| 1. |
- Brehm, Gunnar, et al.
(författare)
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Moths are strongly attracted to ultraviolet and blue radiation
- 2021
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 14:2, s. 188-198
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Tidskriftsartikel (refereegranskat)abstract
- We carried out three choice experiments with 6116 nocturnal lepidopteran individuals (95 species, 7 families, 32 075 counts), each replicated 105 times during the seasons of 2 years. Moths were released indoors at the centre of a 10 × 10 m area with different lamps placed at each corner. In experiment 1, lamps emitted ultraviolet (UV) (peak at 365 nm), blue (450 nm), green (520 nm) or cool white (450 and 520 nm) radiation. In experiment 2, UV was replaced by red (640 nm). In experiment 3, we used UV and three mixed radiation lamps of different emission intensities (365–520 nm). We applied a linear mixed effect model to test for differences in attraction to the light sources. Among all counts, 12.2% (males) and 9.2% (females) were attracted to a lamp. Among the lamp counts, 84% were made at the UV lamp in experiment 1. In experiment 2, 63% of the counts were made at the blue lamp. In experiment 3, most counts were made at the strongest mixed radiation lamp (31%), and the UV lamp (28%). Patterns were generally similar across Lepidopteran families, and for both sexes. Moths are clearly preferentially attracted to short-wave radiation. Even small quantities of UV radiation, emitted, for example, by metal halide lamps and certain mercury vapour tubes, will disproportionately contribute to light pollution. Since blue light also attracts moths strongly, lamps with a low proportion of blue light should be given priority in lighting planning.
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| 2. |
- Aasa, Ulrika, et al.
(författare)
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Variability of lumbar spinal alignment among power- and weightlifters during the deadlift and barbell back squat
- 2022
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Ingår i: Sports Biomechanics. - : Routledge. - 1476-3141 .- 1752-6116. ; 21:6, s. 707-717
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Tidskriftsartikel (refereegranskat)abstract
- The aims of the study were to evaluate the relative and absolute variability of upper (T11-L2) and lower (L2-S2) lumbar spinal alignment in power- and weightlifters during the deadlift and back squat exercises, and to compare this alignment between the two lifting groups. Twenty-four competitive powerlifters (n = 14) and weightlifters (n = 10) performed three repetitions of the deadlift and the back squat exercises using a load equivalent to 70% of their respective one-repetition maximum. The main outcome measures were the three-dimensional lumbar spinal alignment for start position, minimum and maximum angle of their spinal alignment, and range of motion measured using inertial measurement units. Relative intra-trial reliability was calculated using the two-way random model intraclass correlation coefficient (ICC) and absolute reliability with minimal detectable change (MDC). The ICC ranged between 0.69 and 0.99 and the MDC between 1 degrees-8 degrees for the deadlift. Corresponding figures for the squat were 0.78-0.99 and 1 degrees-6 degrees. In all participants during both exercises, spinal adjustments were made in both thoracolumbar and lumbopelvic areas in all three dimensions. In conclusion, when performing three repetitions of the deadlift and the squat, lumbar spinal alignment of the lifters did not change much between repetitions and did not differ significantly between power- and weightlifters.
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| 3. |
- Andersson, Erik, et al.
(författare)
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The effects of skiing velocity on mechanical aspects of diagonal cross-country skiing
- 2014
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Ingår i: Sports Biomechanics. - : Informa UK Limited. - 1476-3141 .- 1752-6116. ; 13:3, s. 267-284
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Tidskriftsartikel (refereegranskat)abstract
- Cycle and force characteristics were examined in 11 elite male cross-country skiers using the diagonal stride technique while skiing uphill (7.5 degrees) on snow at moderate (3.5 +/- 0.3m/s), high (4.5 +/- 0.4m/s), and maximal (5.6 +/- 0.6m/s) velocities. Video analysis (50Hz) was combined with plantar (leg) force (100Hz), pole force (1,500Hz), and photocell measurements. Both cycle rate and cycle length increased from moderate to high velocity, while cycle rate increased and cycle length decreased at maximal compared to high velocity. The kick time decreased 26% from moderate to maximal velocity, reaching 0.14s at maximal. The relative kick and gliding times were only altered at maximal velocity, where these were longer and shorter, respectively. The rate of force development increased with higher velocity. At maximal velocity, sprint-specialists were 14% faster than distance-specialists due to greater cycle rate, peak leg force, and rate of leg force development. In conclusion, large peak leg forces were applied rapidly across all velocities and the shorter relative gliding and longer relative kick phases at maximal velocity allow maintenance of kick duration for force generation. These results emphasise the importance of rapid leg force generation in diagonal skiing.
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| 4. |
- Bjerkefors, Anna, et al.
(författare)
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Three-dimensional kinematic analysis and power output of elite flat-water kayakers.
