Ola Eriksrud

• Westheim, Frederic; Gløersen, Øyvind; Harper, Damian; Laugsand, Håkon Nilsen & Eriksrud, Ola (2023). Reliability of phase-specific outcome measurements in change-of-direction tests using a motorized resistance device. Frontiers in Sports and Active Living. ISSN 2624-9367. 5. doi: 10.3389/fspor.2023.1212414. Fulltekst i vitenarkiv Vis sammendrag

  This study aims to determine test-retest reliability of phase-specific information during initial acceleration, deceleration, and re-acceleration phases of different change-of-direction (CoD) tests using a motorized resistance device (MRD). A total of 21 participants (16 males and five females, with mean age of 22.3 ± 3.9 years, body mass of 75.2 ± 6.9 kg, height of 177.9 ± 6.8 cm) completed the modified 505 (m505), 10-0-5, and 15-0-5 CoD tests on four different test sessions while exposed to an external load (3 kg) provided by the MRD. Outcome variables included overall and phase-specific kinetic (force, power, and impulse) and kinematic (time, distance, velocity, and acceleration/deceleration) data during the initial acceleration, deceleration, and re-acceleration phases. The deceleration and re-acceleration phases were further divided into two subphases, namely, early and late subphases, using 50% of maximum velocity. Reliability was assessed using an intraclass correlation coefficient (ICC), coefficient of variation (CV), typical error (TE), and minimal detectable change (MDC). Good to excellent ICC values (>0.75) and acceptable (<10%) to good (<5%) CV values were observed for most outcome measurements. Specifically, 80.1% (822 out of 1,026) of all variables showed good or better relative reliability (i.e., ICC ≥ 0.75), while 97.0% (995 out of 1,026) of all variables showed acceptable or better absolute reliability (i.e., CV < 10%). In conclusion, the present study demonstrates that the MRD can obtain reliable phase-specific outcome measurements across different CoD tests, providing coaches and researchers with new opportunities to advance our understanding of CoD ability and inform more advanced CoD training prescriptions.

• Johansen, Merethe Lia; Eriksrud, Ola; Thorkildsen, Joachim; Norum, Ole-Jacob Anderssen; Wisløff, Torbjørn & Taksdal, Ingeborg [Vis alle 7 forfattere av denne artikkelen] (2023). Muscle strength characteristics following megaprosthetic knee reconstruction for bone sarcoma. Surgial oncology. ISSN 0960-7404. 48. doi: 10.1016/j.suronc.2023.101944. Fulltekst i vitenarkiv Vis sammendrag

  Objective: To assess muscle strength characteristics in patients with resection and megaprosthetic reconstruction of the knee for bone sarcoma compared to age- and sex-matched controls. Methods: This was a cross-sectional, case-control study. Muscle strength characteristics for knee extension and -flexion were assessed isokinetically at three different joint velocities: 60, 120 and 180°/s, and by the rate of force development (RDFmax) in knee extension. The Toronto Extremity Salvage Score (TESS) was used in patients. Results: Eighteen patients (91.6 months postop.) and 18 controls were included. Relative to controls, patients generated maximal torques of 19%, 23% and 23% in knee extension at 60, 120 and 180°/s, respectively. For knee flexion, patients generated maximal torques of 58%, 53% and 60% at 60, 120, and 180°/s, relative to the controls. RDFmax of the operated leg was 2.75 ± 2.13 N/ms, 7.16 ± 4.78 N/ms for the non-operated leg, and 7.95 ± 4.29 N/ms for the controls. The mean TESS score was 84.0. Conclusion: Patients reached approximately 20% of the maximal knee extension torque. In isometric assessments, they used double the amount of time to generate one-third of the maximal force compared to the controls despite good TESS scores.

• Mai, Patrick; Bill, Kevin; Glöckler, Katharina; Claramunt-Molet, Mireia; Bartsch, Julia & Eggerud, Mathias M. [Vis alle 14 forfattere av denne artikkelen] (2022). Unanticipated fake-and-cut maneuvers do not increase knee abduction moments in sport-specific tasks: Implication for ACL injury prevention and risk screening. Frontiers in Sports and Active Living. ISSN 2624-9367. 4. doi: 10.3389/fspor.2022.983888. Fulltekst i vitenarkiv Vis sammendrag

