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Biomedical subjects

Kenneth W Rundell

Publications and source records attributed to Kenneth W Rundell.

27 records · Page 2Linked to original sources
PubMed2003

Bronchoconstriction during cross-country skiing: is there really a refractory period?

PURPOSE: The asthmatic airway responds to exercise by bronchodilation (BD) during and bronchoconstriction (BC) after exercise. A refractory period induced by an initial exercise challenge that provides protection against BC during a subsequent exercise bout has also been observed. However, no studies examining during-exercise response or refractoriness during long-duration field exercise by elite athletes have been performed. This study examined airway response and refractoriness during approximately 42-min cross-country ski time trial preceded by a 6- to 9-min 2.5-km high-intensity warm-up ski. METHODS: Eighteen elite athletes cross-country skied seven successive 2.5-km loops. Spirometry was performed pre- and at 5, 10, and 15 min post loop 1; loops 2-7 were treated as a race (XCR) with maneuvers performed within 20 s after loops 2-6 and serially for 15 min after lap 7. RESULTS: Nine of 18 subjects demonstrated a >or=10% fall from baseline in FEV(1) (EIB+): five after lap 1 and four during or after laps 2-7. FEV(1) for EIB+ athletes during XCR was not different from post lap 1 FEV. Only one EIB+ subject demonstrated significant refractoriness. Four EIB+ athletes had a less than 10% fall in FEV after the initial 2.5-km exercise challenge but developed EIB (>or=10% fall) during the subsequent 6 x 2.5 km XCR exercise challenge. FEF(25-75) falls mirrored FEV(1), but demonstrated greater BD during XCR. CONCLUSION: Bronchoconstriction occurs in athletes during prolonged exercise and may thus influence performance. Variability in bronchial hyperresponsiveness onset and the lack of significant refractoriness in our study cohort of athletes is consistent with an exercise bronchoconstrictive dysfunction that is different than frank asthma and is yet to be clearly defined.

Adolescent↗
PubMed2003

Effect of muscle oxygenation during resistance exercise on anabolic hormone response.

PURPOSE: The mechanisms that underlie the affect of acute program variables on muscle growth and strength development for strength/power athletes have been of great interest. This investigation examined the affects of two different resistance exercise protocols on muscle oxygenation, and the anabolic hormonal response to such exercise. METHODS: Eleven experienced resistance-trained male athletes performed four sets of the squat exercise using either a low-intensity, high-volume (LI; 15 repetitions at 60% one-repetition maximum [1-RM]) or high-intensity, low-volume (HI; 4 repetitions at 90% 1-RM) load. Venous blood samples were obtained before (Pre), immediate (IP), 20- (20P), and 40-min (40P) postexercise. Continuous-wave near-infrared spectroscopy was used to measure oxygen desaturation during exercise. RESULTS: No differences in muscle deoxygenation were seen between LI and HI. However, time-dependent postexercise reoxygenation was significantly different between the two exercise sessions (35.3 +/- 17.4 s vs 24.5 +/- 14.3 s in LI and HI, respectively). Testosterone and growth hormone (GH) concentrations were significantly elevated from Pre at IP, 20P, and 40P in both LI and HI. GH concentrations were higher (P<0.05) for LI than at HI at 20P and 40P. CONCLUSION: Muscle oxygen recovery kinetics appeared to be influenced by differences in the intensity and volume of exercise, and delayed reoxygenation appears to affect the GH response to exercise.

Adult↗
PubMed2003

Inspiratory stridor in elite athletes.