- 2018
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Ingår i: Sports Biomechanics. - : Informa UK Limited. - 1476-3141 .- 1752-6116. ; 17:3, s. 414-427
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to examine power output and three-dimensional (3D) kinematic variables in the upper limbs, lower limbs and trunk in elite flat-water kayakers during kayak ergometer paddling. An additional purpose was to analyse possible changes in kinematics with increased intensity and differences between body sides. Six male and four female international level flat-water kayakers participated. Kinematic and kinetic data were collected during three tasks; low (IntL), high (IntH) and maximal (IntM) intensities. No differences were observed in any joint angles between body sides, except for shoulder abduction. Significantly greater range of motion (RoM) values were observed for IntH compared to IntL and for IntM compared to IntL in trunk and pelvis rotation, and in hip, knee and ankle flexion. The mean maximal power output was 610 ± 65 and 359 ± 33 W for the male and female athletes, respectively. The stroke frequencies were significantly different between all intensities (IntL 59.3 ± 6.3; IntH 108.0 ± 6.8; IntM 141.7 ± 18.4 strokes/min). The results showed that after a certain intensity level, the power output must be increased by other factors than increasing the joint angular RoM. This information may assist coaches and athletes to understand the relationship between the movement of the kayaker and the paddling power output.
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| 5. |
- Göpfert, Caroline, et al.
(författare)
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Biomechanical characteristics and speed adaptation during kick double poling on roller skis in elite cross-country skiers
- 2013
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Ingår i: Sports Biomechanics. - : Informa UK Limited. - 1476-3141 .- 1752-6116. ; 12:2, s. 154-174
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Tidskriftsartikel (refereegranskat)abstract
- Recent developments in cross-country ski racing should promote the use of kick double poling. This technique, however, has not been the focus in athletes' training and has barely been investigated. The aims of the present study were to develop a function-based phase definition and to analyse speed adaptation mechanisms for kick double poling in elite cross-country skiers. Joint kinematics and pole/plantar forces were recorded in 10 athletes while performing kick double poling at three submaximal roller skiing speeds. A speed increase was associated with increases in cycle length and rate, while absolute poling and leg push-off durations shortened. Despite maintained impulses of force, the peak and average pole/leg forces increased. During double poling and leg push-off, ranges of motion of elbow flexion and extension increased (p < 0.05) and were maintained for hip/knee flexion and extension. Cycle length increase was correlated to increases in average poling force (r = 0.71) and arm swing time (r = 0.88; both p < 0.05). The main speed adaptation was achieved by changes in double poling technique; however, leg push-off showed high variability among elite skiers, thus illustrating important aspects for technique training.
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| 6. |
- Lindinger, Stefan J, et al.
(författare)
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Biomechanical pole and leg characteristics during uphill diagonal rollerskiing
- 2009
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Ingår i: Sports Biomechanics. - : Informa UK Limited. - 1476-3141 .- 1752-6116. ; 8:4, s. 318-333
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Tidskriftsartikel (refereegranskat)abstract
- Diagonal skiing as a major classical technique has hardly been investigated over the last two decades, although technique and racing velocities have developed substantially. The aims of the present study were to 1) analyse pole and leg kinetics and kinematics during submaximal uphill diagonal roller skiing and 2) identify biomechanical factors related to performance. Twelve elite skiers performed a time to exhaustion (performance) test on a treadmill. Joint kinematics and pole/plantar forces were recorded separately during diagonal roller skiing (98; 11 km/h). Performance was correlated to cycle length (r ¼ 0.77; P , 0.05), relative leg swing (r ¼ 0.71), and gliding time (r ¼ 0.74), hip flexion range of motion (ROM) during swing (r ¼ 0.73) and knee extension ROM during gliding (r ¼ 0.71). Push-off demonstrated performance correlations for impulse of leg force (r ¼ 0.84), relative duration (r ¼ 20.76) and knee flexion (r ¼ 0.73) and extension ROM (r ¼ 0.74). Relative time to peak pole force was associated with performance (r ¼ 0.73). In summary, diagonal roller skiing performance was linked to 1) longer cycle length, 2) greater impulse of force during a shorter push-off with larger flexion/extension ROMs in leg joints, 3) longer leg swing, and 4) later peak pole force, demonstrating the major key characteristics to be emphasised in training.
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| 7. |
- Markström, Jonas L., 1985-, et al.
(författare)
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A novel standardised side hop test reliably evaluates landing mechanics for anterior cruciate ligament reconstructed persons and controls
- 2021
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Ingår i: Sports Biomechanics. - : Routledge. - 1476-3141 .- 1752-6116. ; 20:2, s. 213-229
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Tidskriftsartikel (refereegranskat)abstract
- We propose a novel one-leg standardised rebound side-hop test (SRSH) specifically designed for detailed analysis of landing mechanics. Anterior cruciate ligament reconstructed persons (ACLR, n = 30) and healthy-knee controls (CTRL, n = 30) were tested for within-session and test-retest (CTRL only, n = 25) reliability and agreement. Trunk, hip and knee angles and moments in sagittal, frontal, and transversal planes during landing, including time to stabilisation (TTS), were evaluated using intra-class correlations (ICCs), average within-person standard deviations (SW) and minimal differences. Excellent within-session reliability were found for angles in both groups (most ICCs > 0.90, SW ≤ 5°), and excellent to good for moments (most ICCs > 0.80, SW ≤ 0.34 Nm/kg). Only knee internal rotation moment showed poor reliability (ICC < 0.4). Test-retest results were excellent to fair for all angles and moments (ICCs 0.47–0.91, SW < 5° and ≤ 0.25 Nm/kg), except for peak trunk lateral bending angle and knee internal rotation moment. TTS showed excellent to fair within-session reliability but poor test-retest results. These results, with a few exceptions, suggest promising potential of evaluating landing mechanics during the SRSH for ACLR and CTRL, and emphasise the importance of joint-specific movement control variables in standardised tasks.
