Locomotor-respiratory coupling is maintained in simulated moderate altitude in trained distance runners

Abstract

To determine whether acute exposure to simulated moderate altitude alters locomotor-respiratory coupling (LRC) patterns in runners, 13 trained male distance runners performed a running economy and maximal oxygen uptake (V̇o) test in normoxia (NORM) and hypoxia (HYP) ([Formula: see text]= 15.8%; ~2,400 m/8,000 ft) on separate days. Running economy (RE), the degree of LRC, stride frequency-to-breathing frequency quotients (SF/f), ratings of perceived exertion (RPE), and dyspnea were assessed at three common submaximal speeds and V̇o. SF/f were significantly lower at each submaximal speed in HYP (12.9 km/h: 2.91 ± 0.20 vs. 2.45 ± 0.17, 14.3 km/h: 2.53 ± 0.17 vs. 2.21 ± 0.14, 16.1 km/h: 2.22 ± 0.14 vs. 1.95 ± 0.09; P < 0.05). The degree of LRC (range: 36-99%) in HYP was not significantly different than NORM at any of the three common submaximal speeds. However, the degree of LRC was significantly higher at V̇o in HYP than NORM (43.8 ± 3.4% vs. 57.1 ± 3.8%; P < 0.05). RE and RPE were similar at all running speeds. Dyspnea was significantly greater in HYP compared with NORM at 16.1 km/h ( P < 0.05). Trained distance runners are able to maintain LRC in HYP, despite increases in breathing frequency. Within this unique population, years of training may enhance and optimize the ability to maintain LRC to minimize metabolic costs and dyspnea. NEW & NOTEWORTHY Exposure to acute altitude causes increases in ventilation at rest and any submaximal exercising workload, which may alter locomotor-respiratory coupling (LRC). Our data suggest that trained distance runners can maintain LRC during acute exposure to simulated moderate altitude, even when breathing frequency is increased at any submaximal pace.

Individual optimal step frequency during outdoor running

“…There are also indications that the overall cost of muscle activation, rather than the energy cost of locomotion may be minimized (Miller, Umberger, Hamill, & Caldwell, 2012; Neptune & Hull, 1999). In addition, ventilation (Fulton et al., 2018) and even the cardiac cycle (Constantini et al., 2018) is coupled to SF and therefore may influence SF.…”

Equine exercise physiology—challenges to the respiratory system

“…During the canter and gallop, however, breathing frequency and stride frequency are tightly coupled. This is also seen in humans who are trained distance runners ( Fulton et al, 2018 ). This is probably due, in horses, to a combination of the abdomen and its contents acting like a piston, and the flexion of the back and thorax by the limbs.…”

Motor–Respiratory Coupling Improves Endurance Performance during Rhythmic Isometric Handgrip Exercise

“…In this condition, subjects successfully maintained a high coupling rate compared with the control condition with no respiration requirement. Research in various forms of sports, such as running, cycling and wheelchair racing, has shown that MRC would be more stable in experienced athletes and would improve their performance and reduce energy expenditure (6,21,(33)(34)(35). A high level of MRC rate could be kept for athletes even under extreme conditions such as dyspnea and voluntary hyperpnea (6,35).…”

“…A high degree of MRC during activities such as cycling or running can decrease energy expenditure (3), primarily due to mechanical factors such as reduced fatigue in respiratory muscles (2,4). Individuals who engage in regular exercise or sports training can improve their MRC, even under extreme conditions such as hypoxia (5,6). This ability allows them to control their energy consumption and enhance their endurance performance.…”