running one or more kilometers using aerobic metabolism, originated early in the evolution of Homo, and the consequences of early selection for ER may be important in modern Homo. Here we examine ER performance in competitive ER. ER is sex dependent such that men tend to run faster than women, and the influence of sex on ER suggests that it may be modified by testosterone (T). It is shown that a putative proxy for prenatal T, the ratio of the length of the 2nd and 4th digits (2D:4D), is correlated with ER. Thus performance in training for ER was associated with high prenatal T, as measured by low 2D:4D, in both men and women. In cross-country races from 1 to 4 miles, 2D:4D explained about 25% of the variance in both male and female ER. Therefore, speed in ER was dependent on a proxy for prenatal T. 2D:4D correlates with performance in sport and exercises, which test a mix of strength and fitness, but the associations are in general quite weak with 2D:4D accounting for less than 10% of the variance in performance. Our finding that 2D:4D explains about 25% of the variance in ER suggests that prenatal T is important in determining efficiency in aerobic exercise. Early populations of Homo may have been strongly selected for ER and high prenatal T. The implications of this for patterns of predisposition to cardiovascular disease in modern Homo are discussed.

Scrotal injury following restrained impact: A risk of misnavigation

Rally driving is an inherently hazardous motor sport yet the risk of serious injury is minimised through rigorous safety regulations required by its governing body. We describe the management of a deceleration injury resulting in scrotal trauma, sustained despite the use of a competition six point seat harness. Blunt trauma to the scrotum can cause injury ranging from scrotal haematoma to testicular rupture (found in approximately 50% of blunt traumas to the scrotum). Deceleration injury to the external genitalia may result in traumatic dislocation of the testes to an inguinal, pubic or abdominal location. Internal dislocation is usually associated with blunt abdominal trauma and can be overlooked, one study reporting a mean of 19 days delay in diagnosis. Scrotal laceration as seen here usually occurs as a result of traumatic avulsion from entanglement of the skin in machinery or clothing. Whilst the harness used here spared the occupant more severe injuries, it is of concern that this type of injury occurred despite the harness and the three layer suit. The minimum safety standard for harnesses in cross country racing is two shoulder straps and one lap belt, although most drivers prefer a minimum of a four point harness involving straps coming over either shoulder and up from the waist to join in a central quick-release coupling. In this case a six point harness was used: a greater number of points of harness contact should equate with greater restraint. The added crotch strap, fixed at points under the seat, connects to the coupling at a single point . The crotch strap has the advantage of preventing the occupant sliding under the belt ('submarining') and spreads the force of impact more evenly over the body in the event of a crash. For a harness to work it must be done up very tightly, to the point of being uncomfortable. It is possible that in the case described the belt was not as tight as recommended and permitted the occupant to be transported forward after impact into the straps, resulting in the degloving-type injury.

Muscle damage and soreness following a 50-km cross-country ski race

In this study, we examined indirect markers of muscle damage and muscle soreness following a 50-km cross-country ski race completed in 2 h and 57 min to 5 h and 9 min by 11 moderately trained male university students. Maximal strength of the knee extensors, several blood markers of muscle damage and inflammation, and muscle soreness (visual analog scale: 0 = “no pain”, 50 mm = “unbearably painful”) were measured one day before, immediately after, and 24, 48, 72, and 144 h after the race. Changes in the measures over time were analysed using one-way repeated-measures analysis of variance and a Fisher's post-hoc test. Maximal strength of the knee extensors decreased significantly (P<0.05) immediately after the race (mean −27%, s=6), but returned to pre-exercise values within 24 h of the race. All blood markers increased significantly (P<0.05) following the race, peaking either immediately (lactate dehydrogenase: 253.7 IU · l−1, s=13.3; myoglobin: 476.4 ng · ml−1, s=85.5) or 24 h after the race (creatine kinase: 848.0 IU · l−1, s=151.9; glumatic oxaloacetic transaminase: 44.3 IU · l−1, s=4.2; aldolase: 10.0 IU · l−1, s=1.3; C-reactive protein: 0.36 IU · l−1, s=0.08). Muscle soreness developed in the leg, arm, shoulder, back, and abdomen muscles immediately after the race (10–30 mm), but decreased after 24 h (<15 mm), and disappeared 48 h after the race. These results suggest that muscle damage induced by a 50-km cross-country ski race is mild and recovery from the race does not take long.

Postexercise Carbohydrate-Protein-Antioxidant Ingestion Decreases Plasma Creatine Kinase and Muscle Soreness

The authors investigated the effects of postexercise carbohydrate-protein-antioxidant (CHO+P+A) ingestion on plasma creatine kinase (CK), muscle soreness, and subsequent cross-country race performance. Twenty-three runners consumed 10 mL/kg body weight of CHO or CHO+P+A beverage immediately after each training session for 6 d before a cross-country race. After a 21-d washout period, subjects repeated the protocol with the alternate beverage. Postintervention CK (223.21 +/- 160.71 U/L; 307.3 +/- 312.9 U/L) and soreness (medians = 1.0, 2.0) were significantly lower after CHO+P+A intervention than after CHO, despite no differences in baseline measures. There were no overall differences in running performance after CHO and CHO+P+A interventions. There were, however, significant correlations between treatment differences and running mileage, with higher mileage runners having trends toward improved attenuations in CK and race performance after CHO+P+A intervention than lower mileage runners. We conclude that muscle damage incurred during training was attenuated with postexercise CHO+P+A ingestion, which could lead to performance improvements in high-mileage runners.

