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- Carlsson, Magnus, et al.
(författare)
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Gross and delta efficiencies during uphill running and cycling among elite triathletes.
- 2020
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 120:5, s. 961-968
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate the gross efficiency (GE) and delta efficiency (DE) during cycling and running in elite triathletes.METHODS: Five male and five female elite triathletes completed two incremental treadmill tests with an inclination of 2.5° to determine their GE and DE during cycling and running. The speed increments between the 5-min stages were 2.4 and 0.6 km h-1 during the cycling and running tests, respectively. For each test, GE was calculated as the ratio between the mechanical work rate (MWR) and the metabolic rate (MR) at an intensity corresponding to a net increase in blood-lactate concentration of 1 mmol l-1. DE was calculated by dividing the delta increase in MWR by the delta increase in MR for each test. Pearson correlations and paired-sample t tests were used to investigate the relationships and differences, respectively.RESULTS: There was a correlation between GEcycle and GErun (r = 0.66; P = 0.038; R2 = 0.44), but the correlation between DEcycle and DErun was not statistically significant (r = - 0.045; P = 0.90; R2 = 0.0020). There were differences between GEcycle and GErun (t = 80.8; P < 0.001) as well as between DEcycle and DErun (t = 27.8; P < 0.001).CONCLUSIONS: Elite triathletes with high GE during running also have high GE during cycling, when exercising at a treadmill inclination of 2.5°. For a moderate uphill incline, elite triathletes are more energy efficient during cycling than during running, independent of work rate.
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- Carlsson, Magnus, et al.
(författare)
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Oxygen uptake at different intensities and sub-techniques predicts sprint performance in elite male cross-country skiers
- 2014
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Ingår i: European Journal of Applied Physiology. - : Springer. - 1439-6319 .- 1439-6327. ; 114:12, s. 2587-2595
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate the relationship between sprint-prologue performance (using the classical technique) and the oxygen uptake at the lactate threshold (V̇O2obla), maximal oxygen uptake (V̇O2max), and mean oxygen uptake during double poling (V̇O2dp).METHODS: Eight elite male cross-country skiers [age 24.8 ± 4.8 years, (mean ± SD)] completed two treadmill roller-skiing tests using the diagonal-stride technique and a 60 s double-poling test on a ski-ergometer to determine their V̇O2obla, V̇O2max, and V̇O2dp. Performance data were generated from a 1.25 km sprint prologue. Power-function modelling was used to predict the skiers' race speeds based on the oxygen-uptake variables and body mass.RESULTS: There were correlations between the race speed and the absolute expression of the V̇O2obla (r = 0.79, P = 0.021), V̇O2max (r = 0.86, P = 0.0069), and V̇O2dp (r = 0.94, P = 0.00062). The following power-function models were established for race-speed prediction: 1.09 · V̇O2obla(0.21), 1.05 · V̇O2max(0.21), and 1.19 · V̇O2dp(0.20); these models explained 60 % (P = 0.024), 73 % (P = 0.0073), and 87 % (P = 0.00073), respectively, of the variance in the race speed. However, body mass did not contribute to any of the models (P = 0.97, 0.88, and 0.21, respectively).CONCLUSIONS: Oxygen uptake at different intensities and sub-techniques is an indicator of elite male sprint-prologue performance. The absolute expression of the investigated oxygen-uptake variables should be used when evaluating elite male sprint-prologue performances; if skiers oxygen uptake differs by 1 %, their performances will likely differ by 0.2 % in favour of the skier with higher oxygen uptake.
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- Arnell, Magnus, et al.
(författare)
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Modellering av avloppsreningsverk för multikriteriebedömning av prestanda och miljöpåverkan
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Genom att använda detaljerade dynamiska modeller och kombinera resultat från årslånga simuleringar av ARV (såväl vatten- som slamlinjer) med livscykelanalys kan olika driftstrategier utvecklas och utvärderas utifrån en bred uppsättning hållbarhetskriterier fö att maximera resursutvinning och energieffektivitet samtidigt som vattenkvalitén bibehålls och driftskostnaderna kontrolleras. Metodiken har tillämpats vid en omfattande fallstudie av Käppalaverket.
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- Brorsson, Sofia, et al.
(författare)
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A new electronic grip force measurement device for hand evaluation
- 2013
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Ingår i: Abstracts of the Annual European Congress of Rheumatology EULAR. June 12-15, 2013. Madrid, Spain.
