Gender differences in power production, energetic capacity and efficiency of elite cross-country skiers during whole-body, upper-body, and arm poling

2015 ◽  
Vol 116 (2) ◽  
pp. 291-300 ◽  
Author(s):  
Ann Magdalen Hegge ◽  
Elias Bucher ◽  
Gertjan Ettema ◽  
Oliver Faude ◽  
Hans-Christer Holmberg ◽  
...  
Keyword(s):  
Gender Differences ◽  
Power Production ◽  
Upper Body ◽  
Whole Body ◽  
Cross Country

Skeletal muscle mass and distribution in 468 men and women aged 18–88 yr

2000 ◽  
Vol 89 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Ian Janssen ◽  
Steven B. Heymsfield ◽  
ZiMian Wang ◽  
Robert Ross
Keyword(s):  
Skeletal Muscle ◽  
Gender Differences ◽  
Body Weight ◽  
Upper Body ◽  
Whole Body ◽  
Lower Body ◽  
Large Measure ◽  
Imaging Protocol ◽  
Men And Women ◽  
Magnetic Resonance Imaging Protocol

We employed a whole body magnetic resonance imaging protocol to examine the influence of age, gender, body weight, and height on skeletal muscle (SM) mass and distribution in a large and heterogeneous sample of 468 men and women. Men had significantly ( P < 0.001) more SM in comparison to women in both absolute terms (33.0 vs. 21.0 kg) and relative to body mass (38.4 vs. 30.6%). The gender differences were greater in the upper (40%) than lower (33%) body ( P < 0.01). We observed a reduction in relative SM mass starting in the third decade; however, a noticeable decrease in absolute SM mass was not observed until the end of the fifth decade. This decrease was primarily attributed to a decrease in lower body SM. Weight and height explained ∼50% of the variance in SM mass in men and women. Although a linear relationship existed between SM and height, the relationship between SM and body weight was curvilinear because the contribution of SM to weight gain decreased with increasing body weight. These findings indicate that men have more SM than women and that these gender differences are greater in the upper body. Independent of gender, aging is associated with a decrease in SM mass that is explained, in large measure, by a decrease in lower body SM occurring after the fifth decade.

scholarly journals Are Gender Differences in Upper-Body Power Generated by Elite Cross-Country Skiers Augmented by Increasing the Intensity of Exercise?

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0127509 ◽  
Author(s):  
Ann Magdalen Hegge ◽  
Kenneth Myhre ◽  
Boye Welde ◽  
Hans-Christer Holmberg ◽  
Øyvind Sandbakk
Keyword(s):  
Gender Differences ◽  
Upper Body ◽  
Cross Country ◽  
Intensity Of Exercise ◽  
Upper Body Power

Prediction of Race Performance of Elite Cross-Country Skiers by Lean Mass

2014 ◽  
Vol 9 (6) ◽  
pp. 1040-1045 ◽  
Author(s):  
Magnus Carlsson ◽  
Tomas Carlsson ◽  
Daniel Hammarström ◽  
Christer Malm ◽  
Michail Tonkonogi
Keyword(s):  
Body Composition ◽  
Muscle Mass ◽  
Fat Mass ◽  
Lean Mass ◽  
The Body ◽  
Upper Body ◽  
Whole Body ◽  
Cross Country ◽  
The Absolute ◽  
Race Performance

Purpose:To investigate the relationship between race performance and lean mass (LM) variables, as well as to examine sex differences in body composition in elite-standard cross-country skiers.Methods:Thirty-four elite cross-country skiers (18 men and 16 women) underwent a dual-emission X-ray-absorptiometry body-composition test to determine LM, fat mass, and bone mineral content. For both sexes, performance data were collected from a sprint prologue and a distance race.Results:The absolute expression of LM variables (whole-body [LMWB], upper body [LMUB], and lower body [LMLB]) was significantly correlated with finishing time in the sprint prologue independent of sex. Distance-race performance was significantly related to LMWB, LMUB, and LMLB in women; however, no correlation was found in men. Men had a significantly higher LM and lower fat mass, independent of expression (absolute or relative), for the whole body, arms, trunk, and legs, except for the absolute fat mass in the trunk.Conclusions:The absolute expressions of LMWB, LMUB, and LMLB were significant predictors of sprint-prologue performance in both sexes, as well as of distance-race performance in women only. Compared with women, male skiers have a higher LM in the body segments that are major contributors to propelling forces. These results suggest that muscle mass in the lower and upper body is equally important for race performance; thus, more focus of elite skiers’ training should be directed to increasing whole-body muscle mass to improve their competitive performance capability.

Determinants of maximal whole-body fat oxidation in elite cross-country skiers: Role of skeletal muscle mitochondria

2018 ◽  
Vol 28 (12) ◽  
pp. 2494-2504 ◽  
Author(s):  
Sune Dandanell ◽  
Anne-Kristine Meinild-Lundby ◽  
Andreas B. Andersen ◽  
Paul F. Lang ◽  
Laura Oberholzer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Fat ◽  
Fat Oxidation ◽  
Whole Body ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Cross Country

Multi-Objective Optimization of Human Gait With a Discomfort Function

2016 ◽  
Author(s):  
Hyun-Jung Kwon ◽  
Hyun-Joon Chung ◽  
Yujiang Xiang
Keyword(s):  
Joint Torque ◽  
Upper Body ◽  
Whole Body ◽  
Human Gait ◽  
Multi Objective Optimization ◽  
Joint Angles ◽  
Backward Walking ◽  
Multi Objective ◽  
Body Model ◽  
Neutral Angle

The objective of this study was to develop a discomfort function for including a high DOF upper body model during walking. A multi-objective optimization (MOO) method was formulated by minimizing dynamic effort and the discomfort function simultaneously. The discomfort function is defined as the sum of the squares of deviation of joint angles from their neutral angle positions. The dynamic effort is the sum of the joint torque squared. To investigate the efficacy of the proposed MOO method, backward walking simulation was conducted. By minimizing both dynamic effort and the discomfort function, a 3D whole body model with a high DOF upper body for walking was demonstrated successfully.

scholarly journals Near Infrared Spectroscopy for Muscle Specific Analysis of Intensity and Fatigue during Cross-Country Skiing Competition—A Case Report

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2535
Author(s):  
Thomas Stöggl ◽  
Dennis-Peter Born
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Exercise Intensity ◽  
Near Infrared ◽  
Whole Body ◽  
Long Distance ◽  
Specific Loading ◽  
Cross Country Skiing ◽  
Cross Country ◽  
Muscle Groups

The aims of the study were to assess the robustness and non-reactiveness of wearable near-infrared spectroscopy (NIRS) technology to monitor exercise intensity during a real race scenario, and to compare oxygenation between muscle groups important for cross-country skiing (XCS). In a single-case study, one former elite XCS (age: 39 years, peak oxygen uptake: 65.6 mL/kg/min) was equipped with four NIRS devices, a high-precision global navigation satellite system (GNSS), and a heart rate (HR) monitor during the Vasaloppet long-distance XCS race. All data were normalized to peak values measured during incremental laboratory roller skiing tests two weeks before the race. HR reflected changes in terrain and intensity, but showed a constant decrease of 0.098 beats per minute from start to finish. Triceps brachii (TRI) muscle oxygen saturation (SmO2) showed an interchangeable pattern with HR and seems to be less affected by drift across the competition (0.027% drop per minute). Additionally, TRI and vastus lateralis (VL) SmO2 revealed specific loading and unloading pattern of XCS in uphill and downhill sections, while rectus abdominus (RA) SmO2 (0.111% drop per minute) reflected fatigue patterns occurring during the race. In conclusion, the present preliminary study shows that NIRS provides a robust and non-reactive method to monitor exercise intensity and fatigue mechanisms when applied in an outdoor real race scenario. As local exercise intensity differed between muscle groups and central exercise intensity (i.e., HR) during whole-body endurance exercise such as XCS, NIRS data measured at various major muscle groups may be used for a more detailed analysis of kinetics of muscle activation and compare involvement of upper body and leg muscles. As TRI SmO2 seemed to be unaffected by central fatigue mechanisms, it may provide an alternative method to HR and GNSS data to monitor exercise intensity.

Recognition and prediction of driver’s whole body posture model

2022 ◽  
pp. 095440702110686
Author(s):  
Jun Wu ◽  
Jian Liu ◽  
Xiuyuan Li ◽  
Lingbo Yan ◽  
Libo Cao ◽  
...  
Keyword(s):  
Regression Model ◽  
Body Posture ◽  
Upper Body ◽  
Whole Body ◽  
Lower Body ◽  
Key Factor ◽  
Upper Body Posture ◽  
Spatial Coordinates ◽  
Posture Prediction ◽  
Connection Length

The driver’s whole-body posture at the time of a collision is a key factor in determining the magnitude of injury to the driver. However, current researchs on driver posture models only consider the upper body posture of the driver, and the lower body area which is not perceived by sensors is not studied. This paper investigates the driver’s posture and establishes a 3D posture model of the driver’s whole body through the application of machine vision algorithms and regression model statistics. This study proposes an improved Kinect-OpenPose algorithm for identifying the 3D spatial coordinates of nine keypoints of the driver’s upper body. The posture prediction regression model of four keypoints of the lower body is established by conducting volunteer posture acquisition experiments on the developed simulated driving seat and analyzing the volunteer posture data through using the principal components of the upper body keypoints and the seat parameters. The experiments proved that the error of the regression model in this paper is minor than that of current studies, and the accuracy of the keypoint location and the keypoint connection length of the established driver whole body posture model is high, which provides implications for future studies.

scholarly journals Magnetic Resonance-Compatible Arm-Crank Ergometry: A New Platform Linking Whole-Body Calorimetry to Upper-Extremity Biomechanics and Arm Muscle Metabolism

2020 ◽  
Author(s):  
Riemer JK Vegter ◽  
Sebastiaan van den Brink ◽  
Leonora J Mouton ◽  
Anita Sibeijn-Kuiper ◽  
Lucas H.V. van der Woude ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Surface Electromyography ◽  
Motor Units ◽  
Daily Practice ◽  
Muscle Disease ◽  
Upper Body ◽  
Whole Body ◽  
Energetic Efficiency ◽  
The Impact

Abstract Background: Evaluation of the effect of human upper body training regimens may benefit from knowledge of local energy expenditure in arm muscles. To that end, we developed a novel asynchronous arm-crank ergometry platform for use in a clinical magnetic resonance (MR) scanner with 31P spectroscopy capability to study arm muscle energetics. The utility of the platform was tested in an investigation of the impact of daily practice on the energetic efficiency of execution of an arm-cranking task (ACT) in healthy subjects. Results: We recorded the first ever in vivo 31P MR spectra from the human biceps bracii muscle during ACT execution pre- and post-three weeks of daily practice bouts, respectively. Complementary datasets on whole body oxygen consumption, arm muscle electrical activity, arm-force and power output, respectively, were obtained in the mock-up scanner. The mean gross mechanical efficiency of execution of the ACT significantly increased 1.5-fold from 5.7 ± 1.2% to 8.6 ± 1.7% (P<0.05) after training, respectively. However, in only one subject this improvement was associated with recruitment of strictly oxidative motor units in the working biceps muscle. In all other subjects, biceps pH fell below 6.8 during exercise indicating recruitment of anaerobic motor units, the magnitude of which was either unaffected (two subjects) or even increased (two subjects) post-training. Surface electromyography and mechanical force recordings revealed that individuals employed various arm muscle recruitment strategies, using either predominantly elbow flexor muscles (two subjects), elbow extensor muscles (one subject,) or a combination of the two (two subjects), respectively. Three weeks of training improved muscle coordination but did not alter individual strategies. Conclusions: The new platform has produced the first ever in vivo dynamic data on human biceps energy and pH balance during upper body exercise. It allows evaluation of cyclic motor performance and outcomes of upper-body training regimens in healthy novices by integrating these new measurements with whole body calorimetry, surface electromyography and biomechanical measurements. This methodology may be equally valid for lower-limb impaired athletes, wheelchair users and patients with debilitating muscle disease.

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