| 1. |
- Mattsson, C. Mikael, et al.
(författare)
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Effects of prolonged low intensity exercise with energy deficit (military training operation) on markers of muscle protein turnover.
- 2015
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Konferensbidrag (refereegranskat)abstract
- IntroductionIt is well known that ultra-endurance exercise, such as Adventure racing and military operations, often induce substantial energy deficits. This suggests a catabolic state, but the exact effects on protein turnover have not yet been sufficiently investigated. The aim of this study was to examine several markers involved in muscle protein turnover before and after a multi-day physically demanding military training operation.MethodsSeven female (age 21 ± 5 years, weight 71.2 ± 6.6 kg) and seventeen male (age 20 ± 1 years, weight 76.6 ± 6.2 kg) performed a 185 hours military training operation. Energy intake was estimated from food supply and energy expenditure was calculated from continuous heart rate and accelerometer recordings. Muscle biopsies were taken from M Vastus Lateralis before and after the operation.ResultsA negative energy balance of 1,500-2,000 kcal/24 hours was estimated. Body weight declined 3.4 (95% CI 3.0-3.8) kg and muscle explosive strength, evaluated from squad and counter movement jumps, was reduced 5 and 6 %, respectively, after the operation with no difference between genders. Muscle glycogen content was reduced from 269 ± 58 to 181 ± 44 mmol/kg dry muscle (p<0.05) with no difference between genders. Muscle content of mTOR and p70 as well as MAFbx were unchanged while the protein content of MuRF-1 was significantly down regulated in both genders.DiscussionThe study indicated that prolonged low intensity exercise with substantial energy deficit reduces muscle function and muscle glycogen content. Proteins for muscle synthesis mTOR and p70 were unchanged while the down regulation of MuRF-1 indicates a protection against muscle break down during the energy deficit situation, preserving the muscle mass.
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| 2. |
- Marklund, Peter, et al.
(författare)
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Extensive inflammatory cell infiltration in human skeletal muscle in response to an ultra-endurance exercise bout in experienced athletes.
- 2013
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Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 114:1, s. 66-72
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Tidskriftsartikel (refereegranskat)abstract
- The impact of a 24h ultra-endurance exercise bout on systemic and local muscle inflammatory reactions was investigated in nine experienced athletes. Blood and muscle biopsies were collected before (PRE), immediately after the exercise (POST) and after 28h of recovery (POST28). Circulating blood levels of leukocytes, CK, CRP and selected inflammatory cytokines were assessed together with the evaluation of the occurrence of inflammatory cells (CD3(+), CD8(+), CD68(+)) and the expression of major histocompatibility complex class-I (MHC class-I) in skeletal muscle. An extensive inflammatory cell infiltration occurred in all athletes and the number of CD3(+), CD8(+) and CD 68(+) cells were 2-3 fold higher at POST28 compared to PRE (P<0.05). The inflammatory cell infiltration was associated with a significant increase in the expression of MHC class-I in muscle fibers. There was a significant increase in blood leukocyte count, IL-6, IL-8, CRP and CK at POST. At POST28 total leukocytes, IL-6 and CK had declined, whereas IL-8 and CRP continued to increase. Increases in IL-1β and TNF-α were not significant. There were no significant associations between the magnitude of the systemic and local muscle inflammatory reactions. Signs of muscle degenerative and regenerative events were observed in all athletes with various degrees of severity and were not affected by the ultra-endurance exercise bout. In conclusion, a low-intensity but very prolonged single endurance exercise bout can generate a strong inflammatory cell infiltration in skeletal muscle of well-trained experienced ultra-endurance athletes, and the amplitude of the local reaction is not proportional to the systemic inflammatory response.
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| 3. |
- Andersson, Helena M, et al.
(författare)
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Elite football on artificial turf versus natural grass : movement patterns, technical standards, and player impressions
- 2008
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Ingår i: Journal of Sports Sciences. - : Informa UK Limited. - 0264-0414 .- 1466-447X. ; 26:2, s. 113-22
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to examine the movement patterns, ball skills, and the impressions of Swedish elite football players during competitive games on artificial turf and natural grass. Time - motion analyses (36 observations) and technical analyses (16 team observations) were performed and 72 male and 21 female players completed a questionnaire. No differences were observed between artificial turf and natural grass in terms of total distance covered (mean 10.19 km, s = 0.19 vs. 10.33 km, s = 0.23), high-intensity running (1.86 km, s = 0.10 vs. 1.87 km, s = 0.14), number of sprints (21, s = 1 vs. 22, s = 2), standing tackles (10, s = 1 vs. 11, s = 1) or headers per game (8, s = 1 vs. 8, s = 1), whereas there were fewer sliding tackles (P < 0.05) on artificial turf than natural grass (2.1, s = 0.5 vs. 4.3, s = 0.6). There were more short passes (218, s = 14 vs. 167, s = 12) and midfield-to-midfield passes (148, s = 11 vs. 107, s = 8) (both P < 0.05) on artificial turf than natural grass. On a scale of 0-10, where 0 = "better than", 5 = "equal to", and 10 = "worse than", the male players reported a negative overall impression (8.3, s = 0.2), poorer ball control (7.3, s = 0.3), and greater physical effort (7.2, s = 0.2) on artificial turf than natural grass. In conclusion, the running activities and technical standard were similar during games on artificial turf and natural grass. However, fewer sliding tackles and more short passes were performed during games on artificial turf. The observed change in playing style could partly explain the male players' negative impression of artificial turf.
