scholarly journals Physiological and Biomechanical Responses to Cross-Country Skiing in Varying Terrain: Low- vs. High-Intensity

2021 ◽  
Vol 12 ◽  
Author(s):  
Trine M. Seeberg ◽  
Jan Kocbach ◽  
Jørgen Danielsen ◽  
Dionne A. Noordhof ◽  
Knut Skovereng ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Power Distribution ◽  
High Intensity ◽  
Vastus Lateralis ◽  
Time Dependent ◽  
Triceps Brachii ◽  
Cycle Rate ◽  
Muscle Oxygen ◽  
Biomechanical Responses ◽  
Cross Country

The purposes of our study were to investigate the physiological and biomechanical responses to low-intensity (LI) and high-intensity (HI) roller ski skating on varying terrain and compare these responses between training intensities. Nine elite male skiers performed treadmill roller skiing consisting of two 21 min sessions (7 × 3 min laps) at LI and HI with the same set inclines and intensity-dependent speeds (LI/HI: distance: 5.8/7.5 km, average speed: 16.7/21.3 km/h). Physiological and biomechanical variables were measured continuously, and each movement cycle and sub-technique employed were detected and classified with a machine learning model. Both the LI and HI sessions induced large terrain-dependent fluctuations (relative to the maximal levels) in heart rate (HR, 17.7 vs. 12.2%-points), oxygen uptake (V.O2, 33.0 vs. 31.7%-points), and muscle oxygen saturation in the triceps brachii (23.9 vs. 33.4%-points) and vastus lateralis (12.6 vs. 24.3%-points). A sub-technique dependency in relative power contribution from poles and skis exhibited a time-dependent shift from Lap 1 to Lap 7 toward gradually more ski power (6.6 vs. 7.8%-points, both p < 0.01). The terrain-dependent fluctuations did not differ between LI and HI for V.O2 (p = 0.50), whereas HR fluctuated less (p < 0.01) and displayed a time-dependent increase from Lap 2 to Lap 7 (7.8%-points, p > 0.01) during HI. Oxygen saturation shifted 2.4% points more for legs than arms from LI to HI (p > 0.05) and regarding sub-technique, 14.7% points more G3 on behalf of G2 was employed on the steepest uphill during HI (p < 0.05). Within all sub-techniques, cycle length increased two to three times more than cycle rate from LI to HI in the same terrains, while the corresponding poling time decreased more than ski contact time (all p > 0.05). In sum, both LI and HI cross-country (XC) skiing on varying terrain induce large terrain-dependent physiological and biomechanical fluctuations, similar to the patterns found during XC skiing competitions. The primary differences between training intensities were the time-dependent increase in HR, reduced relative oxygen saturation in the legs compared to the arms, and greater use of G3 on steep uphill terrain during HI training, whereas sub-technique selection, cycle rate, and pole vs. ski power distribution were similar across intensities on flat and moderately uphill terrain.

scholarly journals Comparison of Mitochondrial Respiration in M. triceps brachii and M. vastus lateralis Between Elite Cross-Country Skiers and Physically Active Controls

2019 ◽  
Vol 10 ◽  
Author(s):  
Jonathan Berg ◽  
Vidar Undebakke ◽  
Øystein Rasch-Halvorsen ◽  
Lars Aakerøy ◽  
Øyvind Sandbakk ◽  
...  
Keyword(s):  
Mitochondrial Respiration ◽  
Vastus Lateralis ◽  
Triceps Brachii ◽  
Physically Active ◽  
Cross Country ◽  
Active Controls

Comparison of muscle near-infrared spectroscopy and femoral blood gases during steady-state exercise in humans

1996 ◽  
Vol 80 (4) ◽  
pp. 1345-1350 ◽  
Author(s):  
F. Costes ◽  
J. C. Barthelemy ◽  
L. Feasson ◽  
T. Busso ◽  
A. Geyssant ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Steady State ◽  
Oxygen Saturation ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Femoral Vein ◽  
Blood Gases ◽  
Muscle Oxygen ◽  
Venous Oxygen Saturation

