This study examined the changes in the physiological profile of children engaged in organized sporting activity compared to a group of normally active children. Eight children (mean age 11.4 yrs) from each of four popular sports in Australia (badminton, basketball, netball, and tennis) and an equal number of nontraining children were monitored over a 12-week season. Very few differences occurred between the sporting groups and the control group. No change was reported between groups in peak oxygen uptake at the start and completion of the season. Changes occurring within each group did not consistently reflect any sport-specific characteristics over the season. Flexibility improved significantly, with an average gain of 3.76 cm in all groups except basketball players, who gained only 0.69 cm for the 12 weeks. Anaerobic power demonstrated significant improvement only within those sporting groups whose training specifically included explosive based activity. It is suggested that the active nature of the control children and use of only 12 weeks of data collection could have contributed to the limited physiological differences observed between active sporting and nonsporting children.
Geraldine Naughton and John Carlson
Richard B. Kreider, Gary W. Miller, Deborah Schenck, Charles W. Cortes, Victor Miriel, C. Thomas Somma, Pam Rowland, Caroll Turner and Dawn Hill
Six trained male cyclists and triathletes participated in a double blind study to determine the effects of phosphate loading on maximal and endurance exercise performance. Subjects ingested either 1 gm of tribasic sodium phosphate or a glucose placebo four times daily for 3 days prior to performing either an incremental maximal cycling test or a simulated 40-km time trial on a computerized race simulator. They continued the supplementation protocol for an additional day and then performed the remaining maximal or performance exercise test. Subjects observed a 17-day washout period between testing sessions and repeated the experiment with the alternate supplement regimen in identical fashion. Metabolic data were collected at 15-sec intervals while venous blood samples and 2D-echocardiographic data were collected during each stage of exercise during the maximal exercise test and at 8-km intervals during the 404cm time trial. Results indicate that phosphate loading attenuated anaerobic threshold, increased myocardial ejection fraction and fractional shortening, increased maximal oxidative capacity, and enhanced endurance performance in competitive cyclists and triathletes.
Aleksandar Sovtic, Predrag Minic, Jovan Kosutic, Gordana Markovic-Sovtic and Milan Gajic
The modified Chrispin-Norman radiography score (CNS) is used in evaluation of radiographic changes in children with cystic fibrosis (CF). We evaluated the correlation of modified CNS with peak exercise capacity (Wpeak) and ventilatory efficiency (reflected by breathing reserve index—BRI) during progressive cardiopulmonary exercise testing (CPET). Thirty-six children aged 8–17 years were stratified according to their CNS into 3 groups: mild (<10), moderate (10–15), and severe (>15). CPET was performed on a cycle ergometer. Lung function tests included spirometry and whole-body plethysmography. Patients with higher CNS had lower FEV1 (p < .001), Wpeak predicted (%; p = .01) and lower mean peak oxygen consumption (VO2peak/kg; p = .014). The BRI at the anaerobic threshold and at Wpeak was elevated in patients with the highest CNS values (p < .001). The modified CNS correlates moderately with Wpeak (R = −0.443; p = .007) and BRI (R = −0.419; p = .011). Stepwise multiple linear regression showed that RV/TLC was the best predictor of Wpeak/pred (%; B = −0.165; b = −0.494; R2 = .244; p = .002). Children with CF who have high modified CNS exhibit decreased exercise tolerance and ventilatory inefficacy during progressive effort.
Hans Luttikholt, Lars R. McNaughton, Adrian W. Midgley and David J. Bentley
There is currently no model that predicts peak power output (PPO) thereby allowing comparison between different incremental exercise test (EXT) protocols. In this study we have used the critical power profile to develop a mathematical model for predicting PPO from the results of different EXTs.
The purpose of this study was to examine the level of agreement between actual PPO values and those predicted from the new model.