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| 4. |
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| 5. |
- Apró, William, et al.
(författare)
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Leucine does not affect mechanistic target of rapamycin complex 1 assembly but is required for maximal ribosomal protein s6 kinase 1 activity in human skeletal muscle following resistance exercise
- 2015
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 29:10, s. 4358-4373
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Tidskriftsartikel (refereegranskat)abstract
- We examined how the stimulatory effect of leucine on the mechanistic target of rapamycin complex 1 (mTORC1) pathway is affected by the presence of the remaining essential amino acids (EAAs). Nine male subjects performed resistance exercise on 4 occasions and were randomly supplied EAAs with leucine, EAAs without leucine (EAA-Leu), leucine alone, or flavored water (placebo; control). Muscle biopsies were taken from the vastus lateralis before and 60 and 90 min after exercise. Biopsies were analyzed for protein phosphorylation, kinase activity, protein-protein interactions, amino acid concentrations, and tracer incorporation. Leucine alone stimulated ribosomal protein s6 kinase 1 (S6K1) phosphorylation similar to 280% more than placebo and EAA-Leu after exercise. Moreover, this response was enhanced by 60-75% after intake of EAAs compared with that of leucine alone (P < 0.05). Kinase activity of S6K1 reflected that of S6K1 phosphorylation; 60 min after exercise, the activity was elevated 3.3- and 4.2-fold with intake of leucine alone and with EAAs, respectively (P < 0.05). The interaction between mammalian target of rapamycin and regulatory-associated protein of mammalian target of rapamycin was unaltered in response to both resistance exercise and amino acid provision. Leucine alone stimulates mTORC1 signaling, although this response is enhanced by other EAAs and does not appear to be caused by alterations inmTORC1 assembly.
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| 6. |
- Balsom, Paul D, et al.
(författare)
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High-intensity exercise and muscle glycogen availability in humans.
- 1999
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 165:4, s. 337-45
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effects of muscle glycogen availability on performance and selected physiological and metabolic responses during high-intensity intermittent exercise. Seven male subjects completed a regimen of exercise and dietary intake (48 h) to either lower and keep low (LOW-CHO) or lower and then increase (HIGH-CHO) muscle glycogen stores, on two separate occasions at least a week apart. On each occasion the subjects completed a short-term (<10 min) and prolonged (>30 min) intermittent exercise (IEX) protocol, 24 h apart, which consisted of 6-s bouts of high-intensity exercise performed at 30-s intervals on a cycle ergometer. Glycogen concentration (mean +/- SEM) in m. vastus lateralis before both IEx(short) and IEx(long) was significantly lower following LOW-CHO [180 (14), 181 (17) mmol kg (dw)(-1)] compared with HIGH-CHO [397 (35), 540 (25) mmol kg (dw)(-1)]. In both IEx(short) and IEx(long), significantly less work was performed following LOW-CHO compared with HIGH-CHO. In IEx(long), the number of exercise bouts that could be completed at a pre-determined target exercise intensity increased by 265% from 111 (14) following LOW-CHO to 294 (29) following HIGH-CHO (P < 0.05). At the point of fatigue in IEx(long), glycogen concentration was significantly lower with the LOW-CHO compared with HIGH-CHO [58 (25) vs. 181 (46) mmol kg (dw)(-1), respectively]. The plasma concentrations of adrenaline and nor-adrenaline (in IEx(short) and IEx(long)), and FFAand glycerol (in IEx(long)), increased several-fold above resting values with both experimental conditions. Oxygen uptake during the exercise periods in IEx(long), approached 70% of Vo2max. These results suggest that muscle glycogen availability can affect performance during both short-term and more prolonged high-intensity intermittent exercise and that with repeated exercise periods as short as 6 s, there can be a relatively high aerobic contribution.
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| 7. |
- Balsom, Paul, et al.