  Non-contact anterior cruciate ligament injuries typically occur during cutting maneuvers and are associated with high peak knee abduction moments (KAM) within early stance. To screen athletes for injury risk or quantify the efficacy of prevention programs, it may be necessary to design tasks that mimic game situations. Thus, this study compared KAMs and ranking consistency of female handball players in three sport-specific fake-and-cut tasks of increasing complexity. The biomechanics of female handball players (n = 51, mean ± SD: 66.9 ± 7.8 kg, 1.74 ± 0.06 m, 19.2 ± 3.4 years) were recorded with a 3D motion capture system and force plates during three standardized fake-and-cut tasks. Task 1 was designed as a simple pre-planned cut, task 2 included catching a ball before a pre-planned cut in front of a static defender, and task 3 was designed as an unanticipated cut with three dynamic defenders involved. Inverse dynamics were used to calculate peak KAM within the first 100 ms of stance. KAM was decomposed into the frontal plane knee joint moment arm and resultant ground reaction force. RANOVAs (α ≤ 0.05) were used to reveal differences in the KAM magnitudes, moment arm, and resultant ground reaction force for the three tasks. Spearman's rank correlations were calculated to test the ranking consistency of the athletes' KAMs. There was a significant task main effect on KAM (p = 0.02; η2p = 0.13). The KAM in the two complex tasks was significantly higher (task 2: 1.73 Nm/kg; task 3: 1.64 Nm/kg) than the KAM in the simplest task (task 1: 1.52 Nm/kg). The ranking of the peak KAM was consistent regardless of the task complexity. Comparing tasks 1 and 2, an increase in KAM resulted from an increased frontal plane moment arm. Comparing tasks 1 and 3, higher KAM in task 3 resulted from an interplay between both moment arm and the resultant ground reaction force. In contrast to previous studies, unanticipated cutting maneuvers did not produce the highest KAMs. These findings indicate that the players have developed an automated sport-specific cutting technique that is utilized in both pre-planned and unanticipated fake-and-cut tasks.

• Harper, Damian J.; McBurnie, Alistair J.; Santos, Thomas Dos’; Eriksrud, Ola; Evans, Martin & Cohen, Daniel D. [Vis alle 9 forfattere av denne artikkelen] (2022). Biomechanical and Neuromuscular Performance Requirements of Horizontal Deceleration: A Review with Implications for Random Intermittent Multi-Directional Sports. Sports Medicine. ISSN 0112-1642. doi: 10.1007/s40279-022-01693-0. Fulltekst i vitenarkiv Vis sammendrag

  Rapid horizontal accelerations and decelerations are crucial events enabling the changes of velocity and direction integral to sports involving random intermittent multi-directional movements. However, relative to horizontal acceleration, there have been considerably fewer scientific investigations into the biomechanical and neuromuscular demands of horizontal deceleration and the qualities underpinning horizontal deceleration performance. Accordingly, the aims of this review article are to: (1) conduct an evidence-based review of the biomechanical demands of horizontal deceleration and (2) identify biomechanical and neuromuscular performance determinants of horizontal deceleration, with the aim of outlining relevant performance implications for random intermittent multi-directional sports. We highlight that horizontal decelerations have a unique ground reaction force profile, characterised by high-impact peak forces and loading rates. The highest magnitude of these forces occurs during the early stance phase (< 50 ms) and is shown to be up to 2.7 times greater than those seen during the first steps of a maximal horizontal acceleration. As such, inability for either limb to tolerate these forces may result in a diminished ability to brake, subsequently reducing deceleration capacity, and increasing vulnerability to excessive forces that could heighten injury risk and severity of muscle damage. Two factors are highlighted as especially important for enhancing horizontal deceleration ability: (1) braking force control and (2) braking force attenuation. Whilst various eccentric strength qualities have been reported to be important for achieving these purposes, the potential importance of concentric, isometric and reactive strength, in addition to an enhanced technical ability to apply braking force is also highlighted. Last, the review provides recommended research directions to enhance future understanding of horizontal deceleration ability.

• Eriksrud, Ola; Ahlbeck, Fredrik; Harper, Damian & Gløersen, Øyvind Nøstdahl (2022). Validity of Velocity Measurements of a Motorized Resistance Device During Change of Direction. Frontiers in Physiology. ISSN 1664-042X. 13. doi: 10.3389/fphys.2022.824606. Fulltekst i vitenarkiv Vis sammendrag