Eleven male athletes (age 25 ± 5 years, VO2max 62 ± 8 mL · kg–1 · min–1) completed 3 laboratory tests on a cycle ergometer. Each test comprised an EXT consisting of 1-minute workload increments of 30 W (EXT30/1) and 3-minute (EXT25/3) and 5-minute workload increments (EXT25/5) of 25 W. The PPO determined from each test was used to predict the PPO from the remaining 2 EXTs.
The differences between actual and predicted PPO values were statistically insignificant (P > .05). The random error components of the limits of agreement of ≤30 W also indicated acceptable levels of agreement between actual and predicted PPO values.
Further data collection is necessary to confirm whether the model is able to predict PPO over a wide range of EXT protocols in athletes of different aerobic and anaerobic capacities.
Myriam Guerra, Maria Giné-Garriga and Bo Fernhall
The Wingate anaerobic test (WAnT) has not been used to assess individuals with Down syndrome (DS) and it is unknown if it is reliable in this population. We investigated the reliability of the WAnT in 19 adolescents with DS (age = 14.8 yrs; weight = 52.7 kg; height = 146.3 cm). Participants completed, on separate days, two standards WAnT using a resistance of 0.7 Nm × body weight (kg) in individuals ≥ 14 years old, and 0.5 Nm × body weight (kg) in participants < 14 years of age. Data were analyzed using intraclass correlation coefficient (ICC), dependent t tests and Bland-Altman plots. There was a significant difference between days for peak power (210.37 W vs. 236.26 W; ICC = 0.93), but not for mean power (158.72 vs. 168.71 W; ICC = 0.86), time to peak power (6.67 vs. 6.28 s; ICC = 0.69), or the fatigue index (9.33 vs. 5.43 W/sec; ICC = 0.09). Adolescents with DS exhibit low WAnT performance compared with previously published data on adolescents without DS and the reliability of WAnT is questionable in this population.
Nathan G. Lawler, Chris R. Abbiss, Aaron Raman, Timothy J. Fairchild, Garth L. Maker, Robert D. Trengove and Jeremiah J. Peiffer
To examine the influence of manipulating aerobic contribution after whole-blood removal on pacing patterns, performance, and energy contribution during self-paced middle-distance cycling.
Seven male cyclists (33 ± 8 y) completed an incremental cycling test followed 20 min later by a 4-min self-paced cycling time trial (4MMP) on 6 separate occasions over 42 d. The initial 2 sessions acted as familiarization and baseline testing, after which 470 mL of blood was removed, with the remaining sessions performed 24 h, 7 d, 21 d, and 42 d after blood removal. During all 4MMP trials, power output, oxygen uptake, and aerobic and anaerobic contribution to power were determined.
4MMP average power output significantly decreased by 7% ± 6%, 6% ± 8%, and 4% ± 6% at 24 h, 7 d, and 21 d after blood removal, respectively. Compared with baseline, aerobic contribution during the 4MMP was significantly reduced by 5% ± 4%, 4% ± 5%, and 4% ± 10% at 24 h, 7 d, and 21 d, respectively. The rate of decline in power output on commencement of the 4MMP was significantly attenuated and was 76% ± 20%, 72% ± 24%, and 75% ± 35% lower than baseline at 24 h, 21 d, and 42 d, respectively.
Removal of 470 mL of blood reduces aerobic energy contribution, alters pacing patterns, and decreases performance during self-paced cycling. These findings indicate the importance of aerobic energy distribution during self-paced middle-distance events.
Henrike Fischer, Daniel Weber and Ralph Beneke
Mouth guards protect against orofacial and dental injuries in sports. However, special fitted dental splints have been claimed to improve strength and speed and, therefore, to enhance athletic performance.
To test the effects of a neuromuscular fitted dental splint in comparison with a habitual verticalizing splint and a no-splint condition on cycling sprint performance in the Wingate Anaerobic Test (WAnT).
Twenty-three men (26.0 ± 2.0 y, 1.82 ± 0.06 m, 79.4 ± 7.7 kg) performed 3 WAnTs, 1 with the neuromuscular fitted splint, 1 with a habitual verticalized dental splint of the same height and material, and 1 under control conditions without any mouth guard, in randomized order separated by 1 wk.