(författare)
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Maximal-Intensity Intermittent Exercise: Effect of Recovery Duration
- 1992
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Ingår i: International Journal of Sports Medicine. - 0172-4622 .- 1439-3964. ; 13:7, s. 528-533
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Tidskriftsartikel (refereegranskat)abstract
- Seven male subjects performed 15 x 40m sprints, on three occasions, with rest periods of either 120 s (R120), 60 s (R60) or 30 s (R30) between each sprint. Sprint times were recorded with four photo cells placed at 0, 15, 30 and 40 m. The performance data indicated that whereas running speed over the last 10 m of each sprint decreased in all three protocols (after 11 sprints in R120, 7 sprints in R60 and 3 sprints in R30), performance during the initial acceleration period from 0-15 m was only affected with the shortest rest periods increasing from (mean +/- SEM) 2.58 +/- .03 (sprint 1) to 2.78 +/- .04 s (spring 15) (p < .05). Post-exercise blood lactate concentration was not significantly different in R120 (12.1 +/- 1.3 mmol.l-1) and R60 (13.9 +/- 1.2 mmol.l-1), but a higher concentration was found in R30 (17.2 +/- .7 mmol.l-1) (p < .05). After 6 sprints there was no significant difference in blood lactate concentration with the different recovery durations, however, there were significant differences in sprint times at this point, suggesting that blood lactate is a poor predictor of performance during this type of exercise. Although the work bouts could be classified primarily as anaerobic exercise, oxygen uptake measured during rest periods increased to 52, 57 and 66% of maximum oxygen uptake in R120, R60 and R30, respectively. Evidence of adenine nucleotide degradation was provided by plasma hypoxanthine and uric acid concentrations elevated post-exercise in all three protocols. Post-exercise uric acid concentration was not significantly affected by recovery duration.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 8. |
- Berg, Ulrika, et al.
(författare)
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Lack of sex differences in the IGF-IGFBP response to ultra endurance exercise.
- 2008
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 18:6, s. 706-714
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Tidskriftsartikel (refereegranskat)abstract
- The insulin-like growth factor (IGF)-IGF binding proteins (BP) and the pituitary-gonadal axes were investigated during ultra endurance exercise in 16 endurance-trained athletes (seven women). Median duration of the race was 6.3 days. Although food and drink were ad libitum, energy balance was negative. Blood samples were drawn before (PRE), at the end of (END) and 24 h after (POST24h) the race. Serum concentrations of total IGF-I (t-IGF-I) and free IGF-I (f-IGF-I) decreased by 33 (SD 38)% and 54 (19)%, respectively. The decrease in t-IGF-I appeared to be associated to the total energy deficit during the race. At END, the IGFBP-3 fragmentation and IGFBP-1 were increased but these changes did not predict changes in f-IGF-I. An increase in POST24h IGFBP-2 levels in women was the only sex difference. Testosterone was decreased by 67 (12)% in the men and estradiol became undetectable in the women without any detectable increase in LH and/or FSH. In conclusion ultra endurance exercise results in similar IGF-IGFBP responses in men and women reflecting a catabolic state. IGFBP-2 was the only exception, with increased levels in women after exercise. A concomitant decrease in gonadal hormones was not related to endocrine changes in the IGF-IGFBP axis but may be related to local changes in IGF-I expression.
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| 9. |
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| 10. |
- Björkman, Frida, et al.
(författare)
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Regular moist snuff dipping does not affect endurance exercise performance
- 2017
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Physiological and medical effects of snuff have previously been obtained either in cross-sectional studies or after snuff administration to non-tobacco users. The effects of snuff cessation after several years of daily use are unknown. 24 participants with >2 years of daily snuff-use were tested before and after >6 weeks snuff cessation (SCG). A control group (CO) of 11 snuff users kept their normal habits. Resting heart rate (HR) and blood pressure (BP) were significantly lower in SCG after snuff cessation, and body mass was increased by 1.4 +/- 1.7 kg. Total cholesterol increased from 4.12 +/- 0.54 (95% CI 3.89-4.35) to 4.46 +/- 0.70 (95% CI 4.16-4.75) mM L-1 in SCG, due to increased LDL, and this change was significantly different from CO. Resting values of HDL, C-reactive protein, and free fatty acids (FFA) remained unchanged in both groups. In SCG group, both HR and BP were reduced during a four-stage incremental cycling test (from 50 to 80% of VO(2)max) and a prolonged cycling test (60 min at 50% of VO(2)max). Oxygen uptake (VO2), respiratory exchange ratio, blood lactate (bLa) and blood glucose (bGlu) concentration, and rate of perceived exertion (RPE) were unchanged. In CO group, all measurements were unchanged. During the prolonged cycling test, FFA was reduced, but with no significant difference between groups. During the maximal treadmill running test peak values of VO2, pulmonary ventilation (VE), time to exhaustion and bLa were unchanged in both groups. In conclusion, endurance exercise performance (VO(2)dmax and maximal endurance time) does not seem to be affected by prolonged snuff use, while effects on cardiovascular risk factors are contradictory. HR and BP during rest and submaximal exercise are reduced after cessation of regular use of snuff. Evidently, the long-time adrenergic stress on circulation is reversible.
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