Impact of Training Intensity Distribution on Performance in Endurance Athletes

The purpose of this study was to compare the effect of 2 training programs differing in the relative contribution of training volume, clearly below vs. within the lactate threshold/maximal lactate steady state region on performance in endurance runners. Twelve subelite endurance runners (who are specialists in track events, mostly the 5,000-m race usually held during spring-summer months and who also participate in cross-country races [9-12 km] during fall and winter months) were randomly assigned to a training program emphasizing low-intensity (subthreshold) (Z1) or moderately high-intensity (between thresholds) (Z2) training intensities. At the start of the study, the subjects performed a maximal exercise test to determine ventilatory (VT) and respiratory compensation thresholds (RCT), which allowed training to be controlled based on heart rate during each training session over a 5-month training period. Subjects performed a simulated 10.4-km cross-country race before and after the training period. Training was quantified based on the cumulative time spent in 3 intensity zones: zone 1 (low intensity; <VT), zone 2 (moderate intensity; between VT and RCT), and zone 3 (high intensity; >RCT). The contribution of total training time spent in zones 1 and 2 was controlled to have relatively more low-intensity training in Z1 (80.5 +/- 1.8% and 11.8 +/- 2.0%, respectively) than in Z2 (66.8 +/- 1.1% and 24.7 +/- 1.5%, respectively), whereas the contribution of high-intensity (zone 3) training was similar (8.3 +/- 0.7% [Z1] and 8.5 +/- 1.0% [Z2]). The magnitude of the improvement in running performance was significantly greater (p = 0.03) in Z1 (-157 +/- 13 seconds) than in Z2 (-121.5 +/- 7.1 seconds). These results provide experimental evidence supporting the value of a relatively large percentage of low-intensity training over a long period ( approximately 5 months), provided that the contribution of high-intensity training remains sufficient.

The Effect of Supplementation with Branched-Chain Amino Acids on Cognitive Function in Active Dogs

A previous study has shown that human athletes given branched-chain amino acids (BCAA) in the form of a drink before and during exercise performed better on complex cognitive tests following exercise (1). The athletes were given a mixture of BCAA (40% valine, 35% leucine, and 25% isoleucine) in a 7% carbohydrate solution. The total amount of BCAA supplied to the subjects was 5.3 g. The athletes were taking part in a 30-km cross-country race and were asked to perform a variety of cognitive tasks and also to give blood samples before and after the race. The blood samples were necessary for measuring plasma free-tryptophan and plasma glucose concentrations. It is suggested that exercise increases the plasma concentration of tryptophan, which competes with BCAA for a common transport mechanism for entry to the brain. This increased concentration ratio would be expected to lead to an increased rate of transport of tryptophan into the brain, increased brain concentration, and hence increased serotonin (5-hydroxytrptamine, 5-HT). Studies with rats have shown that an increase in the concentration of 5-HT in the brain is associated with sleep as well as reduced levels of aggression (2). If BCAA can provide cognitive improvement in active dogs, then there could be numerous potential benefits for the dog and owner. The particular types of dogs that might benefit are: assistance, show, agility, working, and obedience dogs. Potentially, BCAA could be added in appropriate amounts to commercial diets, but more impact could be achieved if BCAA were provided in a snack or treat that the dog could eat just before an extra boost of energy and cognitive performance is required; similar to the way energy bars are used by humans.

Core Body Temperature During Cross Country Racing with the Nike Ice-Vest

When running in a hot and humid environment, running performance may suffer due to increased body temperature. In the 2005 Olympic Games, a few athletes were fitted with Nike ice vests designed to cool their bodies prior to performance. This appeared especially effective among the marathoners who used the vests. However, no performance body temperatures have been reported from any event. PURPOSE: This study determined the effectiveness of using a Nike ice vest on body core temperature (Tc) during athletic performance (4 km Big Wave Invitational in Hawaii and 5 km Great American Cross Country Festival in North Carolina) in warm (26–27°C), humid (RH = 50–75%) conditions. METHODS: Four hours prior to the start of the race, eight Division I NCAA women athletes at the Big Wave Invitational and 10 at the Great American ingested a radiotelemetry temperature sensor. One hour prior to the start, body temperature was recorded and half of the athletes in each race put on a wetted Race Day T (Nike Inc.) and an ice vest. Three more temperature readings were taken: 10 min and 1 min prior to the start and immediately after each athlete finished the race. Immediately before the start of the race, the ice vest and race-day tee were removed. All subjects ran in the same uniform. Tc was recorded 1 hour, 10 min and 1 min prior to the start of the race and immediately after each athlete finished the race. Repeated measures ANO VA was used to the impact of the ice vest on Tc. ANOVA was used to determine differences between groups in changes of body temperature. RESULTS: Ten minutes prior to the start of the race, Tc was elevated by 0.84 ± 0.37 °C in the no vest group compared to 0.29 ± 0.56 for the ice vest group (p<0.01). This difference in Tc persisted at one minute prior to the start of the race. Immediately after the finish the increase in Tc averaged 2.75 ± 0.62 and 2.12 ± 0.62 (p<0.01) with and without the ice vest, respectively. CONCLUSIONS: Wearing a Nike ice vest prior to cross-country performance in warm, humid conditions allowed athletes to finish the competition with a lower Tc than those who did not wear an ice vest.