scholarly journals Effects of ramp slope on physiological characteristic and performance time of healthy adults propelling and pushing wheelchairs

2015 ◽  
Vol 27 (1) ◽  
pp. 7-9 ◽  
Author(s):  
Young Oh Choi ◽  
Ho Young Lee ◽  
Myoung Hee Lee ◽  
Oh Hyun Kwon
2017 ◽  
Vol 12 (5) ◽  
pp. 684-689 ◽  
Author(s):  
Joseph A. McQuillan ◽  
Deborah K. Dulson ◽  
Paul B. Laursen ◽  
Andrew E. Kilding

Purpose:To determine the effect of dietary nitrate (NO3 –) supplementation on physiology and performance in well-trained cyclists after 6–8 d of NO3 – supplementation.Methods:Eight competitive male cyclists (mean ± SD age 26 ± 8 y, body mass 76.7 ± 6.9 kg, VO2peak 63 ± 4 mL · kg–1 · min–1) participated in a double-blind, placebo-controlled, crossover-design study in which participants ingested 70 mL of beetroot juice containing ~4 mmol NO3 – (NIT) or a NO3 –-depleted placebo (PLA), each for 8 d. Replicating pretreatment measures, participants undertook an incremental ramp assessment to determine VO2peak and first (VT1) and second (VT2) ventilatory thresholds on d 6 (NIT6 and PLA6), moderate-intensity cycling economy on d 7 (NIT7 and PLA7), and a 4-km time trial (TT) on d 8 (NIT8 and PLA8).Results:Relative to PLA, 6 d of NIT supplementation produced unclear effects for VO2peak (mean ± 95% confidence limit: 1.8% ± 5.5%) and VT1 (3.7% ± 12.3%) and trivial effects for both VT2 (–1.0% ± 3.0%) and exercise economy on d 7 (–1.0% ± 1.6%). However, effects for TT performance time (–0.7% ± 0.9%) and power (2.4% ± 2.5%) on d 8 were likely beneficial.Conclusions:Despite mostly unclear outcomes for standard physiological determinants of performance, 8 d of NO3 – supplementation resulted in likely beneficial improvements to 4-km TT performance in well-trained male endurance cyclists.


2020 ◽  
Vol 20 (08) ◽  
pp. 2050057
Author(s):  
SONG-CUI SHEN ◽  
YING-JIA XU ◽  
WEN-XIA FU ◽  
YAN-JIE LI ◽  
JING-JUAN HUANG ◽  
...  

Objectives: This study will evaluate the results of parameters measured during a treadmill exercise test to predict marathon performances. Methods: We studied 171 Chinese recreational athletes who participated in marathons or half-marathons (42.2[Formula: see text]k or 21.1[Formula: see text]k, respectively) between October 2016 and December 2017. The participants completed a survey that included questions about demographics and training, and they underwent a treadmill exercise test according to the Bruce protocol. The number of years in training, mean weekly hours of training, mean weekly training volume, and performance time in subsequent marathon events were recorded and analyzed in this study. Results: The total exercise times achieved on the treadmill test were significantly longer for men compared to women ([Formula: see text]). The performance times in the half-marathons were significantly shorter for men compared to women ([Formula: see text]). Training volume was the only independent predictor of total exercise time on the treadmill and performance time in marathons and half-marathons (all [Formula: see text]). The value of the total exercise time on the treadmill to predict performance times in half-marathons ([Formula: see text]) was superior to full marathons ([Formula: see text]) and significantly better in study subjects aged 30–39 years ([Formula: see text], [Formula: see text]) and 40–49 years ([Formula: see text], [Formula: see text]) compared to study subjects aged 20–29 years and 50–59 years. The percentage of decrease in the maximal heart rate (MHR) at the end of one minute of recovery time was negatively correlated with performance times in marathons. Conclusions: The total exercise time achieved during an exhaustive treadmill exercise test and percentage of decrease in the MHR at the end of one minute of recovery time are accessible parameters that can help athletes manage their expectations and adjust their training plans. A large study that includes additional countries is needed to confirm the value of treadmill exercise test results for predicting marathon performance.


2015 ◽  
Vol 49 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Vasileios Stavrou ◽  
Argyris G. Toubekis ◽  
Eleni Karetsi

Abstract The purpose of this study was to examine the effects of training with intermittent breath holding (IBH) on respiratory parameters, arterial oxygen saturation (SpO2) and performance. Twenty-eight fin-swimming athletes were randomly divided into two groups and followed the same training for 16 weeks. About 40% of the distance of each session was performed with self-selected breathing frequency (SBF group) or IBH (IBH group). Performance time of 50 and 400 m at maximum intensity was recorded and forced expired volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and SpO2 were measured before and after the 50 m test at baseline and post-training. Posttraining, the respiratory parameters were increased in the IBH but remained unchanged in the SBF group (FEV1: 17 ±15% vs. -1 ±11%; FVC: 22 ±13% vs. 1 ±10%; PEF: 9 ±14% vs. -4 ±15%; p<0.05). Pre compared to post-training SpO2 was unchanged at baseline and decreased post-training following the 50 m test in both groups (p<0.05). The reduction was higher in the IBH compared to the SBF group (p<0.05). Performance in the 50 and 400 m tests improved in both groups, however, the improvement was greater in the IBH compared to the SBF group in both 50 and 400 m tests (p<0.05). The use of IBH is likely to enhance the load on the respiratory muscles, thus, contributing to improvement of the respiratory parameters. Decreased SpO2 after IBH is likely due to adaptation to hypoventilation. IBH favours performance improvement at 50 and 400 m fin-swimming.


2009 ◽  
Vol 4 (1) ◽  
pp. 41-53 ◽  
Author(s):  
Michael Wilkinson ◽  
Damon Leedale-Brown ◽  
Edward M. Winter

Purpose:We examined the reproducibility of performance and physiological responses on a squash-specific incremental test.Methods:Eight trained squash players habituated to procedures with two prior visits performed an incremental squash test to volitional exhaustion on two occasions 7 days apart. Breath-by-breath oxygen uptake ( Vo2) and heart rate were determined continuously using a portable telemetric system. Blood lactate concentration at the end of 4-min stages was assessed to determine lactate threshold. Once threshold was determined, test speed was increased every minute until volitional exhaustion for assessment of maximal oxygen uptake (Vo2max), maximum heart rate (HRmax), and performance time. Economy was taken as the 60-s mean of Vo2 in the final minute of the fourth stage (below lactate threshold for all participants). Typical error of measurement (TEM) with associated 90% confidence intervals, limits of agreement, paired sample t tests, and least products regression were used to assess the reproducibility of scores.Results:Performance time (TEM 27 s, 4%, 90% CI 19 to 49 s) Vo2max (TEM 2.4 mL·kg−1·min−1, 4.7%, 90% CI 1.7 to 4.3 mL·kg−1·min−1), maximum heart rate (TEM 2 beats·min−1, 1.3%, 90% CI 2 to 4 beats·min−1), and economy (TEM 1.6 mL·kg−1·min−1, 4.1%, 90% CI 1.1 to 2.8 mL·kg−1·min−1) were reproducible.Conclusions:The results suggest that endurance performance and physiological responses to a squash-specific fitness test are reproducible.


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