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Konferensbidrag (refereegranskat)abstract
- Background: Hand grip force is a good indicator of general muscle strength and can also be used to predict multiple outcomes such as changes in activities of daily living (ADL), disability, mortality and general upper extremity strength. Hand grip force is often measured as the amount of static grip force a subject can produce when measured with a hydraulic dynamometer such as the Jamar or with an electronic device such as the Grippit. The Grippit device measures an average grip force, a peak grip force and force over a set time period. Grippit has shown good reliability for healthy subjects. Grippit, which was developed over 20 years ago in Gothenburg, Sweden is no longer manufactured. Therefore, the need for anewly developed and modernized measurement instrument for use in evaluating hand rehabilitation has arisen. Objectives: The aim of this study was to evaluate the test-retest reliability of the newly developed instrument GRIP-it and to describe and validate the relationship between grip force measurements from GRIP-it and the original Grippit device. Methods: Healthy controls (n=43) were included in the study. Two devices were used to evaluate grip force (Newton, N), (i) GRIP-it a newly developed device and (ii) Grippit. Both instruments were used to measure mean and maximal force over 10 seconds. Results: GRIP-it displayed a mean measurement error of -1.7 ± 0.5% and the corresponding error for Grippit was -1.6 ± 1.9%. All subjects completed the grip force tests and the results for three attempts for each hand. The test-retest reliability was excellent for both pieces of equipment, with ICCs ranging from 0.963 to 0.947 (CI 95% between 0.103 and 0.041) for GRIP-it and from 0.979 to 0.968 (CI 95% between 0.087 and 0.042) for Grippit. Relationships between Grippit and GRIP-itThere was a significant difference between the measured values derived from Grippit and GRIP-it for both the dominant hand (P < 0.001) and the non-dominant hand (P < 0.01). Grippit gives in general a higher grip force measurement than GRIP-it which is also indicated by the slope (β1) of the regression lines that deviates from 1. However, there were no substantial differences in the grip force when comparing the measurements for the dominant hand with the non-dominant hand for either Grippit (P = 0.071) or GRIP-it (P = 0.404). Based on these non-significant differences between hands and the fact that the model estimates for the intercept (β0) and the slope (β1) are contained within the confidence intervals of the model estimates for the opposite hand, a combined model was derived. The linear regression analysis, with grip force measurements for both hands included, gives: GRIP-it = 49.0 + 0.779 · Grippit. This explains 89.6% of the variance in grip force analyzed by GRIP-it (P < 0.001) see Figure 2. To enable an estimation of grip force measured by Grippit based on GRIP-it values a regression analysis with Grippit as dependent variable gives: Grippit = -18.1 + 1.15 · GRIP-it, which explains 89.6% of the variance in grip force analyzed by Grippit (P < 0.001).Conclusions: This study showed that GRIP-it has excellent test-retest reliability. Measurements of grip force with GRIP-it are strongly related to those from the original Grippit. The newly developed GRIP-it shows great potential for use in the assessment of hand function and the evaluation of hand rehabilitation.
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| 8. |
- Carlsson, Magnus, et al.
(författare)
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Physiological demands of competitive sprint and distance performance in elite female cross-country skiing
- 2016
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Ingår i: Journal of Strength and Conditioning Research. - : Lippincott Williams & Wilkins. - 1064-8011 .- 1533-4287. ; 30:8, s. 2138-2144
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to investigate the relationship between elite females' competitive performance capability in sprint and distance cross-country skiing and the variables of gross efficiency (GE), work rate at the onset of blood-lactate accumulation (OBLA4mmol), maximal oxygen uptake (V[Combining Dot Above]O2max), maximal speed (Vmax), and peak upper-body oxygen uptake (V[Combining Dot Above]O2peak). Ten elite female cross-country skiers (age 24.5 ± 2.8 years) completed treadmill roller-skiing tests to determine GE, OBLA4mmol, and V[Combining Dot Above]O2max using the diagonal-stride technique as well as Vmax and V[Combining Dot Above]O2peak using the double-poling technique. International Ski Federations ranking points for sprint (FISsprint) and distance (FISdist) races were used as competitive performance data. There were correlations between the FISsprint and the V[Combining Dot Above]O2max expressed absolutely (p = 0.0040), Vmax (p = 0.012), and V[Combining Dot Above]O2peak expressed absolutely (p < 0.001) and as a simple ratio-standard (p = 0.049). The FISdist were correlated with OBLA4mmol (p = 0.048), V[Combining Dot Above]O2max expressed absolutely (L·min) (p = 0.015) and as a simple ratio-standard (p = 0.046), and V[Combining Dot Above]O2peak expressed absolutely (p = 0.036) and as a simple ratio-standard (ml·min·kg) (p = 0.040). The results demonstrate that the physiological abilities reflected by V[Combining Dot Above]O2max and V[Combining Dot Above]O2peak are indicators of competitive sprint and distance performance in elite female cross-country skiing. In addition, the ability to generate a high Vmax indicates the performance in sprint races, whereas the skier's OBLA4mmol reflects the performance capability in distance races. Based on the results, when evaluating the performance capacity of elite female cross-country skiers, it is recommended to use physiological variables that reflect competitive performance.
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| 9. |
- Carlsson, Magnus, et al.
(författare)
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Prediction of race performance of elite cross-country skiers by lean mass
- 2014
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Ingår i: International Journal of Sports Physiology and Performance. - : Human Kinetics. - 1555-0265 .- 1555-0273. ; 9:6, s. 1040-1045
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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