Effects of Ultratrail Running on Skeletal-Muscle Oxygenation Dynamics

Abstract

The concentric and, particularly, the eccentric loads characterizing this extreme ultratrail-running bout may have led to variations in muscle structure and function, increasing the local muscle deoxygenation profile and the imbalance between O delivery to working muscles and muscle O consumption. This highlights the importance of incorporating graded training, particularly downhill bouts, to reduce the negative influence of concentric and severe eccentric loads to the microcirculatory function and to enhance the ability of runners to sustain such loading.

Influence of exercise duration on cardiorespiratory responses, energy cost and tissue oxygenation within a 6 hour treadmill run

“…Additionally, the absence of change in and at moderate and heavy exercise intensities contrasts with other studies following trail ultramarathons (Millet et al, 2000; Vernillo et al, 2014), and indicates that prolonged running with bouts of heavy intensity, but no downhill component, has small effects on the cardiorespiratory response of trained ultramarathon runners. The absence of change in C r J in our study is also in agreement with results of a study following a 65-km mountain ultramarathon performed on trails (Vernillo et al, 2015), but differs from other studies having measured improved (decreased) cost of running and walking following longer (330 km) mountain ultramarathons (Vernillo et al, 2016a; Vernillo et al, 2014). However, in the current study the uphill gradient condition was chosen to increase exercise intensity while minimizing the contribution of elastic energy in gait, in order to control the possibility raised by other authors that changes in microvascular structure could have increased muscle tissue energy requirements (Vernillo et al, 2016a).…”

“…The absence of change in C r J in our study is also in agreement with results of a study following a 65-km mountain ultramarathon performed on trails (Vernillo et al, 2015), but differs from other studies having measured improved (decreased) cost of running and walking following longer (330 km) mountain ultramarathons (Vernillo et al, 2016a; Vernillo et al, 2014). However, in the current study the uphill gradient condition was chosen to increase exercise intensity while minimizing the contribution of elastic energy in gait, in order to control the possibility raised by other authors that changes in microvascular structure could have increased muscle tissue energy requirements (Vernillo et al, 2016a). Another perspective to explain the absence of change in C r J may reside in the specific muscular adaptations derived from the typical high mileage training performed by ultramarathon runners.…”

“…Despite the expected and marked differences in exercise intensity, TSI also did not decrease significantly between the 10-CR and HILL conditions. Although one previous study observed tissue oxygenation alterations following prolonged duration running (Vernillo et al, 2016a), it is possible that the important downhill running component could have contributed to impair tissue structure and microcirculatory function, leading to altered tissue oxygenation (Vernillo et al, 2016a). In the current study, we sought to minimize the potentially confounding effects of the mode of muscle contraction (such as elicited by repeated downhill running).…”

“…However, other tissue-specific adaptations could also contribute to variations in and C r during prolonged running, such as increased neural input and impairments in the structural integrity of the musculoskeletal system (Kyröläinen et al, 2000; Vernillo et al, 2015). For instance, tissue oxygenation in the vastus lateralis muscle (VL) measured using near-infrared spectroscopy (NIRS) decreased following a 330 km running ultramarathon, without changes in (Vernillo et al, 2016a), though the specific effects of the structural disruption of muscle tissue and of exercise duration on tissue oxygenation were not tested. Contrasting with these results, VL oxygenation increased following a 45-min, high intensity intermittent running exercise (Sear et al, 2010), VL muscle oxygen utilization and muscle blood flow increased following ∼95 min of trail running (Vercruyssen et al, 2012), and VL oxygenation did not change during 4-h of cycling including three, 80 min exercise periods at 45% of maximal power output (Rupp et al, 2013).…”

Peer Review #3 of "Influence of exercise duration on cardiorespiratory responses, energy cost and tissue oxygenation within a 6 hour treadmill run (v0.1)"

“…Manuscript to be reviewed For instance, tissue oxygenation in the vastus lateralis muscle (VL) measured using near-infrared spectroscopy (NIRS) decreased following a 330 km running ultramarathon, without changes in V (Vernillo et al 2016a), though the specific effects of the structural disruption of muscle tissue O 2 and of exercise duration on tissue oxygenation were not tested. Contrasting with these results, VL oxygenation increased following a 45-min, high intensity intermittent running exercise (Sear et al 2010), VL muscle oxygen utilization and muscle blood flow increased following ~95 min of trail running (Vercruyssen et al 2012), and VL oxygenation did not change during 4-h of cycling including three, 80 min exercise periods at 45% of maximal power output (Rupp et al 2013).…”