Near-infrared spectroscopy (NIRS) is a noninvasive way of measuring muscular oxygenation. We evaluated the relationship between NIRS signal [infrared muscle oxygen saturation (IR-SO2mus)] and the femoral venous oxygen saturation (SfvO2) during cycling exercise. Six healthy subjects performed a 30-min steady-state exercise at 80% maximal oxygen uptake in normoxia and hypoxia (inspired O2 fraction = 0.105). IR-So2mus was recorded continuously throughout the tests with the NIRS probe located on the vastus lateralis. During exercise, blood samples were withdrawn every 5 min from radial artery and femoral vein catheters. In normoxia, IR-So2mus initiated a transient nonsignificant decrease at 5 min, then returned to preexercise level, whereas SfvO2 showed a fast decrease, reaching 18% saturation at 10 min without further change. By contrast, in hypoxia, IR-SO2mus and SfvO2 demonstrated a parallel decrease then stabilized at 10 min. We conclude that IR-SO2mus appears to parallel SfvO2 when both the arterial and venous oxygen contents decrease during steady-state exercise in hypoxia, whereas IR-SO2mus does not follow SfvO2 change in normoxia.

scholarly journals PO-096 Correlation between Muscle oxygen and Cardiopulmonary of young cyclists at Ventilation threshold

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Peng Ge ◽  
Bing-hong Gao
Keyword(s):  
Heart Rate ◽  
Gas Exchange ◽  
Oxygen Saturation ◽  
Ventilatory Threshold ◽  
Vastus Lateralis ◽  
Minute Ventilation ◽  
Lower Extremities ◽  
Muscle Oxygen ◽  
Muscle Deoxygenation ◽  
The Relationship

Objective To investigate the relationship between Near-infrared spectroscopy (NIRS)-derived muscle oxygen saturation (SmO2) and Cardiopulmonary indexes at the Ventilatory threshold (VT1 and VT2) during Cardiopulmonary exercise test (CPET) ofyoung cyclists. Methods 12 young cyclists performed a maximal incremental exercise test to exhaustion on a friction-braked cycle ergometer (Monark 839E, Sweden).Heart rate (Polar RS400, Finland) and respiratory gas exchange were measured during the Resting and exercise phases using a breath-by-breath system. SmO2 of active muscles during cycling was measured by NIRS monitors (Fortiori Design LLC, USA), and three of the monitors were placed on both vastus lateralis (VLL & VLR) and left gastrocnemius lateralis (GLL) of left leg. The resting value of the SmO2 of the GLL (SmO2-GLL), the left vastus lateralis (SmO2-VLL), and the right vastus lateralis (SmO2-VLR) was recorded as a baseline.  Then after VT1 and VT2 of each subject were measured by the V-slope method during a CPET, values of muscle oxygen corresponding to the three lower limb sites at two ventilation thresholds was recorded to reflect the muscle oxygenation level at the anaerobic threshold; And the change of muscle oxygen relative to the baseline was calculated to reflect the degree of muscle deoxygenation, which is termed as deoxygenation indexes(ΔSmO2-GLL, ΔSmO2-VLL, ΔSmO2-VLR); As well, Cardiopulmonary indexes including Heart rate (HR), Minute ventilation (VE), Relative oxygen uptake (VO2R), Carbon dioxide production (VCO2) and Respiratory exchange rate (RER) at the Ventilatory threshold were measured. All Results were expressed as mean ± standard deviation. Finally, Pearson correlation analysis was used to determine the relationship between multi-site muscle oxygen saturation of lower extremities and Cardiopulmonary indexes (HR, VE, VO2R, VCO2, RER). The significance level was defined as p<0.05. Results Each subject performed their best to complete the aerobic capacity test. The average VO2peak of the 12 subjects was 42.77 ± 9.69 ml/kg/min (Male: 47.38 ± 9.41 ml/kg/min; Female: 36.31 ± 3.33 ml/kg/min). At rest, the calf and thigh SmO2 were 67.92%± 6.84% (SmO2-GLL), 61.42% ± 13.77% (SmO2-VLL), 64.83% ± 10.62% (SmO2-VLR)respectively; HR, VE, VO2, VO2R, VCO2 and RER were 112.08 ± 14.38, 25.96 ± 8.74 L / min 0.94 ± 0.32 L/min, 15.82 ± 4.30 ml/kg/min, 0.81 ± 0.24 L/min,0.88 ± 0.12 L/min, and 0.38 ± 0.07, respectively. Correlation analysis shows that when adolescent athletes reached the anaerobic threshold level, there was a significant correlation between muscle oxygen and cardiopulmonary: At the time of VT1, for Oxygenation index, SmO2 of GLL was highly negatively correlated with HR (r=-0.69,p<0.05), VE (r=-0.71, p<0.01), VO2R (r=-0.65, p<0.05), VCO2 (r=-0.66, p<0.05) and RER (r=-0.58, p<0.05); SmO2-VLL was also highly negatively correlated with VE (r=-0.70, p<0.05), VO2R (r=-0.70, p<0.05), VCO2 (r=-0.66, p<0.05); Additionally, there is also high inverse correlation between SmO2-VLR and HR (r=-0.66, p<0.05), VE (r=-0.70, p<0.05), VO2R (r=-0.66, p<0.05), VCO2 (r=-0.68, p<0.05), RER (r=-0.60, p<0.05). In terms of deoxygenation indexes, ΔSmO2-GLL was highly negatively correlated with VE (r=-0.61, p<0.05), VO2R  (r=-0.64, p<0.05) and VCO2 (r=-0.59, p<0.05); While, ΔSmO­2-VLL was highly negatively correlated with HR (r=-0.62, p<0.05), VE (r=-0.72, p<0.01),VO2R (r=-0.80, p<0.01) and VCO2(r=-0.84, p<0.01); ΔSmO2-VLR was correlated with HR (r=-0.75, p<0.01), VE (r=-0.62, p<0.05), VO2R (r=-0.58, p<0.05) and RER (r=-0.74, p<0.01), and it also shows highly negative correlation. When VT2 occurred, only SmO2 of the GLL in the oxygenation indexes was highly positively correlated with HR (r=0.65, p<0.05), there was no correlation between GLL-SmO2 and any other gas exchange indexes. In terms of muscle deoxygenation indexes, only ΔSmO2 in the thigh VLR was significantly negatively correlated with RER (r=-0.75, p<0.01). Conclusions Based on these results, there is a high correlation between NIRS-derived regional muscle oxygen saturation (Oxygenation and Deoxygenation indexes) of lower extremities and cardiopulmonary index (HR, VE, VO2R, VCO2, RER) during CPET of young cyclists at first Ventilatory threshold, however, it is still unclear whether there is a significant correlation between muscle oxygen saturation of lower extremities and other cardiopulmonary indexes when second Ventilatory threshold occurs except Heart rate or Minute ventilation.

