Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University Melbourne, VIC, Australia ; Aspetar - Athlete Health and Performance Research Centre, Qatar Orthopaedic and Sports Medicine Hospital Doha, Qatar.
Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University Melbourne, VIC, Australia.
Front Physiol. 2014 Mar 31;5:115. doi: 10.3389/fphys.2014.00115. eCollection 2014.
We explored the effects of the sense of effort and accompanying perceptions of peripheral discomfort on self-selected cycle power output under two different inspired O2 fractions.
On separate days, eight trained males cycled for 5 min at a constant subjective effort (sense of effort of '3' on a modified Borg CR10 scale), immediately followed by five 4-s progressive submaximal (sense of effort of "4, 5, 6, 7, and 8"; 40 s between bouts) and two 4-s maximal (sense of effort of "10"; 3 min between bouts) bouts under normoxia (NM: fraction of inspired O2 [FiO2] 0.21) and hypoxia (HY: [FiO2] 0.13). Physiological (Heart Rate, arterial oxygen saturation (SpO2) and quadriceps Root Mean Square (RMS) electromyographical activity) and perceptual responses (overall peripheral discomfort, difficulty breathing and limb discomfort) were recorded.
Power output and normalized quadriceps RMS activity were not different between conditions during any exercise bout (p > 0.05) and remained unchanged across time during the constant-effort cycling. SpO2 was lower, while heart rate and ratings of perceived difficulty breathing were higher under HY, compared to NM, at all time points (p < 0.05). During the constant-effort cycling, heart rate, overall perceived discomfort, difficulty breathing and limb discomfort increased with time (all p < 0.05). All variables (except SpO2) increased along with sense of effort during the brief progressive cycling bouts (all p < 0.05). During the two maximal cycling bouts, ratings of overall peripheral discomfort displayed an interaction between time and condition with ratings higher in the second bout under HY vs. NM conditions.
During self-selected, constant-effort and brief progressive, sub-maximal, and maximal cycling bouts, mechanical work is regulated in parallel to the sense of effort, independently from peripheral sensations of discomfort.
我们探讨了在两种不同吸入氧分数下，努力感和伴随的外周不适感知对自我选择的自行车功率输出的影响。
在不同的日子里，8 名训练有素的男性以恒定的主观努力（改良 Borg CR10 量表上的“3”）骑自行车 5 分钟，然后立即进行五次 4 秒递增的次最大（努力感为“4、5、6、7 和 8”；两次之间间隔 40 秒）和两次 4 秒最大（努力感为“10”；两次之间间隔 3 分钟）递增。在常氧（NM：吸入氧分数 [FiO2] 0.21）和低氧（HY：FiO2 0.13）下。记录生理（心率、动脉血氧饱和度（SpO2）和股四头肌均方根（RMS）肌电图活动）和感知反应（整体外周不适、呼吸困难和肢体不适）。
在任何运动阶段，功率输出和归一化股四头肌 RMS 活动在两种条件下均无差异（p > 0.05），在恒定努力自行车运动期间随时间变化不变。与 NM 相比，HY 时 SpO2 较低，而心率和呼吸困难感知评分较高，在所有时间点（p < 0.05）。在恒定努力自行车运动期间，心率、整体感知不适、呼吸困难和肢体不适随时间增加（所有 p < 0.05）。在短暂的递增运动阶段，所有变量（除 SpO2 外）均随努力感增加（所有 p < 0.05）。在两次最大自行车运动中，整体外周不适的评分显示出时间和条件之间的相互作用，在 HY 条件下，第二次运动的评分高于 NM 条件。
在自我选择的恒定努力和短暂递增、次最大、最大自行车运动中，机械功与努力感平行调节，与外周不适感觉无关。