  The aim of this study was to determine validity of velocity measurements of a motorized resistance device (MRD) during change of direction (CoD). Eight male (age: 22.1 ± 4.2 yrs; weight: 83.3 ± 17.1 kg; height: 181.6 ± 12.6 cm) and three female participants (age: 21.7 ± 1.5 yrs; mass: 69.7 ± 2.4 kg; height: 167.0 ± 3.6 cm) completed the modified 505 CoD test (m505) with turning off the left and right foot while exposed to external loads (3, 6, and 9 kg) provided by the MRD. Three-dimensional kinematic data were measured (200 Hz) for all tests using a full-body marker set with an additional marker placed on the pulley used to attach the carabiner (CAR) at the end of the line from the MRD to the participant. Average velocity of overall center of mass (COMvel), pelvis (COMpelvis_vel), and pulley (CARvel) was then calculated and compared to the velocity measured by MRD (MRDvel) in 0.5 s intervals 1.5 s before and after CoD. Average velocities from these intervals were then compared using correlational, Bland–Altman analysis, coefficient of variation (CV), and statistical parametric mapping (SPM). Mostly, excellent correlations were observed and ranged from 0.93 to 1.00, 0.53 to 1.00 and 0.93 to 1.00 for the 3, 6, and 9 kg load conditions, respectively. CV values ranged from 0.3 to 3.2%, 0.8 to 4.3%, and 1.5 to 7.7% for the CARvel, COMpelvis_vel, and COMvel comparisons, respectively. The biases for CARvel comparisons ranged from −0.027 to 0.05 m/s, −0.246 to 0.128 m/s and −0.486 to 0.082 m/s across all load conditions and time intervals for the CARvel, COMpelvis_vel, and COMvel comparisons, respectively. SPM analysis indicated significant differences between MRDvel and COMvel and COMpelvis_vel over short time periods during the CoD, but no difference between MRDvel and CARvel. The velocity measurements obtained by a MRD during a m505 test are valid as low biases, low CV’s, and high correlations are observed for the MRDvel to CARvel comparison. As single points of measurement (i.e., laser) has been proven useful to assess other athletic tasks (i.e., sprint running), the single point CARvel comparison is an appropriate comparison for validating MRDvel measurements during the m505 test.

• Rakovic, Elvir; Paulsen, Gøran; Helland, Christian; Haugen, Thomas André & Eriksrud, Ola (2022). Validity and Reliability of a Motorized Sprint Resistance Device. Journal of Strength and Conditioning Research. ISSN 1064-8011. 36(8), s. 2335–2338. doi: 10.1519/JSC.0000000000003830. Fulltekst i vitenarkiv Vis sammendrag

  An increasing number of sprint-related studies have used motorized devices to provide resistance while sprinting. The aim of this study was to establish within-session reliability and criterion validity of sprint times obtained from a motorized resistance device. Seventeen elite, female, handball players (22.9 ± 3.0 years; 176.5 ± 6.5 cm; 72.7 ± 5.5 kg; training volume 9.3 ± 0.7 hours per week) performed two 30-m sprints under 3 different resistance loading conditions (50, 80 and 110 N). Sprint times (t0–5m, t5–10m, t10–15m, t15–20m, t20–30m, and t0–30m) were assessed simultaneously by a 1080 Sprint motorized resistance device and a postprocessing timing system. The results showed that 1080 Sprint timing was equivalent to the postprocessing timing system within the limits of precision (±0.01 seconds). A systematic bias of approximately 0.34 ± 0.01 seconds was observed for t0–5m caused by different athlete location and velocity at triggering point between the systems. Coefficient of variation was approximately 2% for t0–5 and approximately 1% for the other time intervals, although standard error of measurement ranged from 0.01 to 0.05 seconds, depending on distance and phase of sprint. Intraclass correlation ranged from 0.86 to 0.95. In conclusion, the present study shows that the 1080 Sprint is valid and reliable for sprint performance monitoring purposes.

Se alle arbeider i Cristin

• Eriksrud, Ola; Krosshaug, Tron; Mai, Patrick; Glørsen, Øyvind & Westheim, Frederic (2024). Deceleration demands in change of direction tests: insights from measurements using a motorized resistance device .
• Mai, Patrick; Bill, Kevin; Kersting, Uwe; Willwacher, Steffen; Eriksrud, Ola & Krosshaug, Tron (2024). A nine-week ACL injury prevention program for female handball players: Effect on knee joint loading and cutting technique during a handball-specific fake-cut.
• Bill, Kevin; Mai, Patrick; Robertz, Leon; Glöckler, Katharina; Claramunt-Molet, Mireia & Bartsch, Julia [Vis alle 14 forfattere av denne artikkelen] (2022). Knee kinematics and kinetics of sport-specific fake-and-cut maneuvers of varying complexity in female handball players.
• Mai, Patrick; Bill, Kevin; Robertz, Leon; Glöckler, Katharina; Claramunt-Molet, Mireia & Bartsch, Julia [Vis alle 15 forfattere av denne artikkelen] (2022). Can a simplified knee abduction moment estimation be used for athlete screening? Implications for ACL injury prevention.

Se alle arbeider i Cristin