scholarly journals Contractile Properties of MHC I and II Fibers From Highly Trained Arm and Leg Muscles of Cross-Country Skiers

2021 ◽  
Vol 12 ◽  
Author(s):  
Kasper Degn Gejl ◽  
Lars G. Hvid ◽  
Erik P. Andersson ◽  
Rasmus Jensen ◽  
Hans-Christer Holmberg ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Contractile Properties ◽  
Specific Force ◽  
Triceps Brachii ◽  
Mhc I ◽  
Mhc Ii ◽  
Leg Muscles ◽  
Generating Capacity ◽  
Cross Country

IntroductionLittle is known about potential differences in contractile properties of muscle fibers of the same type in arms and legs. Accordingly, the present study was designed to compare the force-generating capacity and Ca2+ sensitivity of fibers from arm and leg muscles of highly trained cross-country skiers.MethodSingle muscle fibers of m. vastus lateralis and m. triceps brachii of eight highly trained cross-country skiers were analyzed with respect to maximal Ca2+-activated force, specific force and Ca2+ sensitivity.ResultThe maximal Ca2+-activated force was greater for myosin heavy chain (MHC) II than MHC I fibers in both the arm (+62%, P &lt; 0.001) and leg muscle (+77%, P &lt; 0.001), with no differences between limbs for each MHC isoform. In addition, the specific force of MHC II fibers was higher than that of MHC I fibers in both arms (+41%, P = 0.002) and legs (+95%, P &lt; 0.001). The specific force of MHC II fibers was the same in both limbs, whereas MHC I fibers from the m. triceps brachii were, on average, 39% stronger than fibers of the same type from the m. vastus lateralis (P = 0.003). pCa50 was not different between MHC I and II fibers in neither arms nor legs, but the MHC I fibers of m. triceps brachii demonstrated higher Ca2+ sensitivity than fibers of the same type from m. vastus lateralis (P = 0.007).ConclusionComparison of muscles in limbs equally well trained revealed that MHC I fibers in the arm muscle exhibited a higher specific force-generating capacity and greater Ca2+ sensitivity than the same type of fiber in the leg, with no such difference in the case of MHC II fibers. These distinct differences in the properties of fibers of the same type in equally well-trained muscles open new perspectives in muscle physiology.

Agreement between muscle oxygen saturation from two commercially available systems in endurance running: Moxy Monitor versus Humon Hex

2021 ◽  
pp. 175433712110157
Author(s):  
Diego Jaén-Carrillo ◽  
Luis E Roche-Seruendo ◽  
Antonio Cartón-Llorente ◽  
Felipe García-Pinillos
Keyword(s):  
Oxygen Saturation ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Time Trial ◽  
Treadmill Running ◽  
Endurance Running ◽  
Muscle Oxygen ◽  
Wearable Systems ◽  
Mean Differences ◽  
Level Of Agreement

Analysis of changes in muscle oxygen saturation (SmO2) in sport settings has become common due to its precise, continuous and non-invasive ability to provide measurements of a particular muscle using near-infrared spectroscopy (NIRS). Therefore, this study aims to determine level of agreement between two affordable NIRS-based oximeter wearable systems for measuring SmO2 level in the vastus lateralis in endurance runners. Seventeen trained endurance male runners (age: 34.2 ± 8.1 years; body mass: 70.5 ± 6.1 kg; height: 1.75 ± 0.04 m; BMI: 23 ± 1.7) completed a submaximal 60-min run-to-exhaustion treadmill running protocol trying to cover the longest possible distance. The SmO2 rates of the vastus lateralis were co-registered and continually obtained from two separate NIRS-based oximeter wearable systems over the running trial. The between-system means comparison reveals no significant differences in SmO2 at any point of the running protocol ( p > 0.217) with trivial-to-small ES (ES < 0.27). Significant relationships ( p < 0.05) were identified between systems with large and very large Pearson coefficients ( r > 0.624). Additionally, substantial and almost perfect ICCs were obtained (ICC > 0.729). Bland-Altman plots exposed homoscedasticity ( r2 < 0.1) for all the periods analysed during the running protocol, with mean differences lower than 3.2% over the time trial. The results found here show the level of agreement between two economical NIRS-based oximeter wearable systems. Notwithstanding their level of agreement, their interchangeable use is not recommended due to the variation shown for SmO2 levels.

scholarly journals Non-Coding RNAs in the Transcriptional Network That Differentiates Skeletal Muscles of Sedentary from Long-Term Endurance- and Resistance-Trained Elderly

2021 ◽  
Vol 22 (4) ◽  
pp. 1539
Author(s):  
Paola De Sanctis ◽  
Giuseppe Filardo ◽  
Provvidenza Maria Abruzzo ◽  
Annalisa Astolfi ◽  
Alessandra Bolotta ◽  
...  
Keyword(s):  
Exercise Training ◽  
High Intensity ◽  
Vastus Lateralis ◽  
Mammalian Target Of Rapamycin ◽  
Differentially Expressed ◽  
Transcriptional Networks ◽  
Vastus Lateralis Muscle ◽  
Age Related ◽  
Wide Range ◽  
Non Coding Rnas

In a previous study, the whole transcriptome of the vastus lateralis muscle from sedentary elderly and from age-matched athletes with an exceptional record of high-intensity, life-long exercise training was compared—the two groups representing the two extremes on a physical activity scale. Exercise training enabled the skeletal muscle to counteract age-related sarcopenia by inducing a wide range of adaptations, sustained by the expression of protein-coding genes involved in energy handling, proteostasis, cytoskeletal organization, inflammation control, and cellular senescence. Building on the previous study, we examined here the network of non-coding RNAs participating in the orchestration of gene expression and identified differentially expressed micro- and long-non-coding RNAs and some of their possible targets and roles. Unsupervised hierarchical clustering analyses of all non-coding RNAs were able to discriminate between sedentary and trained individuals, regardless of the exercise typology. Validated targets of differentially expressed miRNA were grouped by KEGG analysis, which pointed to functional areas involved in cell cycle, cytoskeletal control, longevity, and many signaling pathways, including AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR), which had been shown to be pivotal in the modulation of the effects of high-intensity, life-long exercise training. The analysis of differentially expressed long-non-coding RNAs identified transcriptional networks, involving lncRNAs, miRNAs and mRNAs, affecting processes in line with the beneficial role of exercise training.

Electrical activity and relative length changes of dog limb muscles as a function of speed and gait

1981 ◽  
Vol 94 (1) ◽  
pp. 15-42 ◽  
Author(s):  
G. E. Goslow ◽  
H. J. Seeherman ◽  
C. R. Taylor ◽  
M. N. McCutchin ◽  
N. C. Heglund
Keyword(s):  
Electrical Activity ◽  
Stance Phase ◽  
Biceps Brachii ◽  
Vastus Lateralis ◽  
Activity Patterns ◽  
Relative Length ◽  
Muscular Activity ◽  
Triceps Brachii ◽  
Limb Muscles ◽  
Length Changes

Electrical activity and length changes of 11 muscles of the fore- and hind- limbs of dogs walking, running, and galloping on a treadmill, were measured as a function of forward speed and gait. Our purpose was to find out whether the activity patterns of the major limb muscles were consistent with the two mechanisms proposed for storage and recovery of energy within a stride: a ‘pendulum-like’ mechanism during a walk, and a ‘spring-like’ mechanism during a run. In the stance phase of the walking dog, we found that the supraspinatus, long head of the triceps brachii, biceps brachii, vastus lateralis, and gastrocnemius underwent only minor length changes during a relatively long portion of their activity, Thus, a major part of their activity during the walk seems consistent with a role in stabilization of the joints as the dog ‘pole-vaulted’ over its limbs (and thereby conserved energy). In the stance phase of trotting and/or galloping dogs, we found that the supraspinatus, lateral head of the triceps, vastus lateralis, and gastrocnemius were active while being stretched prior to shortening (as would be required for elastic storage of energy), and that this type of activity increased with increasing speed. We also found muscular activity in the select limb flexors that was consistent with storage of kinetic energy at the end of the swing phase and recovery during the propulsive stroke. This activity pattern was apparent in the latissimus dorsi during a walk and trot, and in the biceps femoris during a trot and gallop. We conclude that, during locomotion, a significant fraction of the electrical activity of a number of limbs muscles occurs while they undergo little or no length change or are being stretched prior to shortening and that these types of activities occur in a manner that would enable the operation of pendulum-like and spring-like mechanisms for conserving energy within a stride. Therefore these forms of muscular activity, in addition to the more familiar activity associated with muscle shortening, should be considered to be important during locomotion.

Effect of Climbing Speed on Pulmonary Oxygen Uptake and Muscle Oxygen Saturation Dynamics in the Finger Flexors

2021 ◽  
pp. 1-9
Author(s):  
Jan Gajdošík ◽  
Jirˇí Baláš ◽  
Dominika Krupková ◽  
Lukáš Psohlavec ◽  
Nick Draper
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Saturation ◽  
Near Infrared ◽  
Cellular Level ◽  
Gas Analysis ◽  
Whole Body ◽  
Flexor Digitorum Profundus ◽  
Muscle Oxygen ◽  
Sport Climbing ◽  
Body Activity

Purpose: Although sport climbing is a self-paced whole-body activity, speed varies with climbing style, and the effect of this on systemic and localized oxygen responses is not well understood. Therefore, the aim of the present study was to determine muscle and pulmonary oxygen responses during submaximal climbing at differing speeds of ascent. Methods: Thirty-two intermediate and advanced sport climbers completed three 4-minute-long ascents of the same route at 4, 6, and 9 m·min−1 on a motorized climbing ergometer (treadwall) on separate laboratory visits. Gas analysis and near-infrared spectroscopy were used to determine systemic oxygen uptake () and muscle oxygen saturation (StO2) of the flexor digitorum profundus. Results: Increases in ascent speed of 1 m·min−1 led to increases of by 2.4 mL·kg−1·min−1 (95% CI, 2.1 to 2.8 mL·kg−1·min−1) and decreases in StO2 by −1.3% (95% CI, 1.9% to −0.7%). There was a significant interaction of climbing ability and speed for StO2 (P < .001, ). The results revealed that the decrease of StO2 was present for intermediate but not advanced climbers. Conclusions: In this study, the results suggest that demand during climbing was largely determined by climbing speed; however, the ability level of the climber appeared to mitigate StO2 at a cellular level. Coaches and instructors may prescribe climbing ascents with elevated speed to improve generalized cardiorespiratory fitness. To stimulate localized aerobic capacity, however, climbers should perhaps increase the intensity of training ascents through the manipulation of wall angle or reduction of hold size.

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