No differences between any splint conditions were found in any aspect of WAnT performance (time to peak power, peak power, minimum power, power drop, and average power). Moderate to nearly perfect correlations between all splint conditions in all WAnT outcomes with coefficients of variation between 1.3% and 6.6% were found.
Irrespective of habitual verticalization or myocentric positioning, dental splints have no effects on any aspect of WAnT performance. Results are comparable to those of test–retest experiments.
Gregory S. Anderson
The purpose of this study was to determine the validity of using the 1600-m distance run (DR) and the maximal multistage 20-m shuttle run (SR) as predictors of aerobic capacity in active boys 10 to 12 years of age. The influence of weight and maximal sprint running speed on test performance scores were also investigated. Both the DR and SR were found to have concurrent validity in the group studied, correlated to a directly measured VO2max (ml kg−1·min−1) determined through a progressive bicycle ergometer test. However, predicted VO2max values using SR results differed significantly from measured values. Weight was not found to be significantly correlated with either of the predictive methods, whereas maximal sprint running speed, as measured through a 40-m dash, was found to correlate significantly with the results of both the DR and SR. These results suggest that the combined influence of running efficiency and anaerobic energy production significantly influence the performance of both predictive methods.
Joel B. Chidley, Alexandra L. MacGregor, Caoimhe Martin, Calum A. Arthur and Jamie H. Macdonald
To identify physiological, psychological, and skill characteristics that explain performance in downhill (DH) mountainbike racing.
Four studies were used to (1) identify factors potentially contributing to DH performance (using an expert focus group), (2) develop and validate a measure of rider skill (using video analysis and expert judge evaluation), (3) evaluate whether physiological, psychological, and skill variables contribute to performance at a DH competition, and (4) test the specific contribution of aerobic capacity to DH performance.
Study 1 identified aerobic capacity, handgrip endurance, anaerobic power, rider skill, and self-confidence as potentially important for DH. In study 2 the rider-skill measure displayed good interrater reliability. Study 3 found that rider skill and handgrip endurance were significantly related to DH ride time (β = –0.76 and –0.14, respectively; R 2 = .73), with exploratory analyses suggesting that DH ride time may also be influenced by self-confidence and aerobic capacity. Study 4 confirmed aerobic capacity as an important variable influencing DH performance (for a DH ride, mean oxygen uptake was 49 ± 5 mL · kg−1 · min−1, and 90% of the ride was completed above the 1st ventilatory threshold).
In order of importance, rider skill, handgrip endurance, self-confidence, and aerobic capacity were identified as variables influencing DH performance. Practically, this study provides a novel assessment of rider skill that could be used by coaches to monitor training and identify talent. Novel intervention targets to enhance DH performance were also identified, including self-confidence and aerobic capacity.
Peter Hofmann and Rochus Pokan
The heart rate performance curve (HRPC) has been shown to be nonlinearly related to work load. This phenomenon has been used to determine a defection point and to be related to the lactate anaerobic threshold. The original method was heavily criticized, and the method was challenged by several authors. However, some authors also demonstrated a high value for this method’s application in various sports conditions. Unfortunately, the HRPC was shown to be not uniform and three different patterns were found. Basic investigations have shown a dependence of the HR-defection on beta1-receptor sensitivity, which gave a plausible explanation of the phenomenon. Important details regarding the testing protocol and the method of turn point determination are given in this review. As a conclusion, we may state that based on numerous studies the method is plausible and valid to determine aerobic exercise performance in various laboratory ergometer and specific sports-related field conditions. Standard protocol conditions adjusted to the exercise performance level of subjects and a computer-supported determination of turn points are necessary to obtain reliable results. Large-scale investigations to validate the heart rate turn point with maximal lactate steady state are still needed. However, from the available literature, the application of this noninvasive method can be recommended to determine aerobic exercise performance in various sports. This noninvasive test is easy to perform repeatedly, which gives interesting possibilities for the monitoring of training adaptation in the short term, such as altitude training or specifc taper forms.