STUDY OBJECTIVES: Diagnosis and medical intervention for exercise-induced bronchospasm (EIB) are often based on self-reported symptoms, without spirometric confirmation. Inspiratory stridor (IS), a symptom of vocal cord dysfunction (VCD), is frequently mistaken for EIB wheeze. Athletes with exercise IS that spontaneously resolves on activity cessation are suspect for VCD and may not have EIB. This study estimated IS prevalence in elite athletes and determined its relationship to EIB. SUBJECTS/METHODS: Three hundred seventy athletes (174 female and 196 male subjects) provided a medical history, and underwent spirometry before and after exercise challenge. Exercise challenges were conducted in cold, dry ambient conditions. EIB positive (EIB +) was defined as a > or = 10% postexercise fall in FEV(1). Athletes were monitored for IS during exercise; 78.4% of the athletes in this study (n = 290) were tested on multiple occasions. RESULTS: EIB was identified in 30% of 370 athletes tested (58 female and 53 male subjects). IS was observed in 5.1% (18 female and 1 male subjects) during exercise and spontaneously resolved in these subjects within 5 min after exercise cessation. Ten IS-positive (IS +) athletes (52.6%) were EIB +, and 8 of these athletes had a previous EIB diagnosis; however, beta(2)-agonist treatment resolved IS in only 2 subjects. Eight of nine IS +/EIB-negative (EIB -) athletes had a previous EIB diagnosis; seven subjects received beta(2)-agonist treatment with no IS resolution. Resting spirometric measurements did not distinguish IS, but postexercise mid-flow (FEF(50)/FIF(50)) ratio > 1.5 was more frequent (33%, p < 0.05) among IS + athletes. The FEF(50)/FIF(50) ratio was higher for IS +/EIB + athletes than for IS -/EIB + athletes (1.97 +/- 1.69 vs 0.81 +/- 0.39, p < 0.05). The postexercise fall in FVC was greater (p < 0.05) for IS +/EIB - athletes (9.2 +/- 5.0%) than for IS-negative (IS -) /EIB - athletes (5.3 +/- 4.3%). No difference in postexercise FEV(1) was identified between IS + and IS - athletes (within EIB + or EIB - groups). CONCLUSIONS: Five percent of athletes were IS +, with EIB comorbidity observed in 53% of these subjects. Misdiagnosis of IS as EIB is common. The lack of a beta(2)-agonist response in combination with postexercise serial spirometry can be useful in excluding solitary IS and confirming EIB diagnosis.

Adolescent↗
PubMed2003

Evaluation of cardiovascular demands of game play and practice in women's ice hockey.

Preparation for the physical demands of competition often involves game simulation during practice. This paradigm is thought to promote physiological adaptations that enhance maximal performance. However, a mismatch between practice intensity and actual competition intensity may not provide adequate training to achieve optimal game-play fitness. The purpose of this study was to evaluate the effectiveness of practice in meeting the cardiovascular demands of a women's ice hockey game. Heart rate (HR) data from 11 U.S. National Women's Ice Hockey team members were collected (5-second intervals) during a game and a typical practice session. Data was normalized to individual HRmax determined during Vo(2)max testing. Working time was defined as a game shift or practice-working interval. Mean working HR was greater during the game than the practice, 90 +/- 2% and 76 +/- 3% of HRmax, respectively (p < 0.05). Mean percent session time (game or practice) >90% HRmax was also longer during the game than the practice, 10.5 +/- 4.1% and 5.6 +/- 3.5% (p < 0.05), respectively. Mean session HR, percent time >80% HRmax, and mean resting HR were not different between game and practice (68 +/- 7% vs. 69 +/- 5%, 23.2 +/- 5.3% vs. 26.1 +/- 9.2%, and 59 +/- 8% vs. 56 +/- 5%, respectively). Elite women hockey players experience significantly greater cardiovascular load during game play than during practice. This mismatch in cardiovascular demand may prevent players from achieving "game shape," thus affecting competition play.

Adult↗
PubMed2002

Exercise-induced bronchospasm in the elite athlete.

The term exercise-induced bronchospasm (EIB) describes the acute transient airway narrowing that occurs during and most often after exercise in 10 to 50% of elite athletes, depending upon the sport examined. Although multiple factors are unquestionably involved in the EIB response, airway drying caused by a high exercise-ventilation rate is primary in most cases. The severity of this reaction reflects the allergic predisposition of the athlete, the water content of the inspired air, the type and concentration of air pollutants inspired, and the intensity (or ventilation rate) of the exercise. The highest prevalence of EIB is seen in winter-sport populations, where athletes are chronically exposed to cold dry air and/or environmental pollutants found in indoor ice arenas. When airway surface liquid lost during the natural warming and humidification process of respiration is not replenished at a rate equal to the loss, the ensuing osmolarity change stimulates the release of inflammatory mediators and results in bronchospasm; this cascade of events is exacerbated by airway inflammation and airway remodelling. The acute EIB response is characterised by airway smooth muscle contraction, membrane swelling, and/or mucus plug formation. Evidence suggests that histamine, leukotrienes and prostanoids are likely mediators for this response. Although the presence of symptoms and a basic physical examination are marginally effective, objective measures of lung function should be used for accurate and reliable diagnosis of EIB. Diagnosis should include baseline spirometry, followed by an appropriate bronchial provocation test. To date, the best test to confirm EIB may simply be standard pulmonary function testing before and after high-intensity dry air exercise. A 10% post-challenge fall in forced expiratory volume in 1 second is used as diagnostic criteria. The goal of medical intervention is to limit EIB exacerbation and allow the athlete to train and compete symptom free. This is attempted through daily controller medications such as inhaled corticosteroids or by the prophylactic use of medications before exercise. In many cases, EIB is difficult to control. These and other data suggest that EIB in the elite athlete is in contrast with classic asthma.

Asthma, Exercise-Induced↗
PubMed2002

Prevalence of body art (body piercing and tattooing) in university undergraduates and incidence of medical complications.

OBJECTIVES: To survey the prevalence of body art (body piercing and tattooing) in university undergraduate students and to determine the incidence of medical complications from these procedures. SUBJECTS AND METHODS: Between February and May 2001, students were offered the opportunity to complete an anonymous, voluntary survey at the beginning of class or organizational meetings. The survey instrument requested information concerning body piercing and tattooing (current or removed) by body site, age, sex, height, weight, body mass index, undergraduate class, athletic status, and the occurrence of medical complications. RESULTS: Four hundred fifty-four (94.4%) of 481 students completed the survey (14.7% of total campus enrollment). The prevalence of body piercing was 51%, and that of tattooing was 23%. The chi2 analysis showed female students were more likely to be pierced than males (P=.002); there was no significant difference in the prevalence of tattooing by sex. Male athletes were more likely to be tattooed than male nonathletes (P=.02). No relationships were shown between piercing/tattooing and age or measures of body somatotype. The incidence of medical complications of piercing was 17%, and these complications included bleeding, tissue trauma, and bacterial infections. Pierced navels were particularly prone to infection. There were no reported medical complications from tattooing. Eighteen percent of piercings (58/315) and 4% of tattoos (6/149) had been removed. CONCLUSIONS: Body art is prevalent among undergraduate university students, and there is a significant incidence of medical complications among students with piercing. Male athletes were significantly more likely to be tattooed than male nonathletes.

Adolescent↗
PubMedDate not supplied

Impulse oscillometry is sensitive to bronchoconstriction after eucapnic voluntary hyperventilation or exercise.

Airway responses were compared following 6-minute eucapnic voluntary hyperventilation and 6-minute exercise challenges by examining resting and post-challenge impulse oscillometry and spirometry variables. Twenty-two physically active individuals with probable exercise-induced bronchoconstriction took part in this study. Impulse oscillometry and spirometry were performed at baseline and for 20 minutes post-challenge at 5-minute intervals. High correlation was found between the two measures of change in airway function for both methods of challenge. Impulse oscillometry detected a difference in degree of response to the challenges, whereas spirometry indicated no difference, suggesting that impulse oscillometry is a more sensitive measure of change in airway function.

Adolescent↗
PubMedDate not supplied

Lung function measured by impulse oscillometry and spirometry following eucapnic voluntary hyperventilation.

BACKGROUND: The efficacy of impulse oscillometry (IOS) to measure airway calibre change is not fully established. OBJECTIVES: To evaluate lung function change after eucapnic voluntary hyperventilation (EVH), and to compare IOS indices with spirometric maximal expiratory flow measurements. METHODS: Twenty subjects (10 airway hyperresponsive [AHR+] and 10 normal [AHR--]) underwent IOS and spirometry before and for 15 min after 6 min EVH (inhaling 5% CO2, 21% O2, balance N2) at a target ventilation of 30 times the baseline value of the forced expiratory volume in 1 s (FEV1) at 20 degrees C. AHR+ was defined by a fall in FEV1 of 10% or greater from baseline after a provoking challenge. Airway resistance at 5 Hz (R5), reactance at 5 Hz, resonant frequency (Fres), area of reactance integrated from 5 Hz to Fres (AX), and FEV1 were determined. RESULTS: No baseline spirometry values correlated with falls in FEV1. Baseline R5 and AX values correlated with peak falls in FEV1 (r= -0.51 and -0.46, respectively; P< 0.05). AHR+ subjects demonstrated greater per cent peak falls in FEV1 than did AHR- subjects following EVH (30.6 +/- 14.0% versus 7.5 +/- 2.6%, respectively; P<0.05). Changes in R5, Fres, reactance and AX were greater for AHR+ subjects than for AHR- subjects and correlated with a fall in FEV1 (r= -0.74, -0.70, 0.69 and -0.73, respectively; P<0.05). At a designated specificity of 80%, the per cent change in R5 (50% or greater) and post-EVH AX (12 cm H2O/L or greater) yielded sensitivities to a 10% fall in FEV1 of 90%. CONCLUSION: IOS is an acceptable measure to determine AHR and can supplement spirometry in lung function evaluation.

Adult↗