Effects of negative air ions on oxygen uptake kinetics, recovery and performance in exercise: a randomized, double-blinded study

Copyright © ISB 2013Limited research has suggested that acute exposure to negatively charged ions may enhance cardio-respiratory function, aerobic metabolism and recovery following exercise. To test the physiological effects of negatively charged air ions, 14 trained males (age: 32 ± 7 years; {Mathematical expression}: 57 ± 7 mL min-1 kg-1) were exposed for 20 min to either a high-concentration of air ions (ION: 220 ± 30 × 103 ions cm-3) or normal room conditions (PLA: 0.1 ± 0.06 × 103 ions cm-3) in an ionization chamber in a double-blinded, randomized order, prior to performing: (1) a bout of severe-intensity cycling exercise for determining the time constant of the phase II {Mathematical expression} response (τ) and the magnitude of the {Mathematical expression} slow component (SC); and (2) a 30-s Wingate test that was preceded by three 30-s Wingate tests to measure plasma [adrenaline] (ADR), [nor-adrenaline] (N-ADR) and blood [lactate] (BLac) over 20 min during recovery in the ionization chamber. There was no difference between ION and PLA for the phase II {Mathematical expression}τ (32 ± 14 s vs. 32 ± 14 s; P = 0.7) or {Mathematical expression} SC (404 ± 214 mL vs 482 ± 217 mL; P = 0.17). No differences between ION and PLA were observed at any time-point for ADR, N-ADR and BLac as well as on peak and mean power output during the Wingate tests (all P > 0.05). A high-concentration of negatively charged air ions had no effect on aerobic metabolism during severe-intensity exercise or on performance or the recovery of the adrenergic and metabolic responses after repeated-sprint exercise in trained athletes. © 2013 ISB

Test–retest reliability of pulmonary oxygen uptake and muscle deoxygenation during moderate- and heavy-intensity cycling in youth elite-cyclists

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordTo establish the test-retest reliability of pulmonary oxygen uptake ( O2), muscle deoxygenation (deoxy[heme]) and tissue oxygen saturation (StO2) kinetics in youth elitecyclists. From baseline pedaling, 15 youth cyclists completed 6-min step transitions to a moderate- and heavy-intensity work rate separated by 8 min of baseline cycling. The protocol was repeated after 1 h of passive rest. O2 was measured breath-by-breath alongside deoxy[heme] and StO2 of the vastus lateralis by near-infrared spectroscopy. Reliability was assessed using 95% limits of agreement (LoA), the typical error (TE) and the intraclass correlation coefficient (ICC). During moderate- and heavy-intensity step cycling, TEs for the amplitude, time delay and time constant ranged between 3.5-21.9% and 3.9-12.1% for O2 and between 6.6-13.7% and 3.5-10.4% for deoxy[heme], respectively. The 95% confidence interval for estimating the kinetic parameters significantly improved for ensemble-averaged transitions of O2 (p<0.01) but not for deoxy[heme]. For StO2, the TEs for the baseline, end-exercise and the rate of deoxygenation were 1.0-42.5% and 1.1-5.5% during moderate- and heavy-intensity exercise, respectively. The ICC ranged from 0.81-0.99 for all measures. Test-retest reliability data provides limits within which changes in O2, deoxy[heme] and StO2 kinetics may be interpreted with confidence in youth athletes

Validity of Treadmill-Derived Critical Speed on Predicting 5000-Meter Track-Running Performance.

Nimmerichter, A, Novak, N, Triska, C, Prinz, B, and Breese, BC. Validity of treadmill-derived critical speed on predicting 5,000-meter track-running performance. J Strength Cond Res 31(3): 706-714, 2017-To evaluate 3 models of critical speed (CS) for the prediction of 5,000-m running performance, 16 trained athletes completed an incremental test on a treadmill to determine maximal aerobic speed (MAS) and 3 randomly ordered runs to exhaustion at the [INCREMENT]70% intensity, at 110% and 98% of MAS. Critical speed and the distance covered above CS (D') were calculated using the hyperbolic speed-time (HYP), the linear distance-time (LIN), and the linear speed inverse-time model (INV). Five thousand meter performance was determined on a 400-m running track. Individual predictions of 5,000-m running time (t = [5,000-D']/CS) and speed (s = D'/t + CS) were calculated across the 3 models in addition to multiple regression analyses. Prediction accuracy was assessed with the standard error of estimate (SEE) from linear regression analysis and the mean difference expressed in units of measurement and coefficient of variation (%). Five thousand meter running performance (speed: 4.29 ± 0.39 m·s; time: 1,176 ± 117 seconds) was significantly better than the predictions from all 3 models (p < 0.0001). The mean difference was 65-105 seconds (5.7-9.4%) for time and -0.22 to -0.34 m·s (-5.0 to -7.5%) for speed. Predictions from multiple regression analyses with CS and D' as predictor variables were not significantly different from actual running performance (-1.0 to 1.1%). The SEE across all models and predictions was approximately 65 seconds or 0.20 m·s and is therefore considered as moderate. The results of this study have shown the importance of aerobic and anaerobic energy system contribution to predict 5,000-m running performance. Using estimates of CS and D' is valuable for predicting performance over race distances of 5,000 m

Occupational illnesses related to physical strains in apple harvesting

introduction. Special strains are an occupational hazard often due to physical loads and inadequately designed work equipment. objective. The aim of this pilot study was to determine occupational illnesses related to physical strains through an experimental design that assesses the associated working postures and oxygen uptake in apple harvesting.Three methods were applied to define the physical stress provoked by apple farming tasks. material and methods. The experiments considered 5 labourers – 3 women and 2 men. The physical fatigue was assessed through oxygen consumption and heartbeat frequency according to UNI EN ISO 8996 standards. Measurements were conducted using a portable metabolimeter(COSMED). Working postures were determined according to Ovako Working Posture Analysis System(OWAS). An interview was conducted to record the labourers’ subjective estimate of the stress. results. The interview results demonstrated neck and dorsal pains and fatigue causes for each operator. The V̇O[sub]2[/sub] was equal to 82.33±27.40 lO[sub]2[/sub]/h for women and 67.00±27.60 lO[sub]2[/sub]/h for men, meaning that it was tiring for some men but for all women. The heart rates were of 115±6.00bpm for women and 113±5.65bpm for men. The V̇CO[sub]2[/sub] was of 63.81±21.45 lCO[sub]2[/sub]/h for women and 45.10±25.53 lCO[sub]2[/sub]/h for men, while energetic equivalent and body surface area were similar for both genders, about 5.60W×h/l O[sub]2[/sub] and 1,80m [sup]2[/sup] on average. Women’s metabolic rate had a very high value – over 290W×m [sup]-2[/sup] , although for the men it was between 200–260W×m[sup] -2[/sup] . According to OWAS, low apple picking was ranked in class 2, high apple picking in class 1, and apple transportation belonged to class 3. conclusion. Related to VO[sub]2[/sub] and VCO[sub]2[/sub] consumption and the identified negative body postures, it is necessary to improve working conditions