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| 8. |
- Markström, Jonas, 1985-, et al.
(författare)
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Side-hops challenge knee control in the frontal and transversal plane more than hops for distance or height among ACL-reconstructed individuals
- 2023
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Ingår i: Sports Biomechanics. - : Taylor & Francis Group. - 1476-3141 .- 1752-6116. ; 22:1, s. 142-159
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Tidskriftsartikel (refereegranskat)abstract
- We compared knee landing mechanics with presumed relation to risk of anterior cruciate ligament (ACL) injury among three single-leg hop tests and between legs in individuals with unilateral ACL reconstruction. Thirty-four participants (>10 months' post-surgery, 23 females) performed the standardised rebound side hop (SRSH), maximal hop for distance (OLHD) and maximal vertical hop (OLVH). We calculated the following knee outcomes from motion capture and force plate data: finite helical axis inclination angles (approximates knee robustness), frontal and transversal plane angles at initial contact, peak angles of abduction and internal rotation during landing, and peak external moments of flexion, abduction and internal rotation during landing. Repeated-measures MANOVA analysis ('sex' as covariate) confirmed that SRSH induced greater angles and moments, particularly in the frontal plane, compared to OLHD and OLVH. There was between-leg asymmetry for peak knee flexion moment for males during OLHD and OLVH, and for females during SRSH. Our results advocate the SRSH over OLHD and OLVH for assessment of knee landing control to screen for movement patterns potentially related to ACL injury risk. However, clear differences in both knee kinematics and kinetics between OLHD and SRSH motivate the use of both tests to evaluate different aspects of landing control.
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| 9. |
- Mikkola, Jussi, et al.
(författare)
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Changes in performance and poling kinetics during cross-country sprint skiing competition using the double-poling technique
- 2013
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Ingår i: Sports Biomechanics. - : Routledge. - 1476-3141 .- 1752-6116. ; 12:4, s. 355-364
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Tidskriftsartikel (refereegranskat)abstract
- In this study, changes in skiing performance and poling kinetics during a simulated cross-country sprint skiing competition were investigated. Twelve elite male cross-country skiers performed simulated sprint competition (4 × 1,150 m heat with 20 min recovery between the heats) using the double-poling technique. Vertical and horizontal pole forces and cycle characteristics were measured using a force plate system (20-m long) during the starting spurt, racing speed, and finishing spurt of each heat. Moreover, heat and 20-m phase velocities were determined. Vertical and horizontal pole impulses as well as mean cycle length were calculated. The velocities of heats decreased by 2.7 ± 1.7% (p = 0.003) over the simulated competition. The 20-m spurting velocity decreased by 16 ± 5% (p < 0.002) and poling time increased by 18 ± 9% (p < 0.003) in spurt phases within heats. Vertical and horizontal poling impulses did not change significantly during the simulation; however, the mean forces decreased (p < 0.039) (vertical by 24 ± 11% and horizontal by 20 ± 10%) within heats but not between the heats. Decreased heat velocities over the simulated sprint and spurting velocities within heats indicated fatigue among the skiers. Fatigue was also manifested by decreased pole force production and increased poling time.
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| 10. |
- Muchaxo, R E A, et al.
(författare)
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Association between upper-limb isometric strength and handcycling performance in elite athletes
- 2022
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Ingår i: Sports Biomechanics. - : Taylor & Francis. - 1476-3141 .- 1752-6116.
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the association among isometric upper-limb strength of handcyclists and sport-specific performance outcomes. At two international events, 62 athletes were tested on upper-limb strength, measured with an isometric-strength setup and with Manual Muscle Test (MMT). Horizontal force (F-z), effectiveness, rate of development, variability, and asymmetries were calculated for upper-limb pull and push. Performance measures were mean (POmean) and peak (POpeak) 20-s sprint power output and average time-trial velocity (TTvelocity). Regression models were conducted to investigate which pull and push strength variables associated strongest with performance measures. Additional regression analyses were conducted with an MMT sum score as predictor. Push and pull F-z showed the strongest associations with all outcomes. Combined push and pull F-z explained (p < .001) 80-81% of variance of POmean and POpeak. For TTvelocity, only push F-z was included in the model explaining 29% of the variance (p < .001). MMT models revealed weaker associations with sprint PO (R-2 = .38-.40, p < .001) and TTvelocity (R-2 = .18, p = 0.001). The findings confirmed the relevance of upper-limb strength on handcycling performance and the significance of ratio-scaled strength measures. Isometric strength outcomes are adequate sport-specific indicators of impairment in handcycling classification, but future research should corroborate this notion and its potential to discriminate between sports classes.
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