Central and peripheral fatigue in knee and elbow extensor muscles after a long-distance cross-country ski race

2016 ◽  
Vol 27 (9) ◽  
pp. 945-955 ◽  
Author(s):  
G. Boccia ◽  
D. Dardanello ◽  
C. Zoppirolli ◽  
L. Bortolan ◽  
C. Cescon ◽  
...  
Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2535
Author(s):  
Thomas Stöggl ◽  
Dennis-Peter Born

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.


1987 ◽  
Vol 64 (3) ◽  
pp. 759-764 ◽  
Author(s):  
Bruce R. Etnyre ◽  
Eva J. Lee ◽  
Hally B. W. Poindexter

The purpose of this study was to examine the effects of different contraction times and delay times prior to a positioning task. While blindfolded, each of 25 subjects learned to produce elbow-extension movements to a short and a long target using a kinesthesiometer. The subject then produced 30 trials without feedback to each target. These control trials were preceded by a foreperiod of 0-, 3-, or 6-sec. delay. The 60 experimental trials were identical to control trials except the subject isometrically contracted elbow extensor muscles for 3 or 6 sec. prior to each trial. Following each isometric contraction the subject delayed movement for 0, 3, or 6 sec. The 3-sec. and 6-sec. prepositioning contractions produced greater undershooting and variability than no prepositioning contractions, and the 0-sec. delay produced less constant error than either the 3- or 6-sec. delay. It was concluded that following isometric contraction, undershooting a target occurred and this effect did not dissipate within a 6-sec. period.


Diagnostics ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 442 ◽  
Author(s):  
Natalia Grzebisz

Cross-country skiing has a positive effect on health. However, without an individual, thoughtful, and professional plan, it can cause irreversible health problems from overload and injury. The impact of exercise on results is well understood within the group of professional athletes. However, this remains unknown within the group of amateur cross-country skiers and marathon runners—in particular, the impact of the summer preparation period in which training loads performed in the oxygen zone combined with resistance training dominate. The aim of this study was to assess changes in the cardiovascular capacity and body mass composition of male cross-country skiers in the preparation period of their macrocycle. Variables were analyzed using basic descriptive statistics: mean and standard deviation (SD). To compare the results from both measurements (initial and final) the paired Wilcoxon test was used. A statistically significant increase was noted in maximum oxygen uptake and maximum minute ventilation, and a decrease in body fat content, maximum lactate concentration and lactate threshold, and heart rate on anaerobic threshold. Research indicated that in the amateur group increases similar to those in top competitors were achieved in the parameters tested, but the initial level was often significantly lower.


2019 ◽  
Vol 14 (9) ◽  
pp. 1190-1199 ◽  
Author(s):  
Øyvind Skattebo ◽  
Thomas Losnegard ◽  
Hans Kristian Stadheim

Purpose: Long-distance cross-country skiers specialize to compete in races >50 km predominantly using double poling (DP). This emphasizes the need for highly developed upper-body endurance capacities and an efficient DP technique. The aim of this study was to investigate potential effects of specialization by comparing physiological capacities and kinematics in DP between long-distance skiers and skiers competing using both techniques (skating/classic) in several competition formats (“all-round skiers”). Methods: Seven male long-distance (32 [6] y, 183 [6] cm, 76 [5] kg) and 6 all-round (25 [3] y, 181 [5] cm, 75 [6] kg) skiers at high international levels conducted submaximal workloads and an incremental test to exhaustion for determination of peak oxygen uptake (VO2peak) and time to exhaustion (TTE) in DP and running. Results: In DP and running maximal tests, TTE showed no difference between groups. However, long-distance skiers had 5–6% lower VO2peak in running (81 [5] vs 85 [3] mL·kg−1·min−1; P = .07) and DP (73 [3] vs 78 [3] mL·kg−1·min−1; P < .01) than all-round skiers. In DP, long-distance skiers displayed lower submaximal O2 cost than all-round skiers (3.8 ± 3.6%; P < .05) without any major differences in cycle times or cyclic patterns of joint angles and center of mass. Lactate concentration over a wide range of speeds (45–85% of VO2peak) did not differ between groups, even though each workload corresponded to a slightly higher percentage of VO2peak for long-distance skiers (effect size: 0.30–0.68). Conclusions: The long-distance skiers displayed lower VO2peak but compensated with lower O2 cost to perform equally with the all-round skiers on a short TTE test in DP. Furthermore, similar submaximal lactate concentration and reduced O2 cost could be beneficial in sustaining high skiing speeds in long-duration competitions.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
S A Eliasson ◽  
P Sarajlic ◽  
P Wandell ◽  
H Wallen ◽  
M Back ◽  
...  

Abstract Background Troponin levels may be elevated after long-distance running, probably due to increased membrane permeability of cardiomyocytes. It is believed that elevated troponin post exercise, in contrast to acute coronary syndromes, normalize within 24 (−48) hours. This phenomenon has been mainly studied in young and elite athletes. However, participation in endurance exercise is increasingly popular among elderly and recreational sportsmen. Purpose To assess troponin levels in master athletes before and up to 7 days after long-distance running. Method We studied 97 participants (56 males and 41 females, matched for age) in the world's largest cross-country race (30 km, Lidingöloppet). They were ≥45 years (53±5 years). Baseline evaluation included a physical exam, blood pressure, BMI, NT-proBNP and an ECG. Blood tests were taken at baseline, immediately after as well as 1d, 4d and 7d after the race, including high sensitive troponin T (TnT), creatinine and high sensitive CRP. Elevated TnT was defined as ≥15 ng/l. Results After the race TnT had increased from 5±3 ng/l at baseline to 46±32 ng/l (range 11–180; p<0.0001). TnT was still significantly elevated at day 1 (16±16ng/l, range 4–106; p<0.0001) and day 4 (8±8 ng/l, range 4–63; p<0.01) with a borderline increase at day 7 (6±3; range 4–22; p=0.062). Both men and women showed a significant TnT increases at day 1 and day 4. Elevated TnT above the diagnostic threshold for myocardial infarction was observed in 96% (post race), 34% (day 1), 9% (day 4) and 3% (day 7). Males had generally higher TnT levels. At day 1, elevated TnT levels were present in 39% of males and 17% of females while all subjects with elevated TnT at day 4 and day 7 were male. Conclusion TnT is elevated in the vast majority of male and female master athletes after participation in a 30 km cross country race. To our knowledge, this is the first report showing that TnT levels can be still significantly elevated four days after endurance running. Prolonged TnT values above the diagnostic threshold for myocardial infarction were predominantly seen in males. Our findings are relevant to the clinical management of patients with increased troponin values after endurance exercise. Acknowledgement/Funding Hjärt och lungfonden (Swedish heart- and lung fund). Governmental grants.


2010 ◽  
Vol 30 (6) ◽  
pp. 413-419 ◽  
Author(s):  
Jelena Z. Popadic Gacesa ◽  
Djordje G. Jakovljevic ◽  
Dusko B. Kozic ◽  
Natasa R. Dragnic ◽  
David A. Brodie ◽  
...  

2021 ◽  
Vol 3 ◽  
Author(s):  
Per-Øyvind Torvik ◽  
Guro Strøm Solli ◽  
Øyvind Sandbakk

Purpose: To investigate the training characteristics of world-class long-distance cross-country skiers.Methods: Twelve world-class male long-distance cross-country skiing specialists reported training from their best season, through a questionnaire and follow-up interviews. Training data were systemized by training form (endurance, strength, and speed), intensity [low- (LIT), moderate- (MIT), and high-intensity training (HIT)], and exercise mode, followed by a division into different periodization phases. Specific sessions utilized in the various periodization phases were also analyzed.Results: The annual training volume was 861 ± 90 h, consisting of 795 ± 88 h (92%) of endurance training, 53 ± 17 h (6%) of strength training, and 13 ± 14 h (2%) of speed training. A pyramidal (asymptotic) endurance training distribution was employed (i.e., 88.7% LIT, 6.4% MIT, and 4.8% HIT). Out of this, 50–60% of the endurance training was performed with double poling (DP), typically in the form of a daily 3- to 5-h session. A relatively evenly distributed week-to-week periodization of training load was commonly used in the general preparation period, whereas skiers varied between high-load training weeks and competition weeks, with half the training volume and a reduced amount of DP during the competition period.Conclusions: To match the specific demands of long-distance cross-country skiing, specialized long-distance skiers perform relatively long but few training sessions and use a pyramidal intensity distribution pattern and a large amount of training spent using the